In seniors, incontinence is often caused by weakening of the bladder muscles. Drinking at least 6 to 8 cups of fluid each day is important in guarding against dehydration. Reduced muscle action and drinking too little fluid play a part in causing constipation. Laxatives should not be used to treat constipation unless recommended by a doctor. But when mixed together, foods and medicines may combine in a way that can keep important nutrients in foods from being used by the body or make drugs less effective.
Some drugs interfere with the body's uptake of important nutrients.
For example, antacids that contain magnesium and aluminum hydroxide may lower uptake of vitamin A in the body. For this reason, mineral oil should not be used as a laxative. Some foods may interfere with the body's uptake of medicine. Dairy products interfere with the absorption of tetracycline, an antibiotic. Some foods may increase the body's uptake of medicine.