Coronavirus and immune system: be aware of Vit D deficiency
In these days I will try to write some articles which can be useful to those who are forced to stay at home. In the meantime I will try to give you some important “health tips” to maintain and improve your wellness. For this reason I want to talk over vitamin D, its importance and how to keep the reserves at the right level.
While all the world is in the clutches of pandemic of novel Covid-19, I would like to call your attention to another pandemic, which is related to the Vitamin D deficiency which can be linked to the novel Coronavirus respiratory infection. Vitamin D insufficiency affects almost 50% of the world’s population while 1 billion people, are estimated having a vitamin D deficiency. The biggest reason for vitamin D deficiency, is that many of us are unaware that the sun exposure is our most important source of Vitamin D. Besides this, we should know that in the last 40 years, only few foods naturally contain vitamin D, because of the intensive breeding practices where the animals don’t eat naturally and don’t see the sunlight (for more info click here), so they are lacking the vitamin D first.
Foods that are fortified with vitamin D are often inadequate to satisfy our vitamin D requirement.
Let’s start by saying that for years Vitamin D, has been considered useful mainly for the maintenance of good skeletal condition. But recent studies show that in addition to this, it is also functional to improve the immunity system, especially during the fight against viral respiratory infections (1, 2, 3, 4, 5). The underlying mechanisms by which vitamin D deficiency could contribute to viral disease development remain poorly understood. The possible interactions between viral infections and vitamin D appear to be more complex than previously thought(6). On the other hand the anti-viral effects of vitamin D could be explained by cathelicidin (in the form of LL-37), human beta defensin 2, and perhaps through the release of reactive oxygen species (7). Among other things, it coincides with the fact that those who are under treatment for Vit D supplements, are less prone to seasonal influenza diseases(8). It was believed that its deficiency was causing only rickets in children and osteopenia, osteoporosis, and fractures in adults, but these recent researches are demonstrating that vitamin D deficiency can be associated with also increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases(9).
The increase in intensive therapies in northern Italy could also depend on this: it is not a fiction that living in an unhealthy, polluted environment (10) with little access to sunlight, people, in majority, who already make part of groups under risk, with disabled immune system, may have caused the final straw? Can the novel Covid-19 can be defined as a concause? Said this, I stop making any other considerations on this issue, because we would enter a quagmire which may not be very functional to today’s topic.
In humans Vitamin D is synthesized by the skin, and by its exposure to direct sunlight, this constitutes the primary source; and it happens thanks to the conversion of the “7-dehydrocholesterol” molecule by the UVB rays in the skin, to cholecalciferol Vitamin D3. This means that you have to try to expose most of your body surface to the sun for at least 15 minutes every day during 10 am-3 pm. We have to think that many people do not have a balcony or their apartments are exposed to the north and so on; in these cases I hope for a common solidarity: get organized with your neighbors to use the common areas of your condominium which offer sun exposure, of course after taking the necessary precautions (when it is impossible to go out in the street). We should repeat this IMPORTANT daily routine. In particular you have to give access to the sun to the categories at risk, the elders and those with weak defense system.
Food sources of Vitamin D, however can be a problem, because although oily fish (mackerel, salmon, etc..) can be a good source, the fish must be wild and not farmed, as they may contain 75% less Vit. D than the wild species. In this period, canned tuna also can be an excellent alternative given the difficulties for access fresh food. Even it is disgusting for many cattle liver is a good source, like cheese and egg yolk but also these sources should come from grass-fed or pasture raised animals, but the same it can be tricky finding these products in these days.
Other options that we have are fortified foods such as some dairy products, soy milk and cereals. And of course the supplements.
It should be remembered that the intake of antioxidants such as Vitamin C, is important to keep high the immune system when we are healthy, but it works less when we are already sick. Vitamin D instead can be an important weapon to fight the disease. I add that by following a well-balanced, healthy and varied diet like the CHEtarian diet, you can keep your physical conditions and defense system at the top. Please write me if you have any doubts and please spread the information as much as possible for the common good.
1) Respiratory epithelial cells convert inactive vitamin D to its active form: potential effects on host defense. Hansdottir S, Monick MM, Hinde SL, Lovan N, Look DC, Hunninghake GW J Immunol. 2008 Nov 15; 181(10):7090-9.
2) Vitamin D decreases respiratory syncytial virus induction of NF-kappaB-linked chemokines and cytokines in airway epithelium while maintaining the antiviral state. Hansdottir S, Monick MM, Lovan N, Powers L, Gerke A, Hunninghake GW J Immunol. 2010 Jan 15; 184(2):965-74.
3) An association of serum vitamin D concentrations < 40 nmol/L with acute respiratory tract infection in young Finnish men. Laaksi I, Ruohola JP, Tuohimaa P, Auvinen A, Haataja R, Pihlajamäki H, Ylikomi T Am J Clin Nutr. 2007 Sep; 86(3):714-7.
4) Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data Martineau AR, Jolliffe DA, Hooper RL, Greenberg L, Aloia JF, Bergman P et al. BMJ. 2017;356:i6583.
5) Vitamin D and Respiratory Tract Infections: A Systematic Review and Meta-Analysis of Randomized Controlled Trials Bergman P, Lindh AU, Björkhem-Bergman L, Lindh JD. PLoS One. 2013; 8:e65835.
6) The interplay between vitamin D and viral infections. Majid Teymoori‐Rad Fazel Shokri Vahid Salimi Sayed Mahdi Marashi First published:06 January 2019 https://doi.org/10.1002/rmv.2032
7) Beard, Jeremy A et al. “Vitamin D and the anti-viral state.” Journal of clinical virology : the official publication of the Pan American Society for Clinical Virology vol. 50,3 (2011): 194-200. doi:10.1016/j.jcv.2010.12.006
8) Preventive Effects of Vitamin D on Seasonal Influenza A in Infants. Zhou, Jian MD et al. The Pediatric Infectious Disease Journal: August 2018 – Volume 37 – Issue 8 – p 749-754 doi: 10.1097/INF.0000000000001890
9) Nair, Rathish, and Arun Maseeh. “Vitamin D: The “sunshine” vitamin.” Journal of pharmacology & pharmacotherapeutics vol. 3,2 (2012): 118-26. doi:10.4103/0976-500X.95506