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The Creighton University Osteoporosis Research Center Fall 2013 Vol. 32 No. 1
Lactose Intolerance
“. . . I know I should drink more milk, but I
can’t. I am lactose intolerant . . .”
I
s that true? What is lactose intolerance? What does
it mean for patients with osteoporosis?
Lactose is the name given to the sugar that is
contained in milk. It’s what biochemists call a
disaccharide, which means it is a complex of two
simple sugar molecules, glucose and galactose.
It’s the principal carbohydrate in the milk of all
mammals. It’s an important source of energy
during growth, but to be utilized by the body, it
first must be split into its component sugars. This
is accomplished by an enzyme that is a part of the
digestive juices of infants, called lactase. [There is a
hint here for you cross-word puzzlers. The technical
names for sugars usually end in –ose, while the
technical names for enzymes, usually end in –ase.]
Lactose is not found in foods other than dairy and,
under ancestral conditions, after weaning, lactose
typically disappeared from the diet, human as well as
lower animal. The body, in its wonderful economy,
reduces its production of lactase as we grow
older, starting sometime after weaning. Under
ancestral conditions, lactase simply wasn’t going to
be needed again. That gradual loss of lactase activity
occurs to a greater extent in individuals of East
Asian or African extraction than in those of European
ancestry, but we all lose some as we grow older.
The problem is that about 10,000 years ago humans
began to domesticate milk-producing animals, and
thus dairy products entered the post-weaning diet.
Our intestines, programmed as they had been over
the millions of years
of primate evolution,
have had very little
chance to catch up
with this relatively
very late addition to
the adult human diet.
Robert P. Heaney, M.D.
In the technical
John A. Creighton University Professor
lingo of the field,
the relative absence
of lactase in the digestive systems of many adults
is called “lactase nonpersistence”, and the fact
that milk sugar cannot be easily digested by such
individuals is termed “lactose maldigestion”. In
individuals who are lactose maldigesters, lactose,
instead of being split and absorbed, moves into
the distal bowel where the bacteria that normally
reside there digest the sugar for their own use,
producing hydrogen gas in the process. Sometimes
that hydrogen gas produces abdominal symptoms
such as bloating, flatulence, cramps or diarrhea.
It’s that condition, induced by the unaccustomed
consumption of milk, that is called “lactose
intolerance”. But not all lactose maldigesters have
symptoms. In fact, most do not. Studies of national
population samples, consisting of people of different
racial backgrounds, have shown that only about 14%
of the adult population has any symptoms at all
that could be related to lactose ingestion, even
though the prevalence of lactose maldigestion must
have been 3 – 5 times higher than the number with
symptoms.
It’s important to understand that lactose is not
found in all dairy products, but mainly in milk and
milk products, and not in products such as cheese.
That’s partly because the molds making the cheese
utilize the lactose as a source of energy, and partly
because lactose, being water soluble, is carried off
in the whey. Moreover, live culture yogurts, which
do contain lactose, also contain organisms that break
down the lactose for us, and hence neither hard
cheeses nor live culture yogurts are likely to evoke the
symptoms of lactose intolerance. It’s also important to
understand that the symptoms of lactose intolerance
are dependent upon how much lactose we ingest.
The amount of lactose in one-half serving of
milk (4 ounces) has never been shown to cause
symptoms, even in those who complain of serious
lactose intolerance. That fact provides a hint as to
how we can deal with the problem in those who
would like to be able to drink milk and yet do have
symptoms.
But, before launching into treatment, it’s useful also to
understand the relationship that exists between us as
human beings and the many billions of
micro-organisms that live with us in our bodies, many
of them in our intestinal tracts. Those of us of an older
generation were taught to fear germs. They were
bad, or dirty, or caused disease, or all of the above.
Manufacturers have made millions of dollars by selling
us products such as antiseptics and disinfectants.
Some germs are, indeed, harmful, but most are
friendly, most of the time.
One of the friendly things these bacteria do is to
help us digest complex compounds in our food
that our intestines aren’t equipped to handle. One
good example are the foods that we recognize as
gas-forming, such as beans and the cruciferous
vegetables – and, in the case of the subject of this
article, milk. The bacteria in our intestines are
capable of producing the enzymes needed to
digest these foods. But our intestinal organisms are
thrifty. They won’t produce the needed enzymes
unless we consume the foods containing these
compounds regularly. What, after all, would be the
point of an organism making a metabolic expenditure
to produce enzymes that it wasn’t going to use?
As it turns out, our intestinal organisms are quite
capable of producing lactase for us, but only so long
as we provide them with a diet that contains milk on
a regular basis.
As a result someone who complains of severe
lactose intolerance symptoms can almost always
be brought up to the point of consuming three full
glasses of milk per day without symptoms if they
build up the exposure gradually, slowly getting the
bacteria in our intestines used to such a diet.
The Creighton University Osteoporosis Research Center • 402.280.4470 • osteoporosis.creighton.edu
The program usually goes something like this:
add a half a glass of milk with a main meal on
day 1, then a half a glass to two meals on day
2, and so forth until one builds up to three full
servings per day. And here’s the important point:
you have to keep drinking that milk, or the bacteria
will stop producing the enzyme needed to digest it
for you. So, obviously, this strategy only works for
people who want to be regular milk drinkers.
What can we do for individuals who want to be able
to drink milk, but only occasionally? They may well
experience symptoms (even though, as we have
seen, most maldigesters never actually do). There
are two options available. One is to use
lactose-reduced or lactose-free milk, generally
available in most grocery stores and the other is to
take a small tablet containing lactase at the time
one drinks the milk. These tablets are also generally
available over the counter in drug or grocery stores.
Getting enough calcium is important, and getting
it in conjunction with the many nutrients that are
contained in milk is even better than getting it in
supplement form. One thing is clear: lifelong milk
avoiders – for whatever reason – run an increased
risk of suffering osteoporotic fractures. So if lactose
intolerance appears to be a barrier to you, then it is
helpful to know that you can train your body (and its
friendly bacteria) to digest the lactose for you. Or,
you can get the needed calcium and other nutrients
from alternative dairy products, such as hard cheese
or live culture yogurts. Either way, don’t let lactose
intolerance get between you and your getting
enough of the nutrients you need for bone health.
Dairy Diaries Update
A heartfelt thank-you to all of the amazing girls
who participated in our Dairy Diaries Study!
Our research study was a huge success due to
the compliance of the participants as well as the
commitment of the parents. We enrolled 274 girls
and all but five of them completed the one-year
study.
We conducted our last study visit in September
2013. We are now busy working on analyzing the
results and hope to share them with all of you
very soon. We will post the overall findings on
our website and in our semiannual newsletter
(November and May), mailed to your home.
Thanks again for your commitment in making this
study an enormous success!
- Dr. Joan Lappe, Principal Investigator
- Margaret Begley, BA, BSN, RN, Project Manager
The Creighton University Osteoporosis Research Center • 402.280.4470 • osteoporosis.creighton.edu
Opportunities to Participate
The Creighton University Osteoporosis Research Center would like you to consider participating
in one of our research studies. Below is a list of our current studies in which you might be
interested. Please feel free to pass this letter on to friends, family and coworkers who may also be
willing to participate.
Muscle Strength Study (both men and women)
This study is one of the first clinical research studies for a new treatment for sarcopenia. Sarcopenia is
an age-associated loss of muscle mass and function. Loss of muscle strength and function is a major
problem for older persons since it can lead to a loss of independence and a greater risk of disability.
Persons with sarcopenia often have difficulty performing their activities of daily living. They can become
extremely frail and very weak.
The purpose of this study is to evaluate the effect of a new drug on improving muscle strength
and function in men and women ages 70 and older. The study will last approximately 6 months.
Compensation for time and travel will be provided for qualified participants. If you know someone that
meets these qualifications, please ask them to contact our research staff at 402.280.2663 and mention
the muscle strength study.
Spine Fracture Study
Many women with low bone density develop spine fractures without even knowing that they have
them. We are offering free Vertebral (spine) Fracture Assessments for qualified women. If you are age
45 and older, please contact our research staff at 402.280.2663 to see if you qualify for a free screening.
This is a two year research study that is comparing two FDA-approved medications to see which of
them will be better at preventing future vertebral fractures. This study will provide free medication and
$300 stipend for participation.
Young Women's Bone Health Study
Currently there is no medication approved for treatment of pre-menopausal women with low bone
mass or osteoporosis. We are collaborating with Columbia University on this project to develop a
treatment option for pre-menopausal women with low bone density or history of a broken bone
(fracture) as an adult.
If you are a female between the ages 20 – 45 and are having regular periods, please contact our office
at 402.280.2663 for a free bone density screening. This study will provide free medication and a $400
stipend for participation.
If you are interested in learning more about any of these
studies, please contact us at 402.280.2663 (BONE) or toll free
800.368.5097. Please leave a message with your name, phone
number and best time for us to call. Or visit osteoporosis.
creighton.edu and click on ORC Research Opportunities.
Know someone who might be interested? Please pass this on . . .
Recent Donations to the
Creighton Endowment for Osteoporosis
In Memory of
Donald D. Callies, Sr.
From: Lorene and Gene Horky
Robert L. McKeon
From: Jim and Jane O’Brien
Mary Niedermyer
From: Dr. and Mrs. Robert Recker
Dennis Pekula
From: Joyce Pekula
Eileen Ann Ryan
From: Dr. and Mrs. Robert Recker
In Appreciation of the work accomplished by the
people of the Osteoporosis Research Center (ORC)
From: Molly Recker
If you are interested in making a donation, please send a contribution to:
Creighton Endowment for Osteoporosis
In memory of Sister Anne Evers
601 North 30th Street, Suite 4820
Omaha, NE 68131
If you have any questions please contact Susan Recker at 402.280.4810
or visit osteoporosis.creighton.edu.
The Osteoporosis
Research Center
Creighton University
2500 California Plaza
Omaha, Nebraska 68178
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Phone: 402.280.4470 • Fax: 402.280.5173 • Website: osteoporosis.creighton.edu • E-mail address: [email protected]
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