Healthy Foods for Healthy Aging
The Case for Protein
Karen S. Kubena and W. Alex McIntosh, Texas A&M University, College Station, TX, Unites States
Abstract
Food choices that older adults make based on the 2015–2020 Dietary Guidelines for Americans (DGA) vary greatly by gender, education level, and race to some degree. Achieving healthy aging often means they must change their ideas about food selection. Encouraging the increased intake of milk and milk products and seafood is based on research that supports multiple benefits from the nutrients and, especially in the case of dairy, bioactive content of these products. Research supporting a high-protein intake for older adults includes preserving function and avoiding frailty and other diseases and emphasizes the need to reconsider the Recommended Dietary Allowance for protein. While cardiovascular and diabetes risk may be slightly increased in individuals, eggs are a wise food choice for older adults because of the high quality of their protein and the bioavailability of lutein and zeaxanthin. A high-protein Mediterranean diet would be a good choice. Healthy eating is one step toward helping older adults have their last years be more about life than about disease.
Keywords
Older adults; dietary guidelines; protein; eggs; dairy; Recommended Dietary Allowances; age appropriate food choices; changes in food habits; moral concerns about meat consumption; Mediterranean diet
Aging results in the accumulation of damage to cellular macromolecules, including DNA, protein, and lipids (Mathers, 2015). While life expectancy has increased consistently in Western societies over the past 200 years, the challenge is to ensure that the additional time in those extra years is free from frailty and chronic poor health (Kirkwood, 2008). Thus, discussion about what has been called the healthy aging phenotype is occurring, a concept defined as “the condition of being alive while having highly preserved functioning metabolic, hormonal, and neuroendocrine control systems at the organ, tissue, and molecular levels” (Franco et al., 2009). The phenotype also results in resilience that minimizes the risk of cardiovascular disease (CVD) and dementia (Kiefte-de Jong et al., 2014).
The human body’s expected life span is affected by the presence of specific genes and lifestyle characteristics that may decrease an individual’s risk of chronic disease. These characteristics include adequate dietary intake that promotes healthy body weight, routine physical activity, adequate sleep, the avoidance of excess stress, and limited exposure to toxins (e.g., by smoking and alcohol). All of these affect chromosomes and likely long-term health (Passarino et al., 2016).
An active area of research involves dietary restriction as a means of increasing life span. Initially only targeting calorie restriction, research has now migrated to the modification of macronutrients. While too early to apply to current older adults, investigations into dietary balance as related to energy-sensing and nutrient-sensing signaling pathways may yield recommendations for modification of macronutrient intake (carbohydrate, protein, and fat) that can lengthen life span and improve health significantly (Fontana and Partridge, 2015). Santos et al. (2016) reviewed studies that suggest that altering proportions of protein and carbohydrate could result in significant changes in life span and perhaps decreased cancer development. Some data indicate that plant as compared to animal protein may be beneficial in suppressing the function of these signaling pathways and thus slow aging and the development of disease—hypertension, for example—while dietary fat seems to have no effect on the pathways (Santos et al., 2016). From a different perspective, Levine et al. (2014), reported that protein intake, either low or primarily of plant origin, was associated with reduced mortality in humans 50–65 years old and related to a reduction in growth hormone (insulin-like growth factor 1), while high protein intake by those 65 years and older reduced mortality (Levine et al., 2014).
A variety of nutrient modifications and, more recently, dietary patterns have been suggested to help individuals achieve the goal of healthy aging. Recommendations about dietary intake come from the federal government, health and professional organizations, and so on. Here we discuss two major federal sources that have focused on promoting Americans’ overall health: Dietary Reference Intakes (DRIs) and Dietary Guidelines for Americans (DGA). We follow with a discussion on nutrients and foods, especially those of particular importance to the health of older adults, i.e., protein and protein-containing foods—and finally the what and why of good food choices. A word about the Mediterranean diet is also in order because this is a tried and true approach to healthy eating.
Recommendations: An Instruction Manual for Eating to Achieve Healthy Aging
Dietary Reference Intakes
Recommendations for energy and nutrient intake for adults in the United States come from the DRIs and now the 2015–2020 DGA (the most recent edition). DRIs are the result of extensive reviews of data from studies on the minimum amount of nutrients needed to prevent deficiencies in nearly all healthy people of the respective gender and age group (Science, 2006). Each DRI is thus composed of several recommendations, including the Estimated Average Requirement (EAR), which estimates the needs of 50% of the population; Recommended Dietary Allowances (RDA), which estimates the needs of the mean plus two standard deviations or 97.5% of the population; Adequate Intakes (AI), which sets a recommended amount of intake although there is inadequate information to set an RDA; and the Tolerable Upper Intake Level, which is the highest level of daily intake of a nutrient not associated with adverse health effects.
Identifying the level of nutrient that meets the needs of healthy people in age-gender groups requires acceptance of the basis for these decisions by scientists, health professionals, and policy makers who use these resources. Protein is an example of a nutrient for which the RDA is the subject of much debate. Not only is the method of determining protein needs being scrutinized but so is the widespread acceptance of the RDA as the optimal level of protein. Wolfe and Miller questioned the use of nitrogen balance to determine protein needs since no physiologically relevant end point is measured (Wolfe and Miller, 2008). When less protein is consumed, the body adapts to conserve body protein, potentially resulting in less nitrogen excretion. The actual situation thus could be a gradual loss of lean body mass not detected by nitrogen balance (Volpi et al., 2013). In the original nitrogen balance studies for development of the protein RDA in 1943, almost all data came from college-aged men; no consideration was given to the increased needs of subgroups such as older adults (Wolfe and Miller, 2008). These researchers indicated that the RDA defines the level of protein required to avoid a deficiency, thus actually leading to a loss of body protein. That is not consistent with the customary concept of the RDA as the appropriate and often now recommended maximum intake of protein.
Within the DRI document is a discussion of acceptable macronutrient distribution range (AMDR) (National Academy of Sciences, 2005a). This concept addresses the question about division of calories among macronutrients because total calories from recommended levels of fat plus carbohydrate and protein totals only about one-third of the total energy recommended. As a component of discussion of the use of the DRIs for diet planning, a table is provided that indicates an appropriate range for dietary intake of macronutrients with the example of a 2000-kcal diet. The range of percentage of energy as protein is 10–35%, according to the AMDR. The calculation of dietary protein as a proportion of energy intake, using daily energy utilization for a 19-year-old sedentary man (76 kg and 1.76 m tall) was reported by Wolfe and Miller (2008). According to the DRI discussion of energy needs, the value in this case would be 37.8 kcal/kg/day. The range of protein intake for this man was then computed to be 0.95–3.3 g/kg or 10% and 35% kcal, respectively. The RDA of 0.8 g/kg is below even the lowest level of this range (National Academy of Sciences, 2005b; Wolfe and Miller, 2008).
Data from the National Health and Nutrition Examination Survey (NHANES) of 2001–10 of people 19 and older (n = 23,876) provided information on usual dietary intakes and the variables related to protein metabolism and dietary intake (Pasiakos et al., 2015). The average intake varied from 0.69 g/kg to 1.51 g/kg body weight, although the recommended level (RDA) is 0.8 g/kg. In all deciles, body mass index (BMI) and waist circumference, the latter a measure of abdominal obesity and a risk factor for CVD, were inversely related while the high-density lipoprotein (HDL) cholesterol level was directly related to protein intake. This is consistent with many other studies but contrary to recommendations from agencies and investigators who suggest that higher protein intake presents a risk for cardiometabolic health.
The Dietary Guidelines for Americans, 2015–2020
The 1990 National Nutrition Monitoring and Related Research Act requires release of a report providing information and guidelines about nutrition and diet for the general public every 5 years. The report, Dietary Guidelines for Americans, is a joint effort by the US Departments of Health and Human Services and Agriculture (Agriculture, 2015) and is based on previous guidelines and current research. The report is used to guide professionals and consumers in diet planning, to formulate health policies and programs at the federal level, and to guide nutrition education in federal education programs.
Another resource, one written to assist the formulation of the 2015–2020 DGA, is the Scientific Report of the 2015 Dietary Guidelines Advisory Committee (Committee, 2015). Within the report is a list of shortfall nutrients, those present at inadequate levels in the diets of a large number of people and dietary components that are overconsumed, i.e., sodium and saturated fats in particular. The 2015 scientific report also defines a healthy diet as one that includes among other things, low-fat and nonfat dairy. A diet also should include less red and processed meats. Concern has been expressed that adoption of the recommendations could adversely affect the intake of important nutrients in an effort to achieve the standard for dietary components such as type of dietary fat (Phillips et al., 2015).
The shortfall nutrients identified in the 2015 scientific report include vitamins A and D, calcium, magnesium, and potassium plus iron in some subgroups. Several of these nutrients are present in animal-source foods in highly bioavailable forms. The new dietary guidelines encourage the intake of many highly nutritious foods, including vegetables, fruits (especially whole fruits), and grains (at least half of which are whole grains), plus some animal proteins. This group includes fat-free or low-fat dairy, including milk, yogurt, and cheese and with the option to substitute soy beverages. Also, a variety of protein foods are recommended, including seafood, lean meats and poultry, and eggs. Again, plant-based foods are offered as options—in particular, nuts, seeds, and soy products.
For a variety of reasons, not the least of which is an interest in health, many people in developed countries have changed their attitudes about foods and their healthfulness and have adopted some level of vegetarianism from nonmeat eater to vegan. Consequently, consumption of some high-nutrient animal-source foods has decreased, including milk and dairy products, meat, poultry, fish, and eggs. Unfortunately, the foods chosen from the ever-changing array of food products may be nutrient dense, although the potential exists that substitutes also could be less nutrient dense and more energy dense. The FDA defined nutrient density as the amount of beneficial nutrients relative to a food’s energy content (Drewnowski, 2005). The value of vegetables, fruits, whole grains, and many other plant-based foods for nutrition and health is not in question, but for those who eat animal-source foods, including appropriate milk and milk products, eggs, fish, poultry, and lean meat can promote nutritional adequacy, particularly with these short-fall nutrients. Aging adults who have consumed animal-source protein foods for many years may not be well served by being encouraged to abandon some of these foods in favor of plant-based foods, from which they could choose breads and desserts.
A 2014 report of trends in the dietary intake of older Americans using the NHANES data revealed that the primary source of energy for this age group, which had been red meat in the 1977–78 study, had been replaced in the 2005–10 NHANES report by breads followed by grain desserts, fruit, milk, and dairy desserts (Johnston et al., 2014). Absent in this ranking are nutritious plant-source foods such as vegetables and legumes and nutritious animal-source foods such as eggs, poultry, fish, and lean meat.
Table 29.1 includes the recommendations for inclusion of food groups by energy level for males and females (sedentary 51+years): 2000 kcal and 1600 kcal, respectively.
Table 29.1
Recommended Amounts of Foods by Day or Week in the 2015–2020 Dietary Guidelines for Americans for Adults Age 51+and Sedentarya
| Food Group | Female: 1600 kcalb | Male: 2000 kcal | Frequency |
| Vegetables (c-eq)c | 2 | 2.5 | Daily |
| Dark green | 1.5 | 1.5 | Weekly |
| Red and orange | 4 | 5.5 | Weekly |
| Legumes | 1 | 1.5 | Weekly |
| Starchy vegetables | 4 | 5 | Weekly |
| Other vegetables | 3.5 | 4 | Weekly |
| Fruits (c-eq) | 1.5 | 2 | Daily |
| Grains (oz-eq) | 5 | 6 | Daily |
| Whole grains | 3 | 3 | Weekly |
| Refined grains | 2 | 3 | Weekly |
| Dairy (c-eq) | 3 | 3 | Daily |
| Protein foods (oz-eq) | 5 | 5.5 | Daily |
| Seafood | 8 | 8 | Weekly |
| Meats, poultry, eggs | 23 | 26 | Weekly |
| Nuts, seeds, soy products | 4 | 5 | Weekly |
| Oils (g) | 22 | 27 | Daily |
| Other (kcal) | 130 | 270 | Daily |
aAppendix 3. USDA Food Patterns: Healthy U.S.-Style Eating Pattern (Agriculture, 2015).
bAppendix 7. Nutritional Goals for Age-Sex Groups Based on Dietary Reference Intakes and Dietary Guidelines Recommendations (Agriculture, 2015).
cAbbreviations: c–eq, cup equivalent; oz-eq, ounce equivalent.
Dietary Protein: The Foundation of a Healthy Body and Healthy Aging
All Proteins Are Not Created Equal
Dietary proteins vary not only in the quantities of amino acids in them but also which ones are included. Essential or indispensable amino acids are those that cannot be synthesized in the body at the level needed to sustain normal function; dispensable amino acids are produced in quantities as needed from fats, carbohydrates, or other amino acids. Evaluation of protein quality is based on the presence of essential amino acids and the balance between them, as well as on digestibility. Dietary proteins vary markedly in amino acid composition but also in the presence or absence of compounds such as matrix components, including fiber and antinutritional factors such as trypsin inhibitor, which usually decreases the use of amino acids (Gilani et al., 2005; Schaafsma, 2005).
Identifying the most appropriate scoring method for proteins is an ongoing project since no system has yet been universally accepted. One system under consideration is the Protein Digestibility-Corrected Amino Acid Score (PDCAAS), which includes an evaluation of amino acid composition and digestibility. However, it does not correct for the presence of antinutritional factors, and scoring (0–1.0) is truncated at 1.0 (Millward et al., 2008). Another system that has been used for many years is the protein efficiency ratio (PER), which is based on animal growth. Protein quality rankings for some foods by these two systems follow (food, PER, and PDCAAS): egg =3.9, 1.00; beef =3.9, 0.92; milk =2.5, 1.00; soy protein =2.2, 1.00; peanuts =1.8, 0.52; black beans =n/a, 0.75; and wheat gluten =0.8, 0.25 (Hoffman and Falvo, 2004). As these data indicate, animal proteins are generally categorized as higher quality than plant proteins. Soy protein is an exception and is considered to be a good-quality protein. Complementation of proteins, which vegans routinely do and formulators of animal feeds do when designing grains for animals, can improve a mixture’s protein quality. Pencharz et al. expressed concern about this option for older adults since a higher intake of complementary proteins is required to provide needed essential amino acids compared to the amount needed from animal protein (Pencharz et al., 2016). Sarcopenia (the loss of lean body mass) and obesity are both concerns for older adults.
How Much Is Enough?
In 1943, requirements for protein by nonpregnant nonlactating healthy adults were determined to be 0.8 g/kg body weight; the requirements had the goal of helping troops in World War II meet the nutritional needs of a fighting force (Wolfe, 2015; Wolfe and Miller, 2008). Protein intake by older adults from NHANES 2003–2004 as reported by Fulgoni was below the RDA level (0.8 g/kg) by 10–25% with 5–9% below the EAR for protein (0.66 g/kg) (Fulgoni, 2008). The body adapts to a change in homeostasis—in this case, low protein intake—by decreasing the metabolism of protein so that the level of nitrogen excretion also decreases. In nitrogen balance, if less nitrogen is excreted when less nitrogen is ingested, nitrogen balance data could be interpreted as being closer to normal than what actually occurs (Volpi et al., 2013). Other concerns about the use of nitrogen balance to determine protein needs expressed by Pencharz et al. include the need for at least 3 days of data and a 7- to 10-day adaptation period between tests of levels of intake (Pencharz et al., 2016). Complete collection and analysis of nitrogen excretion (primarily urine and feces) is a challenge. Finally, calculating nitrogen balance is associated with wide variability because of large numbers for nitrogen intake and nitrogen excretion but small differences between them (nitrogen balance) (Pencharz et al., 2016).
Recent investigations of older adults’ protein needs were conducted with the method now recommended by the Institute of Medicine: indicator amino acid oxidation (IAAO). Utilization of amino acids as measured with the use of stable isotopes is a noninvasive and fairly rapid method with short adaptation between tests (Pencharz et al., 2016). Use of the IAAO to determine protein needs in men 65 and older resulted in an estimated EAR and RDA of 0.94 g/kg/day and 1.24 g/kg/day, respectively (Rafii et al., 2016). The authors concluded that both the current EAR and RDA were underestimated by 30%. These results mimic those of a previous investigation in women 65 and older (Rafii et al., 2015). In that study, the EAR and RDA were found to be 0.96 and 1.29 g/kg/day, about 30–40% higher than the current recommendations.
Evidence of benefits to older adults from higher protein intake has been reported in many areas. Frailty is a clinical syndrome that involves unintentional loss of lean body mass (10 lb/year), which leads to low grip strength, slow walking, exhaustion, and low physical activity (Fried et al., 2001). The presence of the syndrome in a cohort study of 1822 individuals 60 and older was found to be inversely related to dietary intake of total protein, animal protein, and monounsaturated fatty acids (Sandoval-Insausti et al., 2016). A 3-year observation of lean mass in older adults concluded that lower protein intake was associated with large losses of lean body mass (Houston et al., 2008). A case-control study of healthy elderly individuals revealed unhealthy weight loss in subjects with low protein intake (<0.8 g/kg) in comparison to those with a high protein intake (>1.2 g/kg) (Gray-Donald et al., 2014). In another report, supplemental protein provided to elderly people six times a day on a weight-loss diet resulted in higher lean body mass and decreased abdominal fat than those on a more traditional protein level (Arciero et al., 2013).
Myofibrillar protein synthesis in the healthy elderly has been reported to require a higher protein-synthesis response to dietary protein in comparison to younger men (Moore, 2014). Wall et al. suggested that aging results in muscle anabolic inflexibility, a key factor in the development of sarcopenia (Wall et al., 2015). Loss of lean body mass during weight loss while fat mass is essentially maintained is called sarcopenic obesity. Research indicates that decreased muscle mass results in loss of muscle strength (sarcopenia) and is significantly related to increased mortality (Li and Heber, 2012; Reginster et al., 2016). Treatment of this type of obesity requires exercise (preferably resistance), modest energy restriction, and protein supplementation (Han et al., 2011).
NHANES data from 2011 to 2012 illustrate that the prevalence of obesity in people 60 and older is 35.4% (BMI > 30) (Ogden et al., 2014). Obesity is a concern in older adults, one that increases risk of developing and worsening chronic diseases such as type 2 diabetes, hypertension, heart failure, and physical disability (Han et al., 2011). Recommendations to reduce body weight modestly (5–10 kg) have been shown to be effective in controlling these problems but not necessarily as much as in younger groups (Han et al., 2011). Consequently, the use of waist circumference rather than only BMI is recommended to assess the prevalence of adipocytes of visceral abdominal fat, adipokines from which are more likely to be related to inflammation, insulin insensitivity, and so on (Ouchi et al., 2011).
Concerns about older individuals’ increased dietary protein involved previous reports that high protein intake even with calcium supplementation was associated with increased urinary calcium, a concern for bone mineral density (BMD). However, BMD and bone strength were not measured in these studies. Zhu et al. provided a high-protein (30 g whey) or placebo drink (2.1 g protein) and 600 mg calcium to healthy women 70–80 years of age for 2 years (Zhu et al., 2011). Urinary calcium was slightly higher in the whey group, but volumetric BMD and femoral neck strength were not significantly different at the end of the study. High protein intake has been reported to increase calcium absorption with possible long-term effects on bone (Tang et al., 2014).
Other changes in nutrient utilization occur with aging. For instance, requirements for vitamin D increase in older adults because of a potential decreased ability to form vitamin D3 with ultraviolet B light or hydroxylate vitamin D to its hormonal form (Holick, 2014). Also, impaired intestinal absorption related to less secretion of the intrinsic factor required for vitamin B12 absorption due to achlorhydria suggests an increased need for this nutrient (Allen, 2009). Since less energy is used by the body for normal function due to a loss of lean body mass (decrease of as much as 50% by ages 75–80) and there is lower physical activity, nutrient density is a major concern (Kalyani et al., 2014). Therefore, food choice is important; and functional foods work.
Milk: A Natural Functional Food for a Strong and Healthy Body
Because of the extraordinary food human infants receive right after birth, which includes all of the nutrients they need and a plethora of bioactive substances to help them safely grow, it is not a surprise that even after heat treatment, milk for calves is quite excellent for humans as well.
Part of the Scientific Report for the Dietary Guidelines Dietary Advisory Committee focused on nutrient intake in less than needed levels for a significant component of the population of the United States (Committee, 2015). These were called shortfall nutrients because of underconsumption in comparison to the EAR, which meets the needs of 50% of the US population. Of the eight nutrients categorized as shortfall, dairy is considered an important food source for five of them. Each food group included in the dietary guidelines was evaluated to assess its contribution of nutrients and energy across all calorie levels (Appendix E-3.2 Table 29.1 (Committee, 2015)). Information on dairy intake is not specific for older adults; however, data over all calorie levels indicate that dairy foods provide the following nutrients (% EAR): calcium =67%, vitamin D =64%, potassium =21%, magnesium =17%, and vitamin A =32%. A total of 28% of recommended high-quality protein (PER 2.5, PDCAAS 1.0) is provided as well.
Bioactive peptides in milk include calcium, vitamin D, casein, whey, metabolites of milk proteins, and many more that are still being identified. The most active seems to be whey protein, which increases satiety and controls appetite in part by increasing the secretion of anorectic hormones cholecystokinin, leptin, and glucagon-like-peptide 1 and by decreasing the orexigenic hormone ghrelin (Sousa et al., 2012). In addition, whey apparently has a beneficial effect on glucose metabolism in diabetics and obese patients, weight reduction, and maintenance of muscle mass. Levels of cerebral glutathione were observed to increase in older adults as dairy intake increased. This antioxidant is vital for the brain’s capacity to scavenge reactive oxygen species (ROS) and free radicals in oxidative stress (Choi et al., 2015).
Fermented dairy products, cheese, and yogurt have a record of reducing the risk of diabetes while transpalmitoleic acid, a fatty acid in milk, might also be involved (Visioli and Strata, 2014). Tripeptides formed from the action of the microbiota on milk protein have angiotensin-converting enzyme (ACE)-inhibiting activity. ACE inhibitors are potent antihypertensive medications (Phelan and Kerins, 2011). Investigations focusing on cheese illustrated reductions of triglyceride and increased HDL cholesterol. Favorable effects may come from metabolism by the microbiota of indigestible carbohydrates in cheese and other substances found in cheese that resulted in different effects on lipid metabolism of cheese as compared to butter, another high-fat dairy food (Visioli and Strata, 2014). Zjeng et al. suggested that products of microbial metabolism and increased fecal fat output related to cheese intake might play a role in the French paradox (Zheng et al., 2015). Bioactive peptides from milk have been shown to positively affect several aspects of the metabolic syndrome (Ricci-Cabello et al., 2012).
Interest in inflammation as a factor in chronic disease is increasing along with evidence that milk’s bioactivity prevents inflammation (Da Silva and Rudkowska, 2015). Suppression of inflammatory markers, including tumor necrosis factor alpha and interleukin 6, and the downregulation of gene encoding for proinflammatory cytokines has been linked to the intake of dairy products with potential roles for naturally occurring trans fatty acids, milk proteins, and minerals (Kim et al., 2013; McGregor and Poppitt, 2013; Siriwardhana et al., 2013). The recommendation that older adults include two cups of low-fat or fat-free milk each day is beneficial in spite of evidence that high-fat dairy may be more effective than low-fat dairy (Zheng et al., 2015).
Lactose intolerance occurs with a deficiency of the enzyme lactase with symptoms following lactose (the primary carbohydrate in milk) ingestion. The importance of dairy as previously outlined indicates that management of the symptoms rather than avoidance of lactose is needed. Blinded studies illustrated that almost all patients with self-reported lactose intolerance can ingest at least 12 g lactose (one cup milk) without symptoms if taken with other food (Deng et al., 2015). Lactase supplements and low-lactose milk and dairy products if needed usually are effective.
Eggs: A Nutritious Food with Big Health Benefits
Visual impairment with potential blindness is most often related to cataracts (51%), glaucoma (8%), and age-related macular degeneration (AMD) (5%) (Abdel-Aal et al., 2013; Poh et al., 2016). Considered to be partly an oxidative process, AMD was the focus of investigations on slowing the disease’s progression through dietary components (Age-Related Eye Disease Study (AREDS) and Age-Related Eye Disease Study 2 (AREDS 2)) (Broadhead et al., 2015). Evidence was encouraging and resulted in the development of supplements using the study formulations. The AREDS 2 formula replaces beta-carotene (risk of lung cancer in smokers) with the antioxidants eicosapentaneoic acid (EPA) and docosahexaenoic acid (DHA) and the carotenoids lutein and xeazanthin. The latter substances have been identified as being beneficial because of their involvement in the formation of the macular membrane, which protects the eye from ROS damage associated with macular degeneration and cataracts (Blesso et al., 2013b; Meagher et al., 2013).
While dietary intake of eggs was discouraged for decades, that philosophy is slowly changing. Egg consumption has been shown to be associated with an increase in HDL cholesterol and larger HDL cholesterol particles (Fernandez, 2010). Since HDL transports lutein and zeaxanthin to the retina of the eye, higher HDL levels means more of these antioxidants can be delivered to the macula (Blesso, 2013b). The egg yolk content of lutein and zeaxanthin was found to be 292 mcg/g and 213 mcg/g, respectively (Handelman et al., 1999), and the bioavailability of zeaxanthin was shown to be higher from eggs than from other foods (Thurnham, 2007). Data from the NHANES 2003–2004 indicate that dietary intake of lutein and zeaxanthin by adults 71 and older was approximately 1000 mcg/day and 107 mcg/day, respectively (Johnson et al., 2010). The Institute of Medicine’s Panel on Dietary Antioxidants and Related Compounds, Food and Nutrition Board, stated that data were not available to allow development of recommended intakes of lutein and zeaxanthin (National Academy of Sciences, 2000).
The relationship between dietary intake and coronary artery disease (CAD) was identified through studies that began in the 1940s and included the Seven Countries Study led by Ancel Keyes. Initial findings implicated the effect of saturated fat on total serum cholesterol in cohorts in the United States, Japan, and five European countries (Willett, 2006). From feeding trials conducted by Keyes and others, along with another large prospective study in Framingham, Massachusetts, evidence of the beneficial effect of polyunsaturated fat emerged, resulting in early recommendations to reduce saturated fat, including eggs, and increase polyunsaturated fat in the diet. Evidence from a vast amount of subsequent research on diet and CAD over the last 60 years explained many of the complexities of lipid metabolism and thus the impact of dietary factors on development of CAD. A Harvard egg study was a massive prospective investigation using 118,000 subjects from the Health Professional Follow-Up Study (1986–94) and the Nurses’ Health Study (1980–94) (Hu et al., 1999). The frequency of egg consumption (<1/week to >1/day) was evaluated with the development of cardiac events (myocardial infarction, fatal coronary heart disease, and stroke). Results of the study indicated that consumption of as much as 1 egg/day was not related to increased risk of occurrence of cardiac events, although some concern existed about the response of diabetic subjects (Hu et al., 1999). Concern about the response of diabetic or glucose intolerant subjects continues. Studies continue to reveal that egg consumption by nondiabetics is not related to increased cardiovascular risk and may lower risk. Once again, diabetics have some additional risk and should use eggs with caution (Li et al., 2013; Rong et al., 2013; Shin et al., 2013; Tran et al., 2014). Egg consumption results in increased LDL levels for most people, although two good outcomes continue to be reported—increases in LDL particle size and HDL levels increase. Also, the ratio between LDLs and HDLs is unchanged, so the end result is a less atherogenic profile (Blesso et al., 2013a; Herron et al., 2004).
Egg is a source of the highest-quality protein and the shortfall nutrients vitamin D and vitamin A. In addition, vitamin E, riboflavin, and vitamin B12 are provided. Cholesterol content is 186 mg/egg (USDA ARS Beltsville Human Nutrition Research Center, 2012), but concern about direct associations between cholesterol in foods and CVD has decreased. The list of dietary components about which there is concern about overconsumption in the Scientific Report for the 2015 Dietary Guidelines for Americans (Committee, 2015) does not include cholesterol. Recent studies of egg consumption as related to chronic disease resulted in the conclusion that egg consumption of less than two per day by older men was associated with a reduced risk of type 2 diabetes (Djousse et al., 2016; Virtanen et al., 2015). Griffin stated that consensus has been achieved that a relatively small effect of dietary cholesterol, primarily from eggs, on LDL cholesterol and the risk of CVD exists in comparison to other diet and lifestyle factors (Griffin, 2016).
One key recommendation for Healthy Eating Patterns in Chapter 1 of the 2015–2020 Dietary Guidelines for Americans states, “A healthy eating pattern includes: A variety of protein foods, including seafood, lean meats and poultry, eggs, legumes (beans and peas), and nuts, seeds, and soy products.” Recommendations to include eggs in the diet as shown in Table 29.1 is as a part of the protein foods group and a total of 23 and 26 ounce-equivalents (oz-eq)/week for females and males, respectively. That converts to a daily recommendation of 3.3 and 3.7 oz-eq/day for females and males, respectively, for meat, poultry, and eggs (1 egg =1 oz-eq). Based on research, eggs should be a part of the diet of nondiabetic older adults, especially in consideration of AMD.
Eggs are a valuable resource for feeding hungry people. Research will provide the answers to a few unanswered questions.
Seafood: Powerful Help for Healthy Aging
The recommendation for inclusion of seafood in the diet (see Table 29.1) is the equivalent of eight ounces per week for older females and males. Such strong support for seafood intake comes from the research base that is particularly applicable to older adults. Nutritional composition of fish in general includes high-quality protein and significant amounts of two shortfall nutrients, vitamins D and B12. However, the most famous attribute of fish these days, especially high-fat fish, is the fatty acid content.
Marine oils docosahexanoic (22:6n-3) and eicosapentanoic (20:5n-3), generally from fish from northern waters (plus catfish), are considered to be highly beneficial for human health from pregnancy through old age. Research reports support their role in preventing CVD, including decreased triglycerides, platelet aggregation, inflammation, and oxidative stress (Mozaffarian and Wu, 2012). Also, the particle sizes for both LDL cholesterol and HDL cholesterol were reported to increase with DHA, a positive change in these lipoproteins; and the fatty acids have been known for some time to be effective for arrhythmias. Nevertheless, a high-fish diet for 8 weeks by older Australians did not positively impact inflammatory cytokines, blood pressure, or lipids (Grieger et al., 2014). Two studies, one in Greece and the other in countries in the Americas, China, and India, were conducted to assess relationships between fish intake and depression (Albanese et al., 2012; Bountziouka et al., 2009). Results from the first observational study of 1190 people were so positive that the authors were suggesting causation, while the 15,122 subjects in the second study were studied for different types of depression and showed varying results, depending on several variables, not the least of which was country. However, in response to early research, DHA was added quickly to preterm infant formulas to promote neural development (Richard et al., 2016). Further evidence of the involvement of fish oils in brain function comes from studies of cognitive decline in older adults such as the study by Qin et al. (2014). The prospective cohort study of 1566 adults 55 and older continued for 5.3 years and revealed a relationship between fish consumption and slowing cognitive change as well as a positive effect on memory in those 65 and older.
BMD of the hip as related to the intake of fish and polyunsaturated fatty acids (PUFAs) was studied in older adults in the Framingham Osteoporosis Study over a 4-year period. Hip bone density was maintained in those who had higher fish intakes (Harris et al., 2015). Fracture risks in early life, midlife, and later life were related to fish and PUFA intake differently in men and women and were positively associated with lower risk later in life in men and in midlife in women. Choi and Park (2016) observed that consumption of seafood was associated with less risk of osteoporosis in Koreans but not in Americans, perhaps because the Koreans ate four to five times as much fish as the Americans.
The effectiveness of DHA and EPA on cardiovascular risk, cognitive function, and bone health suggests that older adults should strictly adhere to the recommendation for seafood.
Meat and Poultry: A Juicy Issue
Keep It Lean and Keep It Fresh, Not Processed
The DGA recommendation for lean meat and poultry is combined with eggs to total 3.3 and 3.7 oz-eq/day for females and males, respectively, plus 1 and 1.5 c-eq for legumes (total 4.3 and 4.7 oz/c-eq). Nutritional contribution of meat for older adults includes high-quality protein (Wyness, 2015). Asp et al. (2012), demonstrated that consumption of moderate amounts of lean beef was positively associated with muscle mass in a group of older adults. The fatty acid content of meats varies by species, breed, age, and type of feed, among other factors. About half of saturated fatty acids is stearic acid, which is quickly converted in the liver to oleic acid, a monounsaturated fatty acid, which has a neutral if not positive effect on total and LDL cholesterol. Micronutrients in beef include iron, mostly in the heme form, which is far more absorbable (20–30%) than nonheme iron (5–15%) but usually not a concern for older adults. Vitamin B12, a shortfall nutrient, is present in significant amounts (Wyness, 2015). Bioactive peptides make up another component of meat and include peptides that are antihypertensive (ACE inhibition), antithrombotic, or antioxidant (Huang et al., 2013).
Using the Women’s Health Study data, Song et al. (2004) found that women who consumed greater amounts of total red meat in 1993, especially processed meat, tended to be diagnosed with type 2 diabetes 8.8 years later. A review of the relationship between the intake of red and processed meat and the risk of coronary heart disease was reported by Micha et al. (2010). Red meat consumption was not associated with the presence of these cardiometabolic problems, but the intake of processed meat resulted in an increased risk of coronary heart disease and type 2 diabetes. Differences could be related to the high sodium or nitrate content of processed forms (Micha et al., 2010). A meta-analysis of randomized controlled trials on the influence of beef, poultry, and fish on lipoprotein levels conducted between 1950 and 2010 reported no significant differences (Maki et al., 2012). Two large prospective cohort studies in Shanghai investigated differences in total and cause-specific mortality. Red meat intake (95% pork) as compared to poultry was related to both higher total mortality and risk of ischemic heart disease mortality in men but not in women (Takata et al., 2014).
Meat intake, particularly beef, has been associated with health benefits but also risks. Bradlee et al. (2014) reported that the inclusion of lean beef in the diet of adolescent girls was associated with a slight reduction in LDL cholesterol (Bradlee et al., 2014). A 2012 randomized control trial compared the effect of 141 g red meat/day as compared to 28 g/day (DASH diet) on lipoprotein metabolism (Roussell et al., 2012). Total cholesterol and LDL cholesterol were reduced to the same degree in both diets. Using blood lipids and food-intake data, researchers found that beef intake had a negative relationship with total cholesterol and HDL cholesterol but was not related to LDL cholesterol or triglycerides (Asp et al., 2012). Intake of red meat was associated with an increased hazard ratio (HR) for stroke in the prospective cohort study, the Atherosclerosis Risk in Communities Study (quartiles of red meat intake and HR follow: 1.13, 1.44, 1.33, and 1.47) (Haring et al., 2015).
Recently, concerns have been expressed about the association of red meat with the development of cancer. The relationship between red meat intake and the risk of colorectal cancer (CRC) was evaluated with a pooled analysis of 11 studies (Ananthakrishnan et al., 2015). Results indicated that high use of red meat was associated with increased risk of CRC from retrospective case-control studies. A meta-analysis of prospective cohort studies with risk assessments of all-cause, cardiovascular, and cancer mortality by red or processed meat intakes was performed (Wang et al., 2016). Results indicated that higher consumptions of total red and processed meat were related to increased risks of total, cardiovascular, and cancer mortality. Carr et al. (2016) performed a systematic review of prospective studies on associations between red meat subtypes and the risk of CRC that reported risk estimates with colorectal, colon, or rectal cancer or the risk of colorectal adenoma (Carr et al., 2016). Beef consumption was positively associated with an increased risk of CRC and colon cancer, and lamb was associated with a higher risk of CRC. Questions existed about the pork studies, but no association with cancer was found for poultry.
Poultry has also been shown to contain bioactive peptides just like beef and pork (Haring et al., 2015; Huang et al., 2013). Little information is available on the health effects of poultry, although a study of longitudinal changes in BMI related to changes in meat consumption included a significant trend toward decreased BMI in those with the highest intake of chicken as compared to the lowest (Gilsing et al., 2012). Poultry without skin has been designated as a nutrient-dense food by the 2005 DGA (Nicklas et al., 2014). Results suggest that lean red meat and poultry are high-nutrient protein sources that can be included in a healthy diet. As far as processed meats go, the advice is to “cut the baloney.”
Food Choices for the Elderly: Are These Good for Healthy Aging?
Food intake by individuals varies with gender, education, age, and other sociodemographic characteristics. Using data from the 2005–2006 NHANES study, Berner et al. examined the intake of animal protein by animal source by age group and gender (Berner et al., 2013). Beginning with the total percentage of protein from animal sources by women, those between the ages of 51 and 70 got 63.8% of their protein from animal sources, and those older than 70 got 60.7%. The percentages for men in these two age groups were 66.9% and 62.3%, respectively. The authors observed that overall protein consumption appears to have declined since 1988–91. Males and females in the Berner et al., study ate greater amounts of protein foods at dinner time; more than 65% of this protein came from animals (Berner et al., 2013). Red meats served as the greatest source of animal protein for both age groups for men; for women, the greatest source, again regardless of age group, was dairy products. Fish contributed between 4.1% of protein for men 71 and older and 5.9% for women 51–70; eggs accounted for 3.8% of protein for women 71 and older and 5.5% for men 71 and older. A similar study using 2002–2003 NHANES data focused on differences in “dietary adequacy components” (e.g., milk) and “dietary moderation components” (e.g., saturated fat) based on the Healthy Eating Index (Hiza et al., 2013). Those 75 and older had diets that were more adequate in terms of milk; they tended to consume an amount of calories from saturated fat more closely to recommended amounts than did the 65–74 year olds. Among those 65 and older, milk intake was considered more adequate for non-Hispanic whites than blacks, as was women’s intake compared to men in this age group. College-educated seniors consumed more moderate amounts of saturated fat than those who had less than a high school education. Similarly, the calories from saturated fat of those 65 and older who were college educated was considered more moderate than that of both those with some education or an associate’s degree or with less than high school educations. College-educated elderly consumed more total fruits and vegetables than those with less education.
Eating out contributed to beef intake among the elderly as demonstrated in What We Eat in America, NHANES 2011–2012. Daily intake of beef stood at 40 g for women ages 60–69 and 37 g for those 70 and older (Bowman et al., 2013). Men consumed higher quantities than women; intakes of 74 g and 53 g by group, respectively. A comparison study of eight countries found cholesterol intakes ranged from 354 mg in Belgium to 214 mg in Portugal (Haveman-Nies et al., 2001). The amount of fats and oils consumed was highest in Belgium (59 g) and lowest in the United States (6 g). Milk intake was highest in the Netherlands and lowest in both Belgium and Italy. The elderly in the United States and Spain had the highest score on the Greek Mediterranean diet compared of that of the other countries (Haveman-Nies, et al., 2001).
Gille et al. found that more than 90% of middle-aged and elderly Swiss citizens indicated that eating healthily was important to them, but only 71% were familiar with the Swiss Food Pyramid (Gille et al., 2016). Of this group, only 38% said they adhered to this in their food choices. Among all respondents, 3% failed to consumed the recommended servings of dairy (including milk); 68% failed to meet guidelines for the intake of eggs, meat, or fish; and similarly high percentages of respondents consumed less from the cereals, fruits, and vegetable food groups. Men’s consumption of eggs, meat, and fish exceeded that of women’s; women tended to consume more from the cereal, legumes, and potatoes groups. Studies are lacking regarding the consequences of elderly persons’ knowledge of the dietary guidelines in the United States.
Some studies have focused on differences in protein sources by race. Elderly white males consumed 12 g less of meats, poultry, and fish than elderly black males, but this difference was not significant (Bowman, 2009). By contrast, elderly white males consumed a great deal more milk and dairy products than elderly black males. This accounted for 12% of daily energy intake for elderly white males compared to only 7.2% for elderly black males. A similar difference between elderly black women was found. An earlier study of elderly black men and women found that both males and females consumed 330% of the RDA for cholesterol while consuming slightly higher recommended servings of meat, poultry, and fish but eating insufficient servings of milk and cheese (Lee et al., 1998).
Institutional residence also appears to affect the foods the elderly consume. Spanish elderly in institutional settings received more milk products than any other food group, followed by potatoes and sweets and pastries (Mila et al., 2012). These and other high-energy dense foods such as fats and sauces provided much of their energy intake. Fruit and vegetable intake was considered insufficient. A study of low-income elderly living in “sheltered housing” found that many foods were eaten only a few times a week. Of those who only ate certain foods a few days a week, 50% did so for meat, 20% for eggs, 34% for cheese, 23% for yogurt, and 18% for milk (Caughey et al., 1995). Quandt et al. (2009) performed research on low-income elderly in rural counties of Kentucky, indicating that the most frequent breakfast pattern involved bacon, ham, or sausage, eggs, and biscuits. Lunch and dinner tended to include a mixed dish and “starchy” sides. Mixed dishes may have included meat.
Some elderly also exhibit food “pickiness”; some of this may have more to do with eating difficulties rather than dislike (Maitre et al., 2014). This French study found that elderly who indicated a high level of pickiness tended to be malnourished and pickiness had a stronger association than eating difficulties with malnutrition, but those who experienced both difficulty and pickiness were worse off. Donini et al. (2013) studied elderly people suffering from anorexia of the elderly, finding that such persons tended to consume fewer foods than recommended from all food groups, but especially those such as “meat, fish, eggs” and “fruits and vegetables” (Donini et al., 2013).
Kant et al. (2004) used data from the National Health Interview Surveys 1987 and 1992 to study the link between a scale rating healthy eating habits (e.g., eating lean meat, low-fat dairy products, not eating fat from red meat, eating a number of kinds of fruit and vegetables) and mortality, finding that both men and women ages 45 and older were less at risk of dying over time if they made more healthy food choices (Kant et al., 2004). Kant et al. (2009) replicated this study using the National Institutes of Health and American Association of Retired Persons study of adults 65 and older, finding that the risk of mortality was lower for those in the highest quintile of the healthy diet scale (Kant et al., 2009). Both men and women were more likely found in the highest quintile on the healthy diet scale, and healthy eating practices were highest among those with higher income and greater education.
Using NHANES data for the time period 2001–04, Krebs-Smith et al. (2010) found that compared to recommended amounts of MyPyramid food groups, most age groups fell short of meeting those amounts. Far more than half of individuals aged 51–70 consumed insufficient amounts of meat and beans, milk, oils, fruits, whole fruits, total vegetables, dark green vegetables, orange vegetables, legumes, other vegetables, total grains, and whole grains. Slightly fewer of those respondents 71 and older consumed insufficient amounts from these food groups than did those 51–70. In addition, persons in this age group tended to overconsume added sugars and solid fats. More elderly males consumed the recommended amounts of meat and beans than females did of these foods but were more likely to consume less than the recommended amounts total fruits and whole fruits. Older females tended to consume more added sugars than their male counterparts.
One study followed elderly participants over a 5-year period, measuring their food intake and risk factors (Jankovic et al., 2014). Consumption of high-fat meat, high-fat milk, and egg and egg products declined over the period while fruit intake increased; however, these changes appeared to have little effect on the risk factors associated with CVD. Efforts to link a healthy diet to mortality from CVD and CHD found that those with a more healthy diet were less likely to have died from either of these two causes (Stefler et al., 2014). A US study of individuals older than 75 found several dietary patterns. The most frequent dietary pattern (named “sweets and dairy”) consisted of sweets and dairy products (“baked goods, milk, sweetened coffee and tea, and dairy-based deserts”) and the lowest intake of poultry (Hsiao et al., 2013). The second most frequent pattern (named “health-conscious”) consisted of greater intakes of pastas, rice, whole fruits, vegetables, and fish and lower intakes of eggs, bread, fried vegetables, and fats. The final pattern (dubbed “the Western”) consisted of high intakes of eggs, bread, fried vegetables, and fats with less fruit and milk intake. Of interest, red meat was found to be part of all three patterns. Individuals in the group whose pattern followed the “sweets and dairy” tended to have higher rates of hypertension than those in the “health-conscious” group.
Social Influences, Values, Attitudes, and Meat: Behind the Scenes of Food Choices
Studies have found that many people in many countries have come to believe that eating meat is unhealthy and have either reduced or eliminated meat from their diets. Zey and McIntosh (1992) found that women in Texas were more likely to indicate their intention to eat less meat in the future if their husbands or boyfriends supported this intention (Zey and McIntosh, 1992). Respondents who believe that eating meat was good for their health were less likely to intend to consume less meat. No difference was found by age. A similar study performed in Australia found that age was associated with attitudes about meat; elderly respondents were more likely to perceive eating meat as necessary for health and that it caused no risk to health and was not fattening (Lea and Worsley, 2001).
Recently a series of studies have focused on values and morality and meat. One study found that values such as universalism (protecting humans, animals, and the natural environment) and security (“prioritizing personal health, community safety, and protection of resources”) tended to lead these value holders to consume less red meat (Hayley et al., 2015). Those who valued power (“attainment of social status, prestige, and dominance”) tended to consume more red meat. Another study reported that meat eaters expressed fewer concerns for animal health while vegetarians expressed more concern (De Backer and Hudders, 2015). A similar study of red and processed meat found that those who held positive attitudes about animal welfare tended to eat less meat and those with such attitudes tended to be over age 60 (Clonan et al., 2015). However, those more than 60 years of age were no more likely to eat less red meat than those of younger ages. Others have examined disgust as a motivation for excluding meat from their diets; several studies found the greater this reaction, the lower the consumption of meat, but this association was more prevalent among adolescents and young adults than among older adults (Kubberod et al., 2008; Ruby and Heine, 2012). Others have studied what they consider the “meat paradox”—that is, while some people enjoyed eating meat, they experience concerns when they consider how animals are treated. While many spend little time attempting to reconcile these potentially conflicting views, others have adhered to rationales in order to avoid feeling guilty (Piazza et al., 2015). Those who do consume meat drew on arguments that eating meat is natural, normal, necessary, and nice (Piazza et al., 2015). As yet, these researchers have not reported on associations with age and other sociodemographic variables.
Culture, Perceptions of Food Choices, and Eating Habits: Perception Is Reality
Schifflett and McIntosh (1986–1987) studied 805 elderly found in 13 nutrition sites (congregate meal programs) in order to examine the relationship between perceived age-appropriate food choices and future time perspectives. Future time perspective has to do with elderly persons’ views that they cannot plan what they may be doing in the next several years or that they only plan to maintain current activities (a more negative time perspective) versus maintain current activities plus adding new ones (a more positive time perspective). Five patterns of changes or maintenance of their eating habits were identified, including (1) maintaining lifelong eating habits, (2) changing food intake to follow a physician-prescribed diet, (3) following self-prescribed diets that involve fewer sweets and less fat and salt in order to avoid illness, (4) reducing food intake because of lower levels of physical activity, and (5) changing food choices because of taste abilities, social isolation, or reduced income. Those who had a more positive outlooks regarding the future were more likely to change to follow a diet or maintain their food choices than those who had negative outlooks about the future. Those who changed their diet because of their lessened ability to taste food or because they lived alone tended to have a more negative view of the future. These two patterns were stronger for males than for females. Similarly, those who either living with a spouse or alone tended to make more health-related changes rather than negative changes in their diets compared with others who lived with someone else who was not their spouse. Having a low income increased the likelihood that a respondent saw a bleaker future and made food habit changes based on changing taste ability or social isolation, but those who perceived their health had worsened tended make more positive changes in their food choices.
Life satisfaction and perceptions of satisfaction with various aspects of people’s lives change as they age. This occurs because of fewer resources, changes in their connections to significant others, and difficulties in shopping for, preparing, and eating foods. Dean et al. (2008) argue that the more closely tied between the resources available to the individual and the goals they have for “food-related” aspects of their lives, the greater their satisfaction with their food lives. The researchers found that those with greater income, good storage facilities for food, social support, transportation, and abilities to taste and smell as well as a higher congruence between their level and the relevance of their resources were more likely to enjoy a greater level of food-related life satisfaction. Some foods the elderly preferred consisted of foods eaten in the past, which helped them maintain connection with their past (Fjellstrom et al., 2001). In addition to the generation in which the person was born when it comes to food choices, so did the stage of life an individual finds her- or himself. These authors note that those growing up in the 1970s developed a preference for “one-hand food, eaten on the run” but found no particular patterns for earlier generations (Fjellstrom et al., 2001).
The Mediterranean Diet: Fast-Food Advice
The Mediterranean diet is a hot topic and the focus of a vast number of research reports in peer-reviewed journals and discussions in all types of media. The relationship between dietary intake and CAD was first identified through studies that began in the 1940s, including the Seven Countries Study led by Ancel Keyes. Initial findings implicated the effects of saturated fat on total serum cholesterol in cohorts in the United States, Japan, and five European countries (Willett, 2006). From feeding trials conducted by Keyes and others, along with another large prospective study in Framingham, Massachusetts, evidence of the beneficial effect of polyunsaturated fat emerged, resulting in early recommendations to reduce saturated fats and increase polyunsaturated fats in the diet. Evidence from a massive amount of subsequent research on diet and CAD over the last 60 years has explained many of the complexities of lipid metabolism and thus the impact of dietary factors on the development of CAD.
Dietary recommendations to promote cardiovascular health are plentiful, although one particular dietary pattern is enjoying considerable support in developed countries: the Mediterranean diet. This diet was considered to be responsible for a significant component of the variation in the incidence of CAD among the seven countries more than 60 years ago. Participating countries in which the traditional diet was reported surrounded the Mediterranean Sea—Italy, Greece, and countries of the former Yugoslavia. The fundamentals of the diet include a significant amount of olive oil, plant-based foods, fish, and wine. Bach-Faig et al. (2011) described the Mediterranean diet as followed primarily by poor rural societies in the Mediterranean area in the 1960s and including plant foods (cereals, fruits, vegetables, legumes, tree nuts, seed, and olives); olive oil as a major source of fat in the diet; relatively high intakes of fish and seafood; moderate intakes of eggs, poultry, and dairy (cheese and yogurt); and low consumption of red meat. A moderate amount of wine (alcohol) is included as well. The diet’s healthfulness arises from a variety of foods included to prevent deficiencies and culinary methods that capitalize on the components of the diet, especially olive oil (Bach-Faig et al., 2011). Calibriso et al. (2016) reported that polyphenols in olive oil and serum metabolites may result in reduced oxidative stress and inflammatory angiogenic responses that are found in chronic degenerative diseases. Modification of gene expression by these phenolic compounds to protect proteins in cellular mechanisms involved in resistance to oxidative stress and inflammation has been reported (Silva et al., 2015).
Adherence to this food pattern has been reported to have a beneficial effect on chronic inflammation and endothelial dysfunction, conditions related to metabolic syndrome, type 2 diabetes, and CVD (Garcia-Fernandez et al., 2014; Meydani, 2005). Gotsis et al. (2015) reviewed results of studies over a 5-year period in which positive effects of the Mediterranean diet were reported for cancer at several sites (European Prospective Study into Cancer and Nutrition), chronic kidney disease, dyslipidemia, hypertension, type 2 diabetes, obesity, atherosclerosis, nonalcoholic fatty liver disease, and respiratory problems, including asthma and sleep apnea. Protection from cognitive decline associated with use of the Mediterranean diet was reported in a study of an elderly population in Athens (Trichopoulou et al., 2015).
Telomeres are protective sequences of nucleotides at the end of chromosomes that preserve genome stability by permitting normal cell division to take place (Boccardi et al., 2016). Telomere length decreases with each cell division until the telomeres are unable to function normally; this is the point when cell senescence occurs. The enzyme telomerase can repair damage to telomeres and restore cell viability. Oxidative stress and inflammation, which are known to play a role in obesity and cardiometabolic disease, are related to lower telomerase activity. Characteristics of an unhealthy lifestyle are associated with oxidative stress and shorter telomeres (Boccardi, et al., 2016). Investigation into the role of the Mediterranean diet in protecting telomere length in the Prevención con Dieta Mediterránea randomized trial in Navarra, Spain, resulted in stabilization of telomere length after 5 years (Garcia-Calzon et al., 2015). A cross-sectional study of an African American and Hispanic population in Washington Heights, New York City, demonstrated that increasing adherence to a Mediterranean diet was associated with longer telomere length (Gu et al., 2015).
The conclusion that can be derived from these studies is that diet can promote healthy aging. Considering the extensive research on the need for protein in the diet of older adults, increasing the amount of eggs, dairy, and cheese will make the Mediterranean diet one that can be adopted by older adults and anyone else who is on a quest for healthy aging.
Conclusions
The modern human life span has increased greatly over the past 200 years. To ensure that the extra time is spent in health and not in disease, optimal food choices are needed. DRIs and DGAs are good starts, and the Mediterranean diet is available with an arsenal of strong research for encouragement. More eggs, milk, and cheese for older adults will be helpful because without enough protein, the body could be headed for unhealthy aging.