Covid-19, as noted above, is a secondary disease to the pre-existing diseases of those who suffer its most severe complications. Prevention remains the way forward, not only with external precautions(safe distances and masks) but also by strengthening the immune system.
Vitamin D is confirmed to be a key player in stimulating immune defenses, with peculiar efficacy in the prevention of influences affecting the upper respiratory tract. Ibid. including COVID-19. (1)
Sun, diet and exercise
A daily ‘sun bath’ is indispensable. At least 20 minutes of direct exposure to its light, with uncovered face and arms, is the dose needed to synthesize vitamin D. All the more so in fall and winter, when short days and declining temperatures induce spending more time indoors.
Balanced diet (with possible addition of supplements) and exercise complete the health and wellness strategy. (2) To prevent all kinds of ailments and live better, with a gut microbiome in top shape thanks to the Mediterranean diet.
Fig. 1. Worldwide distribution of infections as of 3/31/20, with the northern hemisphere more affected than the southern hemisphere as evidence of different sun exposure (Orrù et al., 2020)
Vitamin D, Italian intuition and suggested doses
The Turin Academy of Medicine, at the dawn of the pandemic, immediately highlighted the crucial role of vitamin D in prevention and treatment of the new coronavirus. Due to its ability to reduce virus replication and mitigate excessive inflammatory responses in the lungs (which, while aimed at fighting infection, can cause injury). (3)
The daily doses last recommended (Grant et al., 2020)-to reduce the risk of infection in the most vulnerable individuals (over-65, severe comorbidities) with severe deficiencies (which is always useful to verify by testing, ed.) are 10,000 IU, to be halved after serum levels reach 40-60 ng/ml (4)
Fig. 2. Immune system imbalance following the onset and development of inflammation, favoring the onset of disease (Zabetakis et al., 2020)
Vitamin D, new evidence
Calcifediol, the metabolic form of vitamin D, showed promising results in one of the very first clinical trials, conducted by the University of Navarre. The significant reduction in intensive care reported in patients already hospitalized as a result of infection has paved the way for subsequent clinical trials, one of which is already planned. (5)
The association between vitamin D deficiency, risk of upper respiratory tract infection and mortality from COVID-19 has since emerged in a very recent study where it shows a substantial increase (+54%) in the chance of contracting the virus in individuals with a calcifediol value of less than 20 ng/ml, compared with those with at least 30 ng/ml. (6)
Immunonutrition
Vitamin D supplementation-along with other vitamins and minerals, as well as Omega 3 fatty acids, in a diet possibly based on organic foods-will help modulate the immune system.
Immunonutrition is therefore achieved with a good diet that includes eggs, dairy and fish, or microalgae and cyanobacteria (e.g., spirulina), hemp and chia seeds to provide Omega3 for vegetarians. With plenty of vegetables and fruits for valuable polyphenols and prebiotic fiber (7,8).
Fig. 3. Functional foods with antiviral action, including dairy products useful for supplementing vitamin D (Alkhatib, 2020)
Attention to the weakest
The elderly and disabled tend to get out of the house little and synthesize lower amounts of vitamin D, in which they are often deficient. It is crucial to ensure they have the support of family and friends to stimulate attention to proper diet. The nutritional recommendations for the over-65s are recalled in this regard. (9)
Obese and diabetics are themselves at risk of vitamin D deficiency and should undergo its periodic analysis, also to reduce risks of vulnerability to infection. Conversely, care must be taken not to take large amounts of this vitamin because it, like other vitamins, proves to be highly toxic in case of overdose. (10)
A message to Hope
Health Minister Roberto Speranza should be informed of the widespread vitamin D deficiency in Italy. At the absolute lowest levels in the European Union, along with Spain and France. (11) This increases the incidence of infections, especially in those groups of people who are most vulnerable due to age or health conditions.
Preventing the spread of Covid-19 and protecting the health of Italian residents in this respect is easy and inexpensive. Just backtrack from the positions taken in recent years by the state and regions, which have reduced vitamin D prescriptions by the public health service to zero. A false saving to be stopped as soon as possible.
Dario Dongo and Andrea Adelmo Della Penna
Notes
(1) Martineau et al. (2017) Vitamin D supplementation to prevent acute respiratory tract infections: systematic review and meta-analysis of individual participant data. BMJ 356:i6583, doi:10.1136/bmj.i6583
(2) Orrù et al. (2020) Inhibitory effects of vitamin D on inflammation and IL-6 release. A further support for COVID-19 management? European Review for Medical and Pharmacological Sciences 24(15):8187-8193, doi:10.26355/eurrev_202008_22507
(3) Zabetakis et al. (2020) Covid-19: The inflammation link and the role of nutrition in potential mitigation. Nutrients 12:1466, doi:10.3390/nu12051466
(4) Grant et al. (2020) Evidence that vitamin D supplementation could reduce risk of influenza and COVID-19 infections and deaths. Nutrients 12:988, doi:10.3390/nu12040988
(5) Castillo et al. (2020) “Effect of calcifediol treatment and best available therapy versus best available therapy on intensive care unit admission and mortality among patients hospitalized for COVID-19: A pilot randomized clinical study.” Journal of Steroid Biochemistry and Molecular Biology 203:105751, https://doi.org/10.1016/j.jsbmb.2020.105751
(6) Kaufman et al. (2020) SARS-CoV-2 positivity rates with circulating 25-hydroxyvitamin D levels. PLoS ONE 15(9):e0239252, https://doi.org/10.1371/journal.pone.0239252
(7) Jovic et al. (2020) Could vitamins help in the fight against COVID-19? Nutrients 12:2550, doi:10.3390/nu12092550
(8) Alkhatib (2020) Antiviral functional foods and exercise lifestyle prevention of Coronavirus. Nutrients 12:2633, doi:10.3390/nu12092633
(9) Derbyshire et al. (2020) COVID-19: is there a role for immunonutrition, particularly in the over 65s? BMJ Nutrition, Prevention & Health 0:1-6, doi:10.1136/bmjnph-2020-000071
(10) Weir et al. (2020) Does vitamin D deficiency increase the severity of COVID-19? Clinical Medicine 20(4):e107-8, doi:10.7861/clinmed.2020-0301
(11) Galmés et al. (2020) Current state of evidence: Influence of nutritional and nutrigenetic factors on immunity in the COVID-19 pandemic framework . Nutrients 12:2738, doi:10.3390/nu12092738
Dario Dongo, lawyer and journalist, PhD in international food law, founder of WIISE (FARE - GIFT - Food Times) and Égalité.
Graduated in Food Technologies and Biotechnologies, qualified food technologist, he follows the research and development area. With particular regard to European research projects (in Horizon 2020, PRIMA) where the FARE division of WIISE Srl, a benefit company, participates.
