Diabetes and Vitamin D
Up to 75% of North Americans are vitamin D deficient, and that can spell a higher risk of a wide range of disorders, including diabetes. Over the summer, two new studies explored whether high-dose vitamin D supplements could slow the progression of diabetes (looks promising) or prevent it altogether (not so much).
Study 1: Vitamin D May Be Beneficial. First, the good news. In July, Canadian researchers reported in the European Journal of Endocrinology that daily vitamin D3 supplements may slow meta-bolic deterioration in people with diabetes.
In the double-blind, placebo-controlled trial, the researchers focused on people with a high risk of developing diabetes or a recent diagnosis of prediabetes or diabetes. The researchers assessed a variety of indicators of participants’ insulin function and glucose metabolism, as well as vitamin D levels. About 46% of study participants had low vitamin D levels at the start of the study.
Half of the participants then took 5,000 international units (IU) of vitamin D daily, while the other half took a placebo. After six months, the participants who took the vitamin D showed improved insulin sensitivity in muscle tissue and improved function of the pancreatic cells that produce insulin (beta cells). This suggests that high doses of vitamin D may slow the progression of diabetes, the authors noted, but they urge caution. As we’re about to see, these findings differ from those in other studies, including a larger one that was published just one month earlier.
Study 2: Vitamin D Probably Won’t Prevent Diabetes. The Vitamin D and Type 2 Diabetes Study, which was published in the New England Journal of Medicine in June, randomly assigned 2,423 people with prediabetes to take either 4,000 IU of vitamin D or a placebo every day for two and a half years. By the end of the study, 24.2% people in the supplement group and 26.7% of people in the placebo group developed diabetes. That difference, the study authors reported, did not meet their standard of 25% reduction, making it statistically insignificant.
At the same time, two other research groups found similar results. A study of 511 people in Norway found a hazard ratio (HR) of 0.90 in people who took vitamin D, while a study of 1,256 people in Japan reported an HR of 0.87. An HR of 1.00 would have shown that vitamin D had no effect, and an HR of 0.50 would show that it cut the risk in half, so the risk was lower, but just slightly. Again, it was not statistically significant.
The Vitamin D and Type 2 Diabetes Study researchers noted that if their study had been powered for a smaller effect, such as a 10% to 15% risk reduction instead of the 25% that they were looking for, they might have concluded that vitamin D could confer some small protective effects, but they were unable to reach that conclusion with the statistical model that they used.
Safety of Vitamin D. These studies used dosages that were considerably higher than the average daily recommended dose of 600 to 800 IU, but the latter did not exceed the tolerable upper limit of 4,000 IU. At that level, no side effects were reported. Vitamin D does interact with several drugs, however, so, it’s important to talk to your physician before taking it.
The post Diabetes and Vitamin D appeared first on University Health News.
Read Original Article: Diabetes and Vitamin D »
