Calcium and vitamin D help hormones help bones
Should women take calcium and vitamin D supplements after menopause for bone health? Recommendations conflict, and opinions are strong. But now, an analysis from the major Women’s Health Initiative (WHI) trial throws weight on the supplement side - at least for women taking hormones after menopause. The analysis was published online today in Menopause, the journal of The North American Menopause Society.
Among the nearly 30,000 postmenopausal women in the hormone trial, some 8,000 took supplemental calcium (1,000 mg/day) and vitamin D (400 mg/day), and some 8,000 took look-alike placebos. These women came from all the hormone groups in the study - those who took estrogen plus a progestogen (required for women with a uterus), those who took estrogen alone, and those who took the hormone look-alike placebos. The researchers looked at how the rates of hip fracture differed among women who took hormones and supplements, those who took hormones alone, and those who took neither.
The supplements and hormones had a synergistic effect. Women using both therapies had much greater protection against hip fractures than with either therapy alone. Taking supplements alone wasn’t significantly better than taking no supplements and no hormones. The benefit of hormone therapy was strong in women who had a total calcium intake (supplements plus diet) greater than 1,200 mg/day. Similarly, the benefit was strong in women who had higher intakes of vitamin D, but the individual effect of each one could not be determined because the two supplements were given together.
The effects translated into 11 hip fractures per 10,000 women per year among the women who took both hormones and supplements compared with 18 per 10,000 women per year among those who took hormones only, 25 per 10,000 women per year among those who took supplements alone, and 22 among those who got neither therapy.
These results suggest, said the authors, that women taking postmenopausal hormone therapy should also take supplemental calcium and vitamin D. Although they couldn’t specify how much, they noted that the benefits seem to increase with increasing total intake of calcium and vitamin D. The dose will depend on keeping side effects, such as constipation from too much calcium, to a minimum, they said.
That differs from the recommendation of the US Preventive Services Task Force (USPSTF), made earlier this year. USPSTF stated there was no basis for recommending calcium and vitamin D supplements to prevent fractures. But now, with a study this large, there may well be.
The study will be published in the February 2014 print edition of Menopause.
Prevent Postmenopausal Fractures
Taking vitamin D and calcium supplements may not help prevent bone fractures in postmenopausal women, according to a new report from a government-appointed panel of experts.
The report found no evidence that taking up to 400 international units (IUs) of vitamin D and 1,000 milligrams of calcium supplements a day reduced the risk of fracture in healthy postmenopausal women. In fact, the report found that these doses of vitamin D and calcium slightly increased the risk of kidney stones. Because of this lack of benefit, the panel, known as the U.S. Preventive Services Task Force, said healthy postmenopausal women should not take vitamin D and calcium supplements at or below these dosage levels (400 IUs for vitamin D and 1,000 mg for calcium) for the purpose of preventing fractures.
However, more research is needed to determine whether or not higher supplement doses can prevent fractures, the task force said.
The Institute of Medicine said people need between 600 and 800 IUs of vitamin D a day, and between 700 and 1,300 mg of calcium a day, depending on their age. While most people in the United States get enough vitamin D and calcium, older adults sometimes fall short of the recommendations and need to increase their intake through food or with a supplement.
The task force recommends taking a vitamin D supplement containing about 800 IUs for the prevention of falls in older adults ages 65 and over who are at risk for falls because they are vitamin D deficient or because they have a history of a recent fall.
The task force also recommends screening women ages 65 and older for osteoporosis as well as younger women who are at an increased risk for fractures.
About 50 percent of postmenopausal women will suffer a fracture related to osteoporosis during their lifetime, and fractures in older adults increase the risk of death, the task force said.
Because calcium helps build bone, and vitamin D helps bones absorb calcium, doctors frequently recommend taking vitamin D and calcium supplements to prevent fractures. Surveys estimate that close to 60 percent of women ages 60 and over take vitamin D supplements or calcium supplements. However, whether these supplements actually prevent fractures was not clear.
Rachael Rettner, MyHealthNewsDaily Staff Writer
Founded in 1989, The North American Menopause Society (NAMS) is North America’s leading nonprofit organization dedicated to promoting the health and quality of life of all women during midlife and beyond through an understanding of menopause and healthy aging.
Its multidisciplinary membership of 2,000 leaders in the field - including clinical and basic science experts from medicine, nursing, sociology, psychology, nutrition, anthropology, epidemiology, pharmacy, and education - makes NAMS uniquely qualified to serve as the definitive resource for health professionals and the public for accurate, unbiased information about menopause and healthy aging.
The North American Menopause Society (NAMS)