A diminished sense of taste and smell, loneliness, physical and mental handicaps, immobility, and chronic illness can militate against adequate dietary intake in the elderly. These changes and a reduction in physical activity result in lower energy and protein requirements compared with those of younger adults. A and B 12 and interferes with the metabolism of protein and energy sources. Some patients with cancer and many with AIDS have anorexia, which complicates treatment. A physician should ensure that biotin, vitamin K, selenium, molybdenum, manganese, and zinc are adequately supplied.
Iron deficiency is the only risk.
However, their lifestyle usually includes regular exercise and abstention from alcohol and tobacco, which may contribute to their better health. Vegans consume no animal products and are susceptible to vitamin B 12 deficiency. Yeast extracts and oriental-style fermented foods provide this vitamin. Intake of calcium, iron, and zinc also tends to be low. A fruitarian diet , which consists solely of fruit, is deficient in protein, salt, and many micronutrients and is not recommended.