CH-1 The Science of Nutrition – Wardlaw’s Perspectives in Nutrition : Chapter Notes

This document contains Chapters 1 to 3 Chapter 1 The Science of Nutrition Overview In Chapter 1, students will be introduced to the basic terminology of nutrition, such as the six classes of nutrients. Measurement of food energy and the physiological fuel values for various macronutrients are presented. Typical dietary patterns of North Americans are discussed in relation to recommendations of health authorities of the United States and Canada. Students will learn the components of nutrition assessment, including analysis of background factors, anthropometrics, biochemical measurements, clinical evaluations, dietary assessment, and environmental influences. Overall health and disease risk are presented as the result of the complex interplay of genetics, lifestyle choices (including nutrition), and environment. Methods of nutrition research are discussed, including several interesting historical examples that contributed to the determination of today’s nutrient recommendations. Finally, students will learn how to evaluate nutrition-related products and advice as scientists and educated consumers. Learning Objectives 1. Define the terms nutrition, carbohydrates, proteins, lipids (fats and oils), vitamins, minerals, water, and calories. 2. Use the physiological fuel values of energy-yielding nutrients to determine the total energy content (calories) in a food or diet. 3. Describe the major characteristics of the North American diet and the food behaviors that often need improvement. 4. Describe the factors that affect our food choices. 5. Discuss the components and limitations of nutritional assessment. 6. List the attributes of lifestyles that are consistent with the Healthy People 2020 goals and those that contribute to the leading causes of health in North America. 7. Describe the role of genetics in the development of nutrition-related diseases. 8. Explain how the scientific method is used in developing hypotheses and theories in the field of nutrition. 9. Identify reliable sources of nutrition information. Teaching Strategies, Activities, Demonstrations, and Assignments 1. Use the Take Action activity in Chapter 1. Have the students follow the instructions, and use it as an object for class discussion regarding their eating habits. A. Make sure they follow the assignment instructions closely because this one-day food record can be used for future activities. They should record all foods and beverages consumed and the serving sizes, in addition to the other data. To allow them to get a sense of serving sizes, bring in measuring cups and devices, and actually illustrate what 1 cup of cereal looks like in a bowl, as well as the serving sizes of other foods. Ask the class to try to eat simple foods during the day of record and to avoid complex mixtures. It can be difficult to break these complex mixtures into individual ingredients for analysis. Even though this is an end-of-the-chapter activity, it would be best if the food record were completed during the first week of class, so it can be used for subsequent activities. Instructors could require a three-day food record so it can be used for future activities. The data, at a later time, can be averaged for the three days to assess nutrient intake. 2. Have students list the various kinds of restaurants in the campus area and tally how often they have frequented them. Do they use college or university food service? How often do they use vending machines? Why do they make the choices they do? What changes would they like to see made in the food and food service choices available? 3. Have students discuss their parents' food habits, both good and bad. How are the students' food habits similar to their parents'? How have their parents' food habits and attitudes affected their eating habits? 4. During the first couple of lectures, have students bring examples of nutrition topics in the popular press to class. Group the articles by syllabus topic and revisit them after students have read the appropriate chapter in the text. Have students form small groups to discuss and evaluate the topics in terms of what they learned about nutrition since the beginning of the course. 5. Have students make a list of five questions they have about food and nutrition. Collect the questions. The last week of the course hand back the questions. Have them divide up into groups and discuss whether they can answer their own questions. If some are left unanswered let them discuss possible answers in their groups. This will be a good way to review course material. 6. Have the students write down what they think is good about their diet and where they think they need improvements. Ask the students to write down any nutritional goals that they may have, what they hope to learn from the course, and why they are taking the course. Students should retain this assignment to review at the end of the semester. Did they make any changes to their diet? Are they making progress towards their nutritional goals? What did they learn from the course that is most valuable and how will they continue to apply nutrition information they learned from the course? Lecture Outline Nutrition Overview Nutrients General Nutrition: the science of food; the nutrients and the substances therein; their action, interaction, and balance in relation to health and disease; and the process by which the organism ingests, digests, absorbs, transports, utilizes, and excretes food substances Nutrients: substances essential for health that the body cannot make or makes in quantities too small to support health Specific biological function Removal from diet leads to decline in human biological function Returning before permanent damage occurs restores impaired biological functions Categorizing nutrients by function Provide energy (most carbohydrates, proteins, most lipids) Promote growth and development (proteins, lipids, some vitamins, some minerals, water) Regulate body processes (proteins, some lipids, some vitamins, some minerals, water) Categorizing nutrients by needs Macronutrients: needed in gram quantities (carbohydrates, proteins, lipids, water) Micronutrients: needed in milligram or microgram quantities (vitamins, minerals) Carbohydrates Composed of carbon, hydrogen, and oxygen Primary dietary sources: fruits, vegetables, grains, beans, and sugars Main types Simple carbohydrates (sugars): sucrose, glucose Complex carbohydrates (polysaccharides): starch, glycogen, fiber Glucose is the major source of energy for most cells; provides 4 kcal/g Body can make glucose from proteins Lipids Composed of carbon, hydrogen, and oxygen Fats are solid at room temperature; oils are liquid at room temperature Yield more energy than carbohydrates; provide 9 kcal/g Insoluble in water; dissolve in certain organic solvents Chemistry of lipids Triglycerides (primary form of lipids in food and the body): 3 fatty acids attached to glycerol Fatty acid: long chains of carbon flanked by hydrogen with acid group at end opposite glycerol Saturated: solid at room temperature; predominate in animal fats; dietary raises blood cholesterol Unsaturated: liquid at room temperature; predominate in plant oils; healthier than saturated fats Essential fatty acids: linoleic and alpha-linolenic acid; must be supplied by our diets Trans fatty acids: unsaturated fats that have been processed to change their structure from cis form to trans form; primarily found in deep-fried foods; dietary intake should be minimized Proteins Composed of carbon, oxygen, hydrogen, and nitrogen Body roles Structural materials Blood components Cell membranes Enzymes Immune factors Provide some energy (4 kcal/g) Formed by bonding of amino acids Vitamins Enable chemical reactions to occur in the body Provide no energy, but help release energy trapped in carbohydrates, lipids, and proteins Fat-soluble (A, D, E, K) More likely than water-soluble vitamins to cause toxicity Water-soluble (thiamin, riboflavin, niacin, B-6, pantothenic acid, biotin, folate, B-12, C) More susceptible than fat-soluble vitamins to destruction by cooking More readily excreted than fat-soluble vitamins Minerals Simple, inorganic structures Not destroyed by cooking, but may leak into cooking water Yield no energy Roles Nervous system function Skeletal system structure Water balance Major minerals: needed daily in gram amounts (e.g., sodium, potassium, chloride, calcium, phosphorus) Trace minerals: needed daily in amounts of less than 100 mg (e.g., iron, zinc, copper, selenium) Water Macronutrient needed in largest amounts by the body Roles Lubricant Solvent Transport medium Temperature regulation Sources Dietary intake: food and beverages By-product of metabolism Phytochemicals and Zoochemicals Phytochemicals: physiologically active compounds found in plants (fruits, vegetables, legumes, and whole grains) Zoochemicals: physiologically active compounds found in foods of animal origin Potential health benefits Reduced risk of cancer Reduced risk of cardiovascular disease Dietary sources are superior to supplemental sources Table 1-3 lists examples of phytochemical and zoochemicals under study Expert Perspective from the Field: Functional Foods Foods rich in phytochemicals and zoochemicals can be referred to as functional foods Provides health benefits beyond those supplied by traditional nutrients May decrease disease risk and/or promote optimal health Four categories of functional foods Conventional foods: unmodified whole foods Modified foods: fortified, enriched, or enhanced Medical foods: food, formula, or supplement used under medical supervision to manage a health condition Special dietary use foods: foods that help meet a special dietary need Energy Sources and Uses Uses Build new compounds Move muscles Transmit nerve impulses Balance ions within cells Calorie: amount of heat energy required to raise the temperature of 1 g of water 1°C Food energy is usually expressed in kilocalories: amount of heat energy required to raise the temperature of 1000 g of water 1°C Physiological fuel values Carbohydrates (4 kcal/g) Fats (9 kcal/g) Proteins (4 kcal/g) Alcohol (7 kcal/g); not essential Energy in food can be measured by using a bomb calorimeter or estimated based on amount of macronutrients present The North American Diet General U.S. Department of Health and Human Services’ National Health and Nutrition Examination Survey (NHANES) and surveys by Health Canada and Agriculture and Agrifood Canada collect information on North American diets Typical macronutrient distribution of North American diets 16% protein 50% carbohydrates 33% fats Many people are eating more than they need to maintain healthy weight Animal sources supply 2/3 protein intake, whereas plant sources dominate in many other countries Half of carbohydrates come from simple sugars; North Americans need to reduce simple sugar intake 60% of dietary fat comes from animal sources; many North Americans exceed saturated fat and cholesterol recommendations North Americans should increase intake of vitamin A, vitamin E, iron, potassium, and calcium North Americans should decrease intake of sodium Older adults consume inadequate vitamin D Women of childbearing age consume inadequate iron General food recommendations Reduce sugared soft drinks Reduce fatty foods Increase fruits Increase vegetables Increase whole grain breads Increase reduced-fat dairy products Multivitamin and mineral supplements may help to meet nutrient needs but do not substitute for an overall healthy diet What Influences Our Food Choices? Hunger: physical need for food Appetite: psychological desire to eat certain foods and reject others Flavor, texture, and appearance preferences Culture Lifestyle Routines and habits Food cost and availability Environment Food marketing Health and nutrition concerns, knowledge, and beliefs Global Perspective: The Price of Food Cost of food as a percentage of income varies widely around the world Differences caused by variety of reasons Substantial amount is spent in the U.S. for food eaten away from home Food production, packaging, and distribution is more efficient in some part of the world Refrigeration reduces food spoilage and expenses in developed countries Food packaging innovations Pest management U.S. government policies affect how food is produced and how prices are set for some foods Nutritional Health Status General Optimal (desirable) nutritional status: body tissues have enough of a nutrient to support normal functions as well as build and maintain surplus stores to be used in times of increased need Undernutrition: nutrient intake does not meet nutrient needs, causing surplus stores to be used Subclinical nutrient deficiency: nutrient stores are depleted, but person exhibits no overt signs or symptoms of deficiency Clinical nutrient deficiency: signs and symptoms of nutrient deficiency become outwardly apparent Sign: feature that can be observed (e.g., flaky skin) Symptom: change in body function that may not be apparent to health care provider (e.g., fatigue, ache) Overnutrition: nutrient intake exceeds nutrient needs Health Objectives for the U.S. for the Year 2020 Healthy People 2020, issued in 2010 by U.S. Department of Health and Human Services, Public Health Service Main objective: help all people attain high-quality, longer lives free of preventable disease, disability, injury, and premature death Table 1-5 lists nutrition-related objectives from Healthy People 2020 Assessing Nutritional Status Background factors Medical history Family medical history Nutritional factors Anthropometric assessment: measurement of aspects of the body (height, weight, skinfold thickness, arm muscle circumference, body composition) Biochemical assessments: measurement of concentrations of nutrients and nutrient by-products in blood, urine, and feces or measurement of enzyme activities Clinical assessments: physical evidence of diet-related diseases Dietary assessments: food frequency, food history, typical intake Environmental assessment: education and economic background Limitations of Nutritional Assessment Many signs and symptoms are not specific Signs and symptoms may be slow to develop Clinical evidence of poor nutritional health may be slow to develop Importance of Being Concerned about Your Nutritional Status Healthy lifestyle practices reduce risk for many diseases Varied diet, rich in fiber, low in animal and trans fat, include fish Avoid becoming overweight Moderate alcohol consumption Exercise for at least 30 minutes daily Avoid smoking Figure 1-8 summarizes health problems associated with poor dietary habits Getting Nutrition-Related Advice Registered dietitians are a reliable source of nutrition advice Rigorous baccalaureate degree program Supervised professional practice Registration examination The Nutrition Care Process Conduct a nutritional assessment Diagnose nutrition-related problem Create an intervention Monitor and evaluate progress Clinical Perspective: Genetics and Nutrition General Although foods and humans contain the same nutrients, the proportions differ Genes dictate the type and amount of nutrients in food that will be transformed and reassembled into body structures and compounds Genes are only one factor that contribute to risk for diseases Genetic tests can detect gene mutations that affect risk for some illnesses Nutritional Diseases with a Genetic Link Most chronic nutrition-related diseases are influenced by interactions among genic, nutritional, and other lifestyle factors Diabetes (types 1 and 2) Some types of cancer (e.g., colon, prostate, breast) Osteoporosis Cardiovascular disease (cholesterol metabolism, salt sensitivity) Obesity Heredity ≠ destiny Your Genetic Profile By recognizing your potential for developing a particular disease, you can avoid behaviors that contribute to it Construct a family tree of illnesses and deaths (genogram) High risk: more than one first-degree relative with disease, particularly if occurred before age 50 or 60 Gene Therapy Use virus to incorporate normal DNA into mutated cells Many obstacles must be overcome before gene therapy can become an effective treatment Genetic Testing Help to predict illnesses that may develop Allows couples to make informed choices about having children Fosters early diagnosis and individualized treatment Limitations Not all diseases may be detected Genetic susceptibility doesn’t guarantee development of a disease No way to cure a specific gene alteration Possible job and medical insurance discrimination Unnecessary radical medical treatments Depression Using Scientific Research to Determine Nutrient Needs General Nutrition knowledge has been gained through research using the scientific method Phenomena are observed Questions are asked and hypotheses are generated to explain the phenomena Research is conducted Incorrect explanations are rejected and the most likely explanation is proposed Research results are scrutinized and evaluated by other scientists; published in a scientific journal Results are confirmed by other scientists and by more experiments and studies Scientific theories, laws, and discoveries always should be subjected to challenge and change Making Observations and Generating Hypotheses Examples: Vitamin C and scurvy Niacin and pellagra Epidemiology: study of diseases in populations Laboratory Animal Experiments Human experiments are most convincing, but not always feasible or ethical Animal model: disease in laboratory animals that mimics human disease Human Experiments Human and animal research must be reviewed and approved by a research review board to ensure that it: Has a valid experimental protocol Is expected to produce important knowledge Will treat study participants fairly and ethically (e.g., informed consent) Migrant studies: examine changes in health of people who move from one country to another Cohort studies: follow a healthy population over time to look for development of diseases Case-Control Study Compare individuals with a condition (cases) with individuals who do not have the condition (controls) Cases and controls should be matched for other characteristics (e.g., age, race, gender) Can provide clues about the cause, progression, and prevention of disease, but cannot claim cause and effect Double-Blind Study Compares one group of participants following a specific protocol (experimental group) with participants in a corresponding group following their usual habits (control group) Placebo: fake treatment (usually given to control group) Random assignment of study participants to experimental or control groups Double-blind: identities of treatments are not known by study participants or researchers; controlled by third-party Reduces risk of researcher bias Reduces risk of placebo effect: control group experiences changes that cannot be explained by the action of the placebo Peer Review of Experimental Results Ensures that only the most unbiased, objective findings from carefully designed and executed research studies are published Results presented in peer-reviewed journals is more reliable than information presented by other media sources Follow-Up Studies One experiment is never enough to prove a hypothesis or provide a basis for nutrition recommendations Results must be confirmed by experiments conducted in other laboratories, under varying circumstances Systematic Reviews Experts search literature for research focusing on a particular topic or question Findings are summarized Quality of studies is graded Evidence across the studies is compared and contrasted Conclusions are written based on research Organizations that create systematic reviews Evidence Analysis Library (EAL) USDA Nutrition Evidence Library e-Library for Evidence for Nutrition Actions (eLENA) Cochrane Collaboration Evaluating Nutrition Claims, Products, and Advice General Apply basic nutrition principles to any nutrition claim Be wary of claims that: Only discuss advantages and ignore possible disadvantages Purport a new or secret scientific breakthrough Offer to cure a disease Sound too good to be true Express extreme bias against the medical community or traditional medical treatments Examine scientific credentials Note the size and duration of any study that is cited to support a claim Be wary of press conferences and other hype Buying Nutrition-Related Products Many claims for popular nutrition-related products are unsubstantiated Dietary Supplement Health and Education Act (DSHEA) of 1994 classified vitamins, minerals, amino acids, and herbal remedies as “foods,” so that FDA cannot regulate them as strictly as medications FDA does not have the resources or authority to challenge every supplement claim Federal Trade Commission may investigate dubious claims Supplement industry is trying to implement self-policing procedures Buyer beware, particularly for off-label uses Allowable claims General well-being Prevention of nutrient deficiency Structure/function claims Maintains bone health Improves blood circulation Disclaimer: “This statement has not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent disease.” Chapter 2 Tools of a Healthy Diet Overview Chapter 2 provides students with the science behind current nutrition recommendations for North Americans. The components of the Dietary Reference Intakes are defined, including Estimated Average Requirements, Recommended Dietary Allowances, Adequate Intakes, Tolerable Upper Intake Levels, and Estimated Energy Requirements. The required and optional elements of food labels are also discussed. The text defines Daily Values as they relate to DRIs and also examines the various nutrition claims allowed on food labels. The development and utility of nutrient databases are presented. Finally, the Dietary Guidelines for Americans and MyPlate are presented as sound nutrition advice based on the latest scientific research. Learning Objectives 1. Explain the purpose of the Dietary Reference Intake (DRI) and its components (Estimated Average Requirements, Recommended Dietary Allowances, Adequate Intakes, Upper Levels, Estimated Energy Requirements, and Acceptable Macronutrient Distribution Ranges). 2. Compare the Daily Values to the Dietary Reference Intakes and explain how they are used on Nutrition Facts panels. 3. Describe Nutrition Facts panels and the claims permitted on food packages. 4. Describe the uses and limitations of the data in nutrient databases. 5. Discuss the Dietary Guidelines for Americans and the diseases they are intended to prevent or minimize. 6. Discuss the MyPlate food groupings and plan a diet using this tool. 7. Develop a healthy eating plan based on the concepts of variety, balance, moderation, nutrient density, and energy density. Teaching Strategies, Activities, Demonstrations, and Assignments 1. Complete Take Action activities, “Are You Putting the Dietary Guidelines into Practice?” and "Does Your Diet Meet MyPlate Recommendations?”. In this activity, students will use the dietary record they kept as suggested in Chapter 1 activities. Having students complete and analyze a three-day food record would provide a more accurate nutrition assessment. Students should hold on to this assessment for future use. 2. Ask students to select nutrition labels from four food products they consume regularly and to calculate the actual amount or percent of RDA of selected nutrients for their age and gender group provided by these products. 3. Provide students with a sample of a day's food intake. Make sure it is high in fat, sodium, simple sugars, and low in fruits and vegetables. Ask students to make changes in this menu to comply with the Dietary Guidelines. 4. People often have difficulty accurately estimating portion/serving sizes of foods they eat. To help students with this, have them estimate food portions in class. You can do this by bringing to class samples of commonly consumed foods, various-sized glasses, bowls, measuring cups, measuring spoons, and a food scale if one is available. Examples of food to bring: puffed rice, Grape Nuts, cooked pasta, bagel or English muffin, chips, peanut butter, shelled sunflower seeds, raisins, orange juice, grape juice, mayonnaise, and some type of salad dressing. Pick and choose students to estimate a portion size using only the bowls and glasses provided. Keep the measuring cups and spoons, as well as the food scale hidden during this phase of the activity. Once portion sizes have been estimated by the students, show them, using measuring cups, measuring spoons, and the food scale, how accurate portion sizes look. They will be amazed. At the same time, discuss how to record food portions, what could happen to one's health when portion sizes are either overestimated or underestimated, how the Food Guide Pyramid and Exchange System differ in serving sizes, and how relatively easy nutrient needs can be met by consuming foods. 5. Find a particular nutritional supplement that exceeds the U.S. RDA for a variety of nutrients. Duplicate the label for each student. Point out in class how many nutrients significantly exceed the USRDA. Given the class's understanding of the U.S. RDA, ask them to discuss the implications of those nutrients exceeding it. 6. Assign students the task of visiting the web site, http://www.dietitian.com/calcbody.php, to complete the Healthy Body Calculator. Discuss the various factors this site uses to assess a “healthy body.” How should individuals interpret their results? Lecture Outline Dietary Reference Intakes (DRIs) General Food and Nutrition Board formed in 1941 to establish the first dietary standards Evaluate nutrient intake of population Plan agricultural production Dietary standards are periodically updated to reflect latest research DRIs were established by scientists from the United States and Canada DRIs vary by life stage and gender after age 9 Recommendations should be applied to average dietary intake Figure 2-1 illustrates the relationship of the DRIs to each other Estimated Average Requirements (EARs) Daily nutrient intake amounts that are estimated to meet the needs of half of the people in a certain life stage Only set for a nutrient when functional markers are available to evaluate the effects of nutrient status on physiological function; currently set for 17 nutrients EARs are adjusted to account for digestibility and absorption Used to evaluate the adequacy of diets of groups, not individuals Recommended Dietary Allowances (RDAs) Daily nutrient intake amounts sufficient to meet the needs of nearly all individuals (97 - 98%) in a life stage Based on a multiple of the EAR for a nutrient (generally, RDA = EAR x 1.2); can only be set for nutrients with established EARs Considers nutrient’s ability to prevent chronic disease in addition to ability to prevent deficiency Goal for usual intake If average intake is habitually lower than RDA (especially lower than EAR), risk for nutrient deficiency increases Adequate Intakes (AIs) Daily intake amounts set for nutrients for which there are insufficient research data to establish an EAR; currently set for essential fatty acids, fiber, certain vitamins and minerals Based on observed or experimentally determined estimates of average nutrient intakes that appear to maintain a defined nutritional state in a specific life-stage group Should cover needs of more than 97 - 98% of individuals in a life-stage group Goal for usual intake Tolerable Upper Intake Levels (Upper Levels, or ULs) Maximum daily intake amounts of nutrients that are not likely to cause adverse health effects in 97 - 98% of individuals in a life-stage group Applies to chronic daily use For most nutrients, ULs are set based on combined intake of food, water, supplements, and fortified foods; refers only to nonfood sources of niacin, magnesium, zinc, and nickel Estimated Energy Requirements (EERs) Average daily energy intake needs for each life-stage group Only serve as estimates because actual EER depends on energy expenditure Set to achieve and maintain a healthy weight Acceptable Macronutrient Distribution Ranges (AMDRs) Range of intake, as a percentage of energy, associated with good health and reduced risk of chronic diseases while providing for recommended intakes of essential nutrients Established for carbohydrate, protein, fat, and essential fatty acids Appropriate Uses of the DRIs Intended mainly for diet planning Apply to healthy people; undernourishment and some diseases may increase nutrient requirements Putting the DRIs into Action to Determine the Nutrient Density of Foods Determining nutrient density Divide the amount of a nutrient in a serving of food by daily recommended intake Divide the calories per serving by daily calorie needs A food is nutrient dense if it provides a greater contribution to nutrient needs than calorie needs Easy way to identify more nutritious choices; more difficult to obtain an overall picture of nutritional quality; some experts recommend averaging nutrient density for key nutrients Empty-calorie foods tend to be high in sugar and/or fat but few other nutrients Daily Values (DVs) General Generic standards developed by FDA to use on food labels because DRIs are age- and gender-specific Set for 4 groups: Infants Toddlers Pregnant or lactating women People over 4 years of age - appear on all food labels except those specifically marketed for infants, toddlers, or pregnant or lactating women Based on combination of Reference Daily Intakes and Daily Reference Values Reference Daily Intakes (RDIs) Set for vitamins and most minerals Usually set at the highest value for any life-stage group from 1968 RDAs Current RDIs tend to be slightly higher than RDAs and related nutrient standards; should be revised to reflect latest scientific evidence Table 2-2 compares Daily Values with current RDAs and other nutrient standards Daily Reference Values (DRVs) Standards for energy-producing nutrients, cholesterol, sodium, and potassium Based on daily calorie intake, using 2000 calories as reference for calculation Larger food labels may list DRVs for 2500 kcal/d as well Calculations based on: Fat: 30% of kcal Saturated fat: 10% of calories Carbohydrate: 60% of calories Protein: 10% of calories Fiber: 11.5 g/1000 calories Putting the Daily Values into Action on Nutrition Facts Panels Required information on food labels: Product name Name and address of manufacturer Amount of product in package Ingredients listed in descending order by weight Ingredients that are common allergens Nutrition Facts panel Country of origin of certain products Food labeling is regulated by FDA in the United States Nutrition Facts panel Presents information for a single serving Serving size is specified by FDA for consistency Serving size may differ from MyPlate recommendations Required Total calories (kcal) Calories from fat Total fat Saturated fat Trans fat Cholesterol Sodium Total carbohydrate Fiber Sugars Protein Vitamin A Vitamin C Calcium Iron Listing of other nutrients is optional Nutrient must be listed on Nutrition Facts panel if label makes a claim about its health benefits or if food is fortified with the nutrient % DV for protein is not mandatory for products marketed for people 4 over years of age because protein deficiency is not a public health concern in the U.S.; such listing requires analysis for protein quality Uses of DVs Determine how a particular food fits into an overall diet Make necessary adjustments for nutrients based on calorie intake Nutrients listed on Nutrition Facts panel are those of greatest public health concern in North America Keep intake below 100% DV for Total fat Saturated fat Cholesterol Sodium Plan to achieve 100% DV for Fiber Vitamin A Vitamin C Iron Calcium Nutrition Facts panel may include a footnote to show intake recommendations for fat, saturated fat, cholesterol, sodium, carbohydrate, and fiber for 2000- (and sometimes 2500-) calorie diet Figure 2-4 highlights prominent features of the Nutrition Facts panel Claims on Food Labels FDA permits and regulates specific label claims Nutrient content claims: describe nutrients in food (see Table 2-3) Calories Total fat Saturated fat Cholesterol Sugar Sodium Fiber Other claims Health claims: describe a relationship between a disease and a nutrient, food, or food constituent Calcium/osteoporosis Low sodium/hypertension Low total fat/cancer Low-fat, fiber-containing grain products, fruits, and/or vegetables/cancer Low saturated fat and cholesterol/cardiovascular disease Low in saturated fat and cholesterol, rich in fruits, vegetables and grains with soluble fiber/heart disease Low saturated fat, low cholesterol, 25 g/day of soy protein/heart disease Foods with plant stanols or sterol esters/heart disease Folate/brain or spinal cord defects Sugar alcohols/tooth decay Conditions for health claims Must use “may” or “might” Must be a good source of fiber, protein, vitamin A, vitamin C, calcium, or iron before fortification Cannot contain more than 13 g fat, 4 g saturated fat, 60 mg cholesterol, or 480 mg sodium Qualified health claims Based on incomplete scientific knowledge Must include disclaimer Food must meet definitions of “healthy” as described in Table 2-3 Structure/function claims: describe how a nutrient affects human body structure or function Do not focus on disease risk reduction Not approved or authorized by FDA Manufacturers are responsible for ensuring claims are accurate and not misleading Global Perspective: Front-of-Package Nutrition Labeling Nutrition Facts panel provides U.S. consumers with accurate information about a food’s nutrient and calorie content However, food industry has tried to condense nutrition labels into nutrition symbols (e.g. check marks, traffic lights, ratings) that are placed on the front of food packages or supermarket shelves Consumers are less likely to check nutritional labels when a symbol appears on the front of food packages Not regulated by FDA Lack of consistency FDA is working with the food industry to develop uniform eligibility criteria for front-of-package food labels Create easy-to-understand labels that consumers can trust Nutrient Composition of Foods General Compare amount of calories and nutrients consumed to dietary standards Determine nutrient density and energy density of foods Nutrient values in databases are average values of analyzed samples, but many factors may affect actual values Farming conditions Maturity and ripeness of plant foods Food processing Shipping conditions Storage time Cooking processes Putting Nutrient Databases into Action to Determine Energy Density and Dietary Intake Energy density compares a food’s calorie content per gram weight of the food Foods low in energy density contain large amounts of water (e.g., fruits, vegetables) Low-energy dense foods can keep calorie intake under control Eating foods with high energy density can help people with poor appetites to maintain or gain weight Table 2-4 lists energy density of common foods Awareness of amounts of nutrients and calories in food can help improve healthfulness of diet Expert Perspective from the Field: Menu Labeling: How Many Calories Are in That? Consumers have the right to know the nutrition content of foods Restaurant food is now a significant portion of the food we eat Evidence indicates that stating calorie content on menus can lead to dietary improvements Fast food customers who reported seeing calorie information at the point of purchase ordered meals with fewer calories When calorie information was included in menus, customers ordered lower-calorie dinners for themselves and their children www.menulabeling.org Dietary Guidelines for Americans General Published by USDA and DHHS every 5 years Foundation of U.S. government’s nutrition policy and education Designed to meet nutrient needs while reducing the risk of obesity, hypertension, cardiovascular disease, type 2 diabetes, osteoporosis, alcoholism, and foodborne illness Guide government nutrition programs, research, food labeling, and nutrition education and promotion Based on meeting nutrient needs primarily with food, although dietary supplements and fortified foods may be warranted in some people Nutrition-related objectives Balancing calories to maintain weight Prevent and/or reduce overweight and obesity through improved eating and physical activity behaviors. Control total calorie intake to manage body weight. For people who are overweight or obese, this will mean consuming fewer calories from foods and beverages. Increase physical activity and reduce time spent in sedentary behaviors. Maintain appropriate calorie balance during each stage of life—childhood, adolescence, adulthood, pregnancy and breastfeeding, and older age. Foods and food components to reduce Reduce daily sodium intake to less than 2,300 milligrams (mg) and further reduce intake to 1,500 mg among persons who are 51 and older and those of any age who are African American or have hypertension, diabetes, or chronic kidney disease. The 1,500 mg recommendation applies to about half of the U.S. population, including children, and the majority of adults. Consume less than 10 percent of calories from saturated fatty acids by replacing them with monounsaturated and polyunsaturated fatty acids. Consume less than 300 mg per day of dietary cholesterol. Keep trans fatty acid consumption as low as possible by limiting foods that contain synthetic sources of trans fats, such as partially hydrogenated oils, and by limiting other solid fats. Reduce the intake of calories from solid fats and added sugars. Limit the consumption of foods that contain refined grains, especially refined grain foods that contain solid fats, added sugars, and sodium. If alcohol is consumed, it should be consumed in moderation—up to one drink per day for women and two drinks per day for men—and only by adults of legal drinking age. Foods and nutrients to increase Individuals should meet the following recommendations as part of a healthy eating pattern while staying within their calorie needs. Increase vegetable and fruit intake. Eat a variety of vegetables, especially dark-green, red, and orange vegetables and beans and peas. Consume at least half of all grains as whole grains. Increase whole-grain intake by replacing refined grains with whole grains. Increase intake of fat-free or low-fat milk and milk products, such as milk, yogurt, cheese, or fortified soy beverages. Choose a variety of protein foods, which include seafood, lean meat and poultry, eggs, beans and peas, soy products, and unsalted nuts and seeds. Increase the amount and variety of seafood consumed by choosing seafood in place of some meat and poultry. Replace protein foods that are higher in solid fats with choices that are lower in solid fats and calories and/or are sources of oils. Use oils to replace solid fats where possible. Choose foods that provide more potassium, dietary fiber, calcium, and vitamin D, which are nutrients of concern in American diets. These foods include vegetables, fruits, whole grains, and milk and milk products. Building healthy eating patterns Select an eating pattern that meets nutrient needs over time at an appropriate calorie level. Account for all foods and beverages consumed and assess how they fit within a total healthy eating pattern. Follow food safety recommendations when preparing and eating foods to reduce the risk of foodborne illnesses. Putting the Dietary Guidelines into Action Table 2-5 offers suggestions for implementing recommended diet changes based on the Dietary Guidelines Control cost of healthy eating by choosing canned and frozen fruits and vegetables and non-fat dry milk Based on current health status and family medical history, identify changes to incorporate into your lifestyle Results of dietary changes sometimes take a while to occur See a registered dietician or physician if the changes are not leading to health improvements MyPlate General Translates nutrition science into practical terms Key elements Balancing calories Enjoy your food, but eat less Avoid oversized portions Foods to increase Make half your plate fruits and vegetables Make at least half your grains whole grains Switch to fat-free or low-fat (1%) milk Foods to reduce Compare sodium in foods like soup, bread, and frozen meals and choose the foods with lower numbers Drink water instead of sugary drinks The www.choosemyplate.gov website has many resources to help consumers use MyPlate and personalize it to their life stage Daily Food Plan The SuperTracker My Food-a-pedia Daily Food Plan Table 2-7 presents MyPlate food serving sizes Grains: 1 ounce equivalent 1 slice of bread 1 c ready-to-eat breakfast cereal ½ c cooked cereal, rice, pasta, or bulgur 1 mini bagel or small tortilla
 1⁄2 muffin
 3 c popcorn Vegetable group: 1 cup 1 c raw or cooked vegetables 1 c vegetable juice 2 c raw leafy greens Fruits group: 1 cup 1 c fruit 1 c 100% fruit juice ½ c dried fruit Milk group: 1 cup 1 c of milk, yogurt, or calcium-fortified soymilk 1 c frozen yogurt or pudding made with milk 1 ½ c ice cream 1 ½ oz of natural cheese 2 oz of processed cheese Meat & Beans group: 1 ounce equivalent 1 oz meat, poultry, fish, or cooked tempeh 1 egg 1 T peanut butter or hummus ¼ c cooked beans ½ oz nuts or seeds Oils: 1 teaspoon 1 t vegetable, fish oil, or oil-rich foods (e.g., mayonnaise, soft margarine) Putting MyPlate into Action Estimate energy needs Use Table 2-6 to formulate meal pattern Use Table 2-7 to determine portion sizes that fit into meal pattern Key points No specific food is required for good nutrition No individual food group provides all essential nutrients in adequate amounts Foods within a group may vary widely in nutrient and energy content Use Figure 2-9 to estimate portion sizes Variety is the key to getting the array of nutrients offered by each food group Helpful hints for a nutritious diet Grains group Make half your grains whole grain Daily serving of whole-grain, ready-to-eat breakfast cereal Limit number of grain products with added fat or sugar Vegetables group Variety ensures optimal nutrients and phytochemicals Fruits group Variety ensures optimal nutrients and phytochemicals Keep the amount of fruit juice to less than half of total fruit intake to ensure fiber intake is higher Select 100% juices rather than punches, fruit-flavored soft drinks, etc., to limit added sugars Dairy group Choose primarily low-fat (1%) and fat-free items Limit dairy desserts and chocolate milk to reduce added sugars Proteins group Limit portion sizes of meats Choose lean meats, poultry without skin, and beans to limit fat intake Avoid fried foods and trim visible fat Include plant sources of protein to boost vitamin E, mineral, and fiber intake Oils Include some plant oils on a daily basis Eat fish twice per week Empty calorie foods Foods in each food group that are high solid fats and/or added sugars but contain few or no nutrients Keep consumption at the level that matches calorie needs Rating Your Current Diet Regular comparison of personal diet to MyPlate recommendations is a simple way to evaluate your overall diet Use The SuperTracker program at www.choosemyplate.gov Even small diet and exercise changes can have positive results Chapter 3 The Food Supply Overview In Chapter 3, students will learn about food insecurity and malnutrition in North America and across the globe. Potential causes of and health effects stemming from malnutrition are discussed. Various strategies for alleviating the problems of domestic and international malnutrition are presented with an emphasis on biotechnology. Methods of food preservation and uses of food additives are described. Next, the authors outline various threats to the food supply, including contamination of food and water by pathogenic microorganisms and environmental contaminants. Bacteria, viruses, parasites, prions, toxins, pesticides, heavy metals, and industrial wastes may cause harm in the food supply. Students will learn how to limit risk for foodborne illness and exposure to environmental contaminants through proper handling of food and/or choosing organic foods. Learning Objectives 1. Describe the health consequences of malnutrition and food insecurity for children and adults. 2. Differentiate food security from food insecurity in the U.S. 3. Describe the major U.S. government programs designed to increase food security. 4. Describe how organic foods differ from conventionally produced foods and their potential benefits. 5. Discuss how genetic engineering is used in foods and the potential risks and benefits of genetically modifying foods. 6. Describe how food additives are used in most processed foods and potential concerns about their use. 7. List important bacterial, viral, and parasitic causes of foodborne illness in the U.S. 8. Describe food handling practices that reduce the risk of foodborne illness. 9. Describe common environmental contaminants (heavy metals, industrial chemicals, pesticides, and antibiotics), their potential harmful effects, and how to reduce exposure to them. Teaching Strategies, Activities, Demonstrations, and Assignments 1. Consider offering extra credit to your students for volunteering at a local food bank or soup kitchen. Have them prepare a presentation to the class about their experience. 2. Assign students to investigate organizations, such as Heifer International (www.heifer.org) and America’s Second Harvest (www.americassecondharvest.org). Discuss the positive impacts of such programs and ways in which students on your campus can become active in the fight against hunger. 3. Host a Hunger Banquet. The event is designed to simulate global food circumstances. Not everyone will eat the same food: 15% will eat in elegance, 30% will eat "simple food" and 55% will eat rice. Based on a lottery ticket system, banquet diners will eat according to the ticket they draw -- the idea is to simulate the global distribution of food. Visit (www.hungerhurts.org or www.hungerbanquet.org) to learn more about the Hunger Banquet concept. 4. Buy 10 inexpensive thermometers. Have students check throughout a week the internal temperature of refrigerators to which they have access. Are they at temperatures lower than 40F? If not, what implications might this have for the potential of foodborne illness? Use this as a springboard for discussion of proper food preparation, cooking, and storing methods. 5. Have students visit a local supermarket, select 10 food products in a specific category, and make a list of the food additives present and their function. Categories could include: canned soups, frozen entrees, frozen vegetable dishes, mayonnaise and salad dressings, cheeses, margarines and spreads, and cake mixes. 6. Have students prepare a chart of the common causes of foodborne illness, symptoms, time of onset, and factors that promote growth. 7. Using the guidelines for preventing foodborne illness presented in the textbook, have students outline for which microorganisms the particular steps would be appropriate and why. 8. Have someone from the local food sanitation department come and present a lecture on good food handling practices. Ask him/her to tell interesting stories regarding how these practices were violated in food establishments that were inspected. 9. Do a demonstration with students using “Glo-germ” and a black-light to illustrate the need for proper hand-washing. Students are always amazed at the amount of “germs” left on their hands, even after careful washing. Lecture Outline Food Availability and Access General Worldwide agricultural yield could provide 2720 kcal/d for each person on earth, but 1 in 8 people (870 million) experience chronic food shortages 2 billion people suffer from micronutrient deficiencies Malnutrition is most common in the developing world (southern Asia, sub-Saharan Africa, and the Caribbean regions) According to FAO, malnutrition accounts for >1/2 world’s disease burden Overnutrition leads to overweight and obesity Nutrition transition: inclusion of more meat, dairy, sugar, fat, processed foods, and alcohol, and fewer grains, vegetables, and fruits as developing countries become Westernized Health Consequences of Malnutrition and Food Insecurity Inadequate energy intake Decline of physical and mental activity Retardation or cessation of growth Wasting of muscle and fat Weakened immune system Increased susceptibility to disease Increased death rates Micronutrient deficiencies Blindness from vitamin A deficiency Mental retardation and brain damage from iodine deficiency Food security: food needs are met all of the time Food insecurity: quality, variety, and/or desirability of diet is reduced and there is difficulty at times providing enough food for everyone in the household Nutrient-poor diets in developed countries Impaired physical and mental health Greater rate of health complaints Abnormal growth Behavioral problems Lower educational achievement Depression, suicide, psychological distress Increased risk of chronic disease In the US, food insecurity and poverty are linked to obesity because high-energy-density, nutrient-poor foods are less expensive Food Insecurity in the U.S. Despite abundant, nutritious, and affordable food supply, 15% of U.S. households report very low food security 46 million people in U.S. (more than 1/3 of whom are children) live at or below poverty guidelines ($24,000 for a family of 4); increased with single-parent households and for certain racial and ethnic groups More than 25% of African-Americans, Native Americans, and Hispanics 13% of Asians and Caucasians Contributors to poverty Low paying jobs Unemployment Lack of health care benefits High housing costs Family break-ups Illnesses Programs to Increase Food Security in the U.S. More than 2/3 of USDA budget is allotted for nutrition assistance programs Some eligible families do not receive aid Examples Supplemental Nutrition Assistance Program (SNAP; known in some states as the Food Stamp Program): provides monthly benefits with Electronic Benefits Transfer card (average $133/month) to be used for food and seeds to grow food; accompanied by SNAP Nutrition Education in most states Special Supplemental Nutrition Program for Women, Infants, and Children (WIC): provides low-income pregnant, breastfeeding, and post-partum women and their infants and children up to age 5 with vouchers to purchase specific nutrient-dense foods; accompanied by nutrition education and referrals to health care and social services National School Lunch Program: helps schools provide nutritious lunches to children by subsidizing cash and food; children of low-income families can receive free or reduced-price lunches School breakfast program: similar to lunch program; must meet federal nutrition guidelines Child and Adult Care Food Program: reimburses eligible child-care and nonresidential adult day-care centers that provide meals and snacks; meals must meet federal nutrition guidelines Programs for seniors: Older Americans Act funds congregate meal programs, home-delivered meals (Meals on Wheels),and Senior Farmers’ Market Nutrition Programs; meals must meet nutrition guidelines and are available at little or no cost Food distribution programs: commodity foods (canned, dry, and some fresh foods) are distributed to low-income households, emergency feeding programs, disaster relief programs, Indian reservations, and older adults Many private programs (notably Feeding America) also assist low-income families at food banks, pantries, soup kitchens, and emergency shelters Table 3-2 lists ways to help fight hunger Food Insecurity and Malnutrition in the Developing World Undernutrition disproportionately affects young children and women Consequences of undernutrition Death Underweight Stunted growth Susceptibility to disease Learning disabilities Maternal malnutrition can lead to malnutrition in fetus and breastfed infants Subsistence farmers: able to grow food for their own family, but not enough to sell for income Causes for food shortages Poor-quality farmland Lack of fertilizer, seeds, and farming equipment Droughts or floods Limited work capacity of farmers due to undernutrition and illness Natural disasters, war, and political unrest worsen food shortages Government corruption plagues relief efforts Migration of families from rural to urban areas results in overcrowding, poor-quality housing, and lack of access to clean water, sufficient food, and medical care Reducing malnutrition through agricultural development Benefits Healthier diets for farmers’ families Ability to earn income from selling food Requirements Funding Infrastructure (e.g., roads, irrigation, electricity, banks) Agricultural research Education Healthy population United Nations Millennium Summit (2000) set goal to reduce extreme poverty and hunger by half by 2015. Some progress has occurred throughout the world Hunger and poverty continue to increase in sub-Saharan Africa and southern Asia Food Production Organic Foods Produced by farming practices that exclude synthetic pesticides, fertilizers, and hormones; antibiotics; sewage sludge; genetic engineering; and irradiation Contributors to consumer demand for organic foods Personal health Environmental health Organic foods are typically more expensive than those grown under conventional circumstances because they cost more to grow and produce Farming practices Biological pest management: use of natural predators, parasites, or pathogens to control agricultural pests Composting Manure application Crop rotation USDA established organic standards 95% of ingredients in an organic food made from multiple ingredients must meet organic standards “Made with organic”: at least 70% of ingredients are organic Not all organic food producers are USDA certified, may not be labeled organic Organic Foods and Health Reduce pesticide intake Organic foods contain fewer pesticides than conventional foods Unknown effects on health May be prudent for infants and young children Protect environment Encourage sustainable agriculture practices Improve nutritional quality Most research does not support advantage of organic food production practices on nutrient content Organic label does not make a food more healthy Food safety Like conventional foods, organic foods may be contaminated with pathogens Consumers should use safe handling practices with all foods to prevent foodborne illness Biotechnology-Genetically Modified Foods General Selective breeding improves yields, resistance to mildew and bacterial diseases, and tolerance to salt and adverse climate conditions Recombinant DNA technology: transfer of genes into a plant or animal to confer a specific trait Genetically modified food Genetically engineered food Transgenic plant, animal, or organism Genetically modified organism GM Crops Common GM crops in U.S. Soy Corn Cotton Canola Sugar beets Primary uses are for pest management Enhance crops’ tolerance for herbicides Bacillus thuringiensis (Bt) protein allows corn to produce toxin to kill caterpillars GM Animals Although genetically engineered animals are under development, none are currently approved for market (concerns over compatibility of wild and transgenic species) Other GM Applications Recombinant bovine growth hormone (rBGH) increases milk production in cows BGH is released from the pituitary gland and stimulates the production of insulin-like growth factor, which stimulates milk production Increases risk for mastitis in cows, may necessitate increased use of antibiotics Although insulin-like growth factor is associated with certain cancers in humans, there is no evidence that drinking milk is associated with these cancers No rBGH is used in production of organic milk rBGH is not approved for use in Canada or Europe Chymosin (rennin; used to make cheese) can be produced by genetically engineered bacteria or yeast rather than being harvested from the stomachs of calves GM Foods of the Future Increased crop yields Tolerance of crops to harsh conditions (e.g., drought, extreme heat, salty soil) Extended shelf-life Increased nutrient density (e.g., golden rice has increased levels of beta-carotene; more heart-healthy vegetable oils; non-allergenic foods) Although biotechnology has great potential to reduce hunger and malnutrition, many barriers exist Lack of access of poor farmers to access technology Most biotechnology research has focused on crops with industrial uses rather than on dietary staples Regulation of GM Foods FDA: ensures food safety USDA: ensures than GM foods are safe to grow EPA: regulates pesticide safety for consumption and the environment Labeling of GM foods or GM ingredients is not required in the U.S. Safety and Other Concerns about GM Foods Introduction of allergens: no evidence of harmful reactions or effects in humans Development of glyphosate-resistant “superweeds” Crosses species lines (inserting a gene from a fish into a grain) Possibility of gene flow from GM crops to plants not intended to be modified Development of Bt-resistant insects: may lead to increased pesticide use by nonorganic farmers Loss of genetic diversity Loss of cultural heritage with older, native foods Insufficient regulation and oversight of GM plants and animals Biopharming: bioengineering plants to produce medications Meat and Milk from Cloned Animals Cloning: making genetically identical animals by nonsexual reproduction Agricultural interest in cloning stems from desire to reproduce the best livestock for economic gain In 2008, FDA determined that meat and milk from cloned cattle, swine, and goats are safe to eat; USDA has not given approval for marketing of cloned milk and meat Food Preservation and Processing General Food preservation processes extend shelf-life by slowing the rate at which microorganisms and enzymes cause food spoilage Methods that decrease water content to deter microbial growth Drying Salting Sugaring Smoking Methods that increase acidity or alcohol to deter microbial growth Fermentation Pickling Methods that use heat to eradicate or reduce microbes Pasteurization Sterilization Canning Methods that slow rate of microbial growth Refrigeration Freezing Methods that inhibit microbial growth Chemical preservatives Irradiation Food Irradiation Uses radiant energy from gamma rays, X rays, or electron beams to extend shelf life and control growth of insects and pathogens in foods Irradiated food is not radioactive Irradiated foods are safe for human consumption according to FDA and other health authorities Fresh meat and poultry Wheat and wheat powder White potatoes Spices and dry vegetable seasonings Fresh shell eggs Fresh produce Irradiated foods (except for dried seasonings) must be labeled with Radura symbol Barriers to use Consumers’ lack of familiarity with the technology Higher cost Concerns about taste and safety of food Food Additives Historical examples Salt Vinegar Alcohol Intentional vs. Incidental Food Additives General Intentional food additive: purposely added to produce a desired effect (e.g., increased shelf life, greater nutritional value, color) Incidental (indirect) food additives: unintentionally incorporated into food through some aspect of food cultivation, processing, packaging, transport, or storage; have no function, but may pose risks (e.g., Bisphenol A (BPA)) Synthetic vs. Natural Additives Toxicity is determined by effects on body, not whether an additive is synthesized in a laboratory or plant Cancer researchers estimate we ingest at least 10,000 times more (by weight) natural toxins than synthetic additives or pesticides Regulation and Safety of Food Additives General 1958 Food Additives Amendment of the Food, Drug, and Cosmetics Act gave FDA jurisdiction over safety of food additives Manufacturers must obtain FDA approval prior to use of additives in foods; are responsible for testing and proving safety with the exception of food additives designated as prior-sanctioned substances and those on the Generally Recognized as Safe (GRAS) List Substances that the FDA or USDA deemed safe for use in foods prior to 1958 Food Additives Amendment are deemed prior sanctioned substances GRAS list contains substances with an extensive history of safe use before 1958 or that have been deemed safe by published scientific evidence Some additives have been removed from the GRAS list due to safety concerns Concerns about Food Additives Many additives on the GRAS list have not been adequately tested Aspartame used as non-nutritive sweetener: concern over cancer, dizziness, headaches Sodium nitrite used to prevent growth of Clostridium botulinum: can be converted to carcinogenic nitrosamines in the stomach; conversion limited by ascorbic acid or erythorbic acid Some artificial colors have been reported to cause allergic-type reactions in children and to increase hyperactive behavior, or linked to cancer in animals Cyclamate was banned due to a study indicating it was a carcinogen, but recent studies refute this evidence, and many countries now permit use of cyclamate Adverse symptoms for sensitive people: sulfites, monosodium glutamate Consumer demand for natural foods: free of added colors and synthetic substances Consuming fewer prepackaged, precooked, frozen, canned, and instant foods, mixes and snack foods will decrease intake of additives Food and Water Safety Foodborne Illness Overview General Sickness caused by ingestion of food containing pathogenic microorganisms or toxins made by these pathogens Many cases are undiagnosed Common symptoms Nausea Vomiting Diarrhea Intestinal cramping Severe effects Development of food allergies Seizures Blood poisoning Organ failure Chronic complications (e.g., arthritis) Death Individuals at High Risk for Foodborne Illness One quarter of population in U.S. is at high risk for foodborne illness Weakened immune system due to disease, pharmaceutical, or radiological treatments Pregnant women and fetuses Lactating mothers Infants and young children Elderly persons Foodborne Disease Outbreaks Large-scale production practices, common in developed countries, increase the impact of contamination Heavy reliance on food prepared outside the home increases risk due to mishandling of foods Mishandling of foods during home preparation is also a risk factor Microbial Pathogens Routes of transmission Contamination by human or animal feces Using contaminated water during food preparation Fecal contamination of soil and irrigation water from farm and wild animals Lack of hand washing after using the bathroom or changing diapers Insects may carry bacteria from sewage to food Contamination by an infected individual Open wound Coughing or sneezing onto food Pets, via unwashed hands of food handlers Cross-contamination: uncontaminated food comes in contact with a pathogen-contaminated food or object (e.g., plate, cutting board, knife) Bacteria: single-cell organisms; many are harmless, but some are pathogenic Examples are detailed in Table 3-4 Salmonella species Campylobacter jejuni Escherichia coli Shigella species Staphylococcus aureus Clostridium perfringens Listeria monocytogenes Clostridium botulinum Vibrio species Yersinia enterocolitica Proliferate with nutrients, water, and warmth (41° - 135°F; see figure 3-4) Most bacteria do not multiply when food is held above or below the danger zone, but Listeria can multiply at refrigeration temperatures High temperatures kill bacteria, but not toxins already produced in food Most pathogenic bacteria require oxygen, but Clostridium botulinum and Clostridium perfringens only grow in anaerobic environments Acidity typically deters bacterial growth, but E. coli can grow in acidic foods Some bacteria survive harsh conditions through spore formation Viruses Only reproduce after invading living cells Examples are detailed in Table 3-5 Norovirus, human rotavirus Hepatitis A virus Parasites Live in or on another organisms, from which they absorb nutrients Protozoa: one-celled animals Helminths: tapeworms and roundworms Examples are detailed in Table 3-6 Trichinella spiralis Anisakis Tapeworms Toxoplasma gondii Cyclospora cayetanensis Cryptosporidium Prions Infectious protein particle that invades the brain and spinal cord Transmitted by consuming infected animal products Example: bovine spongiform encephalopathy (mad cow disease), Creutzfeldt-Jakob disease (human variant) Survive high temperatures; best prevention is to keep infected meat out of the food supply Toxins Molds, algae, and plants produce disease-causing toxins Molds are a type of fungus that grow in dark, moist places May cause food spoilage, crop destruction, allergies or respiratory problems Mycotoxins: cause blood diseases, nervous system disorders, kidney and liver damage Examples are detailed in Table 3-7 Aflatoxin Ergot Ciguatera toxin Shellfish poisoning Scombroid poisoning Tetrodotoxin Safrole Solanine Mushroom toxins Herbal teas (senna, comfrey) Lectins Mycotoxins are rarely a problem in industrialized nations because food production practices minimize mold growth and foods are closely monitored Aflatoxin is produced by a mold that attacks peanuts, tree nuts, corn, and oilseeds Toxins in seafood: toxin-containing algae ingested by some fish and shellfish also cause foodborne disease (e.g., ciguatera toxin, shellfish poisoning) Toxins in plants: Natural toxins are produced by plants to protect from predators; production increases when plants are stressed Licorice Cyanide in lima beans and almonds Nutmeg, bananas, and some herbal teas contain substances that can cause hallucinations Proper food storage, cooking, and varied diet limit the effects of natural toxins Water Safety General Public water supplies are regulated by the EPA under the Safe Drinking Water Act Bacteria Chemical contaminants Toxic metals Local municipal water departments deliver safe water Water treatment involves disinfection (usually by chlorine-based chemical) Private water supplies (e.g., wells) are not regulated by EPA Bottled Water Manufacturers must list source on label Wells Spas Springs Geysers Public water Bottled water safety is regulated by FDA Threats to Safe Water Agricultural runoff Inappropriate disposal of chemicals Municipal solid waste Leaking into waterways Inadequate treatment of human wastes Pollution from boats and ships Preventing Foodborne and Waterborne Illnesses “Farm-to-fork” approach: food growers, processors, distributors, and consumers share responsibility for food and water safety Consumer food safety practices Use good personal and kitchen hygiene Handle food safely Thawing Cooking Chilling Storage Know which foods pose extra risk to those more susceptible to foodborne illness Environmental Contaminants in Foods Lead Damaging to every organ system, especially nervous system and kidneys Impairs synthesis of hemoglobin Particularly toxic for children, whose nervous system is still developing Lower IQ Behavior disorders Impaired coordination Impaired growth and hearing Predisposition for high blood pressure and kidney disease later in life Avoiding lead ingestion Let cold water run for 1 minute before using from pipes in homes built before 1986; hot tap water should not be used for food preparation Keep hands and objects that may be placed in the mouth clean to prevent ingestion of lead dust from lead-based paint in homes Never serve or store food in lead-containing containers Other sources of lead Some candies from Mexico Vegetables grown in contaminated soil Dietary supplements Toys painted with lead-containing paints Preventing lead poisoning Remove lead from environment Ensure adequate iron intake Dioxins Chlorine and benzene-containing chemicals; byproducts of industrial processes and incineration of waste Effects Increases cancer risk Liver and nerve damage Adverse effects on reproduction Increased risk of type 2 diabetes mellitus Routes of exposure Food contamination (animal fats and fish from contaminated waterways) Inhalation Limiting exposure Avoid certain species of fish and those caught in contaminated waterways, as identified by EPA Consume a variety of fish species Mercury Abundant in environment; converted to neurotoxin by bacteria Effects Birth defects Nerve damage Fatigue Poor learning abilities Highest risk populations are children and pregnant/breastfeeding women Avoid shark, swordfish, king mackerel, tilefish Limit albacore tuna to 6 oz (1 meal)/week Limit intake of low-mercury fish (e.g., shrimp, light tuna, pollock, salmon, catfish) to 12 oz (2 meals)/week; small portions for children Be aware of EPA advisories for mercury contamination of local waterways Ongoing research suggests that benefits of fish consumption (source of essential fatty acids) outweigh risks or mercury Polychlorinated Biphenyls (PCBs) Historically used for industrial processes; still detectable in environment Health effects Liver damage Reproductive problems To limit exposure, exercise variety and moderation in fish consumption Pesticides and Antibiotics General Types of pesticides Insecticides Herbicides Fungicides Rodenticides Uses Limit damage to crops Increase agricultural production Improve appearance of fruits and vegetables Prevent formation of carcinogenic aflatoxin Farms, homes, businesses, schools, health-care facilities Synthetic pesticides: many early types resist breakdown and have remained in the environment despite being banned; today’s pesticides are less persistent Organophosphates Carbamates Organochlorine insecticides Pyrethroid pesticides Biopesticides Microbial pesticides (e.g., Bacillus thuringiensis) Genetic modification of plants to produce their own pesticides (e.g., Bt protein) Biochemical pesticides that limit reproduction or growth of pests Problems associated with pesticide use Development of pesticide resistance Pesticide drift to non-target sites Persistence of pesticides in the environment (e.g., soil, water, animal fat) Unintended effects on non-target species Regulating Pesticides EPA Determines whether or not a pesticide is beneficial or poses unreasonable health or environmental risks Sets limits on amounts used on food during growth and processing and how much may remain on final product (tolerance) Food Quality Protection Act of 1996 requires EPA to consider children’s pesticide exposure from foods they normally eat FDA and USDA Test foods for pesticides Enforce EPA pesticide tolerances; reports show that although residues are present, only 0.5% of foods have residues exceeding tolerances Minimizing Exposure to Pesticides Health risks Accidental poisonings related to careless use or storage of pesticides Higher rates of asthma, Parkinson’s disease, prostate cancer, leukemia, and other cancers among people who work with pesticides (e.g., farmers) Concern about chronic, low-level exposure (e.g., pesticide residues in foods) Infants and children are at heightened risk because of developing organ systems, higher doses per kg body weight, inefficient metabolism Steps to minimize exposure Wash and peel fruits and vegetables Trim fat in meat Select a variety of foods Benefits of eating a variety of produce exceed risks of pesticide exposure Certified organic foods are grown without synthetic pesticides, but still may contain small amounts of pesticide residues due to background contamination and pesticide drift Antibiotics Used to promote animal growth and prevent and treat disease in food animals (80% of all antibiotics produced in the U.S.) Concerns about development of antibiotic-resistant strains Use of antibiotics is prohibited in organically produced animals Clinical Perspective: Foodborne Illness can be Deadly High-risk populations include infants and young children, the elderly, pregnant women and their fetuses, and people with impaired immune systems Hemolytic uremic syndrome (HUS) Caused by E. Coli O157:H7 Leads to hemolysis and uremia Symptoms Bloody diarrhea Vomiting Sleepiness Low urine output Requires intensive medical care Listeriosis Caused by Listeria monocytogenes Symptoms Muscle aches Fever Nausea Can spread to nervous system, causing severe headache, stiff neck, loss of balance and confusion Can cause miscarriage, premature delivery, fetal infections, and death Guillain-Barre syndrome (GBS) Caused by Campylobacter jejuni Rare nervous system disorder Peripheral nerves damaged by the body’s own immune system Symptoms Tingling and pain in legs Severe muscular weakness Can lead to paralysis Reactive arthritis Caused by Salmonella, Shigella, Campylobacter Genetic factors play a role in determining who develops reactive arthritis Develops 2-6 weeks after initial infection Causes inflammation throughout body, but especially in the joints and eyes Symptoms Pain and swelling of knees, ankles and feet Inflammation of urinary tract Blistering of palms of the hands and soles of the feet Global Perspective: Traveler’s Diarrhea Afflicts 30-50% of people who travel to areas that tend to be hot and lack advanced water treatment systems and refrigeration According to CDC, it is caused by bacterial infection, spread through contaminated food and water Follow these guidelines to reduce risk: Eat foods that are freshly cooked and served piping hot. Avoid food from street vendors and buffets. Avoid salads and raw fruits and vegetables. Avoid raw or undercooked meat and seafood. Avoid tap water and beverages reconstituted with tap water (including ice and possibly fruit juice and milk). Bottled and sealed beverages, including soft drinks, water, beer, and wine, are generally safe. Beverages made with boiled water, such as coffee and tea, are generally safe. Travelers also can treat tap water by boiling, chemical disinfection, or filtering. Expert Perspective: Organic Foods and Local Food Systems Benefits of consuming organic foods Avoid exposure to pesticides, antibiotics, and synthetic hormones Humane animal treatment Benefits of local food systems Increased biodiversity Increased access to fresh foods Decreased environmental impact Greater community economic development Characteristics of an ideal food system Healthy Optimal nutritional value Free of preservatives and additives Does not promote chronic disease Green No, or low, environmental impact Balanced ecosystems Uses minimal nonrenewable energy Recycles wastes Fair Does not exploit anyone or anything Promotes self-sufficiency of farmers Contributes to economic development of community Affordable and accessible Safe Nutritious Produced in a sustainable manner Equally and regularly available to everyone Limited budgets Buy fruits, vegetables, dairy, eggs, or meat from local organic farmers, identified through farmer’s markets, co-ops, Community Supported Agriculture farms, or Cooperative Extension System websites Buy fresh foods when in season Focus on specific foods with high pesticide residues Instructor Manual for Wardlaw's Perspectives in Nutrition Carol Byrd-Bredbenner, Gaile Moe , Jacqueline Berning , Danita Kelley 9780078021411