We have reported on metabolic syndrome before. Some studies show that one-fourth of Americans have the metabolic syndrome, which is a combination of medical conditions that, when occurring together, increase the risk of developing cardiovascular disease, diabetes, and some forms of arthritis. The American Heart Association says the metabolic syndrome consists of five conditions that occur simultaneously:
- increased waist circumference
- increased triglycerides
- reduced HDL cholesterol
- increased blood pressure
- increased blood sugar
Obesity, inactivity, and low fat diets (high carb) are mostly to blame, but now we have a study that shows low vitamin D levels affect your risk of getting the metabolic syndrome in the future.
Dr. Claudia Gagnon and colleagues from all over Australia followed 6,500 patients for five years after the patients had a vitamin D level test. They found that “for each 10 ng/ml decrease in 25(OH)D, the risk of developing the metabolic syndrome increased by 23%.”
Gagnon C, Lu ZX, Magliano DJ, Dunstan DW, Shaw JE, Zimmet PZ, Sikaris K, Ebeling PR, Daly RM. Low Serum 25-Hydroxyvitamin D Is Associated with Increased Risk of the Development of the Metabolic Syndrome at Five Years: Results from a National, Population-Based Prospective Study (The Australian Diabetes, Obesity and Lifestyle Study: AusDiab). J Clin Endocrinol Metab. 2012 Jun;97(6):1953-61. Epub 2012 Mar 22.
After separating the patients into fifths (quintiles), they found those in the lowest (< 18 ng/ml) and next to lowest (18 – 23 ng/ml) quintiles, had a significantly increased risk compared to those in the highest quintile (34 – 93 ng/ml). There was no evidence of a U shaped curve; the higher the level the less the risk, but the authors cautioned they only had a few patients with higher levels (although it looked to me from their graph they had quite a few up to 50 ng/ml).
In a salute to the Food and Nutrition Board (FNB), the authors state that “for metabolic risk reduction, serum 25(OH)D concentrations need to be at least 20-23 ng/ml.” However, they continued, “… to minimize risk, serum 25(OH)D may need to be much higher but randomized controlled trials of vitamin D supplementation are required to answer this question.” I could see no evidence that their graphic data supported a cutoff at 20 ng/ml, indeed risk steadily decreased as 25(OH)D increased.