Consumption of trace minerals can measurably improve disease resistance in the elderly, according to findings at UC San Diego.
"There seems to be an indication that intakes of the Recommended Dietary Allowance for trace minerals, such as iron and zinc, improve the immune response necessary for disease resistance," said Paul Saltman, a researcher at UCSD's biology department.
Saltman and his colleagues supplemented the diets of 17 elderly patients with the RDA equivalent for iron (15 to 18 milligrams), zinc (15 milligrams), copper (2 to 3 milligrams) and manganese (2.5 milligrams) and found positive change in the immune response after three months.
Deficiencies exist in the elderly due to their limited intake of calories and all nutrients, Saltman said. Changes in taste acuity, salivation and gastrointestinal functions, combined with a number of physiological, social and emotional factors, result in decreased food and nutrient intake in the elderly.
"Elderly who do not consume at least 1,600 calories and eat a varied diet that includes red meat, fish and liver, as well as a variety of other foods, could be deficient in trace minerals," Saltman said.
Iron deficiency is widespread in the elderly, particularly in the underprivileged, Saltman said. Iron, as well as zinc, can also increase susceptibility to bacterial infections, he adds.
"Intake of protein food sources--red meat, liver, shellfish and eggs--and to a limited degree milk and green leafy vegetables, is critical to trace mineral stores.
"If the elderly can assess that their diets include meat and other protein sources, milk, cheese and other calcium sources and vitamin sources from fruits, vegetables and whole grains, they can be reasonably assured that they are meeting their nutrient needs for trace minerals.
"Otherwise, I suggest they take an inexpensive one-a-day vitamin and mineral supplement that supplies at least, but not more than, 100% of the RDA."
Saltman advises prudent use of supplements but warns against substituting them for food in a balanced diet.