On Nutrition: How Fare the Elderly?

Article excerpt

"Nutritional status surveys of the elderly have shown a low-to-moderate prevalence of frank nutrient deficiencies, but a marked increase in the role of malnutrition and the evidence of subclinical deficiencies. Recognition of the changes in nutrient requirements with age and selection of healthy, nutrient-dense foods by older adults can contribute significantly to their adding more life to their years."

--Dr. Jeffrey Blumberg, Human Nutrition Research Center on Aging, Tufts University.

Knowledge has been scanty regarding the nutritional requirements of the elderly. It was long assumed, falsely, that their needs were quite similar to those of younger adults. In recent years, with interest and funding, researchers have begun to discover distinct and substantial differences of the elderly's nutritional needs. Their physiological status and overall health tend to differ from younger adults. Yet, in dietary guidelines up to the present, these two groups have been lumped together in one broad classification, as if the requirements were the same.

For the first time, the forthcoming dietary reference intakes that will update and expand the existing Recommended Dietary Allowances (RDAs) from the last edition (1989) will have a separate category for the elderly.(*)

Recent scientific findings indicate that, to meet elderly needs, the current RDAs may be too low for many nutrients, and too high for a few. There is growing consensus that the goals of the RDAs should be not only to prevent nutrient deficiencies, but to reduce major chronic diseases (e.g., osteoporosis) in the elderly. Reduced energy needs in aging result from the decline in functioning of the metabolic rate, and the lessening of physical activity. At the same time, there is increased need for some nutrients, so the diet of the elderly needs to be nutrient-dense.

The following surveys up-to-date information regarding the nutrient needs of the elderly, covering vitamins, minerals, trace minerals, protein, and other dietary nutrients.

Vitamin Needs

* Vitamin [B.sub.12] -- Serum levels of vitamin [B.sub.12] (cyanocobalamin) decline in aging. Formerly, the prevalence of [B.sub.12] deficiency in the elderly was underestimated. Although it was recognized that anemia could occur in the elderly who were severely depleted of [B.sub.12], those with less severe deficiencies were not recognized. Over time, milder [B.sub.12] deficiencies can lead to various neurological symptoms, such as a burning sensation in the tongue, tingling or numbness in the hands or feet, impaired balance, mental confusion, and dementia. Symptoms may appear even before [B.sub.12] levels drop below the lower limit of the normal range.

It is estimated that about 30% of the elderly are deficient in [B.sub.12] due to atrophic gastritis, an inability of the stomach to secrete enough gastric acid and pepsin to digest food. The "intrinsic factor" is a substance secreted by the stomach that binds [B.sub.12] to the intestinal wall and prepares it for transit into the bloodstream so that [B.sub.12] and other nutrients--such as folate, calcium, and iron--can be absorbed and utilized. If [B.sub.12] deficiency remains uncorrected, bacterial growth, too, can contribute to [B.sub.12] malabsorption.

Many cases of atrophic gastritis result from chronic Helicobacter pylori infection, which is associated with stomach ulcers (see "Good News for Gastric Sufferers," CR, October 1993). People with this type of gastritis may absorb unbound [B.sub.12] normally, but are unable to absorb protein-bound [B.sub.12] from foods. In such cases, a [B.sub.12] supplement may be helpful.

Intramuscular injections (shots) of [B.sub.12], or nasally administered or tableted [B.sub.12] have been given regularly to some vitamin [B.sub.12]-deficient elderly persons. Such supplementation may be helpful in the early stage of atrophic gastritis, because the crystalline form of [B. …