Featured Research

from universities, journals, and other organizations

Low-dose vitamin D may not prevent fractures in healthy women –- what about higher doses?

Date:
June 16, 2012
Source:
University of California, San Francisco (UCSF)
Summary:
Vitamin D and calcium are dietary requirements, but it’s unclear how much is best for us. New draft findings conclude that for healthy, postmenopausal women, daily supplementation with low levels of vitamin D — up to 400 international units — combined with 1,000 milligrams of calcium, does not reduce fracture risk.

Vitamin D and calcium are dietary requirements, but it's unclear how much is best for us. New draft findings by the United States Preventive Services Task Force conclude that for healthy, postmenopausal women, daily supplementation with low levels of vitamin D -- up to 400 international units -- combined with 1,000 milligrams of calcium, does not reduce fracture risk.

However, this amount of supplementation is associated with a small but significantly increased likelihood of developing painful kidney stones, according to the task force.

Because relatively few, high quality studies have been done, the task force was unable to draw conclusions about the fracture-preventing merits of supplementation in healthy men and in premenopausal women.

Nor did studies offer conclusive evidence regarding vitamin D and cancer prevention, according to the task force. Evidence also was inadequate to draw conclusions about supplementation with higher doses.

The task force did not review studies on supplementation that were focused on individuals who already had osteoporosis or vitamin D deficiencies. Nor did the task force investigate other putative benefits of vitamin D.

However the task force did previously recommend vitamin D supplementation to prevent falls among men and women age 65 and older. Falls are a major cause of hip fracture and early death among the elderly, especially among those with osteoporosis.

Vitamin D Benefits, Risks, Not Adequately Studied "We know that vitamin D and calcium are essential for a healthy diet," said task force member Kirsten Bibbins-Domingo, MD, PhD, a UCSF epidemiologist and internist. "We're not making recommendations about the treatment of osteoporosis or of vitamin deficiency. We're making recommendations that apply to generally healthy women who are seeking to supplement their diets to prevent fractures."

The task force reviewed already-published studies to draw conclusions. The public comment period for the new draft recommendations runs through July 10.

To reach its recommendation that healthy, postmenopausal women not take low-dose vitamin D and calcium supplements to ward off fractures, task force members examined 16 studies in which participants took supplements. Formulations and dosages of vitamin D and calcium varied among the studies.

Among them was the Women's Health Initiative (WHI). The WHI included 36,282 health postmenopausal women ages 50 to 79. As part of the study, many women were assigned to take 400 international units of vitamin D3 and 1,000 milligrams of calcium carbonate each day. Results of other studies of low-dose supplementation were consistent with WHI findings, Bibbins-Domingo said.

To prevent fracture, supplementation for healthy, postmenopausal women at low vitamin D doses, with or without calcium, "does not work," Bibbins-Domingo said, and comes with a "small but measurable risk for kidney stones."

Whether benefits outweigh risks for harm at higher supplemental doses remains unclear.

"Many women are taking higher doses of vitamin D already, and that is where there is not sufficient evidence for us to make a recommendation one way or another," Bibbins-Domingo said. The same goes for many other questions related to vitamin D in various patient groups.

"We need more research. There are not enough high-quality studies," she said.


Story Source:

The above story is based on materials provided by University of California, San Francisco (UCSF). The original article was written by Jeffrey Norris. Note: Materials may be edited for content and length.


Cite This Page:

University of California, San Francisco (UCSF). "Low-dose vitamin D may not prevent fractures in healthy women –- what about higher doses?." ScienceDaily. ScienceDaily, 16 June 2012. <www.sciencedaily.com/releases/2012/06/120616145456.htm>.
University of California, San Francisco (UCSF). (2012, June 16). Low-dose vitamin D may not prevent fractures in healthy women –- what about higher doses?. ScienceDaily. Retrieved July 28, 2014 from www.sciencedaily.com/releases/2012/06/120616145456.htm
University of California, San Francisco (UCSF). "Low-dose vitamin D may not prevent fractures in healthy women –- what about higher doses?." ScienceDaily. www.sciencedaily.com/releases/2012/06/120616145456.htm (accessed July 28, 2014).

Share This




More Health & Medicine News

Monday, July 28, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Trees Could Save More Than 850 Lives Each Year

Trees Could Save More Than 850 Lives Each Year

Newsy (July 27, 2014) A national study conducted by the USDA Forest Service found that trees collectively save more than 850 lives on an annual basis. Video provided by Newsy
Powered by NewsLook.com
Google's Next Frontier: The Human Body

Google's Next Frontier: The Human Body

Newsy (July 27, 2014) Google is collecting genetic and molecular information to paint a picture of the perfectly healthy human. Video provided by Newsy
Powered by NewsLook.com
What's To Blame For Worst Ebola Outbreak In History?

What's To Blame For Worst Ebola Outbreak In History?

Newsy (July 27, 2014) A U.S. doctor has tested positive for the deadly Ebola virus, as the worst-ever outbreak continues to grow. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins