Vitamin D threshold values

There is a threshold effect for the interaction between vitamin D concentrations in the blood and measures of glucose metabolism, new research from the US shows for the first time. The research (1) was conducted amid considerable debate over the lower limit of the ‘normal’ range for 25-hydroxyvitamin D (also known as 25-OHD).  Even the experts can’t agree with the Endocrine Society advising a minimum 25-hydroxyvitamin D level of 75nmol/L (30μg/L) and the Institute of Medicine 50nmol/L (20μg/L).