1. Garlic

It's not just that garlic breath keeps people at a distance. The bulb contains aillicin, which fights infection and bacteria. When British researchers gave 146 people garlic extract or a placebo, those who got the garlic were two-thirds less likely to get sick. 

2. Blueberries

Vitamin C is known for its immunity-bolstering effect, and blueberries have plenty of it. Even better, antioxidants are known to protect the lungs from flu, and scientists found that wild blueberries have the most of any fresh fruit.

3. Shellfish

Oysters, crabs, lobsters and clams are high in selenium, which helps white blood cells create the proteins that move flu bugs out of the body. Salmon and herring are high in the omega-3 fats that protect lungs from infection.

4. Mushrooms

Mushrooms contain ergothioneine, a powerful antioxidant, plus natural antibiotics that inhibit microbial growth as well as stimulate the body's immune system. Mushrooms also have the flu-fighting vitamins A, B-complex and C.

5. Chicken soup

Everyone knows Grandma recommended soup to fight a flu bug, but it turns out she had a point. The University of Nebraska found 12 out of 13 brands of chicken soup blocked inflammatory white cells. Given that cold symptoms are a response to those cells building up in the body, the soup actually helps reduce annoying symptoms. Salty broth also thins mucus, much like a cough medicine.

6. Dark turkey meat

Why eat a turkey leg or thigh instead of breast meat? The dark turkey meat has more vitamins and minerals than any other part of the bird. The zinc and selenium in turkey boost immunity and increase white blood cells, and you get the most of them in dark meat.