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.It’s a common assumption to think you should avoid eating fruit if you have diabetes. But the latest science says fruit is perfectly healthy for people with diabetes. Extreme low-carb diets skimp on fruit because, they claim, fruit contains natural sugars that turn into sugar in the body. It’s true that all carbohydrates from food eventually end up as blood glucose—including the carbs in fruit. That said, fruit has a much lower impact on blood sugar levels than other truly harmful foods like candy bars and soda. 

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.