Originally published in The Ottawa Citizen June 3, 2003
Original Title: Lactose intolerance is not an allergy
Often, the term milk allergy is used to describe any physical reaction to milk consumption. Many mistake lactose intolerance for milk allergy.
Lactose intolerance is the inability to break down the dairy sugar lactose (found in milk, cheese and ice cream) into glucose and galactose because of the absence of the enzyme, lactase.
For most lactose intolerant people, ingestion of eight to 12 ounces of milk can produce intestinal cramps and pain, gas (flatulence), bloating and loose watery stools.
These symptoms can vary depending upon the amount of ingested lactose, the person’s ethnic origin and age. Older individuals tend to have less lactase and more severe symptoms.
In milk allergy, the milk proteins cause an allergic reaction that includes itchy red rashes, hives or breathing problems among other symptoms.
Given our culture’s northern European origins, we tend to think lactose intolerance is an abnormal condition. However, it is one of the few lifelong inherited “disorders” that is normal for most people and for others the result of an intestinal infection, medication use or disease.
Although some people can drink a small amount of milk without any symptoms, others are unable to tolerate it.
Lactase levels decrease (hypolactasia) in all land mammals including humans after weaning. Ninety to 95 per cent of lactase is lost by two years of age and continues to wane throughout life.
Worldwide, the loss of lactase is a natural phenomenon. Indeed, almost 100 per cent of adult Asians and North American aboriginals, 60 to 80 per cent of blacks and Ashkenazi Jews, 50 to 80 per cent of Latinos and two per cent of whites of northern European origin lose the lactase enzyme.
It is uncertain whether continued lifetime consumption of dairy products stimulates the production and retention of lactase. It could also be the result of a genetic mutation leading to continued lactase production.
The absence of lactase leaves the undigested lactose to concentrate within the small intestine. This draws fluid into the intestine by a mechanism (similar to some laxatives) called osmosis.
As the lactose moves along the intestinal tract, the intestinal bacteria will ferment it producing gas and further fluid accumulation within the gut.
Lactose is present in some prepared foods including:
- Breads and baked goods
- Processed breakfast cereals
- Pancake, biscuits, and cookie mix
- Instant mashed potatoes
- Soups
- Instant breakfast drinks
- Some margarines
- Non-kosher luncheon meats
- Salad dressings
Candies and other snacks - Powdered coffee creamers
- Whipped toppings
- Yogurt with live bacterial cultures contains bacterial enzymes that help digest lactose.
Some people may tolerate some dairy products like chocolate milk, skim milk and ice cream.?
Dairy products provide about 75 per cent of the daily-recommended calcium plus vitamin A and D, riboflavin and phosphorus.
If dairy products are not an option, eating other high-calcium containing foods like oysters, sardines, shrimp, broccoli, brussel sprouts, kale, collard and mustard greens are reasonable substitutions. Certain brands of orange juice have added calcium.
The mainstay of treatment is dietary restriction of lactose-containing foods. Lactase enzyme supplementation can help people with mild lactose intolerance but are not a substitute for dietary restriction because they may not eliminate all of the symptoms. Nondairy drinks, such as soymilk and rice milk are useful substitutes for milk. Most will tolerate non-dairy synthetic adjuncts like Coffee-Mate.
Drinking smaller servings of milk products is less likely to cause problems.
Combining other foods when drinking milk can slow the process of lactose digestion and reduce the symptoms of lactose intolerance.
Ice cream, milkshakes and aged (hard) cheeses are easier than milk for most people with lactose intolerance but they are high in fat. People with normal weight and cholesterol levels can try them.
Lactaid, a lactose-reduced milk has about 70 per cent less lactose than regular milk can substitute for regular milk. You can also add lactase enzyme into milk prior to drinking.
Irritable bowel syndrome (IBS) is a non-fatal gastrointestinal disorder that can mimic lactose intolerance. This complicates the diagnoses because milk products can cause the same reaction for both conditions. Indeed, 25 per cent of IBS sufferers are intolerant of dairy products.
Restricting lactose may improve these problems. There are diagnostic tests for lactose intolerance that can help differentiate between the two problems.
People who develop lactose intolerance later in life may have colitis or other serious intestinal disorder and should consult their doctor.
© Dr. Barry Dworkin 2003