Vitamin D supplementation lowers fracture risk

Researchers have found that doses of 700 to 800 IU of vitamin D3 per day may reduce the risk of hip fracture by 26 percent and nonvertebral fracture by 23 percent.

The May 11 2005 issue of the Journal of the American Medical Association published the results of a meta-analysis of 12 clinical trials involving vitamin D supplementation in the prevention of fracture. The analysis concluded that supplementation with higher than the commonly recommended 400 international unit (IU) doses of vitamin D reduces the risk of hip and nonvertebral fractures in older individuals.

The vitamin D studies included a total of 19,114 men and women aged 60 and older. The trials used the form of the vitamin known as cholecalciferol, or vitamin D3, which, according to studies cited in the current review, may be much more effective than the dietary form of the vitamin.

The researchers found that doses of 700 to 800 IU of vitamin D3 per day reduced the risk of hip fracture by 26 percent and nonvertebral fracture by 23 percent. Studies that used 400 IU vitamin D3 or less found no significant benefit for either type of fracture. The role of additional calcium supplementation could not clearly be defined from the studies, but it appears that at least 700 milligrams calcium per day may also be necessary for nonvertebral fracture prevention.

JAMA 2005 May 11;293(18):2257-64.

Supplemental vitamin D and calcium reduces risk of diabetes

The incidence of type-2 diabetes is lower among women who get adequate calcium and supplement with vitamin D. Researchers used data from the Nurses Health Study, which includes over 83,000 women, to study the relationship of calcium and vitamin D intake to type-2 diabetes.

After 20 years of follow-up, it was concluded that a combined daily intake of over 1,200 mg of calcium and more than 800 IU of vitamin D was associated with a 33 percent lower risk of type-2 diabetes. Interestingly, dietary vitamin D intake did not appear to provide any statistically significant benefit. But the women who supplemented with at least 400 IU of vitamin D had a 13% lower risk of diabetes when compared to those who took less than 100 IU per day. Both dietary and supplemental calcium resulted in decreased risk of type-2 diabetes, and those with overall intakes above 1,200 mg had a 21% lower risk than those who got less than 600 mg per day.

Elevated intakes of calcium and vitamin D, especially from supplements, are significantly associated with lower incidence of type-2 diabetes.

Diabetes Care 29:650-656, 2006

Calcium and vitamin D enhance heart health benefits of weight loss

Weight loss and reduced waist circumference are related to an improvement in heart health and factors related to metabolic syndrome. According to a new study, supplementing with calcium and vitamin D during weight loss enhances heart health benefits in women with typically low calcium intake.

Recent research has shown that overweight individuals with low calcium and dairy consumption are at increased risk of developing metabolic syndrome. The findings suggest that adequate calcium intake could create a healthier metabolic profile similar to a balanced diet and regular exercise.

In a new study, researchers investigated this issue by testing cardiovascular benefits of long-term calcium supplementation in women with usual low calcium intake. Healthy, overweight or obese women with a daily calcium intake of less than 800 mg/day were randomly assigned to 1 of 2 groups: the group consuming 2 tablets/day of a calcium + vitamin D supplement (600 mg elemental calcium and 200 IU vitamin D/tablet) or the group consuming placebo. Both groups completed a 15-week reduced calorie weight-loss program.

Significant decreases in LDL cholesterol levels, as well as the ratios of Total to LDL and LDL to HDL were seen the calcium +D group. These changes were independent of the changes due to fat loss and reduced waist circumference. A tendency for more beneficial changes in HDL cholesterol, triglycerides, and total cholesterol was also observed in the calcium +D group.

This was the first study to show that consumption of calcium +D during weight-loss enhances the beneficial effect of body weight loss on cardiovascular risk factors in overweight women with typically low calcium intake.

American Journal of Clinical Nutrition, Vol. 85, No. 1, 54-59, January 2007