2011-02-23  Study Sees No Link Between Vitamin D, Diabetes


Low levels of vitamin D don't put older women at greater risk for type 2 diabetes, a large study of U.S. women suggests.

The findings may further temper the enthusiasm for vitamin D that built up in recent years, as studies linked it to lower risks of everything from diabetes, to severe asthma, heart disease, certain cancers and depression.

The problem with those studies is that they were observational, which means that researchers simply looked at people's vitamin D intake, or their blood levels of the vitamin, and whether or not they developed a given health condition.

Those types of studies cannot prove that vitamin D was the reason for any lower disease risk.
"You can't make dietary recommendations based on observational studies," said Dr. Jennifer G. Robinson, a professor of epidemiology and medicine at the University of Iowa and the lead researcher on the new study.

In an interview, she pointed to the recent report on vitamin D from the Institute of Medicine (IOM), an independent scientific body that advises the U.S. government. The report said the evidence didn't show that vitamin D has any health benefits beyond building and maintaining strong bones.

It also said average Americans already have vitamin D blood levels at or above the amount that's needed for good bone health. (Read the entire article)

2011-02-23 Vitamin D may help keep blood sugar under control




Drinking yogurt with extra vitamin D may help people with diabetes regulate their blood sugar, a study from Iran finds.

In the trial, 90 adults with diabetes were divided into three groups, all given daily yogurt drinks: one group received plain yogurt, one got yogurt with extra vitamin D, and one was given yogurt with extra vitamin D and calcium.

At the end of 12 weeks, "we found a relatively remarkable improvement" in blood sugar levels in the groups that got extra vitamin D, compared to the plain yogurt group, co-author Tirang Neyestani, associate professor at National Nutrition and Food Technology Research Institute in Iran, told Reuters Health in an e-mail.

Past studies on the role of vitamin D in diabetes have not been able to show cause and effect.

It's noteworthy that this study does, and that it suggests vitamin D has a positive effect on people with type 2 diabetes, said Dr. Anastassios Pittas, assistant professor of medicine at Tufts University School of Medicine in Boston. He was not part of the study.( Read the entire article)