Calcium Lowers Cancer Risk in Older People: More So
for Women Than Men
Long respected by senior citizens as a nutrient for
building strength in aging bones, calcium now adds cancer fighter to
its resume
Feb.
24, 2009 Senior citizens are well aware of the role calcium plays in
keeping aging bones strong but the nutrient has now been identified as a
cancer fighter. For women, high levels of calcium, have been found to
lower the risk of any type cancer, while in men it appears to lower
risks for colorectal cancer and other cancers of the digestive system.
The Institute of Medicine recommends 1,200
milligrams of calcium for adults age 50 and older, and the 2005 dietary
guidelines for Americans recommend 3 cups per day of low-fat or fat-free
dairy products. These recommendations are based on calciums benefit to
bone health.
Studies of dairy products, calcium intake and
cancer have revealed different results for different cancer sites,
according to the report in the February 23 issue of Archives of
Internal Medicine, one of the JAMA/Archives journals.
Yikyung Park, Sc.D., of the National Cancer
Institute, Bethesda, Md., and colleagues analyzed data from 293,907 men
and 198,903 women who participated in the National Institutes of
Health-AARP Diet and Health Study.
Participants took a food frequency questionnaire
when they enrolled in the study between 1995 and 1996, reporting how
much and how often they consumed dairy and a wide variety of other foods
and whether they took supplements. Their records were then linked with
state cancer registries to identify new cases of cancer through 2003.
About Calcium
You have more calcium in your body than
any other mineral and it has many important jobs.
The body stores more than 99 percent of
its calcium in the bones and teeth to help make and keep them
strong. The rest is throughout the body in blood, muscle and the
fluid between cells.
Your body needs calcium to help muscles
and blood vessels contract and expand, to secrete hormones and
enzymes and to send messages through the nervous system.
It is important to get plenty of calcium
in the foods you eat. Foods rich in calcium include diary
products such as milk, cheese and yogurt, and leafy, green
vegetables.
The exact amount of calcium you need
depends on your age and other factors. Growing children and
teenagers need more calcium than young adults.
Older women need plenty of calcium to
prevent
osteoporosis.
People who do not eat enough high-calcium
foods should take a calcium supplement.
Over an average of 7 years of follow-up, 36,965
cancer cases were identified in men and 16,605 in women.
Calcium intake was not associated with total cancer
in men but was in women - the risk decreased in women with intake of up
to 1,300 milligrams per day, after which no further risk reduction was
observed.
"In both men and women, dairy food and calcium
intakes were inversely associated with cancers of the digestive system,"
the authors write.
Men
The one-fifth of men who consumed the most calcium
through food and supplements (about 1,530 milligrams per day) had a 16
percent lower risk of these types of cancer than the one-fifth who
consumed the least (526 milligrams per day).
Women
For women, those in the top one-fifth of calcium
consumption (1,881 milligrams per day) had a 23 percent lower risk than
those in the bottom one-fifth (494 milligrams per day). The decreased
risk was particularly pronounced for colorectal cancer.
Calcium and dairy food intake was not associated
with prostate cancer, breast cancer or cancer in any other anatomical
system besides the digestive system.
"Dairy food, which is relatively high in
potentially anticarcinogenic nutrients such as calcium, vitamin D and
conjugated linoleic acid, has been postulated to protect against the
development of colorectal and breast cancer," the authors write.
Calcium
has been shown to reduce abnormal growth and induce normal turnover
among cells in the gastrointestinal tract and breast. In addition, it
binds to bile and fatty acids, potentially reducing damage to the mucous
membrane in the large intestine.
"In conclusion, our findings suggest that calcium
intake consistent with current recommendations is associated with a
lower risk of total cancer in women and cancers of the digestive system,
especially colorectal cancer, in both men and women," the authors write.
Editor's Note: The study was funded by the
Intramural Research Program of the National Cancer Institute, National
Institutes of Health.
Keep up with the latest news for senior citizens, baby
boomers
Feb.
24, 2009 Senior citizens are well aware of the role calcium plays in
keeping aging bones strong but the nutrient has now been identified as a
cancer fighter. For women, high levels of calcium, have been found to
lower the risk of any type cancer, while in men it appears to lower
risks for colorectal cancer and other cancers of the digestive system.
Calcium
has been shown to reduce abnormal growth and induce normal turnover
among cells in the gastrointestinal tract and breast. In addition, it
binds to bile and fatty acids, potentially reducing damage to the mucous
membrane in the large intestine.