There have been many reports suggesting foods which can boost the immune system or prevent Covid-19. As a novel virus, there is currently no evidence to support certain foods or supplements preventing Covid-19 or boosting the immune system. In fact, over-activation of the immune system can actually lead to inflammatory disorders and allergic conditions!
Evidence has shown that a balanced diet, inclusive of a variety of fruit, vegetables, unrefined grains, pulses and legumes, oily fish, nuts and seeds can help to support the normal functioning of the immune system. A diet inclusive of these foods will contain iron, zinc, folate, selenium, vitamins A, B6, B12, C and D, which all support the immune system. In the UK, the majority of the population can gain these micronutrients and macronutrients through their diet alone (with the exception of Vitamin D).
Vitamin D is important for maintaining muscle and bone health. Though found in oily fish, eggs and fortified foods; vitamin D is mainly synthesised through sunlight exposure on our skin. It is estimated that 25% of the UK population have vitamin D deficiency. In the UK, it is recommended that all population groups take a 10µg Vitamin D supplement during October-March, due to low levels of sun exposure in these months. This guidance has recently been re-issued during the lockdown period as we are spending more time indoors.
There is currently no strong scientific evidence to show that very high intakes (i.e. mega supplements) of vitamin D will be beneficial in preventing or treating COVID-19. Studies investigating vitamin D and COVID-19 are currently underway, and more are likely to follow.
During this period, we should aim to eat a healthy diet, moderating free sugars, saturated fats and salt to support a healthy immune system and overall health. The public should be encouraged to follow general guidance to help prevent catching and spreading Covid-19, which includes frequent hand washing and wearing a mask.