Quite a few drugs – for example, colchicine, oral antidiabetic agents, and the antibiotic neomycin – can impair absorption of vitamin B12. But because most Americans have good stores of B12 in their livers, it takes prolonged ingestion of these drugs to cause a deficiency.
Long-term use of diuretics, or “water pills,” to treat such conditions as congestive heart failure, can lead to serious potassium depletion. If the potassium loss is not correctedin heart patients taking digitalis, the heart may become more sensitive to the effects of the drug. People taking diuretics regularly should eat foods which are good sources of potassium. These include tomatoes and tomato juice, oranges and orange juice, dried apricots, cantaloupes, figs, raisins, bananas, prunes, potatoes, sweet potatoes, and winter squash.
Modifying the diet to include more foods rich in the vitamins and minerals that may be depleted by certain drugs generally is preferable to taking vitamin or mineral supplements. In fact, supplements of some vitamins can counter the effectiveness of certain drugs.
Fortunately, the diets of most Americans are sufficiently well balanced so that the threat of drug-related nutritional deficiencies can be easily overcome.