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 Should you take high amounts of Vit C? What about “super foods”? Should you be taking an herbal supplement from your local health foods store that promotes immune-boosting properties?

A very common question among cancer patients is, “What foods boost my immune system”? The reality is it’s more than just diet that supports a healthy immune system. Harvard Health Publications has a great article that breaks it down into the following components:

  • Don’t smoke.
  • Eat a diet high in fruits, vegetables, and whole grains, and low in saturated fat.
  • Exercise regularly.
  • Maintain a healthy weight.
  • Control your blood pressure.
  • If you drink alcohol, drink only in moderation.
  • Get adequate sleep.
  • Take steps to avoid infection, such as washing your hands frequently and cooking meats thoroughly.
  • Get regular medical screening tests for people in your age group and risk category.

For our purposes, this post will only discuss diet, but you can read the article here to learn about every component of a healthy immune system.


It has long been thought that consuming copious amounts of Vit C will ward off a cold. While it has been found that deficiencies in some nutrients (zinc, selenium, iron, copper, folic acid, and vitamins A, B6, C, and E) can have negative affects on the immune system, the fact is, unless you are deficient in these micronutrients, taking amounts beyond your daily needs is a moot point. Remember, Vitamin C is water soluble-meaning consuming extra amounts of it will only be flushed out in your urine. So how much of each micronutrient is required and where in your diet can you find them?


Recommended Dietary Allowance

Upper Limit

Food Sources

Vitamin A

Men >19yrs- 900 µg/day

Women >19 yrs- 700 µg/day

3000 µg/day

Sweet potato, greens, broccoli, carrot, pumpkin, tomato, apricot, eggs, milk, cantaloupe


Men >51yrs- 1.7 mg/day

Women >51yrs- 1.5 mg/day

100 mg/day

Tuna, salmon, chicken, turkey, sweet potato, bananas, spinach, avocado, chickpeas, pistachios

Vitamin C

Men > 18yrs- 90 mg/day

Women >18yrs- 70 mg/day

2000 mg/day

Cantaloupe, berries, kiwi, oranges, grapefruit, pineapple, watermelon

Vitamin E

Adults > 14 yrs- 15 mg/day

1000 mg/day

Green leafy veggies, seeds, nuts, fortified cereals, vegetable oils

Folic Acid

Adults > 19yrs- 400 µg/day

1000 µg/day

Dark green leafy veggies, nuts, beans, peas, dairy, eggs, seafood, whole grains, fortified cereals


Recommended Dietary Allowance

Upper Limit

Food Sources


Men >19 yrs- 11 mg/day

Women > 19yrs, 8 mg/day

40 mg/day

Beans, nuts, crab, lobster, fortified cereals, whole grains, dairy, oatmeal, chickpeas


Adults > 51 yrs- 55 mcg/day

400 mcg/day

Nuts, seafood, eggs, cottage cheese, beans, lentils, brown rice, chicken, turkey


Adults > 18yrs- 900 mcg/day

10,000 mcg/day

Sunflower seeds, almonds, lentils, dried apricots, asparagus, turnip greens, mushroom, dark chocolate


Adults > 51yrs- 8 mg/day

45 mg/day

Fortified cereals, chicken, lentils, beans, chickpeas, green peas, eggs, nuts, spinach, rice, tuna

Bottom Line

The immune boosting properties are in numerous foods, so eat a diet rich in a variety of fruits, vegetables, whole grains, and lean protein. Unless you are actually suffering from a deficiency, taking extra supplementation is not necessary, and in this case, more does not mean better.