Progressive development of an intolerance to lactose and decreased lactose absorption during the aging process are inevitable in most people. Reduced intake of milk and milk products containing lactose presents a special problem in older adults. People who have enjoyed milk products throughout their adult life may benefit from continuing their use in later years if severe lactose intolerance does not become a prohibitory factor.
Lactose, or milk sugar, is a small carbohydrate composed of 1 unit of glucose attached to 1 unit of galactose. An enzyme called lactase in the lining of the small intestine breaks down lactose into its individual units, which can then be absorbed into the bloodstream. A deficiency of the lactase enzyme can produce a condition called lactose intolerance. Instead of normal digestion and absorption in the small intestine, the lactose travels intact to the lower intestinal tract where bacteria ferment it to produce energy for their growth. Excess lactose fermentation can produce large amounts of gas and cause abdominal bloating, discomfort, diarrhea and nausea.
Aging and Lactose Intolerance
In most people, the amount of lactase produced in the small intestine is maximum at birth and begins to decline within a few years thereafter. Race and family heritage can influence the rate of decline in lactase production during aging. In some people, lactase production continues through most of their adult lives -- a condition referred to as lactase persistence. Even in lactase-persistent individuals, once you exceed age 74, normal aging of the small intestine may significantly increase lactose malabsorption. However, symptoms of lactose intolerance may be less apparent, according to a clinical study published in the December 2001 issue of “Scandinavian Journal of Gastroenterology.”
Special Considerations in Elderly People
People with lactose intolerance often avoid milk products. Calcium absorption efficiency declines with age, and voluntary milk avoidance in lactose-intolerant older people may further increase the risk for osteoporosis. Lactase deficiency was associated with a reduced bone mineral density in the hip and lower spine, and with increased bone fracture risk in postmenopausal women, according to a clinical study published in the January 2004 issue of “Journal of Bone and Mineral Research.”
Inflammatory bowel diseases, such as ulcerative colitis and Crohn's disease, are often first diagnosed in the elderly. These disorders cause damage to the intestinal lining and compromise nutrient digestion and absorption. A substantial proportion of people with inflammatory bowel disease are sensitive to lactose and experience symptoms of lactose intolerance, according to an October 2011 issue of “Alimentary Pharmacology and Therapeutics.”
Management of Lactose Intolerance
Lactose intolerance may be diagnosed either clinically or with a breath test that can measure elevated levels of the byproducts of bacterial lactose fermentation -- hydrogen and methane gas. People with lactose intolerance can usually tolerate an amount of lactose present in 1 cup of milk without experiencing severe symptoms, however. Ingestion of small portions of milk products evenly divided throughout the day may be encouraged in older adults to help prevent skeletal problems associated with calcium deficiency, according to the conclusions in the “Scandinavian Journal of Gastroenterology” report. The U.S. Department of Health and Human Services has determined that there is insufficient evidence to promote the use of low-lactose products, lactase supplements, fermented milk products or probiotics for effective treatment of lactose intolerance.
- U.S. Department of Health and Human Services – Agency for Healthcare Research and Quality: Lactose Intolerance and Health
- National Institutes of Health – Online Menelian Inheritance in Man: Lactose Intolerance, Adult Type
- Scandinavian Journal of Gastroenterology: Lactose Malabsorption and Intolerance in the Elderly
- Journal of Bone and Mineral Research: Genetic Predisposition for Adult Lactose Intolerance and Relation to Diet, Bone Density, and Bone Fractures
- Gastroenterology and Hepatology: Inflammatory Bowel Disease of the Elderly
- Alimentary Pharmacology and Therapeutics: Association of Lactose Sensitivity With Inflammatory Bowel Disease – Demonstrated by Analysis of Genetic Polymorphism, Breath Gases and Symptoms
- BMC Gastroenterology: A Comparison of Diagnostic Tests for Lactose Malabsorption – Which One is the Best