Nutritional Immunology: How The Foods You Eat Affect Your Immune System

Nutritional Immunology is a scientific field of study, which explores how the foods we eat influence our body’s immune response. The foods you eat don’t just have an impact on your weight, or your day-to-day wellbeing. They can also affect how well your body can respond to foreign invaders, pathogens, viruses, and bacteria.

The immune system is a complex component of the human body, which offers two separate lines of defense.

Your innate immune system is the first form of protection you have against potential threats. It consists of physical barriers, such as cellular defenses, your skin and mucous membranes.

Your adaptive immune system consists of specialized proteins and blood cells which target the specific causes of infection or disease in your body. This ecosystem has its own memory, which is why we become immune to specific illnesses after exposure.

Scientific studies suggest that a person’s diet can influence both parts of the immune system, affecting everything from the strength of our skin barriers to our ability to produce essential blood cells and enzymes.

What is Nutritional Immunology? Diet and the Immune System

Research into Nutritional Immunology tells us there is a direct connection between disease, illness, and diet. The food we eat provides our body with energy, but also with access to crucial substances, used in the creation of essential cells.

Certain dietary patterns and nutritional strategies have been connected with a greater risk of disease, allergic response, and illness.

For instance, typical Western diets often contain high levels of processed substances, saturated fat, sugar, and salt, which contribute to inflammation and increase disease risk.

Alternatively, healthier diets rich in whole foods such as fruits, vegetables and legumes promote healthy immune system functioning.

Diet can influence the immune system in a number of different ways. If we avoid certain essential foods, we can become deficient in critical nutrients, such as iron, which supports blood cell creation, or magnesium, which contributes to DNA synthesis.

A healthy, balanced diet ensures we can access all of the building blocks required for a healthy immune system, and minimize exposure to inflammation, free radicals, and other sources of damage.

The food we eat also influences the gut biome, which experts believe is essential to the functioning of the immune system. The gut microbiota residing in the gastrointestinal tract of the human body regulates immune homeostasis. Changes to the microbiome can cause dysregulation which leads to autoimmune disorders. Our gut needs a healthy balance of bacteria to assist with digestion, detoxification, and protection against pathogens.

Nutritional immunology studies suggest in order to maintain good immune function, we need to consume a balanced diet, brimming with different vitamins, minerals, and enzymes available from whole foods, fruits, and vegetables.

Which Nutrients are Crucial to Your Immunity?

Protecting your immune system via nutritional immunology generally means eating a balanced diet, low in inflammation-causing foods, and high in vitamins and minerals. However, there are some substances which appear particularly valuable for the immune system, such as:

·         Vitamin D: Low levels of vitamin D are frequently associated with reduced immunity. Our skin makes vitamin D when exposed to natural sunlight. However, for those with limited exposure to sunlight, supplementation may be necessary.

·         Iron: Iron is a critical nutrient, which helps to keep immune systems healthy. Although iron is frequently found in red meat, it’s also present in various plants, such as broccoli, as well as wholegrains, nuts, and beans.

·         Copper: Copper also helps to protect and maintain immune system cells. Studies show the immune system requires copper to perform several functions. Nuts and shellfish are often high in this substance, but supplementation may be necessary for those with deficiencies.

·         Vitamin A: Vitamin A is particularly useful for supporting the production of T cells, a type of white blood cell responsible for identifying pathogens. The body converts beta carotenes from leafy vegetables, carrots, red peppers, and various fruits into this substance.

Other essential nutrients, such as Vitamin B6, folate, B12, zinc, and selenium also have a role to play in the production and maintenance of immune cells. You can find these substances throughout various whole foods. Vitamin B6 and B12 is common in eggs, as well as various meat products. Green vegetables and nuts are great sources of folate, while zinc and selenium are common in shellfish, cereal products, meat, and Brazil nuts.

How Certain Foods Can Hinder the Immune System

According to nutritional immunology, the food we eat can either support, or harm or immune system. Unfortunately, many of the foods present in common western diets aren’t beneficial to immunity. They promote inflammatory responses in the body, and can damage immune functioning.

For instance, food high in added sugars and salts can increase inflammatory protein levels, and interfere with the function of protective immune cells. One study conducted in 2012 found that older adults with higher blood sugar levels also had lower innate immune responses.

Diets high in refined carbohydrates and added sugars can also influence the homeostasis of gut bacteria, leading to poorly developed immune cells.

Diets high in saturated fat can also negatively affect gut bacteria, promote inflammation, and inhibit the functioning of white blood cells. Also, diets high in added salt are linked to an increased risk of autoimmune diseases, such as arthritis and inflammatory joint disease.

While the food you eat may not guarantee you’ll end up having a specific disease or illness, it could improve your chances of falling victim to a number of chronic ailments, including heart disease, certain cancers, as well as type 2 diabetes.

How Good Food Choices Can Improve the Immune System

While a Western diet high in processed foods, added sugar, fats, and salts may lead to dysfunction in the immune system, nutrient-dense diets can improve immunity. The Mediterranean diet, for instance, which is high in vegetables, whole grains, and healthy fats, can actively reduce disease risk, lower inflammatory markers, and modulate gut bacteria.

The Mediterranean diet is also high in fiber, which promotes the development of short-chain fatty acids, which are critical for bacterial fermentation. SCFAs can modulate immune response, and improve the performance of the intestinal epithelium, which works to protect us against microorganisms which may cause infection and disease.

Other diets with high levels of vegetables, fruits, fatty fish, nuts, and seeds also contain excellent nutrients crucial to the performance of the immune system. A healthy balanced diet will improve your access to key nutrients such as Vitamin A, D, C, B6, and B12, as well as folate, iron, zinc, and selenium. Experts have even begun to discover vegetarian diets may be particularly beneficial for immunity. They can reduce chronic inflammation markers, and reduce free radicals.

Foods rich in beneficial plant compounds, fiber, vitamins, proteins, and minerals promote healthy gut biome balance, reduce systemic inflammation, and lower the risk of cellular damage. In some cases, they can also improve insulin and blood sugar sensitivity, reducing the risk of diabetes.

In some cases, supplementing your diet with additional nutrients, such as vitamin C, vitamin D, and zinc can help to reduce your risk of infection, according to studies.

How to Boost Your Immune System with Nutritional Immunology

Following the teachings of nutritional immunology, we can improve our immune system functioning naturally, simply by avoiding certain foods, and eating more of the right nutrients. The immune system works best against viruses and infections when it’s supported by a steady stream of crucial nutrients.

To improve your immune functioning, you should avoid foods such as:

·         Fried foods high in saturated fats, which can contribute to inflammation and reduce immune system response, while damaging the gut microbiome.

·        Highly processed foods such as refined grains and sugars, which deplete internal nutrients, increase inflammation, and prevent good immunity.

·         High levels of salt and sugar, which damage the gut microbiome, and cause problems with homeostasis, increasing your risk of infection.

Replacing these foods with plant-based dishes and products high in nutrients, minerals, and vitamins will boost the immune system, and improve your chances of fighting off pathogens. Many whole and plant-based foods are excellent for boosting immunity.

Below are examples of foods to eat more of, to improve your immune system:

·         Foods high in antioxidants: Brightly colored fruits and vegetables are rich in antioxidants which can reduce free radicals and inflammation. Certain mushrooms also include polysaccharides which regulate immunity.

·         Bitter greens: Dandelion, arugula, and other bitter greens are rich in plant enzymes which can promote liver health and support the production of new cells and T cells, which fight off infection and disease.

·         Whole grains and legumes: Fiber-rich whole grains and legumes support a healthy gut microbiome. It may also be useful to add some probiotics to your diet for gut health. Wholegrains and legumes also include zinc and B vitamins.

·         Omega 3 fatty acids: Healthy fatty acids such as omega-3 reduce internal inflammation. Flax seeds and other sources of healthy fats can also help to support the absorption of fat-soluble vitamins (D, E, and A), which support immunity.

Protecting your Immune System with Dietary Choices

Nutritional immunology tells us there’s more to protecting ourselves against disease and illness than exercising regularly and getting vaccinations. It’s important to take a holistic approach to protecting your body from foreign invaders. This includes adjusting your diet to avoid substances which might damage immune functioning, and embrace more vitamin and mineral-rich alternatives.

Since nutritional deficiencies can also have a significant impact on your immune system functioning, it’s worth taking a closer look at your health, to determine whether you have genetically higher needs of any essential nutrients.

Your CircleDNA test can provide you with genetic diet and nutrition reports, giving you insight into the key nutrients you need more of, and the optimal diet plan for you.

This at-home DNA test can also provide you with DNA insights into potential health conditions you may be more susceptible to, based on your genetics. This can help you build a more effective, personalized plan for boosting your immunity with the right nutrition.


  1. NCBI: Nutrition and the Immune System: A Complicated Tango
  2. NCBI: Diet and Immune Function
  3. Immunity: Western Diet and the Immune System: An Inflammatory Connection
  4. NCBI: The role of gut microbiota in immune homeostasis and autoimmunity
  5. NCBI: Copper and immunity
  6. NCBI: The Effect of Short-Term Hyperglycemia on the Innate Immune System
  7. NCBI: Responsiveness of the innate immune system and glucose concentrations in the oldest old
  8. NCBI: Salt, inflammatory joint disease, and autoimmunity
  9. NCBI: Gut microbiome-Mediterranean diet interactions in improving host health
  10. NCBI: A Review of Micronutrients and the Immune System–Working in Harmony to Reduce the Risk of Infection

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