• Old people have considerable weight loss. If they are living alone, their diet tends to become unbalanced as they are reluctant to cook; and, to avoid the trouble of going to a restaurant, they skip meals and frequently subsist on tea and snacks. Their food intake may be further limited by exclusion of certain foods because of high blood pressure, diabetes, heart failure, and kidney diseases.
• Their appetite may be reduced due to restriction of physical activity by arthritis, worries about their own failing health and constipation.
• Digestion may be impaired by improper mastication with artificial teeth. A diet for them should, therefore, help them maintain good health.
• The elderly do not adjust easily to variations in fluid intake. The proportion of fat increases by 5%-10% and thus the body water decreases. Therefore, a 75-year-old man weighing 70 kg may have as much as 7-8 liters less body water than a 35-year-old of the same weight.
• The elderly also have impaired response to dehydration. The diagnosis of dehydration is by examining blood, which shows high serum sodium. The urine is not highly concentrated. The thirst sensation is not so acute.
The bones show osteoporotic changes because of deficiency of calcium, protein, vitamins, minerals and hormones.Osteomalacia manifests as backache, bone pain, and muscle weakness, with low serum calcium and phosphorus, and high phosphatase.
• A large number of the elderly take drugs to increase urine flow (diuretics), resulting in low serum sodium. This causes weakness, confusion, giddiness, low blood pressure on standing up (postural hypotension), falls, transient hemiparesis, and fits.2.
• If the kidneys are damaged, great care should be taken while administering diuretics. Potassium supplementation, too, should not be indiscriminate, because rising potassium level in blood may be dangerous and may cause irregularities of the heart and sudden death.
• Anemia is common in the elderly. Salicylates and anti-inflammatory drugs taken over a prolonged period for chronic arthritis tend to produce alimentary blood loss and anemia. Vitamin B and folic acid deficiency are also common. Anemia in the elderly should be investigated to exclude cancer.
• The elderly are often depressed; this may even be induced by drugs prescribed by physicians. The mental faculty is depressed not only due to arteriosclerosis, but also due to poor intake of vitamins and minerals