Nutrition and immunity: Separating fact from fiction
Simon Steenson, British Nutrition Foundation
This year's coronavirus pandemic has prompted a lot of interest in the link between nutrition, diet and immunity. But it has also led to a host of myths and false claims (often on the internet or social media) that certain foods or supplements can help to protect against Covid-19 infection, or help to improve symptoms.
It is important to stress that these claims about coronavirus are not supported by scientific evidence and should not be trusted. However, a healthy and varied diet is important to support normal immune function.
The immune system is a highly complex network of cells and chemical compounds, which all work together to help defend our body against infections. It shouldn't be surprising then that there are a range of nutrients which have a known role in helping our immune system to function properly.
Below is a list of all 10 vitamins and minerals with an approved health claim for supporting immunity, and the foods that they can be found in.
Vitamin A: Liver and cheese are dietary sources of retinol ("pre-formed" vitamin A). Dark green leafy vegetables and orange-coloured fruits and vegetables, (e.g. carrots, sweet potato, butternut squash, cantaloupe melon and papaya) are dietary sources of carotenoids, which can be converted to vitamin A by the body.
Vitamin B6: Poultry, fish, fortified breakfast cereals, egg yolk, yeast extract, soya beans, sesame seeds and some fruit and vegetables, such as banana, avocado and green pepper.
Vitamin B12: Meat, fish, shellfish, milk, cheese, eggs, fortified yeast extract and fortified breakfast cereals.
Vitamin C: Citrus fruits, blackcurrants, strawberries, papaya, kiwi, green vegetables, peppers and tomatoes.
Copper: Bread, breakfast cereals, rice, quinoa, meat, fish and shellfish, pulses, avocado, dried fruit, nuts and seeds.
Vitamin D: Oily fish, eggs, fortified breakfast cereals, fortified spreads and fortified dairy products. We are all advised to consider taking a supplement of 10 micrograms (µg) a day from October to March, and all year round if we aren't often outdoors.
Folate (vitamin B9): Green vegetables, pulses, oranges, berries, nuts and seeds, cheeses, bread and fortified breakfast cereals.
Iron: Offal, red meat, beans, pulses, nuts and seeds, fish (such as canned sardines, cockles and mussels), quinoa, wholemeal bread and dried fruits.
Selenium: Nuts and seeds (e.g. Brazil nuts, cashews and sunflower seeds), eggs, offal poultry, fish and shellfish.
Zinc: Meat, poultry, cheese, some shellfish (including crab, cockles and mussels), nuts and seeds (in particular pumpkin seeds and pine nuts), wholegrain breakfast cereals and wholegrain and seeded breads.
As you can see above, these vitamins and minerals are found in a wide range of different foods. That is why aiming for a healthy, varied diet is the best way to get all the nutrients that are important for supporting your immune system, as well as for taking care of your general health. One exception is vitamin D, where in the UK everyone is advised to consider taking a supplement during the winter months containing 10 micrograms (often written on labels as 10 µg) to keep bones and muscles healthy, although some groups are recommended to take a vitamin D supplement year-round.
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