No need for postmenopausal women to take more Vitamin D
Women who are postmenopausal do not need to take high doses of Vitamin D as it won’t help strengthen their bones, a new study suggests.
Women who took a high dose of Vitamin D supplements were shown to only absorb slightly more calcium than women on low doses.
But that didn’t seem to matter, because all three regimens produced similar results in terms of bone mineral density, muscle mass and the women’s risk for falling.
“We conclude that there is no reason to take more than the recommended daily allowance for vitamin D,” lead author Dr. Karen Hansen of the University of Wisconsin in Madison said by email.
Falls are a leading cause of fatal and nonfatal injuries among the elderly, according to the U.S. Centers for Disease Control and Prevention.
For older women, this risk of fall-related injuries is compounded by osteoporosis, or thinning bones, which occurs when production of the hormone estrogen declines after menopause.
For most adult women, the recommended daily intake of vitamin D is 600 IU (international units), or 800 IU after age 70, according to the U.S. National Institutes of Health. While few foods provide vitamin D, it can be found in beef liver, canned salmon or sardines, cheese and egg yolks as well as fortified milk and orange juice.
Even though doctors agree vitamin D is essential for bone health, many physicians continue to debate the appropriate role and dose of vitamin D supplements as well as the optimal concentrations of this nutrient in the blood.
Hansen and colleagues examined the impact of vitamin D supplements on 230 women who were at least five years past menopause but no older than 75, and without osteoporosis at the start of the study.
All of them had blood levels of vitamin D that put them at risk for deficiency.
During the study, the women were randomly assigned to take either 800 IU or 50,000 IU of vitamin D, or a dummy pill, once every 15 days for about a year.
Total fractional calcium absorption (TFCA) from the gut increased 1 % among women on the higher dose of vitamin D, but declined 2 % with the lower dose and 1.3 % with the placebo, the researchers report in JAMA Internal Medicine.
While it’s possible that treatment for more than a year might result in a bigger benefit from taking vitamin D, the results suggest that this supplement may be no better than a placebo, Dr. Deborah Grady, deputy editor of the journal, noted in an editorial.
To prevent or slow the progression of osteoporosis, women can stay active, particularly with weight-bearing exercises, Dr. Rita Redberg, editor-in-chief of JAMA Internal Medicine, said by email. Workouts targeting balance such as yoga or pilates may also help prevent falls, she said.
“There were no clinical benefits seen in either low dose or high dose vitamin D for bone health,” Redberg said by email. “I would recommend not starting vitamin D supplementation, or stopping Vitamin D if you have started.”
