Association between the consumption of vegetables and fermented foods and COVID-19 mortality at a country level in Europe. An ecological study

Abstract

Purpose

Many foods have an antioxidant activity, and nutrition may mitigate COVID-19. Some countries with a low COVID-19 mortality have a relatively high consumption of cabbage or fermented foods. To test the potential role of fermented foods and cabbage in COVID-19 mortality in Europe, we performed an ecological study.

Methods

The EFSA Comprehensive European Food Consumption Database performed an analysis on country food consumption. Fermented foods were analysed in sub-study 1, and cruciferous and other vegetables in sub-study 2. We obtained the COVID-19 mortality per number of inhabitants from the Johns Hopkins Coronavirus Resource Center. EuroStat data were used for data on potential confounders at the country level including Gross Domestic Product, population density, percentage of people older than 64 years, unemployment rate and obesity. Mortality counts were analysed using quasi-Poisson regression models - with log of population as an offset - to model the death rate while accounting for over-dispersion. A hierarchical model was used to account for multiple data.

Results

Amoung the variables considered, only fermented vegetables reached statistical significance concerning COVID-19 death rate in sub-study 1.  In sub-study 2, cabbage and cucumber showed significance, although, for cucumber, this was no longer the case after hierarchical assessment. Adjustment did not change the point estimate, and results were still significant.

Conclusions

The negative ecological association between COVID-19 mortality and consumption of fermented vegetables or cabbage supports the a priory hypothesis previously reported. This hypothesis needs to be tested in individual studies performed in countries where the consumption of fermented vegetables is common.