GUILDFORD, England — There have been several reports claiming that lots of vitamin D (higher than 4000IU/d) can help fight off COVID-19 and stop the virus from manifesting severe symptoms. A new study from the University of Surrey, however, disputes this theory.
A team of international researchers from the U.S., United Kingdom, and Europe all agree that there just isn’t enough valid evidence that vitamin D is effective at preventing or treating COVID-19 and its deadly symptoms. The study’s authors specifically warn against ingesting high doses of vitamin D as a means of protecting oneself from the coronavirus.
“An adequate level of vitamin D in the body is crucial to our overall health, too little can lead to rickets or the development of osteoporosis but too much can lead to an increase in calcium levels in the blood which could be particularly harmful,” says lead study author Professor Sue Lanham-New, Head of the Department of Nutritional Sciences at the University of Surrey, in a release.
The research team went through all available data on the influence of vitamin D on viral infections and found no evidence that high doses of vitamin D can help fight COVID-19. If anything, taking too much vitamin D will lead to health complications in many instances. They believe these earlier studies touting the benefits of vitamin D against the coronavirus were based on inadequate research.
There have also been recent claims of there being a link between low vitamin D levels and increased risk of respiratory tract infections, but again, the study’s authors found some big holes in that idea. Prior studies that had come to that conclusion used data from underdeveloped nations, so those findings really aren’t applicable to more developed countries.
“Most of our vitamin D comes from exposure to sunlight, however for many people, particularly those who are self-isolating with limited access to sunlight during the current pandemic, getting enough vitamin D may be a real challenge. Supplementing with vitamin D is recommended but should be done under the current UK guidance,” comments co-author Professor Carolyn Greig of Birmingham University. “Although there is some evidence that low vitamin D is associated with acute respiratory tract infections, there is currently insufficient evidence for vitamin D as a treatment for COVID-19 and over-supplementing must be avoided as it could be harmful.”
“In line with the latest Public Health England guidance on vitamin D, we recommend that people consider taking a vitamin D supplement of 10 micrograms a day during the winter months (from October to March), and all year round if their time outside is limited,” concludes co-author Professor Judy Buttriss, Director General of the British Nutrition Foundation. “Levels of the vitamin in the body can also be supplemented through a nutritionally balanced diet including foods that provide the vitamin, such as oily fish, red meat, egg yolk and fortified foods such as breakfast cereals, and safe sunlight exposure to boost vitamin D status.”
The study is published in BMJ Nutrition, Prevention & Health.