To help the immune system, it is necessary to consume foods rich in vitamins and minerals, reduce the consumption of fat, sugar and industrialized foods that have colorings and preservatives.

Doctors recommend foods rich in selenium, zinc, vitamins C and E, probiotics and omega 3 to boost defenses, because they promote the production of defense cells efficiently. Selenium is present in Brazil nuts, wheat, rice, egg yolks, sunflower seeds and chicken.

Some foods that contain zinc include oysters, shrimp, beef, chicken, fish, liver, wheat germ , whole grains, and nuts.

Vitamin C is found in oranges, tangerines, pineapple, lemon and strawberries. Vitamin E, in sunflower seeds, hazelnuts, peanuts or almonds . Probiotic foods would be natural yogurt and fermented milk. Omega 3 is found in sardines, salmon, tuna and flaxseed.

Likewise, consuming the following foods will allow you to boost your immune system.

1. citrus fruits

Most people turn to vitamin C after having a cold. That's because it helps strengthen your immune system. Vitamin C is believed to increase the production of white blood cells . These are key to fighting infections.

Popular citrus fruits include:

• grapefruit
• oranges
• tangerines
• lemons
• limes
• clementines

Because your body does not produce or store it, you need vitamin C daily to maintain your health. Almost all citrus fruits are rich in vitamin C. With so many varieties to choose from, it's easy to add a little of this vitamin to any meal.

2. red peppers

If you think citrus fruits have the most vitamin C of any fruit or vegetable, think again . Ounce for ounce, red peppers contain twice the vitamin C of citrus fruits. They are also a rich source of beta-carotene. In addition to boosting your immune system , to strengthen defenses, vitamin C can help maintain healthy skin. Beta-carotene helps keep eyes and skin healthy.

3. Broccoli

Broccoli is supercharged with vitamins and minerals. Packed with vitamins A, C, and E, as well as many other antioxidants and fiber , broccoli is one of the healthiest vegetables you can put on your table. The key to keeping its power intact is to cook it as little as possible, or better yet, not at all.

4. garlic

Garlic is found in almost all cuisines in the world. It adds a little zing to food and is a must for your health. Early civilizations recognized its value in fighting infections. According to the National Center for Complementary and Integrative Health Trusted Source , garlic can also help lower blood pressure and delay hardening of the arteries . Garlic's immune-boosting properties appear to come from a high concentration of sulfur-containing compounds, such as allicin.

5. Ginger

Ginger is another ingredient that many turn to after getting sick. Ginger can help decrease inflammation, which can help reduce sore throats and other inflammatory illnesses. Ginger can also help decrease nausea.

6. Spinach

Spinach is on our list not only because it is rich in vitamin C. It is also packed with numerous antioxidants and beta-carotene, which can boost our immune system's infection-fighting ability. Similar to broccoli, spinach is healthiest when cooked as little as possible to preserve its nutrients. However, light cooking improves your vitamin A and allows oxalic acid to release other nutrients.

7. Yogurt

Look for yogurts that have "live and active cultures" printed on the label, such as Greek yogurt. These crops can boost your immune system to help fight disease . Try to get plain yogurts instead of those that are pre-flavated and loaded with sugar. You can sweeten plain yogurt yourself with healthy fruits and a drizzle of honey.

Yogurt can also be a great source of vitamin D, so try to select brands fortified with vitamin D. Vitamin D helps regulate the immune system and is believed to boost our body's natural defenses against disease.

8. almonds

When it comes to preventing and fighting colds, vitamin E tends to outpace vitamin C. However, vitamin E is key to a healthy immune system. It is a fat-soluble vitamin, meaning it requires the presence of fat to be properly absorbed. Nuts, like almonds, are full of vitamin and also have healthy fats. A half-cup serving, which is about 46 whole shelled almonds , provides nearly 100 percent of the recommended daily allowance of vitamin E.

9. turmeric

You may know turmeric as a key ingredient in many curries. But this yellowish spice has also been used for years as an anti-inflammatory in the treatment of osteoarthritis and rheumatoid arthritis.

10. green tea

Both green and black tea are full of flavonoids, a type of antioxidant . Where green tea really excels is in its levels of epigallocatechin gallate, or EGCG, another powerful antioxidant. EGCG has been shown to improve immune function. The fermentation process that black tea goes through destroys a large amount of EGCG. Green tea, on the other hand, is steamed and not fermented, so the EGCG is preserved.

Green tea is also a good source of the amino acid L-theanine. L-theanine can help in the production of germ-fighting compounds in your T cells.

11. papaya

Papaya is another fruit loaded with vitamin C. You can find 224 percent of the recommended daily amount of vitamin C in a single papaya . Papayas also have a digestive enzyme called papain that has anti-inflammatory effects.

Papayas have decent amounts of potassium, B vitamins, and folic acid , all of which are beneficial for your overall health.

12. Kiwi

Like papayas, kiwis are naturally packed with a ton of essential nutrients, including folate, potassium, vitamin K, and vitamin C. Vitamin C increases white blood cells to fight infections, while the other nutrients of kiwi keep the rest of the body functioning properly.

13. Poultry

When you're sick, chicken soup is more than a feel-good food with a placebo effect. It helps improve the symptoms of a cold and also helps protect you from getting sick in the first place. Poultry, such as chicken and turkey, are rich in vitamin B-6 . About 3 ounces of light meat turkey or chicken contain 40 to 50 percent of the recommended daily amount of B-6.

Vitamin B-6 is an important player in many of the chemical reactions that occur in the body. It is also vital for the formation of new, healthy red blood cells. Broth or broth made by boiling chicken bones contains gelatin, chondroitin, and other nutrients useful for intestinal healing and immunity.

14. sunflower seeds

Sunflower seeds are packed with nutrients, including phosphorus, magnesium, and vitamin B-6 . They are also incredibly high in vitamin E, a powerful antioxidant.

Vitamin E is important for regulating and maintaining the function of the immune system. Other foods with high amounts of vitamin E include avocados and dark leafy greens.

15. seafood

Seafood is not what comes to mind for many who are trying to strengthen their immune system, but some types of shellfish are full of zinc.

Zinc doesn't get as much attention as many other vitamins and minerals, but our bodies need it so our immune cells can function as intended.

Seafood varieties high in zinc include:

• crab
• clams
• lobster
• mussels

Keep in mind that you don't want to have more than the recommended daily amount of zinc in your diet. For adult men, it is 11 milligrams (mg), and for women, it is 8 mg. Too much zinc can inhibit immune system function.