Dr Helga Rhein (Letter, 20 May) makes an excellent point by emphasising the importance of nutrition for maintaining general health and, in particular, that of our immune system as part of the battle against coronavirus. She points out that levels of vitamin D in the UK population are low and that maintaining adequate levels is important for overall health, including our ability to fight infection. However, there are other nutrients that are arguably as important in this respect for which UK intake is too low.
Selenium is required by the body to make proteins that are critically important for preventing damage to tissues caused by inflammation. There is good experimental and public-health evidence that low intakes of selenium can increase the virulence and mutation rate of some viruses by failing to control inflammation. Prof Margaret Rayman, an expert in selenium nutrition at the University of Surrey, and her colleagues published a report in the American Journal of Clinical Nutrition in 2020 using data collected in China which showed that a higher selenium level was linked to a greater “cure rate” from Covid-19 infection. Although this relatively small study didn’t show cause and effect, the findings agreed with what is known about selenium and viral infections. This suggests adequate selenium levels may be important for protection against some effects of Covid-19.
Dr Rhein calls for public health bodies to address vitamin D deficiency in the UK. I suggest this should be extended to include other nutrients, including selenium, in which the UK population is at risk of deficiency. There is robust evidence that improving intake through relatively inexpensive means is likely to improve the health of the nation to fight the current viral challenge and to be better prepared against the next one.
Graham Burdge
Professor of nutritional biochemistry, University of Southampton
• You need magnesium in your body for vitamin D to be effective. Also, not everyone is able to absorb it properly. It is fat soluble and if your metabolic processes are compromised you will not get the full benefit.
Monty Goldin (pharmacist)
London
