Calcium is an essential mineral to life. It is
the most abundant mineral in your body and is necessary for
bone initiation and growth in the developing fetus and throughout
life to maintain optimal bone health and structure.
While calcium is often linked to bone health and its importance to optimal bone health
cannot be over-emphasized, there are other important functions
for calcium during a woman’s life. Calcium helps the
body by aiding muscle contraction and relaxation, blood coagulation
and nerve impulse transmission. Unfortunately, approximately
75% of American women do not obtain the recommended amount
of calcium in their diet to help maintain healthy bone structure.
To enlighten and encourage women during their life to
learn about calcium, it is helpful to review the various aspects
of calcium's function throughout the life stages. Therefore, use this
section to learn more about how calcium affects various life
stages, including medications and diseases.
The average woman’s bone mass reaches maximum density
somewhere between the ages of 25 and 35. At age 35, it begins
to decrease, picking up speed during the first five years
following menopause. Although the consequences of osteoporosis are
more evident in postmenopausal women, loss of bone density actually
begins in the perimenopausal years.
Recommended intake varies by age, but calcium remains essential
throughout every stage of life. Teenagers, young women and
post-menopausal women in particular are consuming far less
calcium than is healthy … and less than their bodies’
needs.
Pregnancy
No matter what age a woman is when she becomes pregnant, calcium
is very important to both the mother and the baby. Calcium
from the mother's body is used by the developing baby, putting
increased demands on the mother's supply. During pregnancy,
calcium transfer from mother to developing baby reaches 270 mg
daily, on average, by the third trimester. Additional calcium
may be needed for both mother's and baby's health.
A recent analysis of 14 scientific studies, published in the
Journal of the American Medical Association, found that
women with initially who took about 1,500 mg of 2,000 mg of
supplemental calcium every day while they were pregnant had a significantly
lower risk of preeclampsia, a leading cause of premature birth.
Preeclampsia is a disorder that occurs during pregnancy and
affects both the mother and the developing baby. Affecting at
least 5-8% of all pregnancies, it is a rapidly progressive
condition characterized by high blood pressure and the presence
of protein in the urine. It can possibly result in serious
consequences for both mother and child.
Moreover, research also demonstrates that pregnant women with
low dietary calcium consumption who were supplemented with
calcium during their second and third trimesters gave birth
to babies who had a 15-percent increase in bone mineral content
over children whose mothers were given a placebo during pregnancy. The babies
of mothers who were getting adequate daily dietary calcium
showed no significant difference in fetal bone content between
the treatment group and the placebo group.
The majority of pregnant women don't get the recommended daily
allowance of calcium. Expectant mothers should talk to their
doctors about taking a calcium supplement like TUMS® if
they don’t get enough calcium through their diet.
Why should a woman take extra calcium if she’s pregnant
and already taking a prenatal vitamin?
Most prenatal formulas contain only about 200 mg of calcium
and pregnant women need as much as 1,500 mg per day. Generally,
one should not supplement more than 600 mg at one time. We
recommend two TUMS® E-X tablets taken twice daily with
meals. TUMS® is the daily calcium supplement recommended
by most doctors, as well as a safe and effective treatment
for heartburn during pregnancy.
How long should pregnant women take calcium?
The average American woman is likely to be calcium deficient
both before and after
pregnancy. Moreover, post-pregnancy dieting has been shown
in certain studies to be accompanied by a significant decrease
in bone mineral density.
The benefits of calcium supplementation are not limited to
pregnancy and women can continue to supplement with calcium
every day throughout their lifetime if their diets do not provide the recommended intake level of calcium. When a baby
is nursing, however, there is a high calcium demand,
and to produce the most nutritious milk, the breastfeeding woman will need a highly
nutritious diet, rich in calcium.
Lactating
/ Breastfeeding
Breast milk is an excellent food source for the infant,
containing essential healthy nutrients and immune factors. The
production of breast milk by the mother requires significant
energy and nutrients. It is estimated that an additional 500
calories per day are needed for women who breast feed. It
is often recommended to continue the use of prenatal vitamins
during lactation. Since prenatal vitamins do not include the
total recommended daily amount of calcium, one must be aware
of the need for additional supplementation of this important
mineral. Click
here to learn about calcium requirements and how to take calcium.
Birth Control
Birth control options are a necessity for many adults.
A common form of contraception is DepoProvera ® (DMPA),
which is an injection that prevents pregnancy for three months.
It contains a progestin, a hormone that keeps the woman’s
eggs from being released from her ovaries. Women who use DMPA
for a long time may lose a small amount of calcium from their
bones. Fortunately, most of the calcium comes back as soon
as you stop using DMPA. It is prudent to ensure adequate calcium
intake for women using DMPA. Read the label and talk to your
doctor.
Female Athletes
Adolescent and young adult female athletes are generally very
healthy. However, a sub-group of these women may be causing
irreparable damage to their bodies as they excessively exercise
or train for their sport. ‘The Female Athlete Triad’
is a relatively new term that describes females who excessively exercise
or train for their sport too much. While weight bearing exercise
is important for healthy bone development, excessive exercise
can have the opposite effect on developing bone structure.
Athletes who push themselves with excessive training and restrictive
diets have altered menstrual patterns and bone thinning
disorders. Some have said that the female athlete triad
is ‘old bones in young bodies’. By over-training
and under-eating, the female body goes into a ‘conservation
mode’ that can lead to diminished female hormones and
lack of menses. The lack of female hormones (especially estrogen)
and altered diet, which often lacks sufficient calcium, can
lead to very brittle bones that are prone to fracture. By
educating young athletes about proper eating and training
habits, this condition can be significantly reduced. Proper
nutrition, including adequate calcium intake for bone development
is critical.
What is the impact of diet and exercise — especially
among young athletes — on the risk for osteoporosis?
A young woman or girl who wants to be thinner to enhance performance
may attempt to do so through dieting and excessive exercise,
thereby increasing her risk for low estrogen levels and bone
loss.
Now regarded as a common and serious health problem facing
young female athletes (especially gymnasts and dancers), “female
athlete triad” refers to a combination of three interrelated
conditions that are associated with athletic training: disordered
eating (including anorexia and bulimia), amenorrhea (absence
or irregular menstruation) and osteoporosis, leading to unusual
or frequent stress fractures.
Not all patients have all three components of the triad and
many young athletes with female athlete triad try to hide
their symptoms or behavior from friends, family, trainers
and/or coaches, making diagnosis difficult.
Having adequate calcium in the diet is important for achieving
and maintaining optimal bone health. Studies indicate 77%
of girls age 15-18 years old consumed less than two-thirds
of the recommended dietary allowance of calcium. Proper nutrition,
including calcium, together with regular moderate weight bearing exercise
(such as. weight lifting, resistance training, running), can
help protect young athletes against bone loss and enhance
bone strength.
Menopause
During the menopause transition, significant bone loss can
occur. In fact, during the first 3-5 years after menopause,
a woman can lose significant amounts of her bone mass. This
bone loss leads to more fragile bones. This can equate to
bone thinning and subsequent osteoporosis, which increases
the risk of fractures. Osteoporosis is thought of as a silent
disease until the thinning has resulted in a fracture, which
can lead to crippling pain, long recovery periods and loss
of independence. According to the U.S. Surgeon General's Report, osteoporosis
is a large problem in the U.S. with over 1.5 million fractures
related to osteoporosis each year, including 700,000 vertebral
fractures and 300,000 hip fractures. The national direct expenditures
for osteoporosis fractures are estimated to be $14-17 billion
annually.
Adequate calcium intake is vital to assure sufficient bone
quantity, quality, and strength. Altering reversible risk
factors is also important for osteoporosis prevention. Although
calcium intake alone will not protect a menopausal women from
osteoporosis, adequate intake will ensure that calcium deficiency
is not contributing to a weakening skeletal system.
Many women are being prescribed medications for osteoporosis
prevention and treatment. Medications such as Evista®,
Fosamax®, Actonel® and Miacalcin® are routinely
prescribed during menopause to treat osteoporosis. These medications
must be taken in conjunction with adequate amounts of calcium and vitamin D
for them to work effectively. As John A. Sunyecz, M.D., gynecologist
and president of MenopauseRx,
Inc. points out, "Just because a patient is prescribed
an osteoporosis medication doesn't mean she can stop taking
calcium. The situation is analogous to bricks and mortar in
building a strong foundation. The prescription medication
for the bones are the bricks, while calcium acts as the mortar
to build the best and longest-lasting bone possible."
Colon Cancer
Colon cancer is the third most common malignancy in US women.
Much research is being done on the prevention of colon polyps, which is
thought to reduce the risk of colon and rectal cancer. A large study by
Dr. J. Baron revealed that calcium supplementation was associated with a
significant reduction in the risk of recurrent colon and rectal polyps(1).
This study used 1200 milligrams of calcium over a four-year period and found
a 15% reduction in polyp recurrence. This reduction was seen within the first
year of the study. Other studies have also revealed positive benefits from
calcium supplementation and polyp protection. Therefore, consuming an adequate
amount of calcium for optimal ‘bone health’ may also give protection from colon
and rectal malignancies.
Further analysis of the data from the Dr. Baron study revealed continued
optimism regarding calcium and colon cancer prevention. In this study, 803
men and women who had a prior colon polyp were given calcium (1200 milligrams)
or placebo and followed for 4 years. The investigators measured levels of vitamin D
in the study participants and found that the benefit of calcium on polyp prevention
was seen in individuals with higher levels of vitamin D(2).
A new study by the American Cancer Society shows calcium may lower the risk of
colon cancer for both men and women, while vitamin D might help cut risk in men.
The effect was strongest in people who took supplements, rather than getting these
nutrients from foods. McCullough and her colleagues studied more than 60,000 men
and more than 66,000 women who were already participating in an American Cancer
Society study of nutrition and cancer prevention. The participants were all between
50 and 74-years old when they enrolled in the study in 1992 and 1993. People who
took calcium supplements had about a 30% lower risk of developing colon cancer than
people who did not take supplements(3).
In the future, more studies are needed to determine the exact amount of calcium
and vitamin D needed for colon cancer prevention.
References
- Calcium Supplements for the Prevention of Colorectal Adenomas
Baron, J.A., et al. N Engl J Med 1999; 340: 101-7.
- Grau MV, Baron JA, Sandler RS, et al. Vitamin D, calcium
supplementation, and colorectal adenomas : Results of a
randomized trial. J Natl Cancer Inst 2003;23:1765-71.
- Cancer Causes and Control (Vol. 14, No. 1: 1-12). http://www.cancer.org/docroot/NWS/content/NWS_2_1x_Study_Calcium_
May_Reduce_Risk_Of_Colon_Cancer.asp
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