Actually, more people suffer from food intolerances, which don't involve the immune system. However, food intolerance symptoms—such as intestinal distress—may mimic those of a food allergy. If you have a food intolerance, talk to a nutritionist about diagnosis and treatment; if you have food allergies, you need to see an allergist. Whether you have food allergies or intolerance, you will need to develop a diet that fits your needs and avoids foods that trigger a reaction.
Instinct may tell you to slow down when running in wintery conditions, but the secret to not slipping is actually to speed up and shorten your stride. Aim to have each foot strike the ground 90 times per minute, says Terry Chiplin, owner of Active at Altitude, a Colorado-based facility for endurance athletes. This high cadence helps ensure that each foot lands beneath the center of your weight rather than ahead of it, which can throw off your balance on slick terrain.
Consult your health care professional. Women of childbearing age may want to consider taking folic acid supplements to reduce the risk of having a pregnancy affected with neural tube defects. Many women and teenage girls don't get enough calcium or vitamin D, both of which are critical to healthy bones and avoiding osteoporosis. Some people with diabetes appear to benefit from chromium. Vegetarians, especially vegans, may want to consider supplements to obtain nutrients they aren't getting from animal products.