For the longest time, I thought it was the coffee.
In an attempt to make the brew slightly healthier, I always drank it with about half a cup of warmed skim milk. But even when I went decaf, the morning drink seemed to make me nauseous instead of alert. Some days it caused cramping. Some days things got unmentionably worse.
I gave it up for hot tea with lemon.
But simply giving up coffee didn't seem to stop my frequent tummy troubles. Anticipating when and where I might need a restroom started to take over my life. It wasn't until I'd had a battery of rather invasive and scary tests that my doctor came back with a simple diagnosis: lactose intolerance.
It was something I'd never heard about before, but I was greatly relieved to know that dairy products were the culprit.
In the sphere of health concerns, lactose intolerance doesn't rate high on the alarm scale. It's not life-threatening and can usually be controlled. Yet it can alter the long-term health and lifestyle of the 30 million to 50 million Americans who suffer the digestive distress related to milk, ice cream, cheese and other dairy-based food, according to the National Center for Nutrition and Dietetics.
In the U.S., statistics indicate that lactose intolerance occurs in 90 percent of Asian Americans. That put me, a Japanese American, in that high-risk category. It also strikes 75 percent of African Americans and Native Americans, 50 percent of Latinos and 20 percent of people of European ancestry, many of them Jewish.
Researchers say that genetically, producing lactase is the dominant trait so that if one parent is fine with dairy foods, the children likely will be, too.
"There is definitely a genetic link, but what we're not sure about is how the pattern emerged," says Ann Coulston, a research dietitian and clinical nutritionist at Stanford University Medical Center.
Especially unclear is why people of certain ethnicities are more apt to develop the intolerance. One theory notes that their diets did not include much dairy food until modern times.
What is known is that all sufferers lack sufficient amounts of lactase, the enzyme needed to break down lactose - the sugar found in dairy products. Studies show that only people of Northern European descent keep producing the enzyme throughout their lives, although the amount lessens with age. Those who develop the intolerance lose most of the enzyme in their 20s or 30s.
Without enough of the lactase enzyme, the lactose passes through the intestine without being broken down and absorbed into the bloodstream. The resulting symptoms range from bloating and gas to nausea, severe abdominal pain and diarrhea.
"There's a wide spectrum in the severity of symptoms," explains Barbara Levine, an expert on the subject and clinical professor of nutrition at Cornell University. "Some people can tolerate hard cheeses and cream in their milk; others can't have anything dairy."
"Lactose intolerance has been one of the most difficult things to diagnose," says Levine, "but in the last 10 years, more people and doctors are becoming aware of its prevalence, especially among certain ethnicities."
One caution: A recent study suggested that many people wrongly believe they are lactose intolerant when something else is upsetting their gastrointestinal tract. And, some scientists say, lactose intolerance may have become the trendy ailment of the moment.
Usually, lactose intolerance can be managed with careful monitoring of food. The trick is to find hidden amounts of lactose in foods such as breads and soups and to realize that spaghetti is fine until you sprinkle cheese on top of the sauce.
There are also lactase enzyme tablets that can be taken before eating dairy products. Called by such names as Dairy Ease or Lactaid, they are widely available over-the-counter at drug and health food stores.
But even with the supplement, many people say they can't eat the amount of dairy products recommended as part of a daily diet. And this is what worries doctors and dietitians. Without eating dairy products, it's tough to get enough vitamin D, riboflavin, potassium and most important, calcium.
"The calcium issue is a concern for women anyway, and it's of particular concern when we're talking about Asian women who are lactose intolerant," says Dr. Robert Heaney, a professor of medicine at Creighton University in Omaha, referring to the small stature of most Asian women and the risk of osteoporosis.
"Small-boned women are especially susceptible to calcium loss as they age," adds the osteoporosis expert. "It's very difficult to find alternative foods that supply as much calcium as dairy products."
The recommended daily allowance for calcium ranges between 1,000 and 1,500 milligrams a day for most women. One glass of skim milk supplies about 300 milligrams. A half cup of broccoli has 68 milligrams.
How to get enough calcium and nutrients
If you suspect you might have an intolerance to dairy products, there is a professionally administered breath test that measures the amount of excess hydrogen produced in the body as a result of sugar being improperly digested.
But Barbara Levine, a clinical professor of nutrition at Cornell University, says there is an at-home test: Drink a quart of skim milk first thing in the morning.
"And don't go out for the rest of the day," she warns.
If you exhibit any of the symptoms - bloating, nausea, abdominal cramps, severe gas or diarrhea - chances are you're lactose intolerant.
Nutritionists suggest some of these strategies for eating dairy products and getting enough calcium and nutrients:
-- Drink and eat smaller quantities of dairy products at one sitting and with other foods.
-- Try whole or chocolate milk. The fat and sugar content seems to slow digestion.
-- Eat dairy foods with lower lactose levels, such as aged cheese. Yogurt with active cultures also may be easier to digest.
-- Watch for hidden lactose in products such as nondairy creamers, prescription drugs and baked goods.
-- In addition to the lactase supplements, look for lactose-reduced foods in grocery and health food stores.
-- Eat and drink calcium-fortified products such as orange juice and breads.