Increases the number of immune cells, their function and activity in the body.

5,000 International Units

Orange and red-colored fruits and vegetables (carrots, cantaloupe, peppers, watermelon, etc.), dark green vegetables

Strengthens immunity. Is a component of a powerful antioxidant enzyme that helps protect cells from damage.

2.0 milligrams

Nuts and seeds, fortified ready-to-eat cereals, beans

Too little in the diet may decrease resistance to infections and slow the immune system's response to trouble. Needed to make new, healthy cells, including immune cells.

400 micrograms

Whole grains, fish (especially fattier fish such as salmon, herring and mackerel) and meat

An important ingredient for making enzymes that help kill bacteria which can cause infection.

18 milligrams

Beef, oysters, pumpkin seeds (pepitas), pistachios, peapods, raisins

Too little in the diet reduces the production of certain immune cells. Too little can increase inflammation in the body.

400 milligrams

Halibut, nuts, beans, yogurt, whole grains (oats, whole wheat, brown rice, quinoa, barley), spinach

Increases the activity of immune cells that tackle germs. Calms inflammation which would otherwise damage cells.

For general health: 2-3 servings a fish/week or several servings of plant foods

EPA and DHA (the omega-3 fats found in trout, salmon, mackerel, herring, tuna, halibut, striped bass) + ALA found in flax and chia seeds, walnuts, canola oil and some vegetables

Helps form antibodies and enzymes that fight disease. (Note: too much selenium weakens the immune system.)

70 micrograms

Brazil nuts, oysters, pork, chicken, whole-wheat pasta, sunflower seeds

May mobilize immune cells and help increase the body's resistance to infection.

1.7 milligrams

Almonds, soynuts, yogurt and milk (low-fat), pork, beef

Helps maintain the health of organs (thymus, spleen, and lymph nodes) that make white blood cells.

2.0 milligrams

Fortified breakfast cereals, potatoes, banana, beans, chicken, dark green vegetables, halibut

A powerful antioxidant that keeps cells healthy + increases the production and activity of immune cells.

60 milligrams

Citrus fruits and strawberries, tomatoes, Brussels sprouts and broccoli, red peppers, papaya, kiwi, dark green leafy vegetables

Helps manage the functions of the immune system.

400 International Units (IU)

*Many experts believe we need more than this level.

Sunlight, oysters, most fish, fortified milk and dairy foods, eggs

Helps make a powerful protein in the immune system that attacks viruses and bacteria.

30 International Units

Nuts, seeds, vegetable oils

Needed to produce white blood cells which fight infection and help in healing.

15 milligrams

Oysters, crab, beef, pork, poultry, beans, soy nuts, nuts, fortified cereals