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Rapid response to:


Malnutrition: the silent pandemic

BMJ 2020; 371 doi: (Published 01 December 2020) Cite this as: BMJ 2020;371:m4593

Rapid Response:

Vitamin D and Pandemics Re: Malnutrition: the silent pandemic

Dear Editor

Vitamin D and Pandemics

Henry Mark and colleagues are rightly concerned that there is a silent pandemic of malnutrition during this Covid-19 pandemic, especially because adequate intakes of energy, macronutrients, and micronutrients are critical for immune functioning.[1] They quote Naja and Hamadeh, who list Vitamins A, C, E, B6, B12, Zinc and iron as important. Unfortunately this list does not include Vitamin D.[2]

In contrast, Dr David Grimes emphasises in his Blog that 19 world-wide studies now demonstrate that low blood levels of Vitamin D are associated with severe or fatal Covid-19.

Grimes writes that the emergence of cytogenetics led to the identification of the 1,25(OH)D–VDR dimer to activate what is now a surprisingly large number of genes (in excess of 1,000). Some of these generate even more VDR molecules, a positive feedback mechanism. But 1,25(OH)D can only be used once as after use it is deactivated into 24,25(OH)D. This vital metabolic control prevents a damaging excess of 1,25(OH)D. However it means that a constant supply of 25(OH)D is essential during the escalation of defensive immunity in response to infection, so as to replace the 1,25(OH)D that has been deactivated. The need of vitamin D in defensive immunity is much greater than for the control of ionised calcium, a fact that is seriously under-appreciated.

The latest International studies indicate that a blood level of more than 30ng/ml (75nmol/L) is a level that indicates protection against serious or fatal Covid-19 infection. A target level of 40ng/ml (100nmol/L) would appear to be appropriate, and to achieve this vitamin D in a daily supplement of 4,000 units is effective, perfectly safe, and costs about £12 per year.

1 Mark HE, da Costa GD, Pagliari C, Ungar SA. Malnutrition: the silent pandemic. BMJ 2020;2020;371:m45931 doi: (Published 01 December 2020)

2 Naja F, Hamadeh R. Nutrition amid the COVID-19 pandemic: a multi-level framework for action. European Journal of Clinical Nutrition 2020;74:1117-1121.

Competing interests: No competing interests

02 December 2020
Ellen CG Grant
Physician and medical gynaecologist
Kingston-upon-Thames, Surrey, UK