March/April 2024

March/April 2024 Issue

Nutrition Needs of Aging Adults
By Alexandria Hardy, RDN, LDN
Today’s Geriatric Medicine
Vol. 17 No. 2 P. 24

People are now living longer but not necessarily healthier lives than their predecessors.1-3 The World Health Organization (WHO) suggests this is partially due to a person’s ability to make positive or negative health-related choices throughout their lifetime.1,3,4 Variables within an individual’s control include diet quality, level of physical activity, and hydration status. Environmental and socioeconomic factors also play a role, as cigarette smoking, pollution, food deserts, community, and access to medical care influence nutrition status.1,5 Recognizing and respecting the multitude of factors that contribute to a healthful lifestyle is crucial to the interdisciplinary team as they work to serve a diverse, aging population.1

Population
As life expectancy continues to lengthen, the proportion of aging adults also will continue to change. In the United States, older adults are designated by Feeding America and the 2020–2025 Dietary Guidelines for Americans as adults aged 60 or older.6,7 Much of the research done on aging populations follows this metric; this is also the age at which many community-based feeding programs begin eligibility.7 According to data from the 2020 Profile of Older Americans, the number of Americans who are older than 60 is 74.6 million, which is a 34% increase in the past decade.8 This growth is expected to continue over the coming decades, with a prediction that older adults will compose 25% of the population by 2050 in most continents.2

Primary Health Concerns for Older Adults
An aging population is faced with unique health considerations. Metabolic processes are altered, increasing the risk of developing noncommunicable diseases like diabetes, cardiovascular disease (CVD), certain cancers, and some types of chronic respiratory disease.1,6,9 Cellular damage, including oxidative stress and inflammation, may also develop in those with nutrient deficient diets.1 Moreover, food insecurity, malnutrition, and social interactions present as complications to consider.

One of the primary challenges to feeding an aging population is the existence of multiple barriers to maintaining a healthful diet and making good food choices. Environmental stressors that may increase emotional and mental loads, chronic disease, sleep hygiene, physical activity, and lifestyle decisions like housing and retirement age/ability all can affect nutrition status.1 Per the Hellenic Longitudinal Investigation of Aging and Diet study, elevated risk of poor nutrition is directly correlated with marital status (unmarried older individuals carry the biggest risk), high body mass index (BMI), being male, less formal education, decreased cognitive engagement, and poor dietary habits.10 Some of these factors are within the control of the individual, and some are not, and it’s the job of the interdisciplinary team to help their clients identify which factors they may be willing and able to change. By acknowledging these barriers and being proactive, older adults may be able to delay the physical decline that affects quality of life and their activities of daily living.11

Food Insecurity
Food insecurity also is associated with less access to food, which can lead to decreased nutrient intake and difficulty managing chronic disease.12 The State of Senior Hunger, a report published by Feeding America in 2022, evaluated rates of food insecurity and very low food security using the Food Security Supplement from the US Department of Agriculture (USDA).7 This information forms the basis for the official rates of food insecurity in America.7 The latest report illustrated that 6.8% of older adults are food insecure, and 2.6% are classified as having very low food security; these numbers have risen by 29% and 84%, respectively.7 The number of living older adults also significantly increased, indicating that though their life spans are increasing, their food security is not.7 Within these trends, Blacks and Hispanics, individuals with lower socioeconomic status, renters, and individuals aged 60 to 69 are most likely to be food insecure.7 Understanding the communities most likely to be affected by food insecurity and how to adequately resource them is a critical piece of the older adult nutrition puzzle, as food insecurity is associated with malnutrition.7

Feeding Programs
Community-based food and nutrition programs enable an aging population to remain independent while providing social support, food security, and adequate nutrition.12 These include programs such as the Older Americans Titles I-VII, the Nutrition Services Incentive Program, the Supplemental Nutrition Assistance Program, the Commodity Supplemental Food Program, the Senior Farmers’ Market Nutrition Program, the Emergency Food Assistance Program, and the Child and Adult Care Food Program. Eligibility for these services depends on a variety of factors, including age and income level. Advantages of these types of community-based programs include a general improvement in quality of life and decreases in falls and loneliness.13

Another facet of feeding geriatric patients is resident meals at senior care facilities. The Academy of Nutrition and Dietetics (the Academy) advocates for an individualized nutrition approach to be used in long term care and postacute care settings, arguing that food is directly related to the quality of life experienced by residents.14 This type of feeding approach is known as liberalized feeding, or the opposite of a therapeutic or modified diet. The more involved individuals can be in formulating their meal plans and expressing their dietary preferences, the less likely they are to experience malnutrition and a worsening in their chronic conditions.14 By actively working with a dietitian and other members of the health care team, older adults are more likely to consume adequate quantities of food, fluids, and nutrients.14

Malnutrition
The dietary needs of adults will change as they age, and one of the biggest risk factors they face is malnutrition.11,15 Malnutrition is present in at least 22% of this population, which manifests in physical and mental bodily changes.1 These include, but aren’t limited to, decreased bone and muscle mass, changes in oral health, altered sense of taste and smell, a reduction in cognitive function, increased frailty, and social/emotional changes like loneliness and isolation.1,15 Malnutrition also can exacerbate previously existing chronic illness, as well as act as a risk factor for other age-related changes.11

Malnutrition can be identified by a combination of the following criteria: if clients have lost >5% of their body weight within the last six months or >10% in over six months; if BMI is <20 kg/m2 and if <70 years, or <22 kg/m2 and if >70 years; if muscle mass decreases; if dietary intake decreases to ≤50% of energy requirements within a week or any reduction in two or more weeks; or if they experience a chronic gastrointestinal condition.11 These parameters were published in 2019 at the Global Leadership Initiative on Malnutrition, and a formal diagnosis requires one physical and one biological symptom.11

Food Safety
Educating clients about food safety practices also is critical, as older adults can experience a decrease in immune function, which can leave them more susceptible to foodborne illness.6 They may not consistently follow one set dietary pattern due to many factors, including preference, illness, expense, accessibility, and diminishing appetite. But empowering them to understand the modifiable factors they have control over, like their diets, can help them improve their macro- and micronutrient intake and influence their purchasing decisions.16

Healthy Aging and Dietary Needs
Ideally, a diverse and nutritionally dense diet is available and consumed beginning in childhood to promote positive health outcomes as a person grows and ages.1 As this isn’t always possible for a variety of social, environmental, and economic factors, understanding the unique needs of the body in different life stages is crucial to aging resiliently.1 Members of the interdisciplinary team can help clients understand their changing needs through regular education sessions with a focus on disease prevention and eating to best serve their current life stage. The WHO notes that individualized education focused on diet and physical activity can positively affect health outcomes and is cost effective.1

Relationship Between Aging and Sustainable Diets
A global modeling analysis published in the Lancet Planetary Health studied the intersection of nutrients, disease mortality, and the environment in 150 countries.17 The analysis used the Global Expanded Nutrient Supply, Harvard University, and the USDA databases for nutrient information; calorie information and dietary patterns were provided by the United Nations Food and Agriculture Organization and the WHO.17

The meta-analyses found an association between all types of processed meat and nonprocessed red meat consumption and all-cause mortality.17 The researchers hypothesized this was due to the composition of the meat, in particular the elevated cholesterol, sodium, nitrates, nitrites, and type of fat.17 Replacing these types of animal-based proteins with plant-based proteins such as legumes and nuts, and whole grains may positively impact mortality rates.17

Dairy consumption had no association with mortality, while low-to-moderate seafood intake decreased all-cause mortality, particularly if one serving per day was consumed.17 This is attributed to the high levels of omega-3 fatty acids in fish and the integrity they provide to cell membranes. Increased produce intake resulted in a similar decrease in mortality, particularly when five to 10 servings of fruits and vegetables were consumed daily.17 This decrease is thought to be due to antioxidants, fiber, and various phytochemicals.17

Macronutrient and Fluid Recommendations
Adequate macronutrient intake for aging adults can be difficult to achieve, as many in this population struggle to consume a sufficient amount of energy throughout the day.11 General recommendations for caloric intake in this population are 25 to 30 calories/kg body weight, though needs may be tailored to an individual depending on overall health status and potential noncommunicable diseases.11

Educating older adults on what constitutes a healthful and appropriate diet in this life stage also is important. Many older adults believe they should follow broad public health advice for younger healthy adults, which includes consuming low-sugar and low-fat items and eating an abundance of produce.18 While fruits and vegetables certainly are important to the diet at any age, overconsumption of these foods added to a suppressed appetite may limit overall protein and energy consumption and lead to unnecessary or unintended weight loss.18

Protein
Current protein recommendations for adults aged 65 and older are 1 g/kg or roughly 57 g per day for women and 67 g per day for men.19 Higher rates of intake may be needed as individuals enter new decades or develop new acute or chronic illness, up to 1.2 to 1.5 g/kg body weight.11,20 Risk factors for inadequate protein consumption in this population include inactivity, age, reduced protein synthesis, acute or chronic illness, anabolic resistance, reduced postprandial amino acids availability, decreased muscle blood flow, and strength and mobility.19,21 Consuming an even dispersion of protein throughout the day may be helpful to aid postprandial anabolism and prevent muscle loss and strength.21

Individuals should aim for 25 to 30 g dietary protein per meal, which is thought to be the ideal quantity to ensure adequate muscle protein synthesis.20 Decreases of roughly 30% to 50% of muscle mass are seen in those aged 40 to 80, which is the ideal time to regularly evaluate dietary patterns.20 Ideal dietary protein sources include lean meats, poultry, eggs, seafood, dairy, fortified soy products, and legumes.6

Fat
Fats are essential to maintain cellular structure and provide energy.9 As the body ages, consuming primarily unsaturated fat can decrease the risk of CVD, reduce inflammation, maintain muscle mass, improve insulin resistance, and lower overall mortality risk.9 Polyunsaturated fatty acids, like omega-3 and omega-6 fatty acids, can be found in fatty fish, plant-based oils, nuts, seeds, and avocados.9 If older adults can’t consume or are uninterested in consuming these foods, supervised supplementation may be recommended.9

Carbohydrates
A diet rich in a variety of carbohydrates can help provide much needed energy for an aging population.5 Carbohydrates include grains, dairy products, most plant-based dairy alternatives, starchy vegetables, fruits, and legumes.9 Ideally, whole grains are selected over refined grains to provide dietary fiber. The Dietary Reference Intake for men aged 51 and older is 31 g/day, and for women in the same age group it’s 21 g/day; the average current intake for Americans is 15 g/day.23 Excellent sources of dietary fiber include 100% whole wheat bread, whole grains (eg, millet, amaranth, brown rice), beans, peas, and lentils.6,22 In addition to adding calories to the diet, carbohydrates also may decrease the risk of heart disease, stroke, hypertension, and cancer while reducing mortality risk that comes with those noncommunicable diseases.5,9,24

Fiber intake is an important consideration when increasing or changing carbohydrate intake. Up to 50% of older adults have chronic constipation, and currently there’s little existing research specific to laxative use in the older population.25 Untreated constipation can negatively influence quality of life and can cause incontinence, fecal impaction, and hospitalization. 25,26 This might be an embarrassing topic for individuals to broach unprompted, and conversations should be initiated by the interdisciplinary team, particularly physicians, nurses, or dietitians.26 If a laxative is needed to help alleviate constipation, older adults should opt for an osmotic laxative as opposed to a bulk-forming laxative because fluid needs also would increase; examples include milk of magnesia.26 A stool softener should have less impact on overall fluid intake but still may affect electrolyte balance; regularly assessing labs and dietary intake may be needed to help correct an imbalance.25

Fluids
Because of a lack of thirst common among the aging combined with limited mobility and bladder control issues, many older adults don’t consume enough fluids.6 This can lead to dehydration as well as issues with digestion and absorption, which are problematic since many older adults already struggle with micronutrient deficiencies.6 Chronic dehydration also may be linked to cognitive decline.27

The 2020–2025 Dietary Guidelines for Americans estimate that older adults consume roughly 16 oz less fluid per day than do adults under the age of 60.6 To help increase fluid intake, dietitians can encourage clients to add 100% unsweetened fruit or vegetable juice and low- or fat-free dairy and fortified soy beverages to their diets.6 The WHO, the US National Academy of Medicine, and the US National Center for Health Statistics recommend older adults consume 2.7 L or 3.7 L of fluid per day for women and men, respectively.28

Micronutrients of Concern
Vitamins and minerals are vital to help the body grow, develop, and function normally.9 Micronutrient deficiencies are more difficult to identify than malnutrition and often are discovered through dietary intake forms or lab work.11 The most common micronutrient deficiencies include iron, zinc, folic acid, calcium, and vitamins B6, B12, C, and D.11,22,29,30 When working with older adults to correct these deficiencies, it’s important to use a three-pronged approach that targets variety, type, and quantity of their chosen foods.11 Personalized dietary education provided by the interdisciplinary team and supplement usage also can be helpful tools.30

Calcium
Calcium needs range from 1,000 to 1,300 mg per day for older adults, and postmenopausal women and individuals following a vegan diet are at risk of deficiency.6,31,32 Adding calcium-rich foods and beverages to the diet is important to meet these needs and prevent potential fractures and asymptomatic deficiency. Older adults can incorporate fortified breakfast cereals, plant-based milks, and juice in the morning; yogurt, cheese, or kefir for snacks; and canned fish and dark leafy greens for lunch and dinner. Adequate calcium consumption helps them maintain bone mass and may improve cardiac health.29

Zinc
Bodily inflammation can cause a decrease in plasma stores of zinc, which is problematic as older adults typically underconsume dietary sources of zinc.11,33 Malabsorption and dentition also can affect zinc status.11 Zinc deficiency is associated with decreased appetite and cognition, depression, frailty, a suppressed immune response, and an increase in muscle catabolism.11,34

Dietary sources of zinc include fish and other types of seafood, meat, and fortified or enriched foods like breakfast cereals. The WHO recommends women consume 3 mg and men consume 4.2 mg of high bioavailable zinc daily, with needs increasing as the quantity of zinc becomes less bioavailable. Phytate, a compound found in plants, limits the bioavailability of zinc and its subsequent absorption.33 Individuals who consume a plant-based diet are more likely to struggle with zinc absorption as their phytate intake is higher than an omnivore’s.33 Zinc is also more readily absorbed when consumed with or as an animal-based protein.33

Vitamin B12
Older adults can become deficient in vitamin B12 (cobalamin) primarily if they don’t consume enough foods containing B12 or if their bodies are not absorbing the nutrient; this is common in the aging population.22,35-37 Secondary causes include infection, intestinal bacterial overgrowth, physical inactivity, and drug interactions.36 This water soluble vitamin is most often found in red meat, dairy, eggs, and fortified breakfast cereals.6,35,38 The WHO recommends adults consume 2.4 μg of vitamin B12 daily.31

Vitamin B12 requires intrinsic factor to be absorbed and properly utilized; a lack of B12 in the diet can lead to pernicious anemia and neurologic complications.35,38 Older adults who follow a strict vegan diet are most likely to become deficient in B12 if not properly supplemented.35 There’s no standardized diagnostic toolset to assess deficiency, but clinicians are encouraged to rely on available labs and physical symptoms when making supplement recommendations.37

Vitamin D
Vitamin D is a fat soluble vitamin that’s available as ergocalciferol (vitamin D2) and cholecalciferol (vitamin D3), as well as via sunlight exposure.39 It’s responsible for maintaining bone health and aiding in healthy metabolic processes and function.39 Older adults are most likely to be deficient due to a decrease in physical activities and less time spent outdoors in the sun or participating in outdoor activities.36,39 Dietary sources of vitamin D include fatty fish, egg yolks, and fortified foods and drinks, like certain breakfast cereals and cow/plant-based milks. The average daily intake of vitamin D in many developed countries is 100 to 200 international units (IU) in geriatric patients, with recommendations ranging from 400 to 1,000 IU.39 Supplementation is the most effective way to increase vitamin D levels back to an appropriate range, though up to 90% of aging patients don’t take a vitamin D supplement.39

KORA-Age Study
A population-based study from Nutrients called the KORA (Cooperative Health Research in the Region of Augsburg)-Age study reviewed the serum concentrations of community-dwelling older adults to determine potential micronutrient deficiency.36 The 1,079 adults who were studied ranged in age from 65 to 93 and all lived in Germany.36 The participants filled out health questionnaires regarding diet and physical activity in addition to being interviewed, undergoing a physical examination, and participating in a nonfasting blood draw.36

Baseline data indicated that 47.7% of the participants weren’t physically active, 30.2% had a BMI in an obesity class, and 4.6% were frail.36 Nearly one-quarter of the population had one disease, and 66.8% had two; the authors acknowledged that gender, family support, education background, and alcohol consumption all influenced these statistics.36

After analysis, 52% of the participants had low vitamin D levels, though this was more common in women than men.36 In addition, 27.3% of participants were deficient in vitamin B12, which is more than the estimated 10% to 15% of older adults in the United States who have the same deficiency.36 Folic acid and iron deficiencies weren’t as common, at 8.7% and 11%, respectively.36 The researchers theorize that folic acid deficiency isn’t as common because of national folic acid fortification policies and individuals’ regular consumption of fortified foods.36 Iron deficiency in this population isn’t as robustly studied or well documented, but it’s estimated that anemia and deficiency generally is around 11%.36

Supplementation
Regular, supervised vitamin and mineral supplementation may be important for older adults to stabilize their micronutrient levels.6,11,36 The KORA-Age study researchers theorized that regular supplementation of vitamins B12 and D and folate could help older adults achieve ideal serum micronutrient levels.36 Consuming 500 to 1,000 mg of a calcium supplement may help increase bone density but may not impact fracture risk.40 Oral nutrition supplements also may improve overall appetite and energy intake in older adults who struggle to maintain appropriate caloric intake.41 Screening older adults earlier and more regularly may help prevent subclinical levels and preserve quality of life and functionality.36 All supplements, regardless of form, should be discussed with the interdisciplinary team, particularly pharmacists, dietitians, and physicians.6

Plant-Based Approach to Aging
Traditionally, one of the main concerns when recommending a plant-based diet to older adults is ensuring they consume adequate quantities of diverse proteins, thus preventing amino acid deficiency.21 Branched-chain amino acids (eg, leucine, isoleucine, and valine) may help encourage postprandial anabolism, or protein formation.21 Leucine is similarly available in animal and plant-based proteins, at an average of 9.5 g/100 g and 8 g/100 g, respectively.21

A plant-based diet may aid in preventing age-related cognitive decline, as there’s an association between the types of foods featured in plant-based diets and their neuroprotective properties.42 Foods rich in antioxidants, polyphenols, vitamins, and fatty acids may improve focus and memory, decrease insulin resistance, and positively impact the gut microbiota.5 More research is needed to determine how, why, and what foods may be impactful or if it’s the overall interaction of many different fruits and vegetables working together that yield these results.5,20

The Blue Zones, or areas of the world where older adults live longer and healthier lives, emphasize the role of a plant-based diet in healthy aging.5 The Adventist Health Study 2 showed that after 5.79 years, the 96,000 individuals studied who consumed a vegetarian diet had a lower risk of total mortality.5,43 Other similar analyses emphasize this finding and also report a lower risk of cerebrovascular, cardiovascular, and kidney diseases as well as type 2 diabetes.5

The Nordic Diet and Quality of Life
Quality of life has long been linked to dietary patterns, with 13 out of 15 studies reviewed in the journal Nutrients noting that the higher the dietary quality, the higher the self-reported quality of life.27 A traditional Western diet high in fast food, red meats, and sweetened grains is fairly common among older American adults and is linked to a lower satisfaction with quality of life and cognitive decline.27,44 This is attributed to the Western diet’s abundance of saturated fats and refined grains and decreased emphasis on produce and whole foods.

In contrast, a Nordic diet is associated with a high quality of life and preserved cognitive function, possibly because it boasts a higher concentration of omega-3 fatty acids, antioxidants, and fluids.27,44 A Nordic diet is rich in nonroot vegetables; herbs; seaweed; high-fiber fruits like berries, apples, pears, and peaches; whole grains; poultry; fatty fish like herring, mackerel, salmon, and sardines; vegetable oil (primarily rapeseed); tea; and water.5,44 The primary source of calories should be plant based as opposed to animal based.9 This type of dietary pattern aligns with the notion of a sustainable diet, as the building blocks of the Nordic diet are organically and locally sourced products and limited in processed or refined foods.5

Areas of Future Research and Study Limitations
Continuing to expand the education of and resources available to the interdisciplinary team is a necessary step in preparing practitioners who serve an aging population.1 Designing long-term, high-quality studies that further investigate the relationship between diet and quality of life is important, as a better understanding of the link between the two may impact diet education.27 Developing a screening tool that can assess diet and quality of life is essential as the older adult population continues to grow.44

A study published in the American Journal of Clinical Nutrition examined the quantity and type of protein consumed for five years by adults aged 70 to 79 to determine how it affected muscle mass in the thigh.45 The study determined that greater dietary consumption of total, animal-, or plant-based protein didn’t directly correlate to a change in muscle mass. The researchers recommended additional research be conducted to determine the ideal type and quantity of protein for muscle mass preservation in older adults.45 While studying protein’s impact, formulating studies that focus on subclinical micronutrient deficiencies, particularly serum iron, could be an important tool for better understanding the role of iron and wellbeing in an aging population.36

Putting It Into Practice
Dietitians can help clients to understand that living nutritionally dense lives is possible through careful management and understanding of their metabolism, inflammation, and oxidation levels.1 By optimizing their dietary patterns through the inclusion of key macro- and micronutrients, food groups, and fluids, clients can age resiliently while preventing malnutrition and wasting.1

The entire multidisciplinary team, especially case workers and nurses, can aid in the organization and establishment of screening services at local and national levels by utilizing food insecurity screening questions and coordinating care across a variety of transitional living situations.12 Though dietitians aren’t required to be involved in community-based food and nutrition programming for older adults at a local level, advocating for inclusion and participating in nutrition education at these programs can benefit participants. Acknowledging the eating environment of their older clients is important, as consuming food in a community setting is shown to improve intake and enjoyment.6

Healthy aging can be summarized as growing older but keeping a high quality of life, functionality, vitality, and overall well-being.16 Ultimately, it’s a journey that all individuals, regardless of age, are on together that is affected by their diets, environments, economic status, community support, and many more variables.3 It’s the position of the Academy that ongoing research is needed to provide evidence-based outcomes regarding nutrition screening, education, and assessment and the development of food and nutrition programs to aid in the prevention and treatment of illness related to aging.12

— Alexandria Hardy, RDN, LDN, is a content creator and a freelance food and nutrition writer based in Pennsylvania.

References
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43. Orlich MJ, Fraser GE. Vegetarian diets in the adventist health study 2: a review of initial published findings. Am J Clin Nutr. 2014;100 Suppl 1(1):353S-358S.

44. Shakersain B, Rizzuto D, Wang HX, et al. An active lifestyle reinforces the effect of a healthy diet on cognitive function: a population-based longitudinal study. Nutrients. 2018;10(9):1297.

45. Verreijen AM, Engberink MF, Houston DK, et al. Dietary protein intake is not associated with 5-y change in mid-thigh muscle cross-sectional area by computed tomography in older adults: the Health, Aging, and Body Composition (Health ABC) Study. Am J Clin Nutr. 2019;109(3):535-543.