Lactose intolerance is a real and important clinical syndrome, but quantifying its public health burden is challenging. An NIH Consensus Development panel was convened this week to assess the available evidence on lactose intolerance and health across the age spectrum and across racial and ethnic groups.
The panel will hold a telebriefing to highlight their findings today at 2:00 p.m. EST. Reporters may participate by calling 888-428-7458 or visit http://consensus.nih.gov/2010/lactosemedia.htm for more information.
Many individuals with diagnosed or perceived lactose intolerance avoid dairy products, which constitute a readily accessible source of calcium, other nutrients, and vitamin D (when fortified). Inadequate consumption of these nutrients may increase the risk for chronic health problems, including osteoporosis and decreased bone health.
The panel defined lactose intolerance as the onset of gastrointestinal symptoms--diarrhea, abdominal pain, flatulence, and/or bloating--after ingesting lactose-containing foods and beverages; this is due to deficient levels of lactase, an enzyme necessary to break down lactose. Lactose malabsorption occurs when lactose is incompletely broken down in the intestine, which may or may not result in gastrointestinal symptoms after eating dairy products. Reduction of lactase in humans occurs in childhood and persists through the lifespan in most individuals (lactase nonpersisters). These individuals may or may not have the gastrointestinal symptoms of lactose intolerance. Understanding the distinction and interplay between these conditions is important when considering ways to meet nutritional needs.
"A lot of people who think they have lactose intolerance don't," said panel and conference chairperson Dr. Frederick J. Suchy, chief of pediatric hepatology at Mount Sinai School of Medicine. "They may have other conditions, or they may just need to consume smaller amounts of dairy products. Whether they are truly lactose intolerant or not, it is important that they meet recommended intakes of calcium and other essential nutrients."
Many individuals mistakenly ascribe symptoms of a variety of intestinal disorders, including irritable bowel syndrome and inflammatory bowel disease, to lactose intolerance and avoid lactose-containing foods without undergoing testing. This misconception becomes intergenerational when self-diagnosed lactose-intolerant parents place their children on lactose-restricted diets in the mistaken belief that they will experience symptoms.
"It is startling and disappointing to learn how little we know about the consequences of avoiding lactose-containing products," Dr. Suchy added. "Health care providers are concerned, but we don't have good data on bone health outcomes in people who have lactose intolerance or who avoid dairy products for other reasons."
For diagnosed lactose intolerant individuals, multiple management strategies have been proposed. These include distributing lactose intake throughout the day and/or combining it with other foods, choosing non-dairy foods rich in the nutrients found in dairy products, taking nutritional supplements, ingesting incremental amounts of dairy products over time to increase tolerance, consuming reduced-lactose dairy products, and using probiotics (in supplements and foods). The panel emphasized the need for additional research to better understand the effectiveness of these approaches for decreasing symptoms, optimizing nutritional intakes, and improving health outcomes, with special emphasis on diverse populations.
The panel encouraged health care providers to offer personalized, culturally-sensitive management strategies based on individual preferences. Depending on a variety of factors, some affected individuals could be counseled on ways to increase dairy intake while others could be urged to meet nutrient requirements from other sources. For example, studies show that when consumed with other foods, even individuals diagnosed with lactose malabsorption can consume at least one cup of milk with few or no symptoms.
An updated version of the panel's draft consensus development conference statement, which incorporates comments received during this morning's public session, will be posted later this evening at http://consensus.
The 14-member consensus panel included experts in the fields of internal medicine, pediatrics, pediatric and adult endocrinology, gastroenterology, hepatology, neonatology and perinatology, geriatrics, racial/ethnic disparities, radiology, maternal and fetal nutrition, vitamin and mineral metabolism, nutritional sciences, bone health, preventive medicine, biopsychology, biostatistics, statistical genetics, epidemiology, and a public representative. A complete listing of the panel members and their institutional affiliations is included in the draft conference statement. Additional information about today's telebriefing, conference materials including panel bios, photos, and other related resources, are available at http://consensus.
The conference was sponsored by the NIH Office of Medical Applications of Research and the Eunice Kennedy Shriver National Institute of Child Health and Human Development along with other NIH and Department of Health and Human Services components. This conference was conducted under the NIH Consensus Development Program, which convenes conferences to assess the available scientific evidence and develop objective statements on controversial medical issues.
In addition to the material presented at the conference by speakers and the comments of conference participants presented during discussion periods, the panel considered pertinent research from the published literature and the results of a systematic review of the literature. The systematic review was prepared through the Agency for Healthcare Research and Quality Evidence-based Practice Centers (EPC) program, by the University of Minnesota Evidence-based Practice Center. The EPCs develop evidence reports and technology assessments based on rigorous, comprehensive syntheses and analyses of the scientific literature, emphasizing explicit and detailed documentation of methods, rationale, and assumptions. The evidence report on lactose intolerance and health is available at http://www.
The panel's statement is an independent report and is not a policy statement of the NIH or the federal government. The NIH Consensus Development Program was established in 1977 as a mechanism to judge controversial topics in medicine and public health in an unbiased, impartial manner. NIH has conducted 121 consensus development conferences, and 33 state-of-the-science (formerly "technology assessment") conferences, addressing a wide range of issues. A backgrounder on the NIH Consensus Development Program process is available at http://consensus.
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