The diet is just one of many factors that affects immune health. Along with the foods we eat, our age and life stage, stress levels, personal medical history and genetics (among others!) all influence our susceptibility to infection and illness.
Below, find our tips to optimise immune health with diet.
First, focus on the diet as a whole
From a nutritional perspective, the dietary pattern overall is the most important determining factor for immune health. Generally, immune health is well-supported by a dietary pattern that is largely aligned with the traditional Mediterranean diet, featuring a diverse array of plant-derived foods, including vegetables, fruits, legumes, wholegrains, nuts and seeds, along with moderate amounts of seafood, meat, eggs and dairy. Find our tips for adopting a Mediterranean-style dietary pattern – in a way that works for you – here.
Eating in this way provides an abundance of nutrients that support immunity. The body requires these nutrients in sufficient amounts to adequately fuel the immune system. This is one of the reasons that eating enough overall is also critical to optimise immune health with diet.
The link between gut health and immunity
Research increasingly highlights the balance between gut health and immune function. Populations of beneficial bacteria, dispersed throughout the gastrointestinal tract, create a protective, defensive barrier against disease-causing micro-organisms and also ‘crowd out’ disease-promoting bacterial species. The metabolites produced by beneficial bacteria are also immunoprotective.
Food choices – even in the short term – affect the total number, as well as the number of different species, of bacteria within the gut. Even a few small dietary changes can dramatically improve gut health, and in turn, influence immune function.
Optimise your gut health by:
- Enjoying 30 different plant foods each week. Given the direct influence of the diet on gut bacteria, an intake of 30+ plant foods each week is recommended to achieve optimal microbial diversity within the gut. Include a broad variety of vegetables, fruits, legumes, wholegrains, nuts and seeds, herbs and spices, along with extra-virgin olive oil, to meet this target.
- Focusing on fibre. Fibre provides fuel for beneficial bacteria within the gut. We should be including at least 25-30g fibre daily, however, 30-50g daily is even more beneficial. As plant-derived foods are naturally high in dietary fibre, achieving plant diversity within the diet naturally helps us meet our fibre target. Where possible, leaving the skin on fruits and vegetables is an easy way to further boost fibre intake.
- Enjoying probiotic-rich foods. Probiotic-rich foods deliver additional micro-organisms – such as Lactobacillus and Bifidobacterium bacterial species, for example – directly to the gut. Dietary sources of probiotics include natural yoghurt, sauerkraut, kimchi, miso, tempeh, kombucha and kefir. Kefir has the best evidence for it’s gut health benefits, so is particularly good to include.
- Reducing alcohol and ultra-processed. Alcohol and highly processed foods are known to deplete populations of beneficial bacteria, and promote the growth of harmful species in their place. Examples of ultra-processed foods include chocolate, lollies, soft drinks, and baked goods. Choose your soul food/drink and enjoy it occasionally!
- Managing stress. This one is easier said than done sometimes! Chronicly high stress levels can negatively impact gut health and immune health. Strategies may include mindfulness, breath work, yoga, exercise, or therapy. Seek support if you’re struggling to manage stress levels.
- Supporting sleep. Adults should aim for between 7 and 9 hours of quality sleep each night. Getting adequate sleep is key for both gut health and immune health.
For expert dietary support throughout the flu season and beyond, book your first appointment with one of our wonderful Accredited Practising Dietitians today.
Written by Caitlin Branch, Student Nutritionist, and Amanda Smith, Accredited Practising Dietitian.