Vitamin D May Reduce Risk of Type 2 Diabetes
Results of a meta-analysis reveal that people with the highest blood levels of vitamin D had a 43 percent lower risk of developing type 2 diabetes than people with the lowest levels. These findings demonstrate yet another potential benefit of maintaining healthy levels of vitamin D in the body.
Vitamin D provides many health benefits
The meta-analysis included data from eight observational cohort studies and 11 randomized controlled trials that involved diabetes and measuring vitamin D. The investigators, who were from Tufts Medical Center and Carney Hospital in Massachusetts, found that overall, individuals who consumed more than 500 International Units (IUs) per day of vitamin D had a 13 percent reduced risk of type 2 diabetes when compared with those who consumed less than 200 IU per day.
When looking at blood levels of vitamin D, the 43 percent lower risk of type 2 diabetes was associated with levels greater than 25 nanograms per milliliter (ng/mL) compared with the lowest blood levels, defined as less than 14 ng/mL.
Vitamin D levels in the body are measured using a blood test, which identifies the nonactive form of the vitamin called 25-hydroxyvitamin D (25(OH)D). According to the Vitamin D Council, a healthy level of vitamin D in the blood is around 50 ng/mL or higher.
The human body uses about 3,000 to 5,000 IU of vitamin D daily, and so the Council recommends healthy adults take in at least 5,000 IU daily. The US Food and Nutrition Board, however, places the adequate intake for vitamin D for adults at 600 IU.
The study’s authors point out that a relationship between vitamin D and diabetes has been seen in previous research. A vitamin D deficiency, for example, has been linked to faulty insulin secretion, and to insulin resistance in healthy, glucose-tolerant individuals.
Earlier studies have also reported on a positive role of vitamin D in depression, some cancers, rheumatoid arthritis and other autoimmune disorders, gum disease, and Parkinson’s disease, among others. Its role in helping maintain bone density and preventing osteoporosis has been much studied.
The findings of this meta-analysis are a launching point for additional research into the role of vitamin D in type 2 diabetes. The authors concluded that “high-quality observational studies and RCTs [randomized controlled trials] that measure blood 25-hydroxyvitamin D concentration and clinically relevant glycemic outcomes are needed.”
Mitri J et al. European Journal of Clinical Nutrition 2011; doi: 10.1038/ejcn.2011.118
Vitamin D Council