There are two main forms of calcium—calcium carbonate and calcium citrate—and whether food is necessary depends on which type you’re taking, says Michael Roizen, MD, chief wellness officer at the Cleveland Clinic and medical advisory board member for vitamin company Persona. Calcium citrate doesn’t require food, but the stomach acid produced when you eat helps the body absorb calcium citrate, says Dr. Roizen, who generally recommends calcium citrate. It’s also worth noting that supplements often contain both calcium and fat-soluble vitamin D (which helps absorb the mineral); those should be taken with food too. No matter which form you take, you’re best off taking no more than 600 milligrams of calcium at a time, says Dr. Roizen, author of What to Eat When; the body can’t absorb much more than that at a time, so any extra would be a waste. And save any high-calcium snacks for later on, when your body is ready to absorb more.
Most multivitamins contain a mix of water-soluble vitamins (like B and C) and fat-soluble vitamins, so you’ll want to prep your body to absorb both. “Taking half a high-quality multivitamin in the a.m. and half in the p.m. makes sense since the excess water-soluble components … are urinated out in under 16 hours,” says Dr. Roizen. “So to keep a relatively consistent level, take half with some warm water, tea, or coffee, and be sure to add a little fat beforehand (e.g. a few walnuts—two or three is all that is needed). This should facilitate better absorption of the fat-soluble components.”
Even though there’s no conclusive evidence that echineacea can stop a cold, it’s one of the most popular herbal supplements on the market. Mount Sinai recommends never taking it on an empty stomach, so be sure to eat before taking echinacea. Find out which 13 vitamins and supplements nutritionists take to boost their immune systems.