Your digestive system is an efficient factory that takes the raw materials you supply through your diet, breaks those materials down, uses what it can for maintenance and energy, then eliminates the rest through the efficient trash compactor of your large intestine. Parts of many foods you eat are indigestible by your body but are still important to your health. Other foods may normally be digestible, but due to malabsorption disorders, your body may be unable to make use of them.
The Digestive System
Your mouth is the beginning of your digestive system. Your saliva produces amylase, an enzyme that begins the process of digesting carbohydrates. After chewed food moves through your esophagus and into your stomach, an enzyme called pepsin goes to work on protein. Stomach acid also works to break down the membranes of the cells in the swallowed food. From the stomach, the food mass moves into your small intestine. Here pancreatic enzymes finish the work of digesting carbohydrates and assist bile from the liver in breaking down fats. Nutrients are absorbed in your small intestine. What’s left moves into your large intestine where water is reabsorbed, making stool more solid.
Dietary Fiber
Fiber is carbohydrates that your body cannot digest. Any food you eat that comes from a plant source contains fiber. Soluble fiber, present inside the cells of plants, dissolves in water. It slows the movement of food in the digestive tract, and in so doing, helps control blood sugar levels by slowing the absorption of glucose. Soluble fiber also helps lower cholesterol. Insoluble fiber is present in the cell walls of plants. It adds bulk to stool and keeps it moving through the large intestine, helping to prevent constipation, diverticulosis and hemorrhoids.
Malabsorption Syndrome
Food intolerances and diseases -- or their treatment -- can impair nutrient absorption. These include Crohn’s disease, celiac disease, bacterial infections, lactose intolerance, pancreatitis, AIDS and cancer. Excessive use of alcohol, laxatives and antibiotics can also impair absorption. Because unabsorbed nutrients pass through urine or stool, your doctor can order tests to find the cause. For example, an abnormal amount of fat in stool indicates malabsorption syndrome. To measure fecal fat, you eat at least 80 g of fat per day and collect your stools for one to three days. A normal amount of fat in stool is less than 7 g. If you excrete up to 30 g per day, it suggests malabsorption due to bile acid deficiency or an overgrowth of bacteria. Stool containing between 30 to 60 g indicates celiac disease, while up to 100 g can indicate a pancreatic problem.
Tips for Improving Absorption
To help your body absorb nutrients, chew food thoroughly before swallowing to expose it to digestive enzymes in your saliva, as well as break it down into smaller pieces, providing more surface exposure to digestive fluids in the stomach. Eat fruits, vegetables and grains for dietary fiber. Limit use of antibiotics, laxatives and alcohol. Finally, if you suspect a malabsorption issue, contact your doctor.
References
- National Digestive Diseases Information Clearinghouse; Your Digestive System and How It Works; April 2008
- Colorado State University Extension; Dietary Fiber; J. Anderson, et al.; December 2010
- NYU Langone Medical Center; Malabsorption Syndrome; S. Aaron, M.S., R.D.
- MUSC Digestive Disease Center: Patient Information: Malabsorption Tests
