Lactose intolerance is the inability to digest lactose, the sugar found in milk and dairy products, and affects approximately 25 percent of American adults, although the rate varies according to race and age. The intolerance, which can cause gas or diarrhea, varies in severity, so most people are still able to consume at least some dairy.
The NIH Consensus Development panel said that very little is understood about the health outcomes of restricting dairy consumption, although it has been suggested that lactose avoidance could result in deficiencies of calcium and vitamin D, among other nutrients. Such deficiencies have been linked to chronic health problems, including increased risk of osteoporosis and decreased bone health.
Chief of pediatric hepatology at Mount Sinai School of Medicine and panel and conference chairperson Dr. Frederick Suchy said: "It is startling and disappointing to learn how little we know about the consequences of avoiding lactose-containing products. 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."
Therefore, the panel has called for further research into possible health impacts associated dairy avoidance to be carried out across ages and ethnic groups. Lactose intolerance affects more than 90 percent of Asians and Native Americans, compared to around 75 percent of African Americans, 50 percent of North American Hispanics and about ten percent of European Americans.
But many people are also self-diagnosing lactose intolerance, and this could become particularly problematic if self-diagnosed parents put their children on lactose-restricted diets in the fear that they could also experience symptoms.
Dr. Suchy said: "A lot of people who think they have lactose intolerance don't. 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."
For those who have been diagnosed as lactose intolerant, a number of strategies have been proposed in order to prevent dietary deficiencies. These include supplementation, consuming small amounts of lactose throughout the day, combining lactose-containing products with other foods, increasing tolerance by gradually increasing dairy intake over time, eating low-lactose dairy products, and using probiotics.
Meanwhile, the market for lactose-free dairy products is growing rapidly; US demand for lactose-free milk has increased by 20 percent per year since 1997.