Lactose Intolerance
What is Lactose Intolerance?
The main sugar found in milk is lactose and is actually
made up of two sugar molecules bound together (a di-saccharide). The
body can’t
absorb lactose and it must be broken down
into the two sugar molecules (mono-saccharides) glucose and galactose.
Many people lack the enzyme
lactase that the body uses to break down lactose, so the “milk
sugar” is not absorbed and passes from the small intestine to
the colon.
The problem is that the bacteria living in your large intestine
love lactose and break it down, causing many unpleasant effects. We
think of these bacteria as the “good guys” (and they are)
but in the process of using the lactose they create lactic acid and
other chemicals. Those substances are what causes abdominal discomfort.
Who is Lactose Intolerant?
Lots of people. Most of us begin to lose the ability to make the lactase
enzyme after being weaned. It is those of mostly Northern European and
Scandinavian descent who are still able to make the lactase enzyme well
into adulthood. The theory is that those people who did tolerate lactose
in an environment where cows were a main source of nutrition survived
better and thus passed on the genes for making lactase more successfully.
This means that most other populations not farming such animals are
lactose intolerant by adulthood. Here’s a rough breakdown:
80% of those of Asian descent
79% of Native Americans
75% of those of African descent
51% of Hispanic Americans
21% of Caucasians
When do people with Lactose Intolerance have problems?
Again, this is generally more of a problem in adulthood. Some children
do have true lactose intolerance and it might be worth testing with
their pediatrician to make sure that what appears to be lactose intolerance
is not actually an allergy to milk and milk proteins, not a problem
with milk sugars.
Even those who have lost the ability to make lactase don’t generally
lose it completely. They will often make a small amount -- enough that
they can tolerate small quantities of milk products.
Where can you really find out if you’re Lactose Intolerant?
Symptoms go a long way toward making a diagnosis. Stopping all lactose
for a time is one place to begin. If your symptoms resolve, “rechallenge” yourself
with a glass of milk or some ice cream. Sometimes it takes more than
a single cup, however (see below).
Your doctor can order lab tests and the easiest is the Hydrogen Breath
Test. It measures any hydrogen in your breath before and after drinking
a measured dose of lactose-containing liquid (usually milk). The test
works because we don’t normally exhale hydrogen. The bacteria
in your colon (remember them?) do give off hydrogen when using the lactose
and this is easily measured in your breath after consuming lactose.
Why care about this?
Symptoms, mostly, and all of them are pretty yucky. Here’s the
list:
abdominal bloating
gas
stomach cramps
flatulence
diarrhea
There is an argument that those who avoid milk will end up being deficient
in multiple nutrients including (but not limited to) calcium, B Vitamins,
protein, Vitamin D, copper and zinc. This is plain silly and if you’re
eating a balanced diet there’s no need for milk. The line of reasoning
has been created by those in the dairy industry with the main threat
being a decrease in calcium consumption.
If you are eating even a relatively healthy diet today
you’ll
be getting enough calcium. Starting the day
with a bowl of one of the fortified cereals
will give you as much as 1000 mg of calcium.
Here's a list of the calcium
content of other foods.
How to cope with lactose intolerance
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. For those who are very intolerant even
the lactose contained in some pills is enough to cause symptoms.
Doctors have an expression that they use: "dose dependent." This
means that people will sometimes not have side effects to a certain
medication or substance until they eat more than a certain amount. The
side effects are "dependent" on the "dose."
This is true for many people who have trouble with eating foods that
contain lactose. Some can have 1/4 cup of milk on their cereal and not
have problems but will experience symptoms if they drink a full glass
of milk. Other people will have problems with as little as two tablespoons.
Many people who cannot tolerate fresh milk can eat milk that has been
cultured—like sour cream, yogurt and cheese — but, again,
there are those who have problems with even these.
Here’s a list of the lactose
content in dairy (and
other) foods that might help you.
Lactose is often found in foods where you might not expect it. For
the most lactose intolerant this can be an issue and checking food labels
for the following may help:
lactose, milk solids, nonfat milk solids, margarine, sweet
cream, sour cream, buttermilk, whey,
malted milk
Almost any food can contain lactose and checking the ingredient list
is helpful especially with processed foods such as breads, candies,
chocolate drink mixes, deli meats, cookies, canned soups. dry cereals,
frozen breaded fish and chicken, prepared and processed foods, salad
dressing containing milk or cheese and artificial sweeteners.
There are lactase supplements on the market (the most popular is the
brand name Lactaid). For those that can tolerate a little but not a
lot of lactose this can be a good strategy. By taking a pill containing
the lactase with your meal that contains lactose it’s easier to
tolerate. There’s a number of products on the market that also
carry the Lactaid brand and many do well using such foods (although
they do cost more).