Nutritional Health and Older Adults

By Tammy Petersen, MSE 

Older adults have more variable health than persons of any other age group, so it is hard to predict nutritional problems based only on chronological age. Let's look first at what the experts have to say about the somewhat controversial and very important subject of how much protein active older adults need. Then we will examine how aging affects body systems specific to nutritional health.

Protein

Research is beginning to show that certain nutrients might play a role in slowing sarcopenia. Protein is one of them. Eating extra protein will not enlarge muscles, but in 1995, a Tufts study raised the question as to whether muscle loss in later years could be partly due to a chronic protein deficiency among older people. Researchers found that older women who ate protein at half the recommended level lost lean tissue after just 8 weeks and showed declines not just in muscle function but in immune response as well. Women whose diets were adequate in protein had no such declines.

The body has to compensate for everyday protein losses from skin, nails, hair, sweat, and body fluids, explains Carmen Castaneda-Sceppa, MD, Ph.D., head of the Nutrition, Exercise Physiology, and Sarcopenia Laboratory at Tufts. She says that if daily protein intake is not enough, the body uses muscle as a resource for amino acids, the building blocks of protein. Poor protein intake does not just contribute to muscle loss from within; it also prevents proper muscle maintenance due to the absence of adequate building materials. The idea that a chronic lack of protein depletes muscle reservoirs in older people makes sense, especially when you consider that many seniors are eating less protein than they should. In fact, an estimated one in three people over the age of 60 eats less than the current recommendation of 0.36 grams of protein per pound of body weight (or .8 g/kg). This would be 54 grams a day for a 150-pound person. Some research suggests that older people need even more protein than originally thought. One study at Tufts, for instance, advised adults over the age of 55 to eat about 0.45 grams per pound (or 1 g/kg), which is the equivalent of 68 grams for a 150-pound person. This greater need might be due to a lower efficiency of dietary protein utilization (Wardlaw, 1999).

Experts are still debating the "correct" protein intake for older adults. In any case, make sure seniors are getting at least the current recommended amount of 0.36 g/lb of body weight to thwart off depletion of lean tissue in the body.

For decades, there has been controversy regarding whether a diet rich in protein is good for bone or detrimental to bone. A recent study investigated just that. Scientists considered the association between protein intake and change in bone mineral density in a group of women and men aged 65 and older. Half of the participants received a calcium/vitamin D supplement and the other half received a placebo pill.

The results of the study demonstrated that the women and men who had a diet rich in protein had the most favorable change in bone density over a 3-year period. What is interesting is that this beneficial effect was only seen in the group that also received the calcium/ vitamin D supplement. Those individuals who consumed a diet rich in protein but who did not supplement with calcium and vitamin D did not receive a benefit from that protein. In fact, the protein-only group had an increase in fractures over the three-year study period.

How much protein is needed to receive this benefit? In the aforementioned study, the women and men who benefited most were those whose protein intake averaged about 20% of calories, or approximately 87 grams of protein a day. Caution is warranted because numerous studies have shown that a high protein diet (over 30% of calories) is detrimental to bones.

Taste and Smell

Sensitivity to taste and smell often decreases with age beginning at about age 60. Food often requires stronger seasonings, which can be a problem for people who need to cut back on salt and simple sugar intake. Although there are plenty of other ways to spice up the taste of food, salt and sugar tend to be the most frequently used—and abused. People often need suggestions on how to use new and different flavor enhancers. Sharing recipes that introduce new spices is one means of exposing clients to a completely new realm of taste.

Dental Health

About 30% or more of older people in the US have lost all their teeth often due to gum disease. Replacement dentures enable some to chew normally, but many older adults have problems with their dentures. For some unknown reason, this seems to affect a larger number of men than women. When people have problems chewing, nutrient dense snacks can help alleviate nutritional inadequacies. Sometimes just allowing extra time for chewing and swallowing encourages more eating.

Thirst

Older adults often partially lose their sense of thirst, which results in inadequate fluid intake. Because of this, they are more likely than younger people to become dehydrated. In addition, 25% of the fluid in our diets comes from food. If older adults are not eating enough food, they increase the risk of dehydration even more. Consequently, it is very important for older people to consume adequate amounts of fluid. You should monitor your client’s intake during exercise. About 6-8 cups daily is a good goal; better yet is the newest recommendation of ½ ounce of water per pound of body weight. The approximate fluid recommendation is the same for younger adults with activity and is estimated at 1 ml/kcal expended. One cup is about 250 ml, so every 250 calories expended equals the need for about 1 cup of extra water. Because diuretic use is quite common in older adults, there is an even greater chance that a senior will become dehydrated. Watch carefully if your clients are taking diuretics; they will already have a lower fluid volume as a result of the drug.

Gastrointestinal

The main intestinal problem for older people is constipation. To keep the intestinal tract performing efficiently, older people generally need to consume more dietary fiber than they did in their youth. Regular consumption of nuts, fruits, vegetables, beans, and whole grains usually provides enough fiber. If fiber intake increases, however, water intake also needs to increase to help accommodate this greater bulk. Because medications can cause constipation, a physician should be consulted if this condition persists. Mineral oil is sometimes taken as a laxative, but it should always be taken with caution. It binds fat-soluble vitamins (A, D, E, K) and limits their absorption, so it should not be taken with meals.

Lactase production slows with age, so older people tend to become more lactose intolerant. Most can still eat moderate amounts of cheese and yogurt though, so adequate calcium intake is still possible. In addition, stomach acid production slows as people age, which can cause poor absorption of vitamin B12. Vitamin B12 deficiency can then lead to pernicious anemia, a condition characterized by abnormally large and immature red blood cells that cannot transport and deliver oxygen efficiently. This results in lack of endurance and rapid onset of fatigue during exertion. Lastly, less stomach acid, along with the use of aspirin and antacids, can interfere with iron levels. Again, this can impact endurance and other body processes that rely on proper levels of iron in the blood.

Liver, Gallbladder, and Pancreas

The aging liver tends to function less efficiently. When there is a history of significant alcohol consumption, fat buildup in the liver accounts for some of this decline. Alcohol abuse is a problem among a small but significant group of older adults who might be chronic alcoholics or who might have developed alcoholism later in life while dealing with loneliness and depression caused by retirement or the loss of a spouse. When liver function deteriorates significantly, there is an added possibility for vitamin A toxicity. Elderly people, in general, should not supplement with vitamin A.

The gallbladder also functions less efficiently with age. Gallstones can develop and block bile secretion causing it to pool and back up into the liver instead. Gallstones also interfere with fat digestion by restricting the release of bile into the small intestine.

Although the digestive function of the pancreas declines with age, the pancreas has a large reserve capacity. With advancing age, the pancreas begins to produce less insulin. Insulin is necessary to remove glucose from the blood, so it should be clear that one of the major signs of a failing pancreas is high blood glucose. This is different from what happens in obese people. Although blood glucose levels in obese individuals also rise, the cause is not normally a lack of insulin production. Instead, blood glucose remains elevated after a meal because target cells become insulin resistant, so the insulin that is present cannot do its job.

Kidney Function

As kidney function deteriorates with age, the ability of the kidneys to excrete the products of protein breakdown significantly decreases. Although an increased protein intake of 1g/ kg of healthy body weight has been recommended for physically active older adults, this recommendation does not apply to people whose decreased kidney function causes urea to accumulate in the blood. Urea is a main by-product of protein metabolism that is formed in the liver and excreted by the kidneys. Another problem with aging is that kidney stones often develop. Surprisingly, coffee, tea, and wine consumption might decrease the chance of kidney stones, while orange and grapefruit juice consumption have been shown to increase the risk.

Immune Function

The immune system operates less efficiently with age. Consuming adequate protein, an array of vitamins (especially vitamins E and B6) and zinc helps maximize the health of the immune system. Recurrent sicknesses and poor wound healing are warning signs of a diet that is deficient, especially in protein and zinc. Eating too little food or too few animal proteins is usually the cause. As mentioned earlier, older people often eliminate meat from their diet because it is too hard to chew. Balanced nutrient supplements help ensure adequate vitamin and mineral intake.

Lung Function

Lung efficiency declines somewhat with age, but what does this have to do with nutrition? The decrease in lung efficiency contributes to a general downward spiral in overall body function. More specifically, breathing difficulties limit physical activity and endurance and frequently discourage eating. These changes eventually cancel other efforts to maintain overall health.

Hearing and Vision

Impairments in both hearing and vision indirectly affect a person's ability to maintain a balanced and healthy diet. Elderly people sometimes avoid social situations involving food and shopping for groceries simply because they cannot hear well. Furthermore, degenerating eyesight can affect people’s abilities to get to the grocery store, locate the foods they need, read label contents, and prepare foods at home. Macular degeneration is the usual cause of degenerating eyesight in the elderly. On a positive note, regular consumption of foods rich in carotenoids, in particular dark green, leafy vegetables such as kale, collard greens, spinach, Swiss chard, mustard greens, and romaine lettuce, might decrease the risk of developing this problem. Vitamin C also plays a part in preventing cataracts in the eyes and is just one more reason to eat fruits and vegetables.

Decrease in Lean Tissue

The loss of lean muscle tissue with age leads to a lower metabolism, decreased muscle strength, and reduced energy needs. Even if the person does not lose weight, a larger percentage of the body is in the form of fat as lean mass is lost. Older adults benefit from physical activity because it stimulates food intake, raises energy expenditure, and maintains or increases muscle mass. By eating more, seniors increase their chances of consuming adequate amounts of nutrients.

Cardiovascular Health

Consuming sufficient amounts of vitamin B6, folate, and vitamin B12 is important to avoid elevated blood homocysteine levels, which is an additional independent risk factor for heart disease. Much controversy surrounds the treatment for elevated LDL in adults over the age of 70-75. If these people consume extremely restrictive diets limited in saturated fat and energy that lead to inadequate total weight, or if their diets lack variety, they might become undernourished. This can be a worse predicament for them than having high LDL.

Blood pressure tends to increase with advancing age. This becomes problematic because hypertension is heavily implicated in both stroke and heart attack in older adults. Blood pressure can be lowered in many people by severe sodium restriction, but this is a difficult diet to follow. Minerals such as calcium, potassium, and magnesium also deserve attention when it comes to hypertension. When people consume at least 1000 mg of calcium per day, they often register slightly lower blood pressures, especially systolic blood pressure, as compared to those who consume one-third to one-half that much. Potassium supplementation in the range of 4g/day (about 2g above typical needs) has also been shown to moderately decrease blood pressure. Finally, some studies indicate that magnesium is capable of lowering blood pressure at intakes equal to twice the RDA. Suggesting an adequate calcium level to clients (1200 milligrams a day) is a safe recommendation. Defer any other nutritional recommendations to the experts. One final point: Excess alcohol intake is responsible for about 10% of all cases of hypertension. A prudent intake is one drink per day with a meal, or none at all.

Bone Health

Like everything else, bone density also decreases with age. For older adults in general, calcium intake should increase to 1200 mg/day. Maintaining adequate vitamin D at 10 to 15 ug/day (15 ug/day for adults 70+) is a first step in preserving the health of bone. 
Many older people suffer from hidden osteomalacia, a condition primarily caused by inadequate sun exposure which leads to decreased vitamin D synthesis in the skin. When they can't get regular sun exposure, older people need a dietary (e.g. milk) or supplemental source of vitamin D. Again, alcohol consumption should be in moderation, if at all.

Medications and Nutrient Needs

Medications and old age often go hand-in-hand. Medications can improve health and quality of life, but some of them also affect nutrient needs at any age. Two-thirds of older adults take at least one prescription drug, while one quarter of the elderly population regularly takes multiple prescription drugs. Many drugs affect appetite or absorption of nutrients, so if they are taken over the long term, malnutrition can result. Unfortunately, this is true for many elderly people; they often continue taking prescription drugs for long periods of time before any improvements are noted. These seniors should definitely work with their physicians and pharmacists to coordinate all medications taken. Pharmacists in particular can advise when to take drugs (with or between meals) for greatest effectiveness and the fewest number of side effects.

Drug-related nutritional problems include: (1) increased need for certain minerals or fat soluble vitamins when drugs leach them out of the body prior to absorption; (2) changes in appetite caused by antidepressant agents or certain antibiotics; and (3) blood loss from long-term use of aspirin or aspirin-like medications which strain iron reserves and can lead to anemia. People who take one or more medications for more than just a few weeks should closely watch their diets, eat nutrient-dense foods, and possibly take nutrient supplements to counteract effects of certain medications. As a personal trainer, you should not advise elderly clients on supplements; instead, refer them to their health care provider. A professional who specializes in nutrient and drug interactions should supervise because some supplements can interfere with the function of certain medications, while some medications interfere with the absorption of nutrients. For example, vitamin K can reduce the activity of oral coagulants. In addition, certain types of diuretics leach potassium out of the body.

Be aware of the fact that many people think herbal supplements and vitamins are not harmful because they are "natural." Every year, people poison themselves using minerals, vitamins, and other supplements even though their intent was to maximize health. Your clients need to be advised that just like aspirin or any other medication (prescription or not), vitamins, minerals, and herbs need to be used with caution. There is the danger of overdose and toxicity or interaction with medications. The fat-soluble vitamins A, D, E, and K are examples of “natural” substances that can easily build up in the body when taken in excess. Unlike the water-soluble vitamins, fat solubles are not filtered out by the kidneys. Instead, excessive amounts are stored in fat cells throughout the body and in the liver. Excessive mineral intake can also lead to toxicity, especially with the trace minerals such as iron and copper. Trace minerals are needed at very low levels, so they can become toxic at doses not much above typical needs. Another issue is that many minerals have similar molecular weights and charges. For example, magnesium, calcium, iron, and copper all have similar size and the same electrical charge, and this causes these minerals to compete with each other for absorption. As a result, taking too much of one can cause a deficiency in another.

In conclusion, much can be done to prevent heart attack and stroke just by eating a balanced diet which helps control blood pressure and cholesterol levels and maintains a healthy weight as adults age.

References

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Chau, D.L., Edelman, S.V. Osteoporosis and diabetes. Clinical Diabetes 20(3):153-157, 2002.

Evans, W.E., Johnson, J.A. Pharmacogenomics: the inherited basis for interindividual differences in drug response. Annu Rev Genomics Hum Genet 2:9-39, 2001.

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The Merck Manual of Geriatrics. Merck & Co., Inc, 2004.

Spirduso, W. Physical Dimensions of Aging. Champaign, IL: Human Kinetics. 1995.

Tufts University Diet and Nutrition Letter. Never too late to build up your muscle. 12(September), 6-7, 1994.

U.S. Department of Health and Human Services and U.S. Department of Agriculture. (2005) "Dietary Guidelines for Americans 2005." Available on the World Wide Web: www.health.gov/dietaryguidelines/dga2005/document/pdf/DGA2005.pdf.

Wardlaw, Gordon. Perspectives in Nutrition. New York: McGraw-Hill, 1999.