As we age, a variety of physiological and environmental changes can make it difficult to maintain a healthy lifestyle. Older individuals may begin to consume fewer calories and nutrients and/or limit physical activity as their strength decreases. This may result in malnutrition and other related health issues, which then increases risk of injury, disease, and hospitalizations. Any of these issues can ultimately speed up the aging process and lead to early death. Malnutrition may occur due to limited meal access, modified mealtime experiences, changes in meal quality, or a combination of these factors.

Malnutrition Is Common in Elderly Adults

As we discussed in the beginning of the unit, growing older involves some decrease in body functioning as a whole, and on a cellular level, no matter how healthy of a lifestyle was lived. Declining mitochondrial function results in increased fatigue, reduced ability to fold proteins results in lower lean mass synthesis, and the accumulation of cellular garbage results in increased chronic systemic inflammation.

Depending on the genetic predisposition and the lifestyle up until the senior years, this decline may be more or less extreme, and can lead to decreased nutritional status.

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; however, for others it 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 a engaging in a variety of activities can help reduce the risk of cognitive decline and depression.

In order to prevent malnutrition and other related negative consequences, older individuals are encouraged to remain member of a strong community where they can have ample social interactions. Maintaining multiple active roles, such as parent, spouse, or employee, can increase feelings of being valued and encourage a healthy outlook on life.

Something as simple as consuming meals with other people on a regular basis can increase the chances of regular food consumption, and also gives the chance for socialization.

It is clear that malnutrition is not just a problem of not eating enough or not eating quality foods.

Standard nutrition recommendation tend to focus on adequate nutrient intake, but 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.

Especially in senior living alone increasing frailty, cognitive decline, loss of vision and hearing, and decreasing dexterity makes it difficult to go to a grocery store, purchase food and transport the food home. At home difficulty preparing meals and observing food safety rules can hinder eating regular 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 even more necessary. 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 becomes more and more 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. Stress and anxiety becomes aggravated with decreasing social interactions and mobility. These factors can discourage elderly individuals from regularly consuming balanced meals or partaking in physical activity.

Fatigue may also be related to the ability to have the strength for eating. This may mean that the individual has to rely on someone else to feed them which may not always be an option. This 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 are changing 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.

Looking at the chart above you will see that malnutrition is common especially in hospital and rehabilitation settings. 86 to 91% of seniors being treated for a disease or recovering from a diseases experience malnutrition or are at a risk for it. Around 60% of seniors living at home are well-nourished. This prevalence declines to a third if seniors are living in a nursing home.

During the next section you will learn about physiological factors contributing to malnutrition in more detail.

Physiological Changes Make Seniors Vulnerable to Malnutrition

When Eating Difficulties Develop Meals Become Stressful and Appetite Decreases

Appetite is the body’s natural tendency to desire food. As we age, we may experience anorexia, or lack of appetite. Lack of appetite can be due to the above mentioned sociopsychological factors, but also due to physiological changes causing difficulty eating. The entire situation can lead to skipping meals or eating only very small amounts of food. Either way energy and nutrient intake will become inadequate.

It is not clear if in healthy aging taste and smell perception declines. It is more likely that this decline is connected to age-related diseases. This can lead to an increased desire for additional spices or flavorings for foods. While some may opt for increasing the salt or sugar content of the meal to make up for it, this may not always be the best option. Increasing salt intake can contribute to hypertension most seniors develop. High sugar intake is not ideal since insulin production is not optimal in high age.

A much better solution is to add umami flavors to meals. Foods that amp up the savory flavor of food are mushrooms, especially dried and powders, tomatoes, some herbs, and fish.

Difficulty chewing develops with lose teeth, loss of teeth, or ill-fitting dentures. Harder to chew foods such as steak, crunchy foods, or vegetables might not be an option anymore.

Difficulty swallowing is medically defined as dysphagia. The most common cause for dysphagia is dementia, Parkinson’s, cancer, and stroke. Another cause for dysphagia is sarcopenia of the lingual musculature,  decrease in size and strength of muscle fibers.

Often dysphagia is 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, such as tongue pressing and effortful swallow, but also 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. These levels are categorized as thin, nectar-thick, honey-thick, and spoon-thick.

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

There may be other medical reasons for changing the diet such as declining organ function. Individuals with heart issues may be required to consume low amounts of sodium and fat. Some may be on carbohydrate restrictive diets due to diabetes or other related health conditions.

These diets can at times be limiting and make finding suitable foods more difficult. It is important to find a balance between strictly following the diet and providing some leeway so that the individual is actually consuming food and can maintain quality of life.

Gastrointestinal Changes Increase Satiety

When you talk to seniors about eating and digestion you will often hear a long list of foods that produce digestive problems. The reason for this is age-related changes of digestion. Food intolerances seem to be more common, but are less researched.

In general, gastrointestinal transition time slows down, and enzymes activity decreases. These changes can cause issues such as constipation and reduced ability for nutrient extraction.

Digestion begins in the mouth. Some seniors, often in connection with chronic diseases, experience a reduction in salivary production. This could be due to medications or neurological issues. Lack of saliva makes chewing and swallowing difficult. Dysphagia can develop and drastically limiting food selections.

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.

Intestinal motility also declines, and food travels slower through the GI tract. Because of all of this, older individuals often eat less.

While changes in ghrelin and leptin secretion are less researched and unclear, we know quite a bit about two of the hormones secreted by the gastrointestinal tract during digestion: Cholecystokinin (CCK) and Glucagon-Like Peptide-1 (GLP-1).

CCK is secreted by cells in the duodenum when stomach content is released. One of its functions is to regulate gastric emptying. In older people receptors are more sensitive, and gastric emptying is delayed. This increases satiety as CCK also seems to have a direct feedback to the satiety center in the hypothalamus. CCK also stimulates the gall bladder to contract and release bile into the duodenum which assists in fat digestion.

GLP-1 is involved in blood glucose regulation and insulin secretion as we have discussed(chapter 2). GLP-1 is secreted by the intestine in reaction to the presence of carbohydrates and stimulate 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. During advanced aging, high fat meals stimulate an increased secretion of GLP-1 which increases satiety.

Chronic inflammation of the stomach lining, common in elderly people, and reduced stomach acidity can make digestion of certain nutrients, such as vitamin B12, more difficult. Medications can also affect the pH of stomach acid. One of the purposes of the hydrochloric acid is to reduce pathogens in the food. Less stomach acid means a higher risk for foodborne illnesses.

Risk For Dehydration Increases

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.

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 one 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.

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.

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.

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