Too
Much Coffee May Weaken Bones
Older
women who drink several cups of coffee a day may be putting their health
at risk, claim the authors of a recently published study. The study,
published in the American Journal of Clinical Nutrition, links
high coffee consumption, those who drink more than three or four cups
a day, to an increased risk of bone loss.
Previous
studies have left many researchers baffled, as results regarding caffeine
and bone loss have been conflicting. Some researchers have said that
caffeine is connected with increasing the risk of hip fractures as well
as poor calcium retention. Others such as the National Institutes
of Health Osteoporosis and Related Bone Diseases National Resource Center
(NIH ORBD~NRC) disagree stating that the two are not related if
the woman has an adequate intake of calcium.
What
makes this study unique is the fact that it focuses not just on caffeine
and bone loss but also the impact caffeine may have on women with a
certain genetic makeup. The results of this recent study may spur more
discussion regarding what impact caffeine may actually have on post-menopausal
women.
The
Study
The
study, which was done over a three-year period, involved nearly 100
women whose average age was 71. The participants included both heavy
and light coffee drinkers enabling the researchers to compare the bone
mineral densities of both groups of women.
The
researchers also analyzed any possible link to osteoporosis as well
as any impact caffeine may have on the vitamin D receptor gene. Present
in some women, this receptor gene, called “tt,” affects the body’s ability
to absorb vitamin D. Vitamin D, like calcium, is necessary for healthy
bones. Most people do not know if they carry the tt genotype unless
they have undergone extensive genetic testing.
In
addition, the researchers also noted the participants’ alcohol consumption,
smoking history, dietary intake, and use of vitamins and/or mineral
supplements. The participants did not take any calcium or vitamin D
supplements at the time of the study.
In
order to determine bone loss and the vitamin D absorption rate of the
participants, the researchers took blood and urine samples as well as
scans of the hip, spine, and three other sites at the beginning of the
study, at six-month intervals, and then again at the end of the study.
The
women were divided into two groups according to their caffeine consumption.
Those who consumed less than 300 milligrams of caffeine per day were
considered part of the low-caffeine group while those who consumed more
than 300 milligrams were in the high-caffeine group.
According
to the National Coffee Association, a US trade organization,
an eight-ounce cup of brewed coffee contains anywhere from 65 to 120
milligrams of caffeine, with the average amount being 85 milligrams.
The broad range, explains the trade association, is due to a number
of factors that affect how much caffeine a cup of coffee contains -
factors such as the variety of coffee bean, where it was grown, how
it was processed, and how the coffee was brewed.
Study
Results
At
the end of the study, the researchers discovered that the women in the
high-caffeine category who carried the tt genotype lost more bone over
time than the other participants, including those with the same tt genotype
but who were in the low-caffeine category. The bone loss was especially
significant in the spine area.
The
researchers also noted a higher rate of bone loss in the spine among
those who consumed high levels of coffee in comparison to those who
drank less, regardless of whether the individual carried the tt genotype.
They
conclude that in post-menopausal elderly women, high levels of caffeine
does have an effect on bone loss, especially if the woman carries the
tt genotype.
Always
consult your physician for more information.
What
is osteoporosis?
Osteoporosis is a progressive condition in which bone density is
lost, thereby weakening the bones and making them more susceptible
to fractures.
Who
is affected by osteoporosis?
Osteoporosis is very prevalent in the US. It affects over 10
million individuals, with women four times more likely to develop
osteoporosis than men. Estrogen deficiency is one significant cause
of accelerated bone loss in women during and after menopause.
Other
risk factors for osteoporosis
Although the exact medical cause for osteoporosis is unknown, a
number of factors contribute to osteoporosis, including the following:
- aging
Bones become less dense and weaker with age.
- race
Caucasian and Asian women are most at risk, although all races
may develop the disease.
- body weight
and bone structure
People who weigh less and have small body frames are more at
risk for developing osteoporosis.
- lifestyle
factors
The following lifestyle factors may increase a person's risk
of osteoporosis:
- physical
inactivity
- caffeine
- excessive
alcohol use
- smoking
- dietary
calcium and vitamin D deficiency
- family
history of bone disease
What
are the symptoms of osteoporosis?
Persons with osteoporosis may not develop any symptoms, or may
have pain in their bones and muscles, particularly in their back.
The symptoms of osteoporosis may resemble other bone disorders or
medical problems. Always consult your physician for a diagnosis.
How
osteoporosis is diagnosed
In addition to a complete medical history and physical examination,
diagnostic procedures for osteoporosis may include the following:
- family
medical history
- x-rays
(skeletal) - a diagnostic test that uses invisible electromagnetic
energy beams to produce images of internal tissues, bones, and
organs onto film.
- bone
density test (Also called bone densitometry.) - measurement
of the mass of bone in relation to its volume to determine the
risk of developing osteoporosis.
- blood
tests (to measure serum calcium and potassium levels)
The
effects of this disease can best be managed with early diagnosis
and treatment.
Treatment
for osteoporosis
Specific treatment for osteoporosis will be determined by your physician
based on:
- your age,
overall health, and medical history
- extent
of the disease
- your tolerance
for specific medications, procedures, or therapies
- expectations
for the course of the disease
- your opinion
or preference
The
goals of managing osteoporosis are to decrease pain, prevent fractures,
and minimize further bone loss. Some of the methods used to treat
osteoporosis are also the methods to help prevent it from developing,
including the following:
- Maintain
an appropriate body weight.
- Increase
walking and other weight-bearing exercises.
- Minimize
caffeine and alcohol consumption.
- Maintain
an adequate intake of calcium through diet and supplements.
Vitamin D is also necessary because it facilitates the absorption
of calcium.
- Prevent
falls in the elderly to prevent fractures (e.g., install hand
railings or assistive devices in the bathroom, shower, etc.).
- Consult
your physician regarding a medication regimen.
Always
consult your physician for more information.
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November
2002
The
Study
Study
Results
What
is osteoporosis?
Who
is affected by osteoporosis?
Other
risk factors for osteoporosis
What
are the symptoms of osteoporosis?
How
osteoporosis is diagnosed
Treatment
for osteoporosis
Find
a St. John's Mercy Physician
Online
Resources:
American
Journal of Clinical Nutrition
National
Coffee Association
National
Institutes of Health Osteoporosis and Related Bone Diseases National
Resource Center (NIH ORBD~NRC)
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