Low levels of vitamin D can lead to brittle bones, osteoporosis, and immune system issues. But time in the sun, often thought to be the best source of D, can be just as risky. Here’s how to get your daily dose of 600 IUs (international units).

Martin Carlsson Photography/Getty Images
| Credit: Martin Carlsson Photography/Getty Images

Eat It!

"Cod liver and other fish liver oils, swordfish, salmon, egg yolks, and mushrooms that have been exposed to sunlight are some of the richest food sources of vitamin D," says Pittsburgh-based nutritionist and dietitian Leslie Bonci. Aim for a serving or two of these foods a day. Fortified cereals and milks are another option.

Supplement It!

Only a blood test can reveal a deficiency. "Don't supplement before you know your levels," says Bonci, as vitamin D toxicity is dangerous. Follow your doctor's instructions. D3 may be more readily absorptive than D2 at higher doses to treat serious deficiencies.