Foods that can boost your immunity and vaccine response

9 mins read

Note: Most of the current research on vaccination and malnourishment are based on undernourished children/elderly groups with many gaps in between but other areas encompass sufficient to study for inference.  ‘Clinical trials based on the associations of diet and COVID-19 are lacking’(Shakoor et al., 2021).

*ATTENTION*: This is not medical advice and you should always seek professional medical guidance before undertaking any lifestyle/health decisions.  

Read More: The Effects Of Over Hydration

Vitamins, minerals and an overall well-balanced diet can boost immunity levels greatly (Okawa, Nagai and Hase, 2021), some touted in the news as vital and life-saving. Source: (Huq, 2020)

The big daddy D (Vitamin D) has been the ball of the party as of late, sunny vitamin D of course. Is all that shimmering actually from any gold, though? 

Yes and no. 

The Purpose Of Vitamin D

Vitamin D can help natural and adaptive immunity through balancing inflammation, bacterial destruction, production of cells that ‘clean’ and mop up waste/toxins and increase cellular defence in the respiratory epithelium (a known site which influenza and COVID viruses could attack).

Correlation To COVID-19

A strong correlation has been found between low vitamin D levels and higher rates of COVID-19 infection and severity (D’Avolio et al.,2020). However, it failed to consider selection biases and other probable confounders. Furthermore, most shreds of evidence that find such results only utilise a univariate analysis and can be easily disproved by multivariate analysis which adjusts results for health and sociodemographic factors (Raisi-Estabragh et al., 2020).

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Although unclear whether it can lower infection rates, Daneshkhah et al. (2020) and Lau et al. (2020), put it clearly in pre-prints that vitamin D deficiency is prevalent in more serious cases of COVID-19. More direct testing needs to be done to confirm this hypothesis as to whether the deficiency is indeed causal or merely correlational, based on its ties to COVID-19 associated risk factors.

For example, vitamin D deficiency is higher in older age groups as their skin produces less 7-DHC which enables vitamin D production from the sun but at the same time, older populations have weaker immunities, to begin with, and therefore could be either explanation in mortality rates, with the truth lying somewhere in between I would bet. 


Therefore, has vitamin D been overhyped? Very much so, but more importantly, is there any harm to that? There is. First, there is no real ‘optimal’ number, as all vitamins vary from person to person depending on genetic and environmental factors.

For instance, when bone specialists prescribed what was to them an ‘optimal dosage of vitamin D’ to participants in a trial, many of those with the newer and higher elevated levels saw adverse reactions such as having 20-30% increased rates of fractures and falls in comparison to those on low doses/ participants below ‘optimal’ (Sanders et al., 2010).

As the optimal number prescribed by the specialists was much higher than national averages across countries and medical organisations, it is safe to say that overdosing on vitamin D is dangerous and counterproductive for bone health. Therefore, aggressively promoting the use of vitamin D whereby daily requirements are specific and sensitive would be irresponsible.

Furthermore, it is well-known that the gut creates vitamins we need to survive (Hill, 1997). One may add that only one-third is made and the rest has to be supplemented. I would take the side of caution on this only supplement sporadically if necessary, with a holistic approach to the environment and foods.

Do vitamins From Foods And Supplements Have The Same Effect On Your Body?

No. You miss out on a ton of antioxidants, fibre and biodiversity that could build upon the gut bacteria in your body! In addition to that, the gut lining that will be provoked with copious amounts of processed chemicals may cause a change in the gut bacteria equilibrium (Goto et al., 2014).

I guess at the end of the day, the sun does not shine very brightly on vitamin D anymore until more research reaches new horizons. 

Note: Discuss going forward with any purchase with your primary consultant/physician. A blood test would be sufficient in recognising what you are currently lacking (e.g. Iron, etc..). Lastly, this article stresses again the importance of healthy eating over a lifespan as there is no point in taking vitamin supplements just before a shot, no evidence exists to prove that this is useful or certain to work (Savy et al., 2009). So be that as it may, do continue to eat nutritiously and if you are having to take supplements to compensate for your diet, keep it within limits.


  1. Daneshkhah, A., Agrawal, V., Eshein, A., Subramanian, H., Roy, H.K. and Backman, V. (2020). The Possible Role of Vitamin D in Suppressing Cytokine Storm and Associated Mortality in COVID-19 Patients.
  2. Goto, Y., Panea, C., Nakato, G., Cebula, A., Lee, C., Diez, M., Laufer, Terri M., Ignatowicz, L. and Ivanov, Ivaylo I. (2014). Segmented Filamentous Bacteria Antigens Presented by Intestinal Dendritic Cells Drive Mucosal Th17 Cell Differentiation. Immunity, 40(4), pp.594–607.
  3. Hill, M.J. (1997). Intestinal flora and endogenous vitamin synthesis. European Journal of Cancer Prevention, 6, pp.S43–S45.
  4. Huq, R. (2020). Telling the public to take vitamin D would save lives. [online] 7 Oct. Available at: [Accessed 20 Jun. 2021].
  5. Lau, F.H., Majumder, R., Torabi, R., Saeg, F., Hoffman, R., Cirillo, J.D. and Greiffenstein, P. (2020). Vitamin D insufficiency is prevalent in severe COVID-19.
  6. Okawa, T., Nagai, M. and Hase, K. (2021). Dietary Intervention Impacts Immune Cell Functions and Dynamics by Inducing Metabolic Rewiring. Frontiers in Immunology, 11.
  7. Raisi-Estabragh, Z., McCracken, C., Bethell, M.S., Cooper, J., Cooper, C., Caulfield, M.J., Munroe, P.B., Harvey, N.C. and Petersen, S.E. (2020). Greater risk of severe COVID-19 in Black, Asian and Minority Ethnic populations is not explained by cardiometabolic, socioeconomic or behavioural factors, or by 25(OH)-vitamin D status: a study of 1326 cases from the UK Biobank. Journal of Public Health, 42(3).
  8. Sanders, K.M., Stuart, A.L., Williamson, E.J., Simpson, J.A., Kotowicz, M.A., Young, D. and Nicholson, G.C. (2010). Annual High-Dose Oral Vitamin D and Falls and Fractures in Older Women. JAMA, [online] 303(18), p.1815. Available at:
  9. D’Avolio, A., Avataneo, V., Manca, A., Cusato, J., De Nicolò, A., Lucchini, R., Keller, F. and Cantù, M., 2020. 25-Hydroxyvitamin D concentrations are lower in patients with positive PCR for SARS-CoV-2. Nutrients, 12(5), p.1359.).

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