MONDAY, Dec. 19 (HealthDay News) -- A new analysis on the
effects of vitamin D on bone health shows that it cuts fracture
risk in older adults, but only when taken with calcium
The review of nearly 50 studies on vitamin D -- present in a
small number of foods and produced naturally in the skin with sun
exposure -- by the U.S. Preventive Services Task Force (USPSTF)
also indicates that it's too soon to tell if vitamin D supplements
can help prevent cancer.
Report author Mei Chung, assistant director of the
Evidence-based Practice Center at Tufts Medical Center in Boston,
said she wasn't able to advise specific recommended doses based on
the review, which concluded that a daily vitamin D regimen of
between 300 and 1,100 international units (IUs) combined with 500
to 1,200 milligrams (mg) of calcium reduces fracture risk in those
"I think vitamin D likely has more benefits than we currently know and also [presents] little harm," said Dr. Robert Graham, a vitamin D researcher and internist at Lenox Hill Hospital in New York City, who did not participate in the USPSTF report, published Dec. 20 in the Annals of Internal Medicine.
"An acceptable level is always a moving target," Graham added. "It's a very controversial topic, although I honestly don't know why it's so controversial."
The USPSTF review comes about a year after a more extensive
report by the Institute of Medicine (IOM), the health arm of the
National Academy of Sciences, which said that most Americans and
Canadians up to age 70 need no more than 600 IUs of vitamin D per
day to maintain health, while those 71 and older may need as much
as 800 IUs.
The IOM report took nearly 1,000 published studies into account,
while the latest review incorporated 19 randomized controlled
trials and 28 observational studies to determine the benefits and
harms of vitamin D with or without calcium supplementation on
clinical outcomes of cancer and fractures.
In a related study also published in the
Annals of Internal Medicine issue, the USPSTF noted that
there's still no evidence to support vitamin D supplementation to
prevent heart disease. Limited data suggest that high dosages can
reduce the risk for all kinds of cancer, but more research is
needed to draw a firm conclusion, the USPSTF said. And concern
remains about proper dosing, since too much vitamin D can raise the
risk for kidney and urinary tract stones.
Graham said most people should ask their doctors to test their
blood levels of vitamin D to ensure they're not deficient.
"More physicians are checking vitamin D in their patients," he said. "I think there's greater awareness. At some point we have to decide what's good, what's bad, what's safe and what's not safe. I think we've learned from the last 10 years of this data, that there's still a lot we don't know about vitamin D."
Chung, also an investigator at Tufts Medical Center's Institute
for Clinical Research and Health Policy Studies, said that research
focusing on bone mineral density -- a measurement of bone thickness
-- could be useful to further pin down correct vitamin D doses for
various age groups.
"It could be a shorter trial that could enroll many more people . . . and compare a variety of doses to see which dose we could probably use to the best effect," she said. "If we use fracture as an outcome, it will take much longer and cost a lot of money to enroll a lot of subjects."
The U.S. National Library of Medicine has more on
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
Copyright © EBSCO Publishing. All rights reserved.