Retirement is a common life event that can drastically change the daily life of an older individual. For some this may give them an opportunity to have more time with those that they love and have the opportunity to follow their passions. However, for others the end of work life greatly reduces social contact, especially if the workplace was their main source of socialization and income. As the years go by, many older individuals will also lose loved ones, which further increases the risk of isolation. Both depression and cognitive decline can lead an older individual to neglect their basic needs, such as regular consumption of nutrient-dense foods. Regular social contact and engaging in a variety of activities is essential to reduce the risk of cognitive decline and depression. Maintaining multiple active roles, such as parent, spouse, or employee, can increase feelings of being valued and encourage a healthy outlook on life.

Not only the social life changes but also physical capabilities. At the beginning of this unit you learned that growing older involves a decrease in body functioning no matter how healthy of a lifestyle a person has lived. Loss of bone mass, some degree of atherosclerosis, shifts in hormone function results in a more achy body and slowly declining health. On a cellular level declining mitochondrial function in high age results in increased fatigue and the accumulation of cellular garbage increases low-grade chronic inflammation. The reduced ability of cells to fold proteins properly results in lower lean mass synthesis. The result is that people in high age are less active and have to take more breaks. Muscle loss takes place, strength declines and frailty can develop.

Many older individuals may also lose appetite and begin to consume fewer calories and nutrients resulting in malnutrition. Malnutrition is aggravating fraily. Combined with other related health issues the risk of falls, disease and hospitalizations increases. Any of these issues can ultimately lead to early death.

During this chapter you will explore the factors that lead to malnutrition in older adults.

Before you study the age-related loss of appetite and its consequences a quick review how the energy intake is regulated will allow you to appreciate the complexity of this regulation:

Malnutrition Is Common in High Age

The WHO defines malnutrition as either deficiencies or excesses of nutrients. This means that malnutrition can be under- or overnutrition. The desired nutrition status is an adequate nutrient intake that will allow for optimal physical functioning and the maintenance of some nutrient stores.

As people enter high age the irsk for malnutrition increases. Malnutrition is least common in community dwelling older people (1 – 3 %). This is not surprising since this group lives independently in their own apartments or houses. They tend to be fit enough to take care of themselves, choose the food they prefer and are engaged in their community.

Once an older person requires homecare the prevalence rises to 7 – 8 %. People in hospital settings and long-term care facilities are much more likely to have malnutrition, up to 28 %.

Adequate nutrition is one of the main factors determining how long and more importantly how well a person lives. Malnutrition can trigger weight loss and along with that sarcopenia. A loss of muscle mass and strength can speed up frailty along with cognitive impairement. These are all risk factor for a premature death.

Specific nutrient deficiencies can impact quality of life. Calcium and vitamin D deficiency accelerates osteoporosis; low protein intake and vitamin D deficiency will lead to a loss of muscle mass. Low vitamin intake will alter the immune response leading to a vulnerability for infectious diseases and low intake  of antioxidant nutrients will fuel inflammatory processes.

This makes it clear that the key to a long quality life is an adequate dietary intake. Standard nutrition recommendation tend to focus on recommending adequate nutrient amounts. This sounds easy, but nutrients come from food and adequate food intake depends on access to meals, the ability to purchase and prepare nutrient-dense, healthy meals, and the experience at mealtime. When giving dietary advice all meal related factors need to be considered.

Access to meals: Poverty increases with age. People over 80 years old have a higher poverty rate than any other age group in the US. The poverty rate in elderly increases from 8.4% in 65 to 69 year old adults to 11.1% in the 80+ year old group. The group of seniors most affected are Black and Hispanic Americans and never-married, single women over 65 years old (18%, 17%, 17% respectively). As you have learned in the food insecurity chapter, poverty is a major predictor for the inability to purchase sufficient quality and quantity of foods.

In addition to a lack of financial resources frailty, cognitive decline, a loss of vision and hearing, and decreasing dexterity make it difficult to go to a grocery store, purchase food and transport the food home. A lack of cooking skills, difficulty preparing meals and observing food safety rules can hinder eating regular, healthy meals.

Meal quality: Since all functions decline in high age the gastrointestinal tract is not an exemption. The ability to properly digest foods and extract nutrients decreases due to gastrointestinal decline in old age. Therefore nutrient dense meals providing plenty of nutrients and phytonutrients become essential. Healthy nutrient-rich meals can counter age-related inflammation, provide sufficient amounts of protein to counter loss of muscle mass and provide the energy to support daily physical activity. Meals also need to have an enjoyable flavor and texture so seniors can enjoy meals.

Mealtime Experience: Nutrition professionals tend to think about food quality and quantity but with increasing age it is important to consider the mealtime experience as well. The best tasting, healthiest meal is not enjoyable if all meals are eaten alone. As we all know companionship during a meal allows us to enjoy meals and therefore eat sufficient amounts of food. Elderly, lonely eaters are more likely to eat less.

One hallmark of aging is the loss of resilience. Stress and loneliness can affect older individuals more severely and depression develops. Low mental health can discourage elderly individuals from regularly consuming balanced meals or partaking in physical activity.

Excessive fatigue may also be related to the ability to eat. This may mean that the individual has to rely on someone else to feed them which may not always be an option. The same principle applies to fluid consumption. Some elderly individuals may not be able to easily access fluids or intentionally decline fluids to reduce the amounts of times they use the bathroom because they need assistance to complete each of these tasks.

The mealtime experience can change immensely due to chronic diseases. Taste and appetite can change profoundly in seniors dealing with age related diseases. In addition illnesses such as stroke or loss of teeth can reduce the ability to chew and swallow making meal times a stressful time of the day. Diseases resulting in restrictive diets may also make finding palatable foods more difficult.

Physiological Changes Impacting Appetite Make Seniors Vulnerable to Malnutrition

Anorexia Of Aging

One major factor resulting in malnutrition is the development of anorexia of aging. You might have heard about the eating disorder anorexia nervosa. The term anorexia is defined as the abnormal loss of the appetite for food. Appetite is the body’s willingness or motivation to eat and is our main driver to maintain adequate energy intake.

While many aging individuals will have a healthy appetite around 30 % of community dwelling and 45 % of people in long-term care struggle with anorexia of aging.

Anorexia of aging is the age-related decline in appetite and food intake. This can lead to skipping meals or eating only very small amounts of food. Either way energy and nutrient intake will become inadequate.

As anorexia progresses the reduced food intake will lead to protein-energy malnutrition (PEM). PEM is marked by rapid weight loss, muscle wasting, and fatigue and weakness. Low food intake will result in inadequate protein and micronutrient intake resulting in declining metabolic function and increased risk for disease.

Anorexia of aging accelerates the development of sarcopenia and frailty and the risk for falls increases. Falls in older adults are serious and can lead to fractures and head injuries. Falls can start a cascade of socioeconomic and health consequences.  In addition, recurrent falls may result in fear of returning to daily activities. Independence and quality of life is lost Unintentional falls are the leading cause of injury-related death in people over 65 years of age.

The etiology is multi-factorial. Age-related physiological changes imapct each person differently depending on their lifestyle and genetic predisposition. Declining health—physiological and mental—can trigger the loss of appetite and drive to eat. As discussed above socioeconomic factors alter meal access, quality and experience which in turn leads to a loss of appetite.

When Eating Difficulties Develop Meals Become Stressful and Appetite Decreases

Taste and smell: Part of the aging population will experience a decline in taste and smell perception. However, it is unclear if this decline will happen in healthy aging. It is more likely that this decline is connected to age-related chronic diseases. Olfactory deficits necessary for the richness of the flavor experience are seen mostly in depression and neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease

In any case, bland tasting food is not enjoyable. Many try to counter the blandness by adding more salt and sugar, but this approach may lead to an aggravation of existing hypertension and insulin resistance. Instead, the savory, meaty and brothy flavor of food (called umami) should be enhanced. Adding tomato paste, mushrooms—especially dried and powdered—and herbs during the cooking process can accomplish this. Instead of salt, small amounts of miso paste and soy sauce will add the salt in combination with lots of umami flavor.

Oral health: Difficulty biting and chewing develops with lose and painful teeth, loss of teeth, or ill-fitting dentures. Harder to chew foods such as steak, crunchy snacks and vegetables might not be an option anymore. Reduced saliva production will make it difficult to move food around in the mouth during chewing resulting in a tough food texture that is difficult to swallow. Oral inflammatory disease such as inflamed gumes make biting and chewing painful. Limited food choices and stressful chewing and swallowing take the fun out of eating.

Dysphagia: Imaging that you struggle swallowing chewed bites of food or even sips of liquids. The struggle and fear of asphyxiating can make the meal to the most stressful time of the day.  The difficulty swallowing is called dysphagia and is a cause for malnutrition, dehydration, pseumonia and even asphyxiation.

Dysphagia affects about 7 to 13 % of the aging population. The most common cause for dysphagia is dementia, Parkinson’s, cancer, and stroke. Another cause for dysphagia is sarcopenia of the lingual musculature.

Dysphagia can be easily overlooked and the senior slips rapidly into malnutrition. A speech pathologist can conduct a swallow study and determine appropriate treatment. This can include tongue strengthening exercises and a collaboration with a clinical dietitian who changes the consistency of foods to match swallowing ability.

Dysphagia diets have multiple levels including pureed, mechanically altered, and soft foods. Individuals with dysphagia may also need liquids thickened in order to prevent aspiration, or fluid going into the lungs.

Eating only pureed or semi-liquid food is not enhancing the enjoyment of eating. Recently, 3-D printer enable dietitians to print foods that are adequate for the swallowing difficulties but look more visually appealing.

Gastrointestinal Changes Increase Satiety

Intestinal hormone secretion: So far, the factors impacting appetite you studied are connected with the hedonic side of energy intake regulation. During the last decades scientists also started to understand the physiological side of appetite regulation in high age (homeostatic pathway).

When you start eating your meal the gastrointestinal tract starts excreting hormones that have two functions. First the hormones coordinate digestion (paracrine secretion) and second the hormones circulate the blood stream and reach the hypothalamus in the brain. The endocrine secretion regulates appetite.

Ghrelin is released by the stomach if the last meal is a while ago and the stomach empty. Ghrelin—the only orexigenic hormone—stimulates food intake. Once we start eating ghrelin secretion declines.

Once fat and protein leaves the stomach, the duodenum secretes the hormone CCK. Rising CCK blood concentrations trigger a first appetite suppression. As nutrients are further digested and reach the distal intentine the hormones GLP-1 and PYY are secreted initiating a sustained appetite suppression. GLP-1 is involved in blood glucose regulation and insulin secretion as we have discussed in chapter 2. GLP-1 is secreted by the intestine in reaction to the presence of carbohydrates and stimulates the secretion of insulin before glucose is absorbed into the blood stream. GLP-1 also feeds back to the stomach and the hypothalamus regulating gastric emptying and signaling satiety.

If those hormones are properly secreted and read by the hypothalamus satiety and appetite will regulate an adequate energy intake. In part of the aging population hormone secretion is altered. People eperiencing anorexia of aging tend to have increased CCK, GLP-1 and PYY secretion after a meal. Higher and prolonged blood concentrations of those anorexigenic hormones increases and prolongs satiety after a meal resulting in smaller and skipped meals.

Research for ghrelin is less clear. While some studies report higher ghrelin secretion, others report lower secretion. Keep in mind that these changes are not experienced by all aging people. Many will retain a healthy appetite into high age.

Gastrointestinal transition time: During aging gastrointestinal transition time slows down, and enzymes activity decreases. Since gastrointestinal emptying is delayed food stays longer in the stomach. Some studies also show that less food extends the stomach faster. The stomach has pressure sensors and sends signals to produces less ghrelin. Satiety sets in faster and lasts longer.

Slower passage due to reduced intestinal motility and lower enzyme activity in the small intestine leads to prolonged nutrient contact with the intestinal epithelium. This might be the cause for the increased hormone secretion. Satiety is increased and appetite reduced. In addition, the slower passage of the food through the GI tract and decreased enzyme activity can cause issues such as constipation and reduced ability for nutrient extraction.

One more physiological change: The hormone leptin is secreted mostly by the adipose tissue and contributes to the long-term regulation of energy intake. In younger adults leptin secretion is proportional to the amount of adipose tissue. If a younger person loses weight leptin secretion is lowered and triggers an increased drive to eat. In older people leptin secretion during fasting remains higher which means that the drive to eat is still reduced.

Risk For Dehydration Increases

As discussed in chapter 30 cellular aging increases low-grade chronic inflammation even in people with a healthy lifestyle. This specific type of inflammation is called inflammaging. 

Accumulating cellular garbage—misfolded proteins the cell removes only inefficiently—triggers the inate immune system which in turn secretes proinflammatory cytokines. Higher concentrations of these signaling molecules are now circulating the blood stream and alter how other cells function. Proinflammatory cytokines slow down gastric emptying, hinder appetite regulating hormones and alter taste perception.

So far most of the physiological changes take place in many healthy individuals. Diseases accelerate the anorexia of aging. Neurodegenerative diseases can result in dydphagia. Chronic diseases increase the secretion of pro-inflammatory cytokines even more. Older individuals are more vulnerable to infectious diseases. Catching a cold or the flu can be a major setback. Many medications impact appetite or saliva production. Lastly mental health has also a major impact on appetite.

It becomes clear, that older individuals with chronic disease are much more at risk to develop anorexia of aging compared to individuals with a lifelong healthy lifestyle.

One more idea to think about: There might be medical reasons for changing the diet such as declining heart or kidney function function. Individuals with heart issues may be required to consume low amounts of sodium and fat. Individuals with chronic kidney disease need to restrict protein. Others might be on carbohydrate restrictive diets due to diabetes. Diets due to medical reasons can at times be limiting and make finding appetizing foods more difficult.

Nutritional Status in Elderly Can be Measured with the Mini Nutritional Assessment

The first step in preventing and treating malnutrition is to assess the nutritional status. The Mini Nutritional Assessment or MNA® is a screening and assessment tool used for individuals over the age of 65 who are at risk or currently experiencing malnutrition. It was originally developed in the 1990s and has evolved over time.

The original full MNA was developed to provide a simple, reliable way to screen nutritional status of persons over age 65 and to add a nutrition component to the Comprehensive Geriatric Assessment. The full MNA® has 18 items and classifies the patient as normally nourished, at risk for malnutrition, or malnourished. The MNA is well validated in the hospital, community, and long-term care settings.

To further streamline the MNA® and make it more clinically applicable, researchers revised and revalidated the MNA®-Short Form using pooled data on the MNA® from 28 previously published studies. the new MNA®-SF is a stand-alone screening tool, eliminates the need to complete the longer full MNA®, and reduces time to screen to less than 5 minutes.

If the result of the MNA®-Short Form are indicating malnutrition or a risk for malnutrition a dietitian can conduct a full nutritional assessment to confirm the diagnosis, assess the severety, identify the causes and start a treatment plan.

https://www.mna-elderly.com/development_and_validation.html

What Can Seniors Do to Prevent Eating Difficulties and Reduce the Risk For Chronic Diseases?

A Diet For Seniors Should be Nutrient Dense and Provide Adequate Amounts of Protein

Eating should be enjoyable and culturally appropriate. Therefore, instead of recommending a specific diet, a culturally appropriate, familiar diet should be adapted to old age.

Nutrient-dense: A diet for seniors needs to provide adequate amounts of micronutrients while avoiding empty calories. Reduced appetite and increased satiety as well as a generally reduced need for energy makes it important that food is rich in micronutrients. This will allow for healthy weight maintenance.

Adequate protein: Chewing difficulties can lead to a decreased protein intake from meat. Adequate amounts are necessary to maintain LBM though. Fish, dairy (if tolerated), and plant protein sources are easier to chew and might be an option. Protein powders might be used to supplement.

Cognition maintenance: The Mediterranean diet rich in plant foods supplies antioxidants and fish supplies omega-3 fatty acids. These nutrients are discussed to decrease age-related chronic systemic inflammation and promote a healthy gut microbiome. Studies show moderate benefits on cognition. Fatty fish and plenty of plant food can be easily incorporated in any diet.

This type of diet can be expensive. Counseling by a dietitian can identify inexpensive foods and recipes to go with and identify resources to buy food.

Water, Protein, Vitamin B12, Vitamin D and Omega-3 Fatty Intake Need Special Attention

The corner posts of eating in advanced age is a nutrient dense, plant-heavy diet and adequate protein intake. This will ensure the intake of micronutrients and phytochemicals even if the older person is not eating as much anymore. In addition there are four nutrients that might need special attention due to age-related physiological changes.

Protein intake in older adults will need special attention. While most Americans tend to eat plenty of proteins the usual protein sources such as meat and poultry might be harder to eat due to eating problems. In addition, some older individuals experience food preference changes that decrease their appetite for meat.

Studies show that elderly adults are less responsive to low amounts of amino acid to build muscle. This lack of responsiveness in elderly adults can be overcome with higher levels of protein. Therefore, daily recommendations for protein increases from 0.8 g/kg/d to 1-1.1 g/kg/d in order to maintain adequate muscle mass. Keep in mind that this is a subtle increase equating at most 1 deck-of-card serving of chicken. Inadequate consumption of protein and calories can result in loss of lean muscle mass.

Amino acids have other metabolic functions. This includes immune system, wound healing, blood pressure and bone health. Inadequate protein intake will impair the immune system and wound healing which could mean increased hospitalization time which is in itself a factor contributing to an increased risk of malnutrition.

Vitamin B12 is another nutrient of concern. Around 20% of seniors have mild vitamin B12 deficiency that results in neurological symptoms similar to early dementia symptoms such as memory loss, lack of physical coordination, vision problems, and difficulty speaking.  The diagnosis is rather dementia and not vitamin B12 deficiency because only severe vitamin B12 deficiency will produce pernicious anemia which is easier to diagnose.

The risk for mild vitamin B12 deficiency is related to a chronic inflammation of the stomach lining, atrophic gastritis. Stomach ulcers and certain medications can also cause issues in absorption.

Why is vitamin B12 more susceptible to digestion and absorption issues in high age? The digestion mechanism is very complex and involves several steps as you see on the slide above. The key step impacting vitamin B12 absorption in old age is a reduced production of intrinsic factor by the parietal cells in the stomach. If the stomach lining is chronically inflamed the secretory function of stomach cells declines. Over time the chronic inflammation will lead to replacement of healthy stomach tissue with fibrous tissue.

Most of the vitamin D we need is produced in the top layers of the skin through sun exposure. Food sources for vitamin D are slim and only fish and eggs contain naturally good amounts of vitamin D. The remaining food sources are vitamin D fortified milk, plant milks, and cereals.

With age the ability to produce vitamin D in the skin becomes less effective. In addition, frail seniors might not spend a lot of time outdoors in the sun. More food vitamin D is needed, but milk, the main source of vitamin D might not be consumed due to lactose intolerance.

Vitamin D deficiency causes a variety of issues. As it is important for calcium absorption, deficiency in vitamin D limits the amount of calcium that can be absorbed. This causes the body to pull calcium from the bones, ultimately increasing risk of frailty. Vitamin D deficiency is also linked to decreased cognition, however more research is needed in this area.

Lately omega-3 fatty acids made it on the list of special attention nutrients for seniors. This is related to newer research results showing that adequate consumption of omega-3 fatty acids might help maintain brain health and cognitive function and improve age-related chronic systemic inflammation. Fatty fish consumption, the main source for omega-3 fatty acids is not common in landlocked parts of the US and plant sources seem not to be as effective when it comes to cognition.

Supplementation of all these nutrients, especially if food intake is low, may be necessary to maintain adequate supply in the body.

Water:

Just as the gastrointestinal tract changes, renal function often declines as an individual ages. While some of this decline occurs naturally, the process can be sped up with regular use of medications and chronic conditions such as diabetes. Reduced renal function as well as a declining thirst mechanism can cause issues in hydration maintenance.

This can lead to increase risk of dehydration. Some issues with dehydration include kidney stones and hypovolemic shock.

Preventing Or Reducing Cognitive Decline Can Reduce the Risk For Malnutrition

There are various other lifestyle modifications besides diet that can improve health status in elderly individuals. Cognitive decline can be a normal process of aging, but a healthy lifestyle can help maintain as much cognitive ability as possible.

Not all cognitive function is affected equally by the aging process. Memory function is most affected followed by problem-solving skills and speed processing. There is currently no pharmacological treatment for cognitive decline, but a stimulating environment, a healthy diet, and plenty of exercise can prevent rapid loss.

One of the simplest ways to prevent cognitive decline is through environmental enrichment. This involves activities that provide the learning of new skills such as painting, playing musical instruments or reading. Stimulating hobbies can be started at any age and provide large benefits. Those with higher levels of education or people speaking more than one language show resistance to memory decline.

Another way to reduce risk of cognitive decline is through regular exercise. Aerobic exercise improves hippocampal memory function at any age. It is not clear if the improvement of cardiorespiratory function improves memory function or if there is a similar direct affect we see during environmental enrichment.

While less researched, high social engagement is correlated with hippocampal health. Group interaction seems to be more beneficial than individual relationships. As previously mentioned, regular interaction with others decreases the risk of depression, which can impair cognitive abilities.

Ensuring that the individual continues to take care of the body and mind through diet, exercise, and environmental enrichment decreases the risk of malnutrition, frailty, and overall decline of function.

Interested in More Information?

Poverty Among the Population Aged 65 and Older (April 2021)

Rodríguez-Mañas L, Murray R, Glencorse C, Sulo S. Good nutrition across the lifespan is foundational for Healthy Aging and Sustainable Development. Frontiers in Nutrition. 2023;9. doi:10.3389/fnut.2022.1113060