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Three Ways Food Phytonutrients Boost The Immune System  

By Ritamarie Loscalzo


There is little question that a diet rich in a wide variety of functional foods boosts the immune system, but why is this so?

According to The Institute For Functional Medicine, there could be three mechanisms by which food-derived compounds have the ability to lower the risk and severity of viral infections.

Food phytonutrients:

     1)      Balance inflammatory pathways.

     2)      Increase antioxidant levels and reduce oxidative stress.

     3)      Support the gut microbiome.

Balance Inflammatory Pathways

Inflammation is an important and necessary component of an optimally functioning immune system and critical to the body’s ability to protect itself during the initial stages of an injury or infection.

As I discuss in Optimizing Your Immune System is Critical During Times of Chronic Stress, it’s only when the body continues to release inflammatory mediators that chronic inflammation occurs and can lead to diseases such as diabetes, cancer, and autoimmune disorders.

By avoiding inflammatory foods, such as sugar and the highly processed foods found in the typical Western diet, and increasing the intake of anti-inflammatory foods, such as whole fruits and vegetables rich in phytonutrients, you can effectively help to maintain balance between these inflammatory pathways.

Oxidative Stress vs. Antioxidant Levels

The immune response itself produces countless oxidative compounds in order to kill pathogens. As a result, the immune defense may also act as a source of oxidative stress that can produce damaging free radicals.

One way that diet can counter these harmful consequences is by reducing any oxidative compounds that could be introduced through diet.  When food is grilled, fried and broiled it can create inflammatory compounds referred to as advanced glycation end products (AGEs). Cooking food at lower temperatures using a moist method of preparation, such as steaming, reduces the formation of AGEs.

A second way to use diet to counter the damaging effects of oxidative stress is to increase the intake of functional foods rich with polyphenols and other phytonutrients. At the same time they boost the immune system, filling your plate with these nutritional powerhouses leaves less room for harmful foods low in antioxidants such as unhealthy fats and oils.

When you listen to my ReInvent Healthcare podcast episode called “Culinary Herbs and Spices for Immune System Support”, You’ll multiple ways to incorporate delicious and beneficial herbs and spices into your diet. 

The Immune Modulation Strategies Guide we put together to delve deeper into the immune system contains a wealth of information that includes immune enhancing diet suggestions, nutrients that support immune function, and effective regimes for recovering from colds and flus. It’s also a great starting point for understanding and managing autoimmune disease.

Support the Gut Microbiome

The majority of the immune system is found in the gut which is why diet has such a tremendous impact on the body’s ability to fight off infection.

Eating plenty of fiber, which is then fermented by gut bacteria, produces short-chain fatty acids (SCFA), such as butyrate, which have immune modulating activities that serve to protect the gut barrier function and support innate immunity.

Fermented foods such as miso, kimchi, and sauerkraut provide microorganisms and secondary metabolites that help with immune response, reduce the incidence and duration of respiratory infections, and may be important for specific immune function such as increasing natural killer cells and targeting tumors.

There are more details on the importance of the gut microbiome in my  The Microbiome in the Gut is Foundational to Immune System Health.


The phytonutrients and other food compounds provided by a whole foods diet boost the immune system and therefore, a person’s optimal health.  But it’s an unfortunate statistic that immune system dysregulation is expected to increase by 3%-9% annually.

If you are a functional healthcare practitioner that wants to support clients in their search for real ways to improve their overall health, in addition to resolving chronic immune system challenges, my Nutritional Endocrinology Practitioners Training (NEPT) program has the cutting-edge curriculum you need to take your practice to the next level and empower clients with effective, lasting options.  

Join my graduates as they bring desperately needed change to a broken, disease-focused healthcare system. You too can be a part of the solution.

In my podcast, ReInvent Healthcare………

The Functional Medicine Approach to COVID-19: Lifestyle Practices for Strengthening Host Defense | The Institute for Functional Medicine
Effect of ingesting yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 on influenza virus-bound salivary IgA in elderly residents of nursing homes: a randomized controlled trial: Acta Odontologica Scandinavica: Vol 77, No 7
Foods | Free Full-Text | Lactic Acid Bacteria from Kefir Increase Cytotoxicity of Natural Killer Cells to Tumor Cells
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Medical Disclaimer: The information on this website is not intended to replace a one-on-one relationship with a qualified health care professional and is not intended as medical advice. It is intended as a sharing of knowledge and information from the research and experience of Dr. Ritamarie Loscalzo, drritamarie.com, and the experts who have contributed. We encourage you to make your own health care decisions based upon your research and in partnership with a qualified health care professional.

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