Milk and milk products contain a distinctive carbohydrate called lactose that is digested by a lactose-specific enzyme named lactase. Produced by the cells in the small intestine, lactase splits the disaccharide lactose into glucose and galactose. Lactose intolerance occurs when an insufficient production of lactase allows undigested lactose to pass on to the large intestine. Bacterial activity on lactose results in symptoms associated with lactose intolerance. Some studies report that delaying the passage of undigested lactose into the large intestine by consuming full-fat milk increases lactose digestion.
Types of Lactose Intolerance
Primary lactose intolerance occurs when there is a decrease in the quantity of lactase production after weaning. However, symptoms of lactose intolerance only become prevalent as you grow older and develop an inability to digest lactose. An intestinal injury or surgery may affect lactase production and result in secondary lactose intolerance. Lactase production may restart after your recovery. Another cause of lactose intolerance is a congenital defect in which babies cannot produce lactase at all and therefore cannot digest milk. Symptoms of congenital lactose intolerance are prevalent as early as the first week after birth.
Symptoms of Lactose Intolerance
Abdominal pain, bloating, gas, diarrhea and nausea occur 30 minutes to two hours after milk consumption, when undigested lactose reaches the large intestine and is broken down by bacterial activity. Effects and severity of lactose intolerance vary from person to person, but most people with primary lactose intolerance can digest some amounts of milk and milk products.
Effect of Fat on Lactose Intolerance
A review article in the April 2000 issue of the "Journal of the American College of Nutrition" quotes some studies that report better lactose tolerance from full-fat milk than from fat-free milk. The authors suggest that a higher fat content delays gastric emptying time and increases transit time of lactose in the small intestine. This gives the limited amount of lactase more time to act on lactose. Other studies found that although fat delayed emptying of stomach contents into the small intestine, it did not significantly improve lactose digestion or decrease symptoms of lactose intolerance.
Improving Lactose Tolerance
While the consumption of full-fat milk may be an option, you should consider the higher intake of saturated fat associated with it. You may be able to improve lactose tolerance by consuming small quantities of milk and milk products at a time, making milk part of a meal, eating yogurt and cheese, and trying lactose-free milk.
References
- "Journal of the American College of Nutrition"; Lactose Intolerance; Tuula H. Vesa et al.; April 2000
- University of California San Francisco Medical Center: Lactose Intolerance; February 2011
- National Dairy Council; New Directions in Lactose Intolerance: Moving From Science to Solutions: Dietary Strategies and Approaches for Lactose Intolerance; Cecilia Pozo Fileti, R.D.; July 2010
- "The Journal of the American Osteopathic Association"; Lactose Intolerance; R.Alexander Rusynyk and Christopher D. Still; April 2001
- Cleveland Clinic: Diseases and Conditions: Lactose Intolerance Overview
