I think I'm lactose intolerant because I always get cramps after eating a dish of ice cream, especially if it's really rich. I've started to avoid dairy altogether, but now I'm worried about calcium. What's your advice?
Well, it's quite possible your self-diagnosis is incorrect. If you don't experience digestive problems after drinking milk, for example, it may not be the lactose in the ice cream that's causing the problem.
Lactose intolerance is the inability to fully digest lactose, the sugar found in milk. It's caused by a deficiency in the enzyme lactase, which breaks down lactose into glucose and galactose, two simpler sugars that are easily absorbed into the bloodstream. When lactose isn't broken down, it starts to ferment in the digestive system and can cause bloating, abdominal pain, flatulence or diarrhea.
If your body reacts negatively only when you eat ice cream, it could be that you're consuming more lactose than usual and the lactase in your system can't keep up. (Try a half-portion the next time you treat yourself to ice cream and see if that helps.) Or, it could be something totally unrelated to lactose. The real issue, as you realize, is that you've started to avoid all dairy products, which are among the best sources of calcium out there.
If it helps, your reaction isn't unusual. A February 2010 consensus statement on "Lactose Intolerance and Health" from a National Institutes of Health panel reported that although the true prevalence of lactose intolerance isn't clear, many people who perceive a problem with lactose intolerance avoid dairy and, as a result, do not get enough calcium and vitamin D. That can lead to long-term health risks, particularly osteoporosis and other bone-related issues.
The panel reviewed available research to determine recommendations. While more thorough study is needed, it appears that even people who have been officially diagnosed with lactose intolerance can usually consume 12 grams of lactose -- the amount in one cup of milk -- with no or few ill effects. Often, ingesting even more lactose is possible when consumed with a meal.
Knowing this could help people who believe they are lactose intolerant find ways to get enough calcium in their diet. Youths ages 9 to 18 need 1,300 milligrams of calcium a day; adults ages 19 to 50 need 1,000 milligrams a day; and those age 51 and older need 1,200 milligrams a day. One cup of low-fat milk has about 300 milligrams of calcium.
For detailed information, see the NIH's page on lactose intolerance on its MedlinePlus web site, http://www.nlm.nih.gov/medlineplus/lactoseintolerance.html.
Chow Line is a service of Ohio State University Extension and the Ohio Agricultural Research and Development Center. Send questions to Chow Line, c/o Martha Filipic, 2021 Coffey Road, Columbus, OH, 43210-1044, or firstname.lastname@example.org.
Editor: June is National Dairy Month. This column was reviewed by Julie Shertzer, registered dietitian and program specialist for Ohio State University Extension in the Department of Human Nutrition, in the College of Education and Human Ecology.