Popeye and my mother knew that spinach would make you strong, but will it, or any other food, protect you from COVID-19?

Maybe, but what food?

The answer is not one food but a diet, a diet that works for you and, no surprise, a diet that keeps you healthy.

Trouble is, we know that not everyone in the world has access to the diet of their choice and we know that many can’t afford healthy food. It’s also a fact that many of those who have the means and the choice are not healthy.

So, can eating a healthy diet protect you from COVID-19?

The strongest correlate of suffering a poor outcome from this virus is age, this is because our immune systems lose effectiveness in old age. 

But there is also evidence that a poor diet or being obese or both also affects the severity and complications from contracting the virus.

Essentials for immune system function

According to the European Food Safety Authority, there are six vitamins (D, A, C, Folate, B6 and B12) and four minerals (zinc, iron, copper and selenium) that are essential for the normal function of the immune system. 

A review of these nutrients confirmed their importance and emphasised Vitamin D and iron in the context of Covid-19. This same review looked at Covid-19 case incidence and/or mortality and found an inverse association with Vitamins D, C B12 and iron.

These nutrients are in your diet – if you are eating a variety of fresh, minimally processed foods – foods that Popeye or my mother might recognise.

Clearly, those who are going hungry or who are food insecure are much less likely to be getting enough of these nutrients.

It is also true that many of the foods eaten in wealthy countries neither my mother nor Popeye would recognise. Highly processed foods made with cheap ingredients, cleverly promoted and often missing important nutrients.. 

The poor nutrient status of these foods is contributing to obesity which is a form of  malnutrition although it is not often thought of like that. People assume health complications come from excess fat with a strain on organs but ignore the nutrition imbalance of obese people. Nutrient deficiency also means we tend to eat more to get the nutrients we need.

Obese people are up to 80 times more likely to develop type 2 diabetes. A growing number of studies have demonstrated diabetes as an important risk factor affecting the incidence and severity of a wide range of infections and diabetes is one of the existing diseases associated with COVID-19 symptoms and deaths.

Diet and COVID-19

The most obvious connection so far between diet and COVID-19 is that what people in the developed world eat and increasingly the nutrient deficiencies in the developing world will affect the severity of COVID-19 symptoms, especially at the extremes.

Now more than ever, wider access to healthy foods for all should be a top priority and those of us with the luxury of choice should be mindful of healthy eating habits, if nothing else but to reduce the severity of COVID-19.

Science sources

Bousquet, Jean, Josep M. Anto, Guido Iaccarino, Wienczyslawa Czarlewski, Tari Haahtela, Aram Anto, Cezmi A. Akdis, et al. “Is Diet Partly Responsible for Differences in COVID-19 Death Rates between and within Countries?” Clinical and Translational Allergy 10, no. 1 (2020): 16. 

Butler, Michael J., and Ruth M. Barrientos. “The Impact of Nutrition on COVID-19 Susceptibility and Long-Term Consequences.” Brain, Behavior, and Immunity 87 (July 2020): 53–54.

Dabone, Charles, Ikenna Mbagwu, Mwali Muray, Lovelyn Ubangha, Bagnini Kohoun, Egbe Etowa, Hilary Nare, Getachew Kiros, and Josephine Etowa. “Global Food Insecurity and African, Caribbean, and Black (ACB) Populations During the COVID-19 Pandemic: A Rapid Review.” Journal of Racial and Ethnic Health Disparities, February 8, 2021, 1–16. 

Erener, Suheda. “Diabetes, Infection Risk and COVID-19.” Molecular Metabolism 39 (September 2020): 101044.

Galmés, Sebastià, Francisca Serra, and Andreu Palou. “Current State of Evidence: Influence of Nutritional and Nutrigenetic Factors on Immunity in the COVID-19 Pandemic Framework.” Nutrients 12, no. 9 (September 8, 2020). 

Holly, Jeff M. P., Kalina Biernacka, Nick Maskell, and Claire M. Perks. “Obesity, Diabetes and COVID-19: An Infectious Disease Spreading From the East Collides With the Consequences of an Unhealthy Western Lifestyle.” Frontiers in Endocrinology 11 (September 17, 2020)

Kopp, Wolfgang. “How Western Diet And Lifestyle Drive The Pandemic Of Obesity And Civilization Diseases.” Diabetes, Metabolic Syndrome and Obesity: Targets and Therapy 12 (October 24, 2019): 2221–36. Jayawardena, Ranil, and Anoop Misra. “Balanced Diet Is a Major Casualty in COVID-19.” Diabetes & Metabolic Syndrome 14, no. 5 (2020): 1085–86.

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