Cutting out carbohydrates? Your immune system might not thank you says Dr. Jenna Macciochi. These are the 6 healthiest carbs for your immune system

Any products in this article have been selected editorially however if you buy something we mention, we may earn commission

Carbs are one of the three macronutrients,  meaning nutrients we need we need in large quantities (the others being protein and fat). They may be controversial in the diet world, but carbs play several pretty vital roles in supporting the optimal functioning of our immune system. They come from plant-based foods and are also sources of several essential micronutrients – vitamins and minerals – that are vital to healthy immune function.

How do carbs affect the immune system?

We definitely shouldn’t cut out carbs, but we do need to choose them carefully. The quantity will vary depending on your unique needs and lifestyle. If you want to improve your health and support your immune system, then you should focus on the quality of the carbs you are consuming.

All carbs, whether ‘healthy’ or not will be broken down into simple sugar molecules in our body. It’s this sugar that is used as a source of energy. Demand is increased when fighting an infection. 

Mounting an immune response is energetically quite costly; building new cells and antibodies and getting a fever while fighting an infection raises your resting metabolic rate. Carbs are an important energy source for your immune system.

Sugar and the immune system

But refined carbs such as those found in ultra-processed foods or foods high in added sugar will break down quickly, sending your blood sugar on a rollercoaster. This elevated blood sugar is not good for your immune system. 

Plus, refined carbs are easy to overconsume, crowding out more healthful foods and potentially driving you to an unhealthy weight and poor metabolism – all known to be bad for our immune system.

Carbs feed a healthy gut, which houses 70% of your immune system

Cutting out carbs is detrimental to our gut microbiota – the trillions of microorganisms that reside in our digestive tract.  These play a major role in the health and proper functioning of our immune system. 

Approximately 70 per cent of our immune system is focused along the gut. These helpful bugs train and educate our immune cells ensuring they function optimally both in the gut and in the rest of our body, to protect us. 

The best marker we have of a healthy microbiome is diversity, with each different variety bringing different skills to support our immunity.

One of the best ways you can support your immune system is by nurturing this ecosystem in your gut. Your gut microbes love to chow down on dietary fibre – which is typically found in carbohydrates. They then produce a banquet of metabolic byproducts. Consider it your personalised pharmacy. 

These beneficial byproducts educate our immune cells, support their function and spark signals that dial down inflammation. On a practical level, the higher the diversity of plant fibres we consume, the better we are actively nourishing our immunity.

6 types of carbs your immune system needs

Focus on getting your carbs from fibre-rich foods across all six plant-based food groups: fruit, vegetables, whole grains, legumes, nuts and seeds. 

The key here is diversity. Forget five-a-day, aim for more than 30 different plant-based foods per week. 

Focusing on fibre will help to balance blood sugar and provide many essential vitamins and minerals as well as other plant-based nutrients like polyphenols and flavonoids which have tonnes of immunity-supporting benefits. For example, their anti-inflammatory and antioxidant properties help to lower baseline inflammation and protect your body from daily wear and tear.

Tips to get your 30-a-week sources of plant-based fibre

  • Challenge yourself to add new fruit and veg to your weekly shopping list.
  • Add legumes and pulses like lentils, chickpeas and beans to fibre up classic dishes such as Bolognese. These cheap and nutritious staples are a great plant-based sustainable protein source too.
  • For porridge, switch to wholegrain oats which are a rich source of dietary fibre and sprinkle nuts and seeds (another source of fibre) onto your breakfast.
  • Fermented foods are also good for the gut and can help with the digestion of carbs. Try kombucha,  kefir, or sauerkraut.
  • Crowd out the quantity of less fibre-rich foods such as refined carbs found in cakes, biscuits, and other baked goods.
  • Check the carb-to-fibre ratio on the nutritional information listed on a product. It is a quick way to calculate how fibre-rich a food is. Aim for at least 1g of fibre to every 10g of total carbohydrate.
  •  Aim for 30g of fibre per day. But remember, any change to your dietary fibre intake should start slow, building up gently to allow your digestive system time to adapt.
  •  If you are looking for way to increase your fibre intake, psyllium husks or inulin powder (try Easy Fibre Cleanse by Healthspan £14.95  for psyllium or Easy Fibre Inulin £14.95 ) are useful ways to add fibre to meals particularly if you need help with regular bowel movements.

Add a probiotic supplement if you struggle to digest carbs

Probiotics are ‘good’ bacteria in a supplement form (also found in certain foods). They may be helpful if you feel your gut microbiota isn’t up to scratch or you struggle to digest carbs. We are still learning about how probiotics support our immune system but there is good evidence for taking one of the best probiotics you can to mitigate some of the negative effects of antibiotics on your microbiota. Try Super 20 Pro by Healthspan, £16.95.

Studies also show that taking probiotic supplements can support your immunity and reduce the duration and severity of colds and common upper respiratory tract infections resulting in fewer days off sick. We do not know if there is a role for probiotics in Covid yet.

MORE GLOSS: Dr Jenna's easy immune system explainer and what you can do to support it

Dr Jenna Macciochi is an immunologist and an ambassador for wellbeing brand  Healthspan.


·      Daniel McDonald et al. The American Gut Consortium, Rob Knight. mSystems May 2018, 3 (3) e00031-18; DOI: 10.1128/mSystems.00031-18

·      Reynolds A, Mann J, Cummings J, Winter N, Mete E, Te Morenga L. Carbohydrate quality and human health: a series of systematic reviews and meta-analyses. Lancet. 2019 Feb 2;393(10170):434-445. doi: 10.1016/S0140-6736(18)31809-9. Epub 2019 Jan 10. Erratum in: Lancet. 2019 Feb 2;393(10170):406. PMID: 30638909.

·      Catherine J Andersen, Kelsey E Murphy, Maria Luz Fernandez, Impact of Obesity and Metabolic Syndrome on Immunity, Advances in Nutrition, Volume 7, Issue 1, January 2016, Pages 66–75,

·      Jonathan M. Peake, Oliver Neubauer, Neil P. Walsh, Richard J. Simpson. Recovery of the immune system after exercise. Journal of Applied Physiology, 2016; jap.00622.2016 DOI: 10.1152/japplphysiol.00622.2016

·      de Vrese M, Winkler P, Rautenberg P, Harder T, Noah C, Laue C, Ott S, Hampe J, Schreiber S, Heller K, Schrezenmeir J. Probiotic bacteria reduced duration and severity but not the incidence of common cold episodes in a double blind, randomized, controlled trial. Vaccine. 2006 Nov 10;24(44-46):6670-4. doi: 10.1016/j.vaccine.2006.05.048. Epub 2006 Jun 6. PMID: 16844267.

·      Lenoir-Wijnkoop I, Merenstein D, Korchagina D, Broholm C, Sanders ME, Tancredi D. Probiotics Reduce Health Care Cost and Societal Impact of Flu-Like Respiratory Tract Infections in the USA: An Economic Modeling Study. Front Pharmacol. 2019 Aug 28;10:980. doi: 10.3389/fphar.2019.00980. Erratum in: Front Pharmacol. 2019 Oct 11;10:1182. PMID: 31555138; PMCID: PMC6722238.