Eating for Immunity - How to Fight off Infections

Updated: Aug 21, 2019

Your immune system is a wonderful thing.

It does an incredible job protecting you against disease-causing microorganisms and fighting off infections.

Whilst there isn't a specific "immune-boosting" diet, following a healthy lifestyle is the single best step for keeping your immune system strong and healthy.

This article looks at some simple steps that you can follow to keep you immune system healthy.

Eating a Healthy and Balanced Diet

This might seem obvious, but it couldn't be more important.

A diet which is rich in fruits and vegetables, wholegrains and pulses, lean meats, fish, dairy (or plant-based alternatives), and small amounts of heart-healthy fats will provide you with an array of immune-boosting vitamins and minerals.

Antioxidant nutrients such as vitamin C and E, selenium, iron and zinc are thought to play an important role in protecting us against infections cause by bacteria, parasites and viruses (1). Antioxidants are man-made or natural molecules which may delay or prevent some types of cell damage (2).

Fruits and vegetables are brilliant sources of antioxidants, and there is strong evidence to suggest these foods also play a role in reducing risk of several diseases such as Type 2 Diabetes, Coronary Heart Disease and Stroke (3, 4, 5).

Good dietary sources of antioxidants include:

  • Vitamin C: citrus Fruits, red and yellow peppers, kiwi fruit, broccoli, strawberries

  • Vitamin E: vegetable oils (i.e. corn or sunflower), nuts, seeds, green leafy vegetables

  • Selenium: brazil nuts, fish, meat, eggs, mushrooms, milk and yoghurt

  • Iron: red meat, poultry, nuts and seeds, grains, dried fruit, certain breakfast cereals

  • Zinc: meat, fish, legumes (chickpeas, lentils, beans), nuts, seeds, dairy, eggs

For the majority of healthy people, you can get all your nutrients through your the foods that you eat. Nutritional supplements are expensive and we don't have enough scientific evidence to recommend the use of antioxidant supplements.

Nutritionist's Top Tip: Our best advice is to eat the rainbow! The more colours and varieties of foods eaten (particularly fruit and vegetables), the better.

Moderate your Alcohol Intake

UK guidelines recommend that men and women consume no more than 14 units of alcohol per week.

We should also avoid drinking all our units in one go and have several alcohol-free days during the week.

The effects of alcohol on the immune system is poorly understood, however a small study in America found that a single episode of binge drinking in young adults significantly disrupted the immune system (6).

Some scientists have proposed that this could be due to the effects on the gut microbiota and the gut barrier function (7).

Nutritionist's Top Tip: Don't exceed the recommended alcohol guidelines

Stress Less

Stress is an inevitable part of day-to-day life, so the key is to learn to manage it effectively.

Over the past decade many studies have explored the link between stress and immunity. Stress-mediators can pass through the blood-brain barrier and therefore impact the immune system (8). It is now accepted that there is an association between stress and immunity (9).

Different things work for different people. You could try regular exercise, mindfulness or meditation. Some people find that journalling their thoughts and worries helps, whilst others prefer to talk to someone (i.e. a trained counsellor) about their worries .

Find what works for you and build it into your daily life.

Useful Resources for Mindfulness:

  • Apps: Calm (free), Headspace (free), Buddhify

  • Website: free mindfulness exercises and tips from Mind charity

  • Course: Be Mindful (part of the Mental Health Foundation charity) runs a 4-week online mindfulness course developed by qualified teachers. It's listed in the NHS Digital Library.

  • Course: Breathworks offers mindfulness courses to manage pain, stress and illness.

  • Book: ‘Mindfulness: A practical guide to finding peace in a frantic world’ by Prof Mark Williams and Dr Danny Penman

  • Podcasts: 10% Happier, The Self Help & Mindfulness Mode by Bruce Langford

Eat more Gut-Friendly Bacteria:

The gut microbiota is thought to play an important role in immunity, and diet is one of the most important factors for diversifying your gut microbiota (10).

Probiotics are live bacteria with beneficial effects on our health, particularly in the gut.

Try to regularly eat probiotic-containing foods, as these can help to the microbiota return to normal and improve gut health, particularly after a course of antibiotics.

Examples of probiotic foods include:

  • Kefir

  • Sauerkraut

  • Kombucha

  • Kimchi

  • Pickled vegetables

  • Yoghurt

It's important to feed the good gut bacteria, and prebiotics can help the gut bacteria to flourish. Prebiotics are described as non-digestible food ingredients which probiotics can feed off.

Examples of prebiotic foods include:

  • Onions

  • Garlic

  • Leeks

  • Asparagus

  • Bananas

  • Flaxseed

  • Apples

  • Cocoa

Probiotic supplements may help people to manage certain medical conditions, but it really depends on the strains, mixtures and quantities (11).

This is an evolving area of science, however the US Probiotic Guide has a useful resource which shows you which bacterial strains have been shown to be effective in certain diseases or conditions.

If you'd like to trial a probiotic supplement, speak to your dietitian who can make suitable recommendations.

Nutritionist's Top Tip: Include a variety of probiotic and prebiotic foods in your diet

Written by Harriet Smith, RD

Surrey Dietitian

United Kingdom

©2018 by Surrey Dietitian.