1. Tea: Try drinking green, chamomile, or black. Loaded with antioxidants they boost immune function, fight cold and flu, and destroy cell-damaging free radicals.
2. Zinc: have 15 to 25 mgs of zinc a day as some consider it the single most important nutrient for maintaining optimal immune function. It can be found in red meat, poultry, beans, nuts and fortified cereal.
3. Almonds: are full of vitamin E which helps boost the immune system by increasing the amount of the body's cells that destroy germs. 
4. Broccoli: helps mucous membranes form to protect your body from damage by repelling environmental threats. It also contains vitamin A, C, and glutathione, all of which are known to help boost immunity. 
5. Vitamin C: Studies found that people who take vitamin C experience 45 to 91 percent reduction in common cold incidence while most people find them in citrus fruits, strawberries actually have a higher vitamin C concentration. 
6. Fiber: helps to support the production of white blood cells that fight bacteria. Fiber also allows your body to absorb immune boosting nutrients. Try a bowl of steel-cut oats with flax-seed. 
7. Mushrooms: contain beta-glucans known to enhance immunity. They also contain selenium, deficiencies in this nutrient are linked to developing the flu.
8. De-Stress:  Try yoga, tai chi, or meditation. Stress causes the immune system to be more susceptible to the common cold and other viruses. 
9. Watermelon: The antioxidant glutathione found in watermelon helps fight and fortify cells against infections. 
10. Yogurt: Yogurt containing "live and active cultures" may reduce your changes of getting a cold. 
11. Simple sugars: avoid them! Sugary foods and sugary juices can impair immune function.
12. Vitamin D: linked to immune function and regulation, deficiency increases the risk of infections. Few foods contain vitamin D and its best to get your dose from short periods of sun exposure without sunscreen.
13. Garlic: several antioxidants found in garlic battle immune system invaders. It has strong anti-viral, anti-bacterial, and anti-fungal qualities. 
14. Capsaican: studies have shown that capsaican, the substance that makes hot peppers hot, can fighting colds before they start when taken daily by increasing your
15. Echinacea: this supplement stimulates production of white blood cells. It has anti-bacterial, anti-microbial, and anti-viral powers that strengthens the body's natural immunity. It can be found in teas or taken as a supplement.