What to eat to support your immune system

What to eat to support your immune system

Wouldn’t it be great if there was one magical food to boost our immune system and protect us from unwanted illness? Well there isn’t, but the good news is there are things we can do in our diet and lifestyle to help.  One of these is to look after the microorganisms we already have in our body, gut bacteria otherwise known as the gut microbiome.

How does good gut health help the immune system?

Research is showing us a healthy gut microbiota (gut bacteria, fungi and viruses living in our gut,) can influence how our immune system functions. The gut contains trillions of these micro-organisms including more than 1000 species. These bugs and their genetic material out number the human genome so they can certainly have an influence if we go by the numbers of them!

What can these bugs do?

  • They can send signals to the immune system by breaking down and fermenting fibre that you eat which produces short chain fatty acids. These fatty acids enter the blood stream and signal to other parts of the body including the immune system.
  • They can physically block out the bad guys from entering the blood stream, by looking after the intestinal (gut) lining which acts as a barrier to pathogens (bad bacteria, viruses)
  • The magic process of digestion, breaking down your food into nutrients small enough to be absorbed into your blood stream and travel throughout the body, involves good gut bacteria. When the gut is not working efficiently nutrients can miss out on absorption and you may not have all the nutrients you need, including those needed for a strong immune system.
  • They are also involved in reducing inflammation in the gut to reduce the risk of inflammatory bowel disease .

What you eat influences what gut bacteria you have and therefore influences the strength of your immune system.

What should I eat for a healthy gut?

  1. Eat plenty of plant foods as these contain dietary fibre (unlike animal foods that don’t), some of which is acts as prebiotic fibre. This means it is fibre that is food for your gut bacteria to ‘eat’ and produce the important fatty acids for signalling to the immune system. That doesn’t mean you shouldn’t eat animal products, just more plant than animal in the overall diet. Aim for 2 fruit and 5 serves of vegetables a day.
  2. Use legumes and lentils regularly in your diet; think beans- baked beans, chickpeas, kidney beans and more. These are rich in dietary fibre called prebiotic fibre that the bacteria ‘eat’ (ferment) producing the beneficial short chain fatty acid gases.
  3. Cook, cool and then eat some of your carbohydrate rich foods such as potatoes, rice and pasta. As you cook the food, starch breaks down so you can digest it- i.e. you can’t chomp into a raw potato or rice grain- and when it is cooled some of that starch realigns again forming retrograded starch or resistant starch. It is physically resistant to digestion, even if you reheat it again. This enters the large intestines of your gut where the bacteria there ‘eat’ it like they do the prebiotic fibre, again producing those good gases! Hence flatulence is an important part of gut health! The song – ‘beans, beans, good for my heart, the more I eat the more I fart!’, could have, ‘heart’ replaced with, ‘gut’ doesn’t quite have the same ring to it!
  4. Choose wholegrain breads, rices, noodles and breakfast cereals. Not only do they also have some fibre to feed your gut bacteria they also have valuable minerals such as zinc that the immune system needs.
  5. You can also eat foods that contain live bacteria such as yoghurt, drinking yoghurt (e.g. Rokeby Farms Probiotic Milk, Filmjolk), kombucha and kimchi (watch the salt). Some of these fermented foods including plant fermented food such as sauerkraut are of benefit for not only the live cultures they may have, but also for the metabolites produced from the bacterial fermentation that has taken place in making the food. You eat these metabolites.
  6. Drinking less alcohol and more water is also important for your gut health, but you probably knew that already, so I will keep this point short!

Eat seafood, particularly the oily kind, think sardines, salmon, tuna, maceral . The omega 3 research is showing increases the amount of bacteria that produce the helpfull short chain fatty acids we have been talking about. If you don’t like fish there is some omega 3 fat found in walnuts and flaxseeds but this is in a different form and it is not as well absorbed as that from animal sources. If seafood is not a favourite try making fish burgers, salmon patties, home made fish fingers, fish tacos or eat lean red meat such as kangaroo that does have some omega 3 too.

Food high in Prebiotic Fibre

  • Cashews, pistachios
  • Oats
  • Cooked cooled rice, potato, pasta
  • Barleymax, barley, rye bread
  • Legumes, lentils
  • Garlic, Onions, leek, Mushrooms, savoy cabbage
  • Nectarines, peaches, watermelon, pomegranate
  • Human breast milk


We are unlikely to avoid illness completely even if we are fastidious with precautions and eat the best diet possible but you can make a good start with these diet tips, along with good sleep hygiene and regular exercise too.

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