A new study has revealed that vitamin D3 can strengthen and defend the immune system. Interestingly, D3 has been found to be more effective than vitamin D2 in fighting illnesses including COVID-19. The research was carried out by the Universities of Surrey and Brighton. The scientists tested two types of vitamin D supplements (D2 and D3) in the gene activity in the participant’s blood. They also found that the D3 triggered a vital part of the immune system.

Lead author Professor Colin Smith said “we have shown that vitamin D3 appears to stimulate the type 1 interferon signaling system in the body – a key part of the immune system that provides a first line of defence against bacteria and viruses. Thus, a healthy vitamin D3 status may help prevent viruses and bacteria from gaining a foothold in the body.”

Vitamin D3, also known as Cholecalciferol is produced when the skin is exposed to sunlight. It can also be found in some foods and can be taken as a dietary supplement. However, people in cold parts of the world where there is little sunlight can lack vitamin D3 as the body naturally produces it through sun exposure. Professor Smith also added: “Our study suggests that it is important that people take a vitamin D3 supplement, or suitably fortified foods, especially in the winter months.”

Surprisingly in Africa, despite the amount of sunlight the continent receives, the melanin responsible for the dark skin of Africans reduce the absorption of vitamin D. This supplement could reduce vitamin D deficiency and boost the immunity for Africans and the rest of the world. 
 

The scientists called for further research into the effects of vitamin D2. They also recommended vitamin D3 fortified foods and supplements. “While we found that vitamin D2 and vitamin D3 do not have the same effect on gene activity within humans, the lack of impact we found when looking at vitamin D2 means that a larger study is urgently required to clarify the differences in the effects,” said co-author Professor Susan Lanham-New. These results show that vitamin D3 should be the favoured form for fortified foods and supplements.

Vitamin D helps to keep bones, teeth and muscles healthy. It also helps regulate calcium and phosphorus in the body. Although vitamin D has few food sources, the best sources are fatty fish and fish oil supplements.