Why Do I Keep Getting Sick? 10 Potential Causes + MD-Approved Fixes

In addition to eating a well-balanced, healthy diet, Moday recommends taking 1,000 mg of vitamin C (divided into two doses) daily, along with 15 mg of zinc, and 2,000 IU of vitamin D3. She also suggests upping your intake of zinc-rich foods, such as oyster, crab, pumpkin seeds, and dark chicken meat.

If you live in an area where you don’t get a lot of sunlight, or you’re chronically deficient in vitamin D, you may need considerably more. Work closely with your doctor—and monitor your vitamin D levels yearly—to make sure you’re getting enough.