Washing your hands, healthy eating and exercise are the best ways to keep your immune system in tip-top shape. But adding specific supplements can also help your natural defenses stay strong all season long. Here are some of the top natural recommendations:

Omega-3s. Found naturally in fish, these EFAs increase phagocyte cell activity, which boosts the immune system.

Astragalus. This ancient Chinese herb stimulates white blood cells and boosts immunity.

Vitamin C. Best known for its ability to boost immune system health, this powerful vitamin serves so many other functions as well.

Vitamin D. A Harvard study shows that people with low levels of Vitamin D were 36% more likely to have upper respiratory infections.

Zinc. Yale research reveals that zinc can help shorten colds by slowing the multiplication of the virus in the nose and throat.