Fortify Your Immunity with Nutrition

Original Blog Post written by Sharon Palmer, MSFS RDN “The Plant-Powered Dietitian”

Title: Build Up Your Immune Defense with Diet, March 2020 (Updated October 13, 2020)


Translated and Edited by: East Valley Community Health Center Nutrition Department


Studies show a diet rich in key nutrients may help strengthen our immunity one whole food at a time. Let’s learn together which foods to add into our daily routine to stay healthy this season.

Vitamin C. According to the National Institutes of Health, more than 30 clinical trials have examined the effects of vitamin C on cold prevention, yet overall they do not support a significant reduction in risk. Still, there’s no harm in pushing vitamin C-rich foods, such as papaya, red peppers, broccoli, strawberries, citrus and tomatoes as part of your healthful diet.

Vitamin E. Its documented role in the immune system has led immunology researchers to study vitamin E. In a study published in The Journal of the American Medical Association, vitamin E supplementation was found to reduce the risk of upper respiratory infections, in particular the common cold. Foods packed with vitamin E include nuts, olives and leafy greens.

Zinc. Studies show that people with low serum zinc levels experience twice the frequency of pneumonia (as well as longer duration and more antibiotic use,) compared with those who have adequate zinc levels. In a study in the American Journal of Clinical Nutrition, zinc supplementation resulted in 65 percent fewer occurrences of infection. More research is needed to confirm these observations. Zinc plant-based food sources include beans, nuts and whole grains.

Vitamin D. While we need more evidence, scientists recognize that the sunshine vitamin may have important functions within the immune system. Research shows that patients with tuberculosis respond better when treated with vitamin D or sunlight. In addition to sunlight, you can find vitamin D in fortified foods and beverages, as well as mushrooms exposed to light, and in salmon and sardines.

Calories. The potential immune benefits of calorie restriction have attracted the interest of researchers. If you decrease calories too much and it results in nutritional deficiencies, it’s not good for the immune system.

Probiotics. These live microorganisms can exert health benefits by improving the number of beneficial bacteria in the gut. A study in The Journal of Nutrition found that a fermented milk drink containing the probiotic lactobacillus casei strain Shirota significantly increased natural killer cell (an important immune cell) activity. However, only certain strains of probiotics have been tested for immune benefits; thus, it’s important to look for clinical proof.

Mushrooms. Curiously, mushrooms have captured scientists’ attention in immune research. When mice were fed a powder made of white button mushrooms, the natural killer cell activity increased significantly, according to a study published in The Journal of Nutrition.



It’s important to keep in mind that foods contain a synergy of nutrients that work in unison to provide health benefits versus supplements which only provide one or two nutrients.

The best approach for fostering a healthy immune system is to eat a nutrient-rich diet that meets all of your body’s needs.


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