Nutrition in the elderly with particular reference to essential trace elements

The aim of this study was to investigate the nutritional status of 24 apparently healthy and 20 housebound elderly people. Subjects were studied whilst they lived in their own homes, ate self-selected diets and continued their usual daily activities. In addition to metabolic balance studies being used to assess the adequacy of the diet with regard to the essential trace elements zinc, coper, iron, manganese, chromium, selenium, cobalt and nickel, and the macronutrients nitrogen, calcium, phosphorus and magnesium, the levels of several elements were also determined in various blood fractions. Suitable analytical techniques were developed for the measurement of certain trace elements in biological material. Information was also obtained relating to the biochemical, haematological and anthropomorphic status of the subjects. The intake and excretion of the nonessential elements lead and cadmium was also measured. The healthy subjects were in equilibrium for all of the essential elements measured (with the exception of positive selenium balance) in spite of many of the mean dietary intakes falling below the recommended intakes for younger individuals. The levels of the majority of the nutrients measured in plasma, whole blood and leucocytes were comparable with those found for younger people. The results suggested that the dietary intake of trace elements and macronutrients in the healthy elderly people was compatible with good health and allowed certain recommendations relating to adequate dietary intakes to be made. The findings for the housebound were quite different from those obtained for the healthy elderly. They had a low dietary intake of, and were in negative balance for, zinc and copper. The levels of these elements in the leucocytes were also reduced when compared to the healthy elderly. The housebound were in apparent equilibrium for selenium but their status was quite different to that observed in the healthy group. The subjects were also in overall negative balance for nitrogen, calcium and phosphorus and had certain blood indices suggestive of a suboptimal nutritional state. The possible causes of these findings are discussed and recommendations have been made with regard to improving the nutritional status of this group of people.