The most common complaint among older people is constipation. If you have constipation, check with your doctor who often orders thyroid tests and a barium enema to rule out a cancer or other obstruction or diabetic nerve damage. Usually these tests are normal and you need to correct your diet. Eat whole grains and stop eating foods made from white flour. Exercise and try to empty your colon soon after eating breakfast.

PHYSIOLOGY: After you eat, the pyloric sphincter at the end of the stomach closes, and food is not allowed to pass into your small intestine until is converted to a liquid soup. Some food is absorbed, but most of the liquid soup passes to your colon, where fluid is rapidly absorbed. The longer stool remains in your colon, the more water is absorbed, the harder stool becomes, and the more difficult it is to pass.

HOW DRIED FRUITS PREVENT CONSTIPATION: All carbohydrates are made up of combinations of sugars. Before any carbohydrate can be absorbed, it must first be broken down into single sugars that are almost always absorbed before they reach your colon. Only single sugars can be absorbed. Dried skins of fruits contain fiber that your body cannot break down, and sugars imbedded so deeply in the fiber that these sugars cannot be absorbed in the small intestines. So, when these sugars reach the colon, bacteria ferment them rapidly and break them into 1) small particles that draw large amounts of fluids into the colon, and 2) gas that dilates the colon and pushes stool toward the opening.

TREATMENT: To prevent or treat constipation, the goal is to move everything from your colon as soon as possible because the longer it stays, the harder it becomes.

• Exercise every day . Exercise causes giant contractions of the colon which push food out. The longer and harder you exercise, the greater the movement of food toward the outside.

• Drink plenty of fluid because dehydration increases the rate that fluid is absorbed from your colon.

• Avoid constipating foods: low-fiber foods such as flour and sugar water; and high-fat foods such as cheese, eggs, and meats.

• Eat lots of high-fiber foods that hold extra water in your colon: vegetables, whole grains, beans, nuts.

• Foods particularly effective for pushing food onward include dried fruit, such as prunes, apricots, cranberries or apples.

• Try to empty your colon less than a half hour after eating. It's called the gastro-colic reflex. When food reaches your stomach, the stomach is stretched, sending a message along nerves from the stomach to cause the colon to contract and push foods forward. The longer stool remains in your colon, the drier and harder it becomes. So you want to empty your colon as soon as it fills.

Updated 1/12/15