Wednesday, April 02, 2003

Bones Need Vitamin D

Researchers from Creighton University find even women with normal levels of vitamin D can benefit from vitamin D supplementation. They say the vitamin D ensures calcium is effectively absorbed.

- 2003/04/02

Doctors have long known calcium absorption is impaired in the presence of vitamin D deficiencies, but they have been less clear about the level of vitamin D needed to fully normalize absorption of calcium. Researchers conducted two studies one year apart among a group of healthy postmenopausal women to assess the impact of vitamin D supplementation in women with so-called "normal" levels of blood vitamin D. During the first study, the women were given 500 mg calcium supplements but no additional vitamin D. In the second study, they were pretreated with vitamin D supplementation for three weeks before taking the calcium supplements. All had several blood tests over 12-hour intervals to measure absorption of calcium. The investigators found women in the lower end of the normal range for blood vitamin D levels were less able to adequately absorb the calcium supplements. Women in the higher blood vitamin D level group had calcium absorptive efficiencies ranging from 45-percent to 65-percent greater than those in the lower vitamin D level group. Vitamin D is an important nutrient found in food. It is also made in the skin via exposure to sunlight. Due to worries about skin cancer, however, many people are minimizing their exposure to the sun, thus decreasing the amount of vitamin D they receive from this source.

SOURCE: Medical Breakthroughs