Not milk? If you regularly develop digestive symptoms, such as abdominal cramps, bloating, gas, diarrhea, or nausea shortly after drinking milk or consuming food with dairy, you're not alone. But is it an allergy or an intolerance? Here's the difference.

Lactose Intolerance

Lactose intolerance is the inability to fully digest lactose, the sugar in milk. Lactase is the enzyme responsible for breaking down lactose into two simple sugars, glucose and galactose, which are then absorbed in the blood stream. About 50 percent of Americans are lactose intolerant, although the rates are higher for African Americans, Asians, Hispanics, American Indians, and individuals with celiac or Crohn's disease.

Milk Allergy

Some individuals, however, have a true milk allergy. Their immune system identifies milk proteins as harmful and goes into attack mode. Allergic reactions usually occur shortly after consuming milk and symptoms include wheezing, vomiting, hives, digestive problems, and, in rare cases, anaphylaxis, the narrowing of the breathing airways. Long term, milk allergies can cause loose, bloody stools, diarrhea, cramps, coughing or wheezing, runny nose, watery eyes, itchy rash, and colic in babies. Most children outgrow milk allergies by age three.

Unfortunately, for those who are allergic to milk, avoiding dairy is necessary, but not sufficient. Many products include hidden sources of milk proteins. Read ingredient lists carefully, and be alert for casein (a milk derivative) or whey, the two main proteins that cause an allergic reaction. Also, avoid products with ingredients such as milk solids, non-fat dry milk products, and milk by-products.

Missing Out on the Health Benefits of Milk?

The United States Department of Agriculture's (USDA) food pyramid recommends three glasses of milk per day. Milk advocates tout it as a great source of calcium, vitamin D, and protein. However, some health experts believe milk does not live up to its reputation and, in fact, may have negative health effects.

Mark Hyman, MD, points out that until about 10,000 years ago, we didn't domesticate animals so we did not have access to cow's milk. Dr. Hyman says humans did not evolve to digest milk regularly, and typically stop producing significant amounts of lactase by age five.

Hyman, who is the head of nutrition at Harvard's School of Public Health, is one of the most vocal critics of the USDA's dairy guidelines. He says claims of milk's benefits-such as reducing fractures, for example-are not based on scientific evidence. Furthermore, countries with the lowest dairy consumption also have the lowest rates of osteoporosis.

Instead of consuming dairy to ensure healthy bones, Hyman recommends exercising and obtaining adequate calcium primarily from dark green leafy vegetables, sesame tahini, sea vegetables, and sardines or salmon with the bones.

Alison Massey, RD, reviewed this article.




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Hyman, Mark, MD. "Dairy: 6 Reasons You Should Avoid It at all Costs." Blog. Web. 24 June 2010.