Salus journal

Healthy Planet. Healthy People.

Public health / Community resilience


Health and resilience versus disease – urban life and vitamin D deficiency

09 Jul 2020 | 0

Nutritionist Kate Cook considers the relationship between health, resilience and vitamin D deficiency in the context of COVID-19.

It’s difficult right now to be able to look at 2020 with anything approaching objectivity.  It certainly seems like the strangest of times. 

As a nutritional expert, it seems odd that often missing in the discourse around COVID-19 is the idea that the severity of the disease and outcome does not seem equally devastating to everyone. We know there are vulnerable groups: the elderly and those with co-morbidities (primarily insulin resistance or diabetes), as well as other conditions such as cancer or heart disease; males with darker skins also seem unfairly targeted.

Added to this, urban centres attract pockets of disease spikes. Is it our cities, urban living and globalised community that produce the very factors that make a pandemic inevitable? Doesn’t it seem prudent to examine why resilient, healthy individuals do not fall prey to this nasty pathogen, why they can almost brush it off or, apparently, have the disease without even knowing? This would imply that some people, even whole communities, are more much resilient and able to fend off an attack on their immune systems more effectively than others. If this is the case, what can we do to mitigate a second wave, most likely to hit us in the autumn, according to some experts.

The unseemly rush to produce universal technical solutions, whether medical or app-based tracking systems, raises worrying questions around not so much the technology but who controls the technology; are there better, cost-effective solutions that assume that we don’t all come from the same low health base, and gives us some agency to access part of our own solution?

Now, in mid-summer, in the stage of reflection after the initial heat of the crisis, it seems prudent to examine the root causes that give rise to a less resilient workforce and population, to see if there are adjustments we can make to enhance our ability to fend off the pathogen. It’s no easy task to get to root causes; from poverty, to food security issues, to stress – solving systemic issues is a much harder task than seeking shiny tech solutions, with clear objectives and end goals. It’s much more likely that rather than the issues being universal, they are specific and differ according to each community. This patchwork of causative issues provides no easy answers to be addressed by universally applied solutions.  -

The sunshine vitamin and resilience

Could one focus be on recognising the role vitamin D deficiency may play in boosting resilience worldwide. With many people adopting Western cultural norms and lifestyles, working long hours enclosed in homes or offices, it’s estimated that vitamin D, the so-called “sunshine vitamin”, currently affects more than one billion people of all ages worldwide.1,2 According to the United States’ Centers for Disease Control and Prevention (CDC), 95 per cent of children and 87 per cent of adults in America have less than the ideal level of vitamin D (100 nmol/litre), yet less than 1 per cent of black children have achieved a healthy level.3

Although there are no controlled studies demonstrating vitamin D’s role with regard to the current crisis, there are 20 studies underway as of June 2020 and their outcome will be keenly awaited. A problem with existing studies has been that rather than looking at the serum level of vitamin D, the studies have focused on the dose. As the effectiveness of the dose is determined by other factors (for example, other nutritional co-factors such as magnesium) the studies hitherto on other conditions have been mixed. 

But one study of particular interest is a retrospective analysis at the University of Chicago, which looked at 4000-plus patients4 and found that patients with an untreated vitamin D deficiency were associated with an increased risk of COVID-19 infection.  Another observational study, which involved 212 patients in Southeast Asia, carried out multinomial logistic regression to predict clinical outcomes of patients infected with COVID-19 based on their vitamin D levels. Findings reported that of those with severe disease, only 4 per cent had normal levels, while 95 per cent of those with mild COVID-19 had normal levels.5 A comment in the British Medical Journal noted that skin pigmentation could be playing a part in outcomes of disease in the black, Asian and minority ethnic (BAME) community.6

Early studies of vitamin D focused on its role in bone health, but vitamin D plays a wide-ranging role in many of the body’s systems, even influencing our genetic code. The human immune system is vastly complicated, but it seems that vitamin D plays a crucial role in modulating and down-regulating the cytokine storm, by inhibiting the production of pro-inflammatory cytokines.7-8 Vitamin D plays a part in nearly all immune cells, including monocytes, B and T lymphocytes, white blood cells, macrophages, dendritic cells, as well as the epithelial cells of the lungs, and is proven to be helpful in combatting influenza.9

Final thoughts – our healthy cities

Our lifestyles, with the majority of our lives spent inside, chained to computers and married to stress, could be detrimental to our health and resilience. We need life-giving sunshine (only available from March to September in the northern hemispheres) for the very core of our health and immunity to function. Putting health at the heart of city design is critical for the health of the urban citizen and ever-more pressing.

About the author

Kate Cook is a nutritional expert of 20 years and author of seven books – Kate focuses on corporate wellbeing and is currently undertaking an MA in Anthropology of Food at SOAS University of London.


  1. Hoick, MF. The vitamin D deficiency pandemic: Approaches for diagnosis, treatment and prevention. Rev Endocr Metab Discord, 2017; 18: 153-165
  2. Van schoor, NM, Lips, P. Worldwide vitamin D status. Best practice and research. Clinical Endocrinology & Metabolism, 2011; 25: 67 1 080
  3. Centers for Disease Control and Prevention (CDC), National Center for Health Statistics’ (NCHC) National Health and Nutrition Examination Survey. Hyattsvill, MD; US Department of Health and Human Services, Centers for Disease Control and Prevention, 2013-2014.
  4. Meltzer, DO, et al. Association of Vitamin D deficiency and treatment with COVID-19 incidence. medRxiv preprint doi: https//
  5. Alipio, M. Vitamin D supplementation could possibly improve clinical outcomes of patients infected with coronavirus 2019 (COVID-19). Last posted 7 May, 2020
  6. Grant, WB, Boucher, BJ. Vitamin D deficiency due to skin pigmentation may explain much of the higher rates of COVID-19 among BAME in England. BMJ comments, 6 June, 2020
  7. Sharifi, A, Vahedi, H, Nedjat, S, Rafieir, H, Hosseninzadeh-Attar, MJ. Effect of single-dose injection of vitamin D on immune cytokines in ulcerative colitis patients: A randomized placebo-controlled trial. APMIS, 2019; 127, 681-687
  8. Greiller, CL, et al. Modulation of the immune response to respiratory viruses by vitamin D nutrients, 7 (2015); 4240-4270, 10.3390/nu7064240
  9. Cannell, JJ, Vieth, R, Umhau, JC, Holick, MF, Grant, WB, Madronich, S, Garland, CF, Giovannucci, E. Epidemic influenza and vitamin D. Epidemiol. Infect., 2006; 134:1129-1140. doi: 10.1017/SO950268806007175

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