Understanding the Truths and Misconceptions about Lactose Intolerance
Lactose Intolerance is a commonly cited condition of the inability to drink milk, but it may also be one of the most misunderstood. Most Americans think they have the condition, but actually may not, according to a new consensus conference statement by the National Institutes of Health.
Lactose is the sugar found in milk and dairy products. It is a disaccharide made of two components: glucose and galactose. Lactose is digested and absorbed in the intestine after being broken down by an enzyme called lactase. When the body is deficient in this enzyme, lactose passes through the intestine without being fully absorbed, causing bloating, cramping, intestinal gas, and diarrhea.
There are three major types of lactose intolerance. Primary lactose intolerance is common in areas where children do not drink cow’s milk, such as in Asia or Africa. The body only makes enough lactase enzyme to breakdown incoming dairy products, so when less is eaten, less is made. Some studies have found that Chinese and Japanese populations lose about 20-30% of their ability to digest lactose within three to four years after weaning from breast milk or a milk-based formula.
Other ethnic groups more likely to present with a primary lactose intolerance include African Americans, Native Americans, and Mexican Americans.
The second type is called secondary lactose intolerance, where a condition causes a temporary reduction in lactase production. This can occur after gastrointestinal surgery, when the intestinal villi are disturbed, after a bout with gastroenteritis, or after exposure to intestinal parasites. Irritable bowel syndrome and celiac disease may also influence the ability to digest and absorb lactose.
The third type of lactose intolerance is congential, meaning that it is present at birth. A genetic disorder prevents the enzymatic production of lactase.
Dr. Frederick Suchy of the Mt. Sinai School of Medicine in New York feels that many Americans shun dairy products after inappropriately self-diagnosing lactose intolerance. He is concerned that many will then not get adequate amounts of dietary calcium and vitamin D, necessary for strong bones among other important body functions. While there are many non-dairy forms of calcium available, care in meal planning must be taken to ensure the RDA for these nutrients are met.
For some, a deficiency in the lactase enzyme does not mean completely avoiding all dairy products. In fact, some people can tolerate up to 12 grams of lactose, the equivalent of one cup of milk. Yogurt, buttermilk, and hard cheese are often better tolerated dairy foods because they are slightly lower in lactose. Also, people may better tolerate smaller portions of dairy several times a day, instead of in one large serving.
Also available is an oral over-the-counter enzyme replacement product, such as Lactaid or Dairy Ease. These can be taken with milk products to assist with digestion. Alternative milk products are also available that are low or void of lactose, including goat’s milk, soy milk, rice milk, and almond milk.