Aside from ensuring that you practice excellent hygiene, you can also boost your immune system by eating certain foods. Your diet does play an extremely important role in the strengthening of your immune system, but sadly most of us no longer eat foods that will help us to fight off viruses and diseases. Truth is, you cannot just eat one orange or grapefruit, and instantly expect a cold to disappear or be prevented. A truly healthy immune system requires consistency in diet, exercise and sleep.

With very few exceptions, it is better that you get your vitamins and minerals from fresh food than pills, as such, here is a list of thirteen foods that will help to boost your immune system.

1. ELDERBERRY

This is a notorious old folk and Native American remedy. The extract of these very dark berries have been proven to be effective against the influenza viruses in many test tube studies. This fruit is also extremely rich in antioxidants and also help to fight inflammation.

2. BUTTON MUSHROOMS

Don't be too quick to dismiss mushrooms. It contains a mineral known as selenium and a high level of antioxidants. Selenium has been known to prevent the contracting of more severe forms of the flu virus. Button Mushrooms are also rich in niacin and the B vitamin riboflavin- both of which play an essential role in building and maintaining a healthy immune system. Mushrooms also have antibacterial and anti-tumor effects.

3. ACAI BERRY

Dubbed as one of the greatest 'super foods', the dark color of the Acai berry, the same with elderberries, signifies how high an antioxidant content it has. Even though Acai has not been linked to any particular disease, its high antioxidant content will help your body to fight the aging process as well as stave off diseases.

4. OYSTERS

Known as both an aphrodisiac and an immune booster, oysters have a high zinc content. Low zinc levels have been directly linked to infertility in both men and women as seen from studies conducted by the Mayo Clinic. Zinc is also an antiviral agent and is extremely important with regards to the body's ability to heal wounds.

5. WATERMELON

This equally hydrating and refreshing fruit is a powerhouse of antioxidants, in particular glutathione, which is known for fighting infections. It is also packed with Vitamins A, C and K, all of which are essential for the immune system

6. CABBAGE

This is one of the greatest sources of the immune strengthening glutamine. It is also packed with antioxidants, Vitamins C, E, A, and cabbage juice is a powerful cure for stomach ulcers, even though it is slightly acidic. Doctors have reported that patients with severe cases of stomach ulcers see improvements in as little as 2-3 days after drinking a glass of cabbage juice twice per day.

7. ALMONDS

Packed with vitamin E, niacin, riboflavin, healthy oils and plant proteins, almonds are powerhouse immune boosters. They can be made into almond flour and blended into almond milk. However, you consume them; because they are excellent for the immune system.

8. GRAPEFRUIT

Grapefruits are a great source of flavonoid, which is a natural chemical that is essential for activation of the immune system. It is also an excellent source of Vitamin C and K. Many people who dislike grapefruits stick with oranges and tangerines- which offer similar benefits.

9. GARLIC

Garlic is a great natural remedy against H pylori, the bacteria that causes stomach ulcers. It is also known to sooth headaches, and clean the blood. In addition to all this, it is packed with several anti-oxidants that help to fight viruses and bacteria that invade the body.

10. SPINACH

This is another vegetable that is classed as a 'super food' due to how nutrient rich it is. It provides a great source of folate, which is essential for DNA repair and a creation of new cells in the body. It is also high in fiber which is needed for the digestive tract, and a good source of Vitamin C, K, and iron. Eaten lightly cooked or raw, gives the best results.

11. TEA

Green tea or black tea? Whichever your preference is, you will still benefit from the disease fighting flavonoids and polyphenols they hold within. These two nutrients are powerful anti-oxidants that look for free radicals in the body and destroy them. We recommend decaf, but caffeinated works just as fine.

12. SWEET POTATO

Just like crunchy carrots and most other root vegetables and fruits, sweet potatoes are high in antioxidant beta-carotene that kills free radicals. They are also high in fiber and Vitamins A, E and D.

13. BROCCOLI

This easy to find vegetable is an immune boosting classic. It is packed with nutrients that protect the body from damage and high in Vitamins A, C, D, B and glutathione.

With this comprehensive list, you will find your trips to the doctor and those pharmacy bills will near disappear.