Nine out of ten people with type 2 diabetes had low blood levels of vitamin D in a Johns Hopkins University School of Medicine study. Low D meant higher long-term blood-sugar levels. The link: D helps your body produce and use the blood sugar -controlling hormone insulin more efficiently.
Aim for 1,000 to 2,000 IU of D a day from supplements. Your best bet: Take one that contains vitamin D3 (cholecalciferol) — it’s three to four times more potent than vitamin D2 (ergocalciferol). While fish and fortified milk provide some D, it’s nearly impossible to get enough from food every day. Your skin produces vitamin D when exposed to the sun, but experts warn that too much sun raises skin cancer risk. Supplements are safer.