Living With Lactose Intolerance
Difficulty digesting dairy products
is a surprisingly common problem that can be addressed with
careful attention to one’s diet.
Although dairy products are ubiquitous in the Western diet (and
a common source of calcium), a large portion of the population
has at least some difficulty digesting milk and foods made with
milk. In fact, this condition—called lactose intolerance—affects
up to 50 million Americans. But its extent varies widely by race
and ethnicity. People of Northern European descent are affected
less frequently than blacks, American Indians, and Asian-Americans.
Lactose intolerance comes in degrees, and many people who have
difficulty digesting lactose can still consume small amounts
of dairy products—such as milk, yogurt, and cheese—without
experiencing undue symptoms. However, some people are severely
lactose intolerant and need to eliminate dairy completely from
What Is Lactose Intolerance?
Lactose intolerance is a deficiency of the enzyme lactase, which
is responsible for the digestion of lactose, the major sugar
in milk. (Milk and all products made from milk contain lactose.)
Normally lactase, which is produced in the lining of the small
intestine, breaks down lactose into the simpler sugars glucose
and galactose. The liver then converts galactose into glucose,
which enters the bloodstream and is used by cells as an energy
source. Most people with lactose intolerance do not have enough
lactase to digest lactose properly.
In many people, the ability to digest lactose declines with
age. They begin to produce less lactase after age two but usually
experience no symptoms. As some people age, however, the inability
of the small intestine to produce a sufficient amount of lactase
to break down lactose can start to cause symptoms: As lactose
enters the colon, bacteria use it to form gases and other products
that can result in the classic manifestations of lactose intolerance—gas,
bloating, crampy abdominal pain, and diarrhea.
Diagnosing Lactose Intolerance
Lactose intolerance usually develops slowly, and the symptoms
associated with it can have other causes. If you think you are
lactose intolerant, you can first check for it on your own. Try
excluding all dairy products from your diet for about three days;
if drinking a glass of milk after this period causes symptoms,
you may be lactose intolerant.
Your doctor can confirm a diagnosis of lactose intolerance by
taking a medical history and discussing with you the results
of your dietary manipulations. If necessary, the doctor can run
a blood or breath test to confirm the diagnosis.
Dealing With Lactose Intolerance
The amount of lactose that lactose-intolerant people can handle
varies widely; some experimentation should help you determine
what you can eat. In most cases, dairy products don’t have
to be avoided. Yogurt and aged cheeses, for example, may be well
tolerated because they contain lactase-producing bacteria that
lower their lactose content. A cup of milk per day, particularly
when consumed with other foods, may be possible for many people
who are lactose intolerant. And recent studies have suggested
that gradually increasing the amount of lactose in your diet
may help improve your tolerance.
In addition, various digestive aids are available to help people
consume lactose better. For example, the addition of lactase-containing
drops to milk can convert 75% to 90% of the lactose to glucose
and galactose after overnight refrigeration. Specialty milks
are also available that have lactase added during the manufacturing
process to reduce significantly the amount of lactose in them.
And tablet forms of lactase can also be taken with dairy products,
but be aware that these products vary in their ability to reduce
symptoms and may not entirely relieve the effects of lactose
intolerance. Your doctor can advise you on which ones to use.
People with severe lactose intolerance should try to remove
not only obvious sources of lactose—such as milk, yogurt,
and cheese—but also “hidden” sources from their
diet. These sources include some baked goods, processed breakfast
cereals, salad dressings, mashed potatoes, candies, soups, and
even medications and vitamins. The ingredients “milk,” “whey,” or “curds” on
a product label indicate that the product contains lactose.
Getting Enough Calcium
Because they tend to eat less dairy than others, people with
lactose intolerance often have low calcium intakes, which can
lead to weakened bones and osteoporosis. Therefore, they often
need to get their calcium from other sources. Nondairy foods
that are high in calcium include green vegetables (including
broccoli, collard greens, turnip greens, and kale) and fish with
soft, edible bones (such as sardines and salmon). Calcium-fortified
foods and drinks such as cereal, tofu, oatmeal, orange juice,
and soy milk are also excellent sources. People who restrict
their dairy intake will probably need to take a calcium supplement.
The recommended daily intake for calcium is 1,000 mg (1,200 mg
for people over age 50). Because the body cannot absorb more
than 600 mg of calcium at one time, divide any amount larger
than that into two doses. It’s also best to take calcium
supplements with food; stomach acid, as well as other nutrients,
enhances the absorption of calcium.