Lactose intolerance is perhaps the best-known food intolerance. (Some people
have a shortage of an enzyme called lactase and so can’t digest dairy products.)
But there’s another intolerance—recently named—that causes embarrassment and
discomfort in millions of Americans. It’s called complex carbohydrate
intolerance.

When people with this problem eat complex carbs, such as vegetables, legumes
(for example, kidney beans, lentils, lima beans), grains, and nuts, they suffer
excess gas, cramping, bloating, abdominal pain, and in some instances diarrhea
or constipation.

Complex carb intolerance can have other unhappy consequences as well. For
example, people learn to steer clear of their dietary troublemakers.
Unfortunately, these are the same nutritious foods that health experts recommend
we consume more of to help ward off heart disease, certain cancers, type 2
diabetes, and a number of digestive malfunctions.

Also, some intolerance symptoms mimic other serious abdominal problems. As a
result, sufferers may visit the doctor and a series of diagnostic tests may then
be performed, to no avail.

What causes the intolerance?

People who are intolerant of complex carbs don’t have enough digestive
enzymes to break down complex carbs into simple sugars. Only simple sugar can be
absorbed into the bloodstream from the small intestine. As a result of the
digestive enzyme shortfall, undigested carbohydrates pass into the large
intestine, where they’re fermented by microbes. The products of this
fermentation are the gases hydrogen and carbon dioxide, and fatty acids—which in
turn cause gas and provoke the other characteristic symptoms of complex carb
intolerance.

Across the population, there’s a broad range in the level of enzyme
deficiency, as well as in the tolerance for its consequences. A person may do
fine with a moderate portion of complex carb foods but experience symptoms after
eating a larger serving.

Managing symptoms

People with complex carbohydrate intolerance can try a number of tactics to
minimize symptoms. Besides limiting the amount of complex carbs in their diet,
they may eat more slowly and chew thoroughly. The discomfort of gas may be
avoided by cutting back on chewing gum, hard candy, and tobacco products.
Exercise moves gas more rapidly through the digestive tract and so may reduce
discomfort. A number of over-the-counter products are available. For example,
those containing simethicone are said to reduce gas. There are also remedies for
nausea, indigestion, diarrhea, and constipation. Peppermint and other herbs help
soothe the digestive tract. Beneficial bacteria in the digestive tract called
probiotics may relieve gas and bloating caused by gut microbes. And the
antibiotic tetracycline may be prescribed for bacterial overgrowth in the small
intestines.

Zeroing in

The only treatment that goes to the core of intolerance and effectively
prevents symptoms is enzyme replacement. The digestive enzyme that best
dissolves the many chemical bonds of complex carbs is
alpha-galactosidase. In a number of studies, this enzyme (typically
the over-the-counter product Beano was used) reduced gas, bloating, belching,
and diarrhea. Alpha-galactosidase should be taken whenever an intolerant person
eats at least a half-cup serving of a complex carbohydrate food.

Alpha-galactosidase, which is derived from a mold, is generally
safe. However, it should be avoided by anyone who is allergic to mold. Also, the
enzyme is not recommended for people with diabetes because taking it will result
in more glucose entering the bloodstream from a meal containing complex carbs.
Also, women who are pregnant or breastfeeding should consult with their doctor
before using the enzyme.

Getting it right

With a greater understanding of the source of their problem, people who
experience chronic gas and bloating are more likely to find treatment that lets
them return to consuming a balanced, healthful diet—not to mention the relief
that comes with not having to worry about eating in company.