Some people cannot drink or eat
milk or milk products because they cannot tolerate lactose, the main
sugar in milk. (In fact, milk sugar is another term for lactose.) The
reason some people cannot tolerate lactose is that their bodies are
unable to break it down into a form that can be absorbed by the small
intestine. This inability is due to insufficient lactase, the enzyme
which breaks down lactose in their intestines. As a result, undigested
lactose is left in the intestines, where it comes into contact with the
bacteria naturally present there. This can cause a number of unpleasant
digestive symptoms.
People at Risk
Children are at risk for developing lactose
intolerance at an early age; roughly 70 percent of the world's
population of children begins to lose the ability to make the enzyme
lactase after being weaned. The prevalence of the condition in the
general population, on the other hand, is unknown. However, it is
considered to be overestimated. Only one out of every five people who
suspect they have lactose intolerance actually have symptoms after
drinking a single glass of milk.
Symptoms
Lactose intolerance is characterized by:
- abdominal bloating
- gas
- stomach cramps
- flatulence
- diarrhea
The frequency and severity of the symptoms seem
to be dose-related. In general, the larger the amount of lactose
consumed, the greater the risk of more frequent and severe symptoms.
Health Consequences
The biggest concern about lactose intolerance
is not the condition itself so much as the risk that people will stop
consuming milk and milk products in order to avoid unpleasant symptoms.
Stopping milk consumption would jeopardize the intake of essential
nutrients that milk and milk products supply, such as:
- calcium
- riboflavin
- protein
- vitamin A
- vitamin D
- copper
- zinc
Many people with lactose intolerance can manage
to consume enough products that are rich in these nutrients to meet
recommended requirements, through various dietary strategies such as
consuming lactose-containing foods in smaller amounts or using
lactose-reduced products.
If you are one of the few people who truly
cannot tolerate any dairy products at all, it is very important to make
sure you get enough calcium from other sources, such as calcium
supplements and non-dairy, calcium-rich foods. The following are all
good sources of calcium.
- tofu
- broccoli
- kale
- salmon with bones
Dietary Triggers
Just about any ordinary diet contains lactose
intolerance "triggers" that people with this condition need to
watch out for. Keep in mind, however, that some lactose-containing foods
have more lactose in them than others. If you know the lactose content
of various foods, you will find it much easier to make decisions about
whether you can consume any of them, and in what amounts, without
suffering adverse effects.
Lactose Content of Selected Foods
|
Food |
Amount |
Lactose (grams) |
|
Whey, dry |
1 oz. |
19-21 |
|
Yogurt, low-fat |
8 oz. (1 cup) |
5-19 |
|
Milk |
8 oz. (1 cup) |
9-14 |
|
Yogurt, whole-milk |
8 oz. (1 cup) |
10-12 |
|
Buttermilk |
8 oz. (1 cup) |
9-12 |
|
Milk, acidophilus skim |
8 oz. (1 cup) |
11 |
|
Ice milk |
6 oz. (3/4 cup) |
8 |
|
Ice cream |
6 oz. (3/4 cup) |
3-8 |
|
American pasteurized processed cheese |
1.5 oz. |
0-6 |
|
Ricotta cheese |
4 oz. (1/2 cup) |
0-6 |
|
Velveeta cheese |
1.5 oz. |
4 |
|
Cottage cheese |
4 oz. (1/2 cup) |
0-4 |
|
Orange sherbet |
6 oz. (3/4 cup) |
1-2 |
|
Half and half |
2 Tbsp. |
1 |
|
Sour cream |
2 Tbsp. |
1 |
|
Hard cheese (most) |
1.5 oz. |
1 |
|
Cream cheese |
1.5 oz. |
0-1 |
|
Butter or margarine |
1 Tbsp. |
0 |
The presence of lactose in certain foods is not
always clear-cut. When reading food labels, watch for these words and
phrases. They may indicate the presence of lactose in the product.
- milk solids
- nonfat milk solids
- lactose
- margarine
- sweet cream
- sour cream
- buttermilk
- whey
- malted milk
The following are foods that may contain
lactose.
- breads
- candy
- chocolate drink mixes
- cold cuts
- cookies
- cream soups
- dry cereals
- frostings
- frozen breaded fish and chicken
- hot dogs
- prepared and processed foods
- salad dressing containing milk or cheese
- sugar substitutes
Dietary Strategies
Even though low lactase levels generally will
persist in people who have them, problems with lactose intolerance often
can be avoided through dietary strategies. For some people, drinking or
eating smaller amounts of lactose-containing foods may prevent symptoms.
For others, gradually increasing the intake of lactose may improve
tolerance. Many people find that simply consuming lactose with a meal or
solid food minimizes problems.
Read the following for important facts that can
help you establish effective dietary strategies for specific kinds of
foods.
Milk
- Whole milk is better tolerated than
lower-fat milk.
- 1 percent chocolate milk may be better
tolerated than regular low-fat milk.
Cheese
- Cheese may be better tolerated than milk due
to a lower lactose content.
- Cheese is also well-tolerated because during
the cheese-making process, most of the whey is removed (and the
lactose with it). In mature, ripened cheese, lactose disappears
entirely within three to four weeks.
- Specific kinds of cheese which you can
reasonably expect to tolerate fairly well include cheddar, Colby,
Swiss, Parmesan and cottage cheese.
Ice cream
- Like cheese, ice cream has less lactose than
milk and may therefore be tolerated better.
Yogurt
- Yogurt that is labeled "active yogurt
culture" or "live and active cultures" is generally
well tolerated.
- Most U.S. yogurt has an appreciable amount
of lactose in it, but it seems to be better digested than the
lactose in milk.
- Frozen yogurt, as well as yogurt containing
fruits, sweeteners or flavorings, will generally not be digested as
well as plain yogurt.
- Frozen yogurt and ice cream, because of
their solids and fat content, are tolerated to about the same
degree.
Lactose-reduced foods
- Lactose-reduced milks (low-fat, skim, nonfat
and calcium-fortified chocolate) with 70-100 percent of their
lactose hydrolyzed are widely available today.
- Lactose-reduced cottage cheese, pasteurized
processed cheese and ice cream are also available in some markets.
- These products increase the cost of milk or
milk products and may not be necessary for persons who can tolerate
the lactose equivalent of a cup of milk per serving.
- If you cannot tolerate a small serving of
milk at all, you can make lactose-reduced milk at home by incubating
it with a lactase preparation overnight. Adding 5-10 drops of a
liquid lactase preparation to a cup of milk hydrolyzes 70-100
percent of the lactose.
Oral enzyme replacements
- Taking an oral enzyme replacement tablet at
the beginning of a meal improves tolerance to lactose in milk or
foods. Dairy Ease, Lactaid and Lactrase are names of some of the
capsules available.
- Be sure that any oral enzyme replacement you
take has sufficient acid stability to withstand digestion by the
stomach.
- If you can tolerate the lactose equivalent
of a cup of milk per serving, you may find it more convenient and
less expensive to just drink a small amount of milk with your meals
than to take an enzyme replacement.
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