Nutrition in the Adult Years
This chapter emphasizes the background and tools for encouraging adults to set nutrition-related lifestyle goals that promote positive health and reduce risk factors. Other chapters of this text provide in-depth information about the major chronic diseases and conditions that affect food and nutrition choices in the adult years, including cardiovascular disease (CVD), diabetes, cancer, weight control, and osteoporosis. The focus here is on achieving and maintaining positive health, and in making lifestyle choices to achieve the goals for Healthy People 2020 (see Chapter 10).
Setting the Stage: Nutrition In The Adult Years
This chapter focuses on nutrition- and food-related behaviors for the years following adolescence but before one is deemed an “older adult,” often defined as age 65. Admittedly this is a large age span, and, like all population groups, it is heterogeneous. The dietary reference intakes (DRIs) on the inside cover of this text provide an overview of the nutrient recommendations for age groups under the DRI umbrella. Nutrient needs are similar but, as in all life stages, are affected by gender, state of health, medications, and lifestyle choices such as eating behaviors, smoking, and activity. These are markers, determined through assessment, that the nutrition and health professional can use to determine this population’s needs. Other markers are less evident and include the adult’s perceptions of quality of life and motivation in the areas of nutrition and health. When the objectives are prevention and behavior change, such markers become critical.
A first step for dietetics and health professionals is to recognize that many adults are prime targets for nutrition and health information that offers positive guidance. As with any group, adults need to be approached with strategies and guidance that fit their health and education needs. The American Dietetic Association (ADA) Trends surveys offer some insights. These surveys include a representative sampling of adult Americans with a focus on food, nutrition, and activity messages and consumers’ reactions to these messages. Because this survey was conducted every 2 years for 12 years and was repeated in 2008, Trends provides a snapshot of attitudes about the importance of nutrition, activity, and sources of information. In 2002, 38% of Americans believed they had made significant adjustments in achieving a healthful and nutritious diet. Trends 2008 continued to show positive gains in that 43% of the respondents noted they were making positive steps (ADA, 2008).
Eating Habits of American Adults
Surveys such as ADA Trends support the idea that an increasing number of adults, more women than men, are seeking nutrition information and using it to make positive lifestyle changes. In a recent survey almost 70% of 30,000 U.S. adults said that they are trying to eat healthier foods; half are looking for nutrition value and have an ongoing concern about controlling calories (Dornblaser, 2006). According to the ADA’s survey three in five consumers said diet, nutrition, and physical activity are “very important” to them personally, women more so than men. Younger adults were less likely than older adults to rate diet and nutrition as “very important,” whereas exercise and physical activity were very important across the life cycle. Of relevance is the fact that reasons for not adjusting their diet or exercise patterns more were most likely to be satisfaction with their current health and nutrition status (79%) and concerns for not having to give up foods they like (73%). For those interested in changing their beliefs and behaviors, time limitations, lack of practical information, and unclear guidelines were noted (ADA, 2008)
A review of the health and nutrition information in magazines and on television reinforces the idea that nutrition and health information is “in.” However, consumers are selective about their personal concerns. The International Food Information Council (IFIC) Foundation Food and Health Survey found that half of Americans are trying to lose weight, two thirds report making changes in the types and amounts of food eaten, and 70% express concerns with their weight (IFIC, 2009). Messages regarding the potential benefits and risks of certain foods and nutrients are being heard by consumers. Messages such as the negative effect of saturated fat, trans-fatty acids, and sodium are acknowledged; two in five adults said they were planning to eat more whole grains during the year they were surveyed (Harris Interactive Poll, 2006). This has driven the marketing of “healthful foods” as well as the demand for creating and marketing foods that fit this image (Sloan, 2006).
Where consumers get their information is another factor to consider. Both the source and the message affect the scientific value, but to the adult consumer the promise of specific benefit is more important than the standard “it’s good for you” message. Both television and magazines are major sources of food and nutrition information for adults, and the Internet has surpassed newspapers. When it comes to credible sources, 78% of survey respondents rate registered dietitians as credible, followed by doctors and nurses (ADA, 2008.)
Consumers are using the labels on foods and beverages, including both the Nutrition Facts Panel and other label information, to get health information. Although 84% of the population is aware of MyPyramid which has recently been updated to MyPlate, only 25% report customizing their diets using these guidance systems (IFIC, 2009). Consumers will continue to need help in using the new website, www.chooseMyPlate.gov to improve their diets.
Nutrition Information and Education for Adults
Frequently, mainstream adults are ignored as a unique segment of the population needing a positive message. Preventive strategies are likely to be targeted to address the formative years of prenatal, infancy, childhood, adolescence, and young adulthood. The older adult group is likely to be targeted with health intervention strategies and quality-of-life messages. But the population group in the middle of the continuum, the adult age 25 to approximately 65, is likely to be segmented in reference to a disease state, a life event, or a lifestyle choice. For example, adults are targeted as having or being at risk for diabetes or heart disease, in need of a medication, being pregnant, or being an athlete.
The adult who is not pregnant, an athlete, or “sick,” but who seeks guidance on normal nutrition or prevention of disease may be directed toward diets for chronic disease or weight loss. Such information may be a good fit when the information is based on science. Fortunately, the guidance provided by such groups as the American Heart Association (AHA), the ADA, the American Diabetes Association, and the American Cancer Society (ACS) mirror the Dietary Guidelines for Americans 2010 (DGA) (USDHHS, 2010). The AHA released guidelines in 2006 defining new goals with a focus on improving overall health and achieving improved cardiovascular health of all Americans by 20% by 2020 (Lloyd-Jones, 2010).
Adults are prime targets for information on chronic disease prevention and weight management; however, the messages may appear to be conflicting or less sensational than advice promising quick solutions. In spite of this, health education and public health programs, along with improved research and care, have contributed to changes in morbidity and mortality of the adult population (Centers for Disease Control and Prevention [CDC], 2009a). U.S. adults are on a path to positive change, moving from knowledge to action (National Center for Health Statistics [NCHS], 2009).
Adults in the awareness and action stages are likely to be looking for answers, often short-term fixes or reversals of a health problem. For example, adults might want to know where carbohydrates fit into the total diet and whether there are “better carbs.” What’s the message on fat now that trans-fats have been almost banned? Are there “good fats?” What is a “healthy” or “unhealthy” food or diet? Should I be buying organically grown or locally grown foods? What should I do about sodium? How can I practice food safety?
Guidance based on science generally addresses total diet and lifestyle rather than single nutrients or foods. The concepts of healthful eating, nutrient density, and nutritious food are being debated by food and nutrition professionals. The idea of expressing nutrient density using food labels is a major discussion point. Unfortunately, food and nutrition debates are fodder for media coverage, adding to the confusion and perception of mixed messages. There is ongoing effort to sort out information on food labels, particularly front-of-package systems meant to help consumers understand what is in their food (Institute of Medicine [IOM], 2010; Thompson, 2010).
But adults are a population group with both the interest and the ability to seek out their own resources and answers. A search for information on choosing foods for health can result in evidence-based information such as the DGA, as well as questionable guidance based on single studies or product promotion. The combination of marketing and electronic media makes it easier to mix science with speculation and outright untruths. Adults with an interest in improving the nutritional quality of their diet may end up with noncredible advice pointing to supplements as quick-fix solutions.
Consider the adult years as a time for health promotion, health maintenance, and disease prevention, along with the interventions that accompany the progression of chronic disease that can come with aging. It is a time for adults to take responsibility and control. The Food and Health Survey and the ADA Trends study are examples of benchmark studies that provide a snapshot of consumer attitudes on food and health. Such studies provide the dietetic and health professional the information on “hot buttons” issues of importance to consumers. Examining these and other surveys targeting adults is critical to presenting relevant information and also initiating and reinforcing positive nutrition and health behaviors.
The Wellness Years
The adult years are a broad span chronologically and are complicated by physiologic, developmental, and social factors. Along with their genetic and social history, adults have accumulated the results of behaviors and risks from environmental factors. These factors shape the heterogeneity of the adult years. Nonetheless, the adult years are an ideal time for positive health promotion and disease prevention messages. In the transitions from early to middle adulthood, health and wellness may take on a new importance. This may be the result of a life event or education (an epiphany) which triggers an awareness that being well and staying well are important. Examples include learning the results of a screening for blood pressure, cholesterol, or diabetes; facing the reality of death; the self-reflection that occurs when personal health or that of a peer or family member is in crisis; or realizing that clothes don’t fit as well as they should. Regardless of the reason, the concept of wellness takes on a new meaning and these events are teachable moments.
The Wellness Councils of America (WELCOA) describes wellness as a process that involves being aware of better health and actively working toward that goal (WELCOA, 2009). With this mindset, a state of wellness can exist at any age and can start at any point in a person’s life course. Wellness is more than physical health and well-being. A state of well-being includes mental and spiritual health and encompasses the ability of a person to move through Maslow’s Hierarchy of Needs (Maslow, 1970).
The ability to address nutrition needs requires food security (i.e., access to a safe, acceptable, and adequate source of food). The current economic climate has put added emphasis on food security. Hispanic and black Americans in all age groups are more likely to live in poverty than white and Asian Americans (CDC, 2009a). Indeed, the highest levels of food insecurity are in black and Hispanic households (CDC, 2006a).
In 2008, it was estimated that 85% of U.S. households were food secure throughout the entire year and 15% were food insecure at least some time during the year, an increase of 11.1% over 2007 (U.S. Department of Agriculture [USDA] and Economic Research Service [ERS], 2010). Hunger and poverty statistics released by Feeding America, formerly Second Harvest, note that in 2008 39.8 million people were living in poverty (Food Research and Action Center, 2010).
Participation in the Supplemental Nutrition Assistance Program (SNAP), previously “Food Stamps,” is a marker of food insecurity. Slightly more than half of all Americans between the ages of 20 and 65 will at some point receive food stamps, an indicator of the risk for food insecurity in the adult years (Sandoval et al., 2009). Although most SNAP recipients are children or older adults, working-age women represent 28% of those enrolled in the program and working-age men represented 14% (USDA and ERS, 2010). Access to affordable food is a basic requirement for wellness and nutrition in the adult years.
One’s perceptions of personal health (both mental and physical) relate to views on wellness and perceptions of quality of life. Health-related quality of life (HRQOL) is a concept used to measure the effects of current health conditions on a person’s day-to-day life. To capture this and create a tool for professionals, the CDC measures population HRQOL perceptions, including the perception of “feeling healthy.” Using HRQOL, one can learn about how adults relate their health to their daily performance. Americans report feeling “unhealthy” approximately 6 days a month and “healthy” or “full of energy” approximately 19 days a month; adults with the lowest income levels and more chronic diseases report more “unhealthy” days (CDC, 2006a).
The adult years offer unique opportunities to evaluate health status, build on positive factors, and change the negative factors that affect quality of life. See Fig. 20-1. Because adults are teachers, coaches, parents, caregivers, and worksite leaders, targeting the wellness-related attitudes and behaviors of adults can potentially have a multiplier effect. A positive wellness focus may influence not only the health of the adult, but also those in his or her sphere of influence.
Lifestyle and Health Risk Factors
Lifestyle choices, including activity, lay the framework for health and wellness. The health of people living in the United States has continued to improve during the previous 55 years in part because of education that has led to lifestyle changes. Life expectancy has continued to increase (projected at 77.9 years), and the morbidity and mortality rate from heart disease, cancer, and stroke has dropped. Overall mortality was 25% higher for black Americans that white Americans in 2007; this has only slightly improved since 1990 when the gap was 37% (CDC, 2009a). This is an area for increased emphasis on prevention and intervention initiatives.
Even when the emphasis is on wellness, there is a strong link to risk factors that influence morbidity and mortality. In the United States the leading causes of death and debilitation among adults include (1) heart disease, (2) cancer, (3) cerebrovascular disease, (4) chronic lower respiratory disease, (5) accidents (unintentional injuries), and (6) diabetes (CDC, 2009b). Chronic diseases, including heart disease, stroke, cancer, and diabetes, are among the most costly and preventable of all health problems and account for one third of the years of potential life lost before age 65 and for 75% of the nation’s medical care costs (CDC, 2009b). Four of these chronic diseases have links to diet and lifestyle, including CVD, diabetes, certain cancers, and osteoporosis.
Overweight and obesity is either a precursor or complication in all of these diseases. The prevalence of overweight, as measured by a body mass index (BMI) of 25 or more, has increased at all ages, but appears to be holding steady. It is important when looking at the overall health of adults to consider elevated BMI as a major risk factor. Hypertension, hyperlipidemia, and elevated blood glucose are often seen together with or without obesity, known as the metabolic syndrome.
Obesity and overweight directly link with calorie imbalance. It is estimated that less than half of U.S. adults participate in regular physical activity, with one fourth reporting no activity. Many health risks in the adult years, including coronary artery disease, certain types of cancer, hypertension, type 2 diabetes, depression, anxiety, and osteoporosis have a relationship with lack of participation in regular physical activity and poor eating behaviors. One cannot achieve positive health without a combination of physical activity and food choices that fit personal needs for energy balance and nutrition.
On the other end of the weight spectrum is chronic underweight, frequently accompanied by undernutrition. Anorexia nervosa is the extreme condition, found in both genders across the age span. An unhealthy weight or unhealthy concern about body weight not only affects overall health but in women can also affect fertility and the ability to conceive.
Health Disparities
Implementation of Healthy People goals are based in part on eliminating disparities that increase the health risks for affected populations. Such disparities are related to inadequate access to a safe and affordable food supply and health care based on race, ethnicity, gender, education, income level, and geographic location. Inadequate access to care is a disparity that has a major effect on a person’s wellness. Men of working age are nearly twice as likely as women to have no usual source of health care (NCHS, 2009). Chronic diseases and obesity have been shown to be more of a burden to racial minorities and women (CDC, 2009a, 2010). There is a higher incidence of heart disease, diabetes, and obesity or overweight in low-income, black, and Hispanic populations (AHA and American Stroke Association, 2005). These same population groups have limited access to preventive care, nutrition education, and guidance (U.S. Department of Health and Human Services [USDHHS], 2010).
Food insecurity and limited access to healthful foods are also disparities. It is often more expensive to eat healthy foods than less healthy, high-calorie foods. Limited skills in the areas of wise food purchasing and food preparation coupled with limited food and equipment resources further complicate a person’s ability to follow advice for a healthy lifestyle. This emphasizes the need for adult consumer education in basic food skills.
The problems associated with chronic diseases are similar in other countries (World Health Organization [WHO], 2009). Human immunodeficiency virus, acquired immune deficiency syndrome, tuberculosis, and tropical diseases are barriers to global achievement of positive health status. Indeed, the eight United Nations millennium development goals seek to reduce the number of people who suffer from hunger and increase access to safe water and sanitation (WHO, 2009).
Emphasis: Women’s Health
The reproductive years constitute a significant stage of a woman’s life. Many issues that affect the health of women are related to the monthly hormonal shifts associated with menses. Osteoporosis, heart disease, and some cancers are disease states that are affected by specific hormones. Pregnancy and breast-feeding have an effect on a woman’s health (see Chapter 16). Breast-feeding helps control weight, lower the risk for diabetes, and improves bone health (Stuebe et al., 2005). Therefore encouraging women to breast-feed is a potential prevention strategy for the future health of both the mother and her infant.
Shifts of estrogen and progesterone hormones trigger the female reproductive cycle and affect health. Associated with menses is a complex set of physical and psychologic symptoms known as premenstrual syndrome (PMS). Reported symptoms vary, but are described as general discomfort, anxiety, depression, fatigue, breast pain, and cramping. Such symptoms are reported to occur approximately 1 week to 10 days before the onset of menses and increase in severity into menses. Currently, there is no single cause or intervention identified for PMS. Hormone imbalance, neurotransmitter synthesis defects, and low levels of certain nutrients (i.e., vitamin B6 and calcium) have been implicated (National Institutes of Health [NIH] and Office of Dietary Supplements [ODS], 2007). A diet high in sodium and refined carbohydrates has been implicated, but the evidence is not complete enough to make recommendations (NIH and ODS, 2007). A greater emphasis on a plant-based diet of whole grains, fruits, vegetables, lean or low-fat protein sources, and low-fat dairy or soy beverages is a reasonable intervention and may cause relief in some women. Exercise and relaxation techniques have been reported as lessening the symptoms.
When menses end, either because of age or surgical removal of reproductive organs, women have unique health and nutrition concerns. Perimenopause and menopause generally begin in the late forties. However, genetics, general health, and the age that menses began can alter the timing of this marker. Typically, estrogen production decreases around age 50, when endogenous estrogen circulation decreases approximately 60%. The effects include a cessation of menses and the loss of the healthful benefits of estrogen. Even after the ovaries cease production, a weaker form of estrogen continues to be produced by the adrenal glands, and some is stored in adipose tissue (Barrett-Connor et al., 2005).
As estrogen decreases, symptoms associated with menopause may occur. Both the onset of menopause and the reported side effects vary. Some women experience a gradual decline in the frequency and duration of menses, whereas others experience an abrupt cessation. The symptoms most often reported include low energy levels and vasomotor symptoms (hot flashes). Bone, heart, and brain health are affected. The decrease in circulating estrogen limits the body’s ability to remodel bones, resulting in a decrease of bone mass. Lower levels of circulating estrogen also affect blood lipid levels, increasing both total cholesterol and low-density lipoprotein cholesterol levels, and decreasing high-density lipoprotein (HDL) levels. Brain function, particularly memory, is also affected; negative changes may be somewhat alleviated with hormone therapy (MacLennan et al., 2006).
Managing menopause promotes emphasis on plant-based foods for the benefits of phytoestrogens, soluble fiber, and other components. Having sufficient calcium, vitamin D, vitamin K, and magnesium, and using the DRI as the guideline, is important for protecting bone health. Although soy (isoflavones) continues to be suggested by the popular press as a way to control hot flashes, current research does not support these suggestions for all women.
Heart disease, cancer, and stroke continue to be the leading causes of death in women (CDC, 2006b). As reported earlier, weight is a risk factor for heart disease and some cancers. Weight gain is an issue for women, with the 35% prevalence of obesity in American women aged 20-74 years as compared with 33% in the same aged men. One-half of non-Hispanic black women and two fifths of Hispanic women are obese, compared with one third of non-Hispanic white women (CDC, 2009a). Physical activity with aerobic endeavors and resistance and weight-bearing exercise is protective for bone, cardiovascular, and emotional health. The key nutrition message is one of balanced food intake with nutrient dense foods that are low in fat.
Emphasis: Men’s Health
The leading causes of death among American men include heart disease, prostate and lung cancers, and unintentional injuries (CDC, 2006c). For the adult man, a diet that supports reducing the risk for heart disease is especially important because men develop heart disease at a younger age than women. Regular exercise and activity are important. Along with contributing to cardiovascular health, weight-bearing exercise has a positive effect on bone health.
Another issue in adult men is iron intake. Unless adult men are diagnosed with iron-deficiency anemia and require additional iron, they should not get additional iron from multivitamin or mineral supplements, enriched sports drinks, or energy bars. Excessive iron intake is problematic because it is an oxidant in the body; men and postmenopausal women do not have menstruation, pregnancy, or lactation to get rid of excess iron. A certain percentage of men carry the genetic variant for hemochromatosis and iron overload, and in this situation iron is particularly dangerous. See Chapter 33.
Interventions: Nutrition and Prevention
Adults are in the ideal life-cycle phase for health promotion and disease prevention nutrition advice because of the combination of life experience and influence. This group has the potential to shape personal lifestyle choices and influence others. The tools are in place, including the DGA, MyPlate, and the Nutrition Facts panel on food labels. Alternative patterns exist to support those who choose to be vegetarian or vegan (Craig et al., 2009).
Implementation of positive choices and moving people along the continuum of a healthy lifestyle are other issues. Many consumers are aware of the concerns associated with lifestyle and diet (IFIC, 2009). They are also aware of the implied promises for good health that come with messages from the media, friends, and health professionals. However, they are unlikely to move from awareness to action without motivation stronger than another promise. Consumers often do not want to give up the foods they like for fear that healthy foods would not taste good (ADA, 2008). A total diet approach of making gradual changes of food and lifestyle choices may help. The Small Step Program available through the U.S. Department of Health and Human Services is an example of such an approach in a simple, Internet-based program (USDHHS, 2006). “America on the Move” is another program that puts emphasis on achievable goals while maintaining calorie balance through small changes.
However, the steps to prevention and health promotion, even when small, are personal responsibilities that cannot be legislated. Americans have many choices: what and where they eat, where they receive their information, and what they include or remove from their lifestyle. Adults in our culture value choice; it is a right, even if it leads to poor health, chronic disease, or death. Some messages are directed at reaching adults where they live and work. Adults in developed countries are mobile, and for the working adult populations, much of the day is tied to a work site. There are increasing efforts in both the private and public sectors to promote positive work site nutrition-related behaviors and programs.
Food Trends and Patterns
Where one eats, who prepares it, and how much is consumed are all patterns of behavior and choice. There is no stereotypic “adult” when it comes to lifestyles. Adults may be single or partnered, with or without children, working outside the home or at home. The sit-down family meals at home have given way to eating on the run, take-out, and drive-through. Too little time for planning or preparation and limited cooking skills can lead to reliance on processed foods, speed-scratch cooking (combining processed with fresh ingredients), or more food prepared out of the home. Today’s economic climate and changing dietary recommendations present new challenges. The nutrient-dense approach is essential (Miller et al., 2009). Reaching both men and women with an understandable and relevant message, especially heads of households or gatekeepers, is critical.
According to the consumer price index (CPI) it is estimated that Americans spend up to 48.5% of their food dollars away from home. The CPI for food measures the average change over time in the prices paid by urban consumers, using a representative market basket of consumer goods and services. The Economic Research Service (ERS) of the USDA follows these expenditures and manages the data set. This is a valuable resource for monitoring expenditures and planning for meaningful interventions.
Changing food patterns and the use of more processed and purchased foods result in an increase of foods higher in sodium with added fat and sweeteners, and a decrease in use of basic foods such as fruits, vegetables, and whole grains. Portion sizes (either the amount presented or the amount eaten) replace serving sizes (what is recommended as a serving by the DGA or other source), as others determine what is considered a “meal” or “snack.” Portions have continued to increase in size, as evidenced from using the tool “Portion Distortion” available at http://hp2010.nhlbihin.net/portion/keep.htm.
Dietary changes have affected nutrition and are already reflected in the current concerns for weight and nutrient imbalances. The DGA 2010 and MyPlate can be viewed as attempts to put more emphasis on basic foods that are nutrient-dense rather than calorie-dense, and on total amounts of foods per day rather than numbers of servings. The most current information is reflected in the information used to shape the 2010 DGAs (USDHHS, 2010).
Current adult diets are likely to be higher in total fat than the 30% of total calories recommended in the 2010 DGA and include a predominance of carbohydrates as added sugar and refined grains. Fruit and vegetable guidelines are not being met. Although chicken and fish servings have increased, animal sources outweigh plant-based protein sources. Health guidelines continue to move in the direction of increasing plant based foods. Key nutrients that may be in short supply are calcium, magnesium, and potassium; the antioxidants vitamins A, C, and E; and vitamin D (USDHHS, 2010).
Nutritional Supplementation
The position of the ADA that the best nutritional strategy for promoting optimal health and reducing the risk of chronic disease is to wisely choose a wide variety of nutrient-rich foods. Additional nutrients from fortified foods and supplements can help some people meet their nutritional needs as specified by science-based nutrition standards such as the DRI (Hasler et al., 2009). In making this statement, the ADA puts food first but leaves the door open for those with specific nutrient needs, identified through assessment by a dietetic or health professional, to be nutritionally supplemented.
Traditionally, one thinks of vitamins and minerals, fiber, and protein as nutrient supplements, generally in a pill, capsule, or liquid form. The DRIs are the standards used with most adults. However, food fortification is another form of nutrient supplementation. The level of fortified foods (such as “energy bars” or “sports drinks”) in the marketplace puts another layer of potential nutrient sources in the mix with traditional supplements. Less traditional supplements such as herbals and other natural dietary “enhancers” are also added to the array of supplements available to consumers.
Americans frequently do not meet the dietary recommendations for promoting optimal health. Several segments of the adult population fall into high-risk groups who are unlikely to meet their nutrient needs because of life stage (e.g., pregnancy), alcohol or drug dependency, food insecurity, chronic illness, recovery from illness, or choosing a nutritionally restrictive diet or lifestyle (ADA, 2008). Other persons with special needs include those with food allergies or intolerances that eliminate major food groups, persons using prescription drugs or therapies that change the way the body uses nutrients, those with disabilities that limit their ability to enjoy a varied diet, and those who are just unable or unwilling because of time or energy to prepare or consume a nutritionally adequate diet. These adults potentially need a nutritional supplement. See Chapter 13.
Functional Foods
Adults interested in attaining and maintaining wellness are frequently interested in altering dietary patterns or choosing foods for added health benefits. The desire for fewer calories and multiple health benefits, especially when children are in the home, is driving the growth in the U.S. functional foods market. Examples of functional foods are fruits and vegetables (especially dark colored ones), flax seeds, whole grains, the oils of fish, certain spices, yogurt, nuts, soy, and legumes that are believed to have benefits beyond their usual nutrient value (IFIC, 2010). Functional foods can include whole foods and fortified, enriched, or enhanced foods. The potential benefit for health is when these foods are consumed as part of a varied diet on a regular basis (Marra and Boyar, 2009).
Providing this information to the segment of the adult population that is looking for ways to enhance its health not only gains the adults’ attention but also takes nutrition guidance to a higher level. Research continues to provide information on dietary patterns and components of foods that may have added benefits for health. Helping to lower blood cholesterol or control blood sugar, serving as an antioxidant or scavenger against harmful components, promoting a healthy gastrointestinal tract, or stimulating activity of detoxification enzyme systems in the liver are examples of benefits being reported and researched for validity. See Focus On: Eating to Detoxify.
Focus On
Eating To Detoxify
Current thinking on eating to detoxify for optimal health is based on a system of choosing foods to protect, maintain, and renew the body. The body is protected from xenobiotics (compounds foreign to the body) by natural barriers, including the gastrointestinal system, the lungs, and the skin. When compounds that are potentially harmful or unknown cross these barriers, the body’s detoxification systems, which are series of metabolic reactions, go into play, with the result of decreasing the negative effect of the xenobiotics, drugs, or toxins.
Toxins may be of external origin (also referred to as xenobiotics or exogenous toxins), such as chemicals and pollutants in the air or water, food additives, or drugs. They may also be generated internally (referred to as endogenous toxins), as the end-products from the metabolism of hormones, bacterial byproducts, and other complex molecules. The prolonged presence of these molecules can have damaging effects on tissues or lead to undesirable imbalances.
The detoxification process occurs in two classical steps, named Phase 1 and Phase 2, each involving a battery of enzymes of broad specificity. Specifically, Phase 1 reactions are catalyzed by the cytochrome P450 (CYP450) supergene family of isoenzymes, which have very broad substrate specificity. The products generated from Phase 1 reactions are often reactive intermediate metabolites or reactive oxygen species, which may cause tissue damage. The reactions in Phase 2 generally involve conversion or conjugation of the intermediate metabolites of Phase 1 by the addition of a water-soluble group to the reactive site into the final products that are eliminated. In some cases, a toxin may be directly converted via Phase 1 or Phase 2. Although both phases have different characteristics, it is essential that they function in balance with one another to minimize the presence of intermediate metabolites and carry through an effective detoxification.
Although as much as 75% of detoxification activity occurs in the liver, much of the remainder takes place in the intestinal mucosa wall. An additional small percentage occurs in other tissues. Although the liver is thought of as the detoxification site, it makes sense that the intestine also plays an important role in detoxification, because the gastrointestinal lining provides the initial physical barrier to the largest load of xenobiotics.
The potential power of these systems to protect the body is demonstrated by a closer look at the major barrier, the gut. More than half the body’s lymphoid tissue surrounds the digestive tract. Gut-associated lymphoid tissue (GALT) generates almost 70% of the body’s antibodies and contains the greatest number of lymphocytes in the body. It is the GALT immunoglobulins that prevent absorption of bacteria and viruses. Secretory immunoglobin A is a part of the major immune system of the gut and has been reported to directly deactivate enzymes and toxins from bacteria such as Escherichia coli.
The mechanisms for the food and nutrient link to detoxification are being explored, but it is suggested that phytochemicals are involved, along with more traditional nutrients that build and support the enzyme systems. Isothiocyanates such as sulforaphanes found in cruciferous vegetables; organosulfuric compounds in garlic, onions, and other members of the allium family; and the components present in prebiotics (nondigestible food products that stimulate the growth of bacteria already present in the colon); and the bacteria of probiotics are examples of food choices that can affect detoxification in both prevention and healing.
Foods with phytochemicals that boost detoxification include:
• At least 1 cup of cruciferous vegetables (cabbage, broccoli, collards, kale, Brussels sprouts) daily for their Phase 2 enzyme promoting effect
• A few cloves of garlic, which also promote Phase 2 enzymes
• Decaffeinated green tea in the morning.
• Fresh vegetable juices including carrots, celery, cilantro, beets, parsley, and ginger
• Herbal teas containing a mixture of burdock root, dandelion root, ginger root, licorice root, sarsaparilla root, cardamom seed, cinnamon bark and other herbs
• High-quality, sulfur-containing foods—eggs or whey protein, garlic, onions
• Limonene in citrus peels, caraway, and dill oil
• Bioflavonoids in grapes, berries, and citrus fruits that promote Phase 1 enzymes
• Dandelion greens to help liver detoxification, improve the flow of bile, and increase urine flow
• Celery to increase the flow of urine and aid in detoxification
• Cilantro, which may help remove heavy metals
• Rosemary, which has carnosol, a potent booster of detoxification enzymes
• Curcuminoids (turmeric and curry) for their antioxidant and antiinflammatory action
• Chlorophyll in dark green leafy vegetables and in wheat grass
Lyon M et al: Clinical approaches to detoxification and biotransformation. In Jones DS, editor: Textbook of functional medicine, Institute for Functional Medicine, Gig Harbor, Washington, 2006.
Hyman M: Systems biology, toxins, obesity, and functional medicine in managing biotransformation: the metabolic, genomic, and detoxification balance points, The Proceedings from the 13th International Symposium of The Institute for Functional Medicine, Gig Harbor, Wash, 2006, Institute of Functional Medicine.
Adults who have no major health problems that would restrict food choices can benefit from guidance on meeting the recommendations of MyPlate and the DGA as a first step. This guidance is based on increasing the intake of fruits, vegetables (including legumes), grains (with emphasis on whole grains), and seeds and nuts—some of the same foods known to have components that go beyond the benefits associated with major nutrients. Most of these components that are considered dietary enhancers are associated with plant foods.
Phytochemicals or phytonutrients (from the Greek word phyto for plant) are biologically active and naturally occurring chemical components in plant foods. In plants phytochemicals act as natural defense systems for their host and offer protection against microbial invasions or infections. They also provide color, aroma, and flavor, with more than 2000 plant pigments identified (see Figure 20-2). These include flavonoids, anthocyanins, and carotenoids (see Chapter 4). There is even interest in resveratrol from grape juice and red wines. See Focus On: Alcohol: A Functional Food? As part of human consumption phytonutrients can have an anti-oxidant, detoxification, and anti-inflammatory functions in the body.
Focus On
Alcohol: A Functional Food?
There are some benefits to moderate intake of alcohol for specific population groups. The extent to which these benefits are related to lifestyle are unclear. There is evidence that increasing alcoholic beverage consumption is associated with a decline in total diet quality (Breslow, 2010). However, light to moderate intake of alcohol is associated with a lower risk for cardiovascular disease (CVD); these benefits appear to be independent of other CVD risk factors, including age, sex, smoking habits, and BMI. Women age 55 and older and men age 45 and older at risk for heart disease were in the groups most likely to benefit (USDHHS, 2006). In younger adults, the benefits may be offset by the increases in alcohol-related accidents.
Polyphenols in red wine (especially Pinot Noir) have protective effects. The question of energy intake by those who enjoy wine is a factor, and lifestyles are being explored. For example, in a Danish study of 3.5 million supermarket purchases, those who bought wine were also more likely to buy fruits, vegetables, olives, and low-fat cheeses than those who bought beer (Johansen et al., 2006). The high wine intake by the French, the “French paradox” and with Mediterranean diets has also shown benefits.
Based on the literature, the best advice may be to proceed cautiously. One should be the legal age to use alcohol; drink responsibly; enjoy it with a healthful meal; and be medically able to use alcohol based on health, life stage (no alcohol while pregnant or breast-feeding), and medications. Moderation is defined as one drink a day for women and up to two drinks per day for men. A drink is defined as 12 oz of regular beer, 5 oz of wine, or 1.5 oz of 80-proof distilled liquor.
Soy is another example of a food with value beyond quality protein. The health benefits of soy products or components of soy include reducing the risk for heart disease and certain types of cancer and reducing vasomotor symptoms (hot flashes) in menopausal females. Note that soy itself, as a plant, has no cholesterol and is a source of isoflavones, a phytoestrogen or plant estrogen. In 1999 the Food and Drug Administration (FDA) approved a food label claim for soy, addressing its potential role in reducing the risk of heart disease (Food and Drug Administration, 1999). To qualify, the food needs to have 6.25 g of soy protein in one serving; be low in fat (less than 3 g); be low in saturated fat (1 g or less) and cholesterol (less than 20 mg); and have no more than 480 mg of sodium for an individual food, 720 mg if an entrée, and 960 mg if a meal. In January 2006 the AHA released the results of a review of 22 randomized trials on the effect of soy protein with isoflavones on serum cholesterol (Sacks et al., 2006). The committee found that soy protein and isoflavones have not been shown to lessen vasomotor symptoms of menopause and show no significant effects on HDL cholesterol or triglyceride levels. This controversy illustrates the questions that arise when studying the use of food or food components at levels beyond what are consumed in a traditional diet (Maskarinec, 2005).
Foods that fit the FDA label claim for soy protein have a positive nutrition profile by virtue of the label requirements, and moderate amounts of soy foods can be part of a balanced diet even for cancer survivors (Maskarinec, 2005). The ACS concludes that cancer survivors may safely consume up to three servings daily (American Cancer Society, 2010). Soy can be used to displace animal protein and help lower intake of saturated fat, but soy is not recommended as a therapy to reduce LDL cholesterol or other cardiovascular risk factors (Lichtenstein et al., 2006). Whole soy foods continue to be a reasonable part of a diet with a role in both disease prevention and health promotion. (Messina, 2009).
One cannot address dietary guidance without considering the issues of both functional components and functional foods. Rather than isolating and promoting food components, current thinking supports the emphasis on food as a package and as a first source for nutrients and potential enhancers (Figure 20-2). In the big picture it is the person’s health status, lifestyle choices, and genetics that form his or her potential for wellness, but dietary enhancement is a tool that gains attention and helps the person move forward on the wellness continuum.
FIGURE 20-2 Phytochemicals in vegetables can have powerful anti-oxidant, detoxification, and anti-inflammatory functions in the body. (© 2011 Photos.com a division of Getty Images. All rights reserved.)
Clinical Scenario
Lee is a 35-year-old woman who lives in an urban neighborhood with her husband and 12-year-old daughter. She is 5 ft, 10 in tall and currently weighs 165 pounds. In the past 2 years she has gained 10 pounds. At a recent neighborhood health fair Lee’s blood glucose and blood pressure screening results were higher than they had been a year ago but were still in a good range. She has a family history of heart disease and diabetes and recognizes that her weight gain is an issue. Her grandmother recently died of colon cancer. Both she and her husband work full time, and blending their schedules with that of their daughter is hectic. Lee does all the cooking and shopping, although they eat out (fast food or take out) for most lunches and at least two dinners a week. They have no regular activity or exercise. They have minimum health insurance that requires a large copayment; thus they don’t have an ongoing health care routine.
Lee made an appointment with her health care source. She asked for some dietary counseling and was asked to bring a 1-day food recall for the registered dietitian. She reported the following: breakfast: egg and sausage on a bagel, coffee; mid-morning: low-fat snack bar from vending machine with coffee; lunch: double burger with cheese on a bun and large fries, diet soda; dinner: chicken and rice casserole, corn, lettuce salad with diet ranch dressing; evening: dish of ice cream.
Nutrition Diagnostic Statements
1. Physical inactivity related to lifestyle issues as evidenced by no regular physical activity and a 10-lb weight gain.
2. Undesirable food choices related to high fat and low fruit and vegetable intake as evidenced by diet history revealing high-fat foods at every meal and an average of one fruit or vegetable each day.
1. What lifestyle factors and nutrition triggers are likely to be identified by the dietitian?
2. What foods should Lee consider including in her diet to build a prevention-related meal plan?
3. Plan a meal pattern and two sample meals that illustrate your recommendations, including at least one at-home and away-from-home breakfast, lunch, and dinner.
https://aom3.americaonthemove.org/default.aspx
Centers for Disease Control and Prevention Health
http://www.cdc.gov/nchs/hdi.htm
Dietary Guidelines for Americans
http://www.dietaryguidelines.gov
Food and Agriculture Organization
http://www.healthypeople.gov/hp2020/Objectives/TopicAreas.aspx
U.S. Department of Agriculture: Agricultural Research Service
U.S. Department of Agriculture: MyPlate
References
American Cancer Society. Accessed March 2010 from www.cancer.org.
American Dietetic Association (ADA). Nutrition and you: trends 2008. Chicago: American Dietetic Association; 2008.
American Heart Association, American Stroke Association. A nation at risk: obesity in the United States. Stanford, Calif: Robert Wood Johnson Foundation; 2005.
Barrett-Connor, E, Laughlin, GA. Hormone therapy and coronary artery calcification in asymptomatic postmenopausal women: the Rancho Bernardo Study. Menopause. 2005;1(1):40.
Breslow, RA, et al. Alcoholic beverage consumption, nutrient intakes and diet quality in the US adult population, 1999-2006. J Am Diet Assoc. 2010;110:561.
Centers for Disease Control and Prevention (CDC). Chronic disease prevention and health promotion. http://www.cdc.gov/nccdphp/overview.htm, 2010. [Accessed 20 January 2010 from].
Centers for Disease Control and Prevention (CDC): Data 2010: The Healthy People 2010 database, 2006a. Accessed 1 April 2010.
Centers for Disease Control and Prevention (CDC). Health data interactive. http://www.cdc.gov/nchs/hdi.htm, 2009. [Accessed March 2010 from].
Centers for Disease Control and Prevention (CDC). Leading causes of death in females: United States. http://www.cdc.gov/women/lcod/, 2006. [Accessed March 2010 from].
Centers for Disease Control and Prevention (CDC). Leading causes of death in males: United States. http://www.cdc.gov/men/lcod/index.htm, 2006. [Accessed March 2010 from].
Centers for Disease Control and Prevention (CDC). National vital statistics report: deaths: final data for 2006. http://www.cdc.gov/nchs, 2009. [Accessed March 2010 from].
Craig, WJ, et al. Position of the American Dietetic Association: vegetarian diets. J Am Diet Assoc. 2009;109:1266.
Dornblaser, L. Trends in the food industry. Chicago: Food Marketing Institute (FMI) Trade Show; 2006.
Food Research and Action Center (FRAC). Hunger and poverty statistics: hunger in America. Accessed March 2010 from http://feedingamerica.org.
Food and Drug Administration (FDA). Qualified health claims: withdrawn soy protein and cancer. http://www.cfsan.fda.gov/~dms/lab-qhc.html, 1999. [Accessed 7 October 2005 from].
Harris Interactive Poll, Gullo K, eds. Healthcare news: Healthy eating messages appear to be resonating with consumers, according to new Harris interactive survey. Harris Interactive: Rochester, N.Y., 2006. Accessed 15 May 2007 from. http://www.harrisinteractive.com/news/allnewsbydate.asp?NewsID51039
Hasler, CM, et al. Position of the American Dietetic Association: functional foods. J Am Diet Assoc. 2009;109:739.
Institute of Medicine (IOM). Examination of front-of-package nutrition rating systems and symbols. Accessed March 2010 from http://www.iom.edu/Activities/Nutrition/NutritionSymbols.aspx.
Institute of Medicine (IOM), National Academy of Sciences (NAS). Dietary reference intake (DRI) series. Washington, DC: National Academies Press; 1998-2004.
International Food Information Council (IFIC). Background on functional foods, IFIC Foundations. Accessed 12 June 2010 from http://www.foodinsight.org/Resources/Detail.aspx?topic=Background_on_Functional_Foods.
International Food Information Council (IFIC). Food & health survey: consumer attitudes toward food, nutrition & health: a benchmark survey 2009. Washington, DC http://www.foodinsight.org/, 2009. [Accessed March 2010 from].
Johansen, D, et al. Food buying habits of people who buy wine or beer: cross sectional study. Br Med J. 2006;332:519.
Lichtenstein, AH, et al. Diet and lifestyle recommendations revision 2006: a scientific statement from the American Heart Association Nutrition Committee. Circulation. 2006;114:82.
Lloyd-Jones, DM, et al. Defining and setting national goals for cardiovascular health promotion and disease reduction. Circulation. 2010;121:586.
MacLennan, AH, et al. Hormone therapy, timing of initiation, and cognition in women older than 60 years: the REMEMBER pilot study. Menopause. 2006;13:28.
Marra, MV, Boyar, AP. Position of the American Dietetic Association: nutrient supplementation. J Am Diet Assoc. 2009;109:2073.
Maskarinec, G. Commentary: soy foods for breast cancer survivors and women at high risk for breast cancer. J Am Diet Assoc. 2005;105:10. [1524].
Maslow, A. Motivation and personality, ed 2. New York: Harper; 1970.
Messina, M, et al. Report on the 8th International Symposium on the Role of Soy in Health Promotion and Chronic Disease Prevention and Treatment. J Nutr. 2009;139:796S.
Miller, GD, et al. It is time for a positive approach to dietary guidance using nutrient density as a basic principle. J Nutr. 2009;139:1198.
National Center for Health Statistics (NCHS). Health, United States, 2004 with chart book on trends in the health of Americans. Hyattsville, Md: NCHS; 2009.
National Institutes of Health (NIH), Office of Dietary Supplements (ODS). Dietary supplement fact sheet: B6. http://ods.od.nih.gov/factsheets/vitaminb6.asp, 24 August 2007. [Accessed May 2010 from].
Sacks, F, et al, Soy protein, isoflavones, and cardiovascular health: an American Heart Association Science Advisory for Professionals from the Nutrition Committee. Circulation 2006;113:1034. Accessed 15 May 2006 from. http://www.circulationaha.org
Sandoval, DA, et al. The increasing risk of poverty across the American life course. Demography. 2009;46:717.
Sloan, AE, Top 10 functional food trends. Food Technol. 2006;60(4):22. Accessed 15 May 2006 from. www.ift.org
Stuebe, AM, et al. Duration of lactation and incidence of type 2 Diabetes. JAMA. 2005;294:2601.
Thompson, A. FDA working to replace misleading food labels, Live Science. Accessed March 2010 from http://www.livescience.com/health/food-labels-100314html.
U.S. Department of Agriculture (USDA), Economic Research Service (ERS). Food CPI and expenditures. Accessed March 2010 from http://www.ers.usda.gov/Briefing//CPIFoodANDEspenditures/.
U.S. Department of Health and Human Services (USDHHS). http://www.healthypeople.com, 2010
U.S. Department of Health and Human Services (USDHHS). Small steps: a web-based wellness program. http://www.smallstep.gov, April 2006. [Accessed 1 April 2006 from].
U.S. Department of Health and Human Services (USDHHS). Dietary Guidelines for Americans, 2010, ed 7. Washington, DC: U.S. Government Printing Office; December 2010.
Wellness Councils of America (WELCOA), The 7 benchmarks of success. Omaha, Nebr: WELCOA; 2009. Accessed March 2010 from. http://www.welcoa.org/
World Health Organization (WHO), Progress on health-related millennium development goals (MDGs). Copenhagen: WHO; May 2009. http://www.who.int/whosis/whostat/2009/en/index.html [accessed March, 2010].