source of calcium

Photo: Arx0nt/Getty Images

3 of 6

Why you might be low: Don't eat a lot of dairy, or on one of the latest dairy-free diets (hey there, Whole30!)? If you're not actively adding other sources of calcium to your diet, it's possible that you're not getting enough.

Why you need it: You know calcium is essential for strong bones and teeth (that's where 99 percent of the calcium in your body goes, after all), but your body also needs it for vascular and muscular function.

Where to find it: Four servings of dairy a day is plenty (that's 8 ounces of milk or yogurt or one ounce of hard cheese), says Behar. But, of course, if you're not on the dairy train at the moment, try dark leafy greens like kale and turnip greens, or broccoli. Tofu made with calcium sulfate is also a good option.