Lactose Intolerance
Lactose
intolerance develops when the body has difficulty digesting whole and skim milk
and other dairy products. Lactose is a milk sugar and like most sugars, it is
broken down by enzymes in the intestinal tract so it can be absorbed as an
energy source. The enzyme that breaks down lactose is called lactase. When the
intestine does not contain lactase, then lactose intolerance can occur. It is a
troublesome and annoying problem, but it is never a serious one.
Who Has Lactose Intolerance?
As commonly expected, infants and small children have the enzyme lactase so they
can digest mothers' milk. However, during childhood, lactase begins to disappear
in many people. Some ethnic groups are more likely to develop lactose
intolerance. By adolescence, it is gone in about 75% of African-Americans, Jews,
Native Americans, Mexicans, and in 90% of Asians. So the condition is very
common.
What Are The Symptoms?
When undigested lactose reaches the colon (large intestine), it is broken apart
by bacteria. Lactic acid and other acidic chemicals result. It is these products
that create the symptoms of lactose intolerance. These symptoms include nausea,
abdominal cramps and rumbling, bloating, rectal gas (flatus), and diarrhea. They
usually occur 30 minutes to two hours after ingesting lactose-containing foods.
The severity of symptoms usually depends on the amount of lactose ingested and
how much of the enzyme, lactase, remains in the intestinal tract.
The Diagnosis
First, the physician reviews the patient's medical history. Sometimes that is
enough to determine the problem. However, to make a definitive diagnosis, one of
several tests may be needed:
Lactose Tolerance Test - A test dose of lactose is ingested and blood
sugar determinations are made over several hours. If lactase is present to
break down the lactose load, then the blood sugar level rises. If no lactase
is present, the blood sugar level does not change.
Hydrogen Breath Test - When lactose is broken down by the colon's
bacteria, hydrogen is released, which then passes out through the lungs. The
amount of hydrogen released after a lactose meal can indicate a problem.
Stool Acidity Test - When lactose breaks down to lactic and other
acids in the colon, the resulting acidity can be detected by a simple
measurement of stool acidity.
The Home Do-It-Yourself Test - Since lactose intolerance is not a
serious disorder, some people may want to test themselves at home. First,
avoid milk and lactose-containing foods for several days. Then on a free
morning, such as a Saturday, drink two large glasses of skim or low-fat milk
(14-16 oz). If symptoms develop within four hours, the diagnosis of lactose
intolerance is fairly certain.
Treatment
Therapy depends on whether a patient is willing to tolerate the symptoms. If the
symptoms are mild, then avoiding large amounts of milk and milk products may be
enough. For those who are very sensitive to small amounts of lactose, there are
two options. First, all foods should be carefully checked for lactose. Grocery
items such as bread, baked goods, cereals, instant potatoes, soups, margarine,
lunchmeat, salad dressings, pancakes, biscuits, cookies, and candy can contain
hidden lactose. Even prescription and over-the-counter drugs may contain
lactose. The patient must become a label reader looking for and avoiding
"milk" and "lactose".
The second option is buying milk to which lactase, the enzyme, has been
added. Lactase drops or tablets are also available which can be placed in milk.
A pharmacist or food store manager can provide advice. There are
over-the-counter lactase tablets that can be taken with meals to replace the
enzyme the body no longer has. Finally, a variety of lactose-free products are
now available in the specialty section of food stores.
Calcium and Lactose
Milk is a major source of calcium and calcium is necessary for good health and
strong bones. Most people need 1000 mg of calcium a day, except for pregnant and
nursing females (1200 mg per day) and post-menopausal females (1500 mg per day).
The following list from the National Institutes of Health provides some
information on the calcium and lactose contents of food.
For the lactose-intolerant individual, ingesting enough calcium may be
difficult. Calcium supplements, such as calcium carbonate, are often
recommended. The decision to take calcium supplements should be discussed with
the physician.
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