From “Science Blog” a report on lack of vitamin D and the effect on diabetes and heart disease. click here for more info! And for the good news Shaklee Corporation provides suggested vitamin D levels in all products with vitamin D. The most expensive food supplement you can buy is one that does not work. How do you know if a food supplement works? Ask to examine 3rd party clinical studies on the specific product your are interested in. Click here for more info on Shaklee Products.