A vitamin that you should never miss? Vitamin D, for sure, whose importance is becoming increasingly clear thanks to the various researches whose results are being published in recent weeks in the sector magazines. In fact, as emerges from a very recent study that appeared in the journal Gastroenterology thanks to the work of a team from the Harvard TH Chan School of Public Health, Boston (Kim et al, Gastroenterology, 2021), vitamin D, taken with the diet, helps to prevent colon cancers and intestinal polyps. In addition, vitamin D supports the immune system, especially that of the airways, and adequate levels of this vitamin protect against the risk of having serious complications in case of coronavirus infection (Shah et al, QJM, 2021 - Teama et al, Sci Prog, 2021).
Vitamin D and colon
Cellular degeneration and colon polyps are on the rise in the younger population under 50. Vitamin D has been shown in the laboratory to fight colon cancer. Not only that, from blood tests carried out on large population samples, it was found that the quantities of vitamin D are decreasing, due to a reduction in the general population, but especially in adults under 50 years of age, in the consumption of foods containing vitamin D such as fish, mushrooms, eggs and milk. Therefore, Harvard researchers questioned whether vitamin D deficiency could explain this increase of cases of colon tumors and polyps. To understand this, the scientists drew on health, diet and lifestyle data from 94,205 people between the ages of 25 and 42 who participated in a large study that began in 1989 and called the Nurses' Health Study II. The volunteers were followed up until 2015 and what emerged was that those with higher levels of vitamin D also had a significantly lower risk of developing colon cancer and intestinal polyps. In particular, it was observed that the introduction of 300 IU or more of vitamin D per day, corresponding to three glasses of milk, led to a 50% reduction in getting colon cancer. However, it is important to underline that this protective effect has been observed above all with regard to vitamin D taken with the diet and not through supplements, even if this point has not been clarified by the researchers. Therefore, other studies will have to follow to shed light on this aspect and to understand whether the protective effect of vitamin D can also be observed in people over 50 years of age.
Vitamin D and respiratory immune system
Vitamin D plays a key role in regulating the immune system. Above all, it helps to prevent, in case of infection, an exaggerated production of pro-inflammatory substances, the famous cytokine storm, which can cause serious damage such as thrombus formation. Not only that, several studies have shown that a vitamin D deficiency is associated with an increased risk of respiratory tract infection. Then, the researchers analyzed the link between vitamin D and the effects of the coronavirus in case of infection. What emerged was that low vitamin D values are associated with a longer duration of the disease and longer hospitalization. An explanation is provided by the same researchers who observe that vitamin D is able to provide protection to the lungs in case of acute infection by increasing the expression of the ACE2 protein. In the case of coronavirus infection, however, ACE2 is reduced, leading to an increased risk of pulmonary edema, oxidative stress, inflammation and fibrosis. These findings were observed in both the adult population and children.
