How the immune system works
The immune system is one of the most complex bodily systems. Once we have had a disease, our body produces specific memory cells. Typically, our immune system is stronger in adulthood as we have been exposed to more pathogens and built up our immunity. This can be why children become ill more frequently than teenagers and adults, up to a certain age.
What is the role of nutrition?
The complexity of the immune system means that it cannot be modified acutely by a specific nutritional intervention. There is currently no convincing evidence that any food or dietary pattern can ‘boost’ our immune system. Rather, adhering to a healthy diet provides ongoing support to the immune system and may even delay the process of immunosenescence (the natural gradual deterioration of the immune system as we get older).
What should we be eating this winter to boost our immune systems?
There are many nutrients that are involved with the normal functioning of the immune system, which is why maintaining a healthy balanced diet is the best way to support immune function. Important nutrients for effective immune function are (and foods high in these nutrients):
- Copper – bread, fortified breakfast cereals, meat, fish, beans, pulses, seeds, nuts
- Folate – bread, fortified breakfast cereals, citrus fruits, beans, pulses
- Iron – fortified breakfast cereals, wholegrains, meat, pulses, green leafy veg, nuts, eggs, dried fruit
- Selenium – bread, nuts, seeds, seafood
- Zinc – fortified breakfast cereals, meat, fish, wholegrains, beans, nuts
- Vitamin A – milk, eggs, orange coloured fruit and veg
- Vitamin B6 – meat, fish, milk, cheese, seeds, eggs, wholegrains
- Vitamin B12 – eggs, milk, cheese, meat, fish, Marmite, fortified breakfast cereals
- Vitamin C – fruit and vegetables, potatoes
- Vitamin D – fortified breakfast cereals, eggs, oily fish
No single one food is recommended over another. Eating a variety of foods will help to maintain a healthy balanced diet. The immuno-protection of many of these nutrients is based on their antioxidant capacity (oxidation is a chemical reaction that can damage cells), which is in fact lost if consumed in excess.
In addition to healthy eating, being physically active, reducing stress and getting enough sleep will also all help support immunity function.
Are there any supplements that ‘boost’ or protect from Covid-19?
There is currently no evidence nor EU approved health claims that any supplement can ‘boost’ immune systems and prevent or treat viral infections, like Covid-19.
Making sure we meet dietary requirements for many vitamins and minerals is important for good health and normal immune functioning. Eating a healthy balanced diet should provide all the necessary nutrients needed. In case of specific challenges in meeting the dietary requirements, supplements can be used to add nutrients to diets.
Gut health and the immune system
Gut microbiota has been a hot health topic for a while now. The gut and its microbiota have been shown to impact metabolism, immunity and even behaviour.
It is thought that the predominance of the beneficial bacteria, referred to as the probiotic bacteria, such as bifidobacteria and lactic acid bacteria, ensure good health and prevent diseases of the gut and other organs in the body. Probiotics fight harmful foreign substances and can prevent the growth of harmful bacteria by producing organic acids that lower the PH in the intestine.
To support good gut health, the advice is to eat a wide range of foods, a diverse microbiota is a healthy one, a diet including different food types can lead to a diverse microbiota. High fibre foods promote microbiome diversity such as fruits and vegetables, beans, legumes and wholegrains. Live plain natural yoghurt, and fermented foods, such as kefir, kimchee and kombucha, are also thought to support a healthy gut.
- Eat plenty of fruit and vegetables – a large variety, especially of vegetables.
- Eat a diet high in fibre – fruit, vegetables, wholegrains, beans and lentils.
- Include food with good bacteria (probiotics) live yoghurts, kefir and fermented foods such as kimchee and sauerkraut – aim for something living every day!
In the words of the British Dietetic Association: “You cannot ‘boost’ your immune system through diet, and no specific food or supplement will prevent you catching Covid-19 / Coronavirus. Although eating a well-balanced diet can help ensure the normal functioning of the immune system, no individual nutrient, food or supplement is going to ‘boost’ it beyond normal levels. Good hygiene practice remains the best means of avoiding infection.”
If you are concerned about nutrient provision in your menus for your pupils, it is important that you seek advice from a registered dietitian, or other healthcare professional, and that you follow the current advice set out by the Government, NHS and Public Health England.
allmanhall, the food experts and procurement partners specialising in education, can help! Please do get in touch if you need support.