Boost your immunity before you fly

Yogurt is cultured with lactic acid, which strengthen the digestive system and the entire immune system. Stock up on a brand of yogurt that contains plenty of live cultures, and eat yogurt every day for a few days before you fly. A drinkable yogurt makes a super-healthy and convenient preflight or in-flight snack. If you really dislike yogurt or cannot eat dairy, take a probiotic supplement, but remember to refrigerate it to preserve the live cultures. Eat a diet rich in fruits and vegetables, especially dark leafy greens like kale and brightly, and colored fruits such as berries.