With advances in medicine, more people are reaching a ripe old age. The factors contributing to longevity include better hygiene, nutrition, preventive medicine, and (possibly) antibiotics.
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 litres 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.
A large number of the elderly take drugs to increase urine flow (diuretics), resulting in low serum sodium.
Potassium deficiency occurs with less than 50 mEq (mmol) intake per day. The patients exhibit muscle weakness, apathy, and fecal impaction. Constipation leads to loss of appetite and further restriction in food intake.
If the kidneys are damaged, great care should be taken while administering diuretics.
Some dietary advice on purchasing food within the financial means may go a long way in providing better nutrition.
The lower metabolic rate in the elderly reduces calorie requirement. A retired life, arthritis and angina reduce physical activities to a minimum. Calories should therefore be restricted to combat any tendency to obesity. On the other hand, if there is loss of weight, adequate calories should be supplied to regain normal weight.
Deficiency of protein is common in the elderly, and is one of the factors producing edema, anemia, and lowered resistance to infections. Protein rich foods like meat and fish are expensive, require cooking, and may be difficult to chew without teeth. Among vegetarians, pulses provide an appreciable amount of protein, though in old age such foodstuffs increase flatulence.
The daily protein intake should be about 70 g. If this amount cannot be provided with regular meals, commercial protein preparations or skimmed milk powder should be given as a supplement.
With advancing age, fats are difficult to digest. Older people tend to have higher blood cholesterol level. Much attention need not be paid to reducing it. Ingestion of unsaturated fats, like vegetable oils (except coconut and palm oil), reduces blood cholesterol. About 40-50 g fat daily should be advised.
Old people tend to take more carbohydrate and less protein. Bread, biscuits, cakes and pastry are cheap, readily available, do not require cooking, and can be stored; hence, they form the bulk of the diet. Such a diet produces protein deficiency, anemia, and constipation due to lack of roughage. Anemia and constipation in turn reduce appetite and enhance malnutrition.
VITAMIN AND MINERALS
Vitamin deficiency, particularly of vitamin B-complex, is common with an unbalanced diet; a daily supplement of a multivitamin tablet is advised.
Vitamin C deficiency, and sometimes even scurvy, occur in those not eating fruits and vegetables and those who cannot cook (widowers). In institutions for the old, mass catering destroys vitamin C. There is a seasonal variation in vitamin C intake, being lower in winter than in summer. The most useful test to diagnose deficiency is white cell ascorbic acid (normal-over 2 mg per 100 ml).
The blood pressure, particularly systolic pressure, rises with old age. The intake of sodium should not be drastically reduced; a sodium-poor diet is also deficient in protein. Sodium restriction is not more likely to decrease blood pressure in the older than in the younger subject. Calcium supplement mayor may not decrease blood pressure.
Osteoporosis is common; the exact reason is not determined, but it may be partly due to diminished intake and absorption of calcium, and partly to a deficiency of sex hormones leading to loss of protein. A combination of androgen and estrogen has been recommended for senile osteoporosis.
An adequate fluid intake should be ensured. Intake may be varied according to the diet and season. The excretion of over 1200 ml of urine indicates proper fluid balance. Many old people are reluctant to drink liquids as they have to urinate frequently, particularly with diseases like diabetes, chronic nephritis, and prostatic enlargement. They should be induced to take sufficient liquids during the day, and to refrain from drinking at night so that their sleep is not disturbed.
About 1.5 million people in the US currently reside in 20,000 nursing homes. Many of these require assistance in eating. Normal eating requires more than the serving of complete nutrition. There should be adequate supervision to see that the elderly also consume the food served.
The elderly should be given small frequent feeds and an early dinner. This prevents disturbed sleep due to gaseous distension. Not infrequently, old people have poor coronary circulation, and so physical exertion-particularly climbing stairs immediately after a meal should be avoided.
Secondary hyperparathyroidism is common; this may be the result of both renal insufficiency and hypovitaminosis