Controversy exists surrounding optimum blood levels of vitamin D. Current government guidelines for sufficient blood levels of vitamin D as well as daily intake are based on those required for bone health and are much lower than what are now believed by many experts to help prevent cancer, diabetes and cardiovascular disease. National Institutes of Health guidelines recommend a minimum blood level of 15 ng/mL as adequate for bone and overall health. However, many experts now feel that 30 to 100 ng/mL should be the goal. Levels above 150 ng/mL are potentially toxic and can be life-threatening.

In this study, vitamin D levels averaged 23.1 ng/mL among people with metabolic syndrome and 27.8 ng/mL in healthy controls, a difference that was found to be significant. Vitamin D deficiency in this study was defined as less than 20 ng/mL, and was found in 30 percent of subjects with metabolic syndrome and 8 percent of healthy controls. "Insufficiency" was defined as less than 30 ng/mL: 84 percent of the metabolic syndrome group and 67 percent of controls were found to have insufficient levels.

Jialal's team intends to continue to investigate the connections between vitamin D and metabolic syndrome. They plan to study diets of subjects with and without metabolic syndrome to determine whether vitamin D intake is adequate. According to Jialal, it is possible that people with metabolic syndrome have higher than average needs for vitamin D. Because the vitamin is fat-soluble, it tends to get sequestered in fat, making it less likely to circulate in the blood and to be available to other tissues.

They also plan to undertake a study on vitamin D supplementation for people with metabolic syndrome to see if it lowers fasting blood sugars and increases insulin sensitivity, trends that would lower the risk of developing diabetes.

"We have the potential to significantly delay or prevent the emergence of diabetes, heart attacks and strokes in people with metabolic syndrome through vitamin D supplementation," said Dr. Jialal. "This may offer a very simple yet powerful weapon to combat this burgeoning health problem in our society."

Source: University of California - Davis Health System