Effects of a healthy Nordic diet on plasma 25-hydroxyvitamin D concentration in subjects with metabolic syndrome: a randomized, placebo-controlled trial (SYSDIET)
At northern latitudes, vitamin D is not synthesized endogenously during winter, causing low plasma 25-hydroxyvitamin D (25(OH)D) concentrations. Therefore, we evaluated the effects of a healthy Nordic diet based on Nordic nutrition recommendations (NNR) on plasma 25(OH)D and explored its dietary predictors. In a Nordic multi-centre trial, subjects (n = 213) with metabolic syndrome were randomized