Nutrition to support immune health

Research continues to show that what we eat directly impacts how our immune system functions.  This is particularly important for people with ME/CFS and Long Covid as immune health has been shown by research to be affected in these conditions.

Here we look at the key nutrients that are important for immune health and steps you can take to strengthen this aspect of health.

1.   Why nutrition matters for immunity

Nutrient deficiencies can weaken our immune system. Both macronutrients like protein and fats, and micronutrients such as vitamins and minerals, play vital roles. Additionally, phytochemicals and functional foods—like probiotics and certain plant compounds—can modulate immune responses.

2.   The power of protein in chronic illness

Protein is crucial for building immune cells like cytokines and antibodies. During illness or stress, our bodies need even more protein. Stress hormones and inflammation can break down muscle and reduce new protein production, making adequate intake even more essential.

Key immune-boosting amino acids

The protein that we eat is made up of amino acids and a number of these are essential for a strong immune system.

Arginine

• Helps production of nitric oxide in macrophage cells, which enables them to fight pathogens

• Induces the decline of oxidative stress

• Causes a reduction of inflammation in the intestine and re-establishes mucosal immune equilibrium

Tryptophan

• Metabolites produced by tryptophan metabolism (e.g kynurenic acid & NAD) control inflammation

• Tryptophan metabolism controls hyperinflammation and induces long term immune tolerance.

• Depletion of tryptophan impacts cytokine production and can prevent T-cell activation and proliferation

Glycine, Glutamine and Cysteine to make Glutathione

Glutathione is a powerful antioxidant which is made in the cells from three amino acids– Glutamine, Glycine and Cysteine. Glutathione is extremely important to immune health, as it:

• Helps eliminate Reactive Oxygen Species (ROS) which reduces oxidative stress

• Is needed for the innate immune response including the proper function of T-cell lymphocytes and stimulates the production and activity of natural killer cells

Diagram showing how glutamine, glycine and cysteine are required to make Glutathione and proteins which supply these amino acids

Getting enough high-quality protein

In order to make sure your body is getting the amino acids which are so essential for the immune system, it is essential to eat enough high quality protein in your diet every day.

Animal-Based Sources

Animal sources of protein are highly digestible and complete. Foods such as  chicken, beef, fish, dairy, eggs are all complete proteins which are easily absorbed by the body.

Plant-based protein

Good sources of plant protein include the following options:

• Soy and mycoprotein (Quorn) provide complete protein.

• Combine grains + legumes or nuts + legumes to form complete protein in meals

How much do you need?

Aim for 1.2 – 1.5g of protein per kg of bodyweight daily. Spread intake throughout the day, with 25–35g per meal. Make sure your breakfast includes plenty of protein.

Protein content of foods per 100g

3.   The importance of fats

There are two essential types of polyunsaturated fats:

• Omega-3s (anti-inflammatory)

• Omega-6s (can be pro-inflammatory in excess)

In a typical Western diet, the ratio if Omega 6 fatty acids to Omega 3 fatty acids is far higher than traditional diets, and today many people have a ratio of 16:1 or higher (omega-6:omega-3). Unfortunately,  this fuels inflammation in the body. When you are suffering from a chronic health condition such as ME/CFS or Long Covid it is particularly important to reduce this ratio, as this can reduce inflammation in the body. Ideally aim for aim for 4:1 or lower.

How to improve your Omega 6:Omega 3 ratio:

• Eat oily fish (mackerel, sardines, salmon)

• Choose omega-3-rich nuts/seeds (walnuts, flax, chia)

• Avoid seed oils and ultra-processed foods

4.   The Role of Vitamin D

Vitamin D is both a vitamin and hormone and is known for reducing inflammation and supporting immune regulation.  Vitamin D down-regulates certain immune responses and inhibits specific pro-inflammatory cytokines.

Our main source of Vitamin D comes from the sunshine in the Summer months. It is also possible to get some vitamin D from foods such as  oily fish, eggs, mushrooms.

Vitamin D sufficiency has been linked to lower risk of severe COVID-19 and considered helpful for Long COVID and ME/CFS symptoms.

How to boost your Vitamin D levels

• Sun exposure -  15 min/day in summer.

• Supplement daily from October–March (or year-round if needed).

• Check your Vitamin D blood levels - 75–100 nmol/L is optimal.

5.   Other essential nutrients for immune health

Other essential nutrients for immune health, and food sources of these foods include:

Vitamin A:

• Retinol: Liver, dairy, oily fish.

• Carotenoids: Sweet potato, carrots, kale.

B Vitamins:

• Found in meat, fish, eggs.

• Vegans need B12 supplements or to use fortified foods.

Zinc & Selenium:

• Zinc: Shellfish, dairy, legumes.

• Selenium: Brazil nuts, fish, tofu, mushrooms.

6. Final Thoughts

Supporting your immune system does not require large numbers of supplements — just nutrient-dense, whole foods, plenty of protein, and healthy fats. Those with ME/CFS or Long Covid can consider using nutrition to support their immune health.