Possible roles of phytochemicals with bioactive properties in the prevention of and recovery from COVID-19

Abstract

Introduction: There have been large geographical differences in the infection and death rates of COVID-19. Foods and beverages containing high amounts of phytochemicals with bioactive properties were suggested to prevent contracting and to facilitate recovery from COVID-19. The goal of our study was to determine the correlation of the type of foods/beverages people consumed and the risk reduction of contracting COVID-19 and the recovery from COVID-19.

Methods: We developed an online survey that asked the participants whether they contracted COVID-19, their symptoms, time to recover, and their frequency of eating various types of foods/beverages. The survey was developed in 10 different languages.

Results: The participants who did not contract COVID-19 consumed vegetables, herbs/spices, and fermented foods/beverages significantly more than the participants who contracted COVID-19. Among the six countries (India/Iran/Italy/Japan/Russia/Spain) with over 100 participants and high correspondence between the location of the participants and the language of the survey, in India and Japan the people who contracted COVID-19 showed significantly shorter recovery time, and greater daily intake of vegetables, herbs/spices, and fermented foods/beverages was associated with faster recovery.

Conclusions: Our results suggest that phytochemical compounds included in the vegetables may have contributed in not only preventing contraction of COVID-19, but also accelerating their recovery.

Keywords: COVID-19; beverages; consumption habits; foods; phytochemicals; prevention; recovery.

Figure 1

(A) Symptoms that showed significant differences between the “Not tested” and “Tested positive” groups. *Chi-square test, p < 0.05. (B) Self-reported senses of smell, taste, and chemesthesis by the “Not tested” and “Tested positive” groups and comparison of the occurrences of chemosensory dysfunction in the sense of smell, taste, and chemesthesis. ***Chi-square test, p < 0.001.

Figure 2

(A) Intake of tea, herbal tea, coffee, apple cider, alcohol, and hot chocolate. **p < 0.01, ***p < 0.001. (B) Discrepancy of observed values from expected values in the chi-square test results on beverages. The colors indicate that the observed values were higher than the expected values (smaller to larger discrepancy indicated by pink to red color) and the observed values lower than expected values (smaller to larger discrepancy indicated by light to dark blue). Gray color indicates there were no or negligible discrepancies.

Figure 3

(A) Frequency of consuming various types of foods by the three groups. *p < 0.05, **p < 0.01, ***p < 0.001. (B) Discrepancy from expected values in the chi-square test results on foods. The colors indicate that the observed values were higher than the expected values (smaller to larger discrepancy indicated by pink to red color) and the observed values lower than the expected values (smaller to larger discrepancy indicated by light to dark blue). Gray color indicates there were no or negligible discrepancies.

Figure 4

(A) Frequency of consuming fruits by the three groups. *p < 0.05, **p < 0.01, ***p < 0.001. (B) Discrepancy from expected values in the chi-square test results on fruits. The colors indicate that the observed values were higher than the expected values (smaller to larger discrepancy indicated by pink to red color) and the observed values were lower than the expected values (smaller to larger discrepancy indicated by light to dark blue). Gray color indicates there were no or negligible discrepancies.

Figure 5

Percentage of participants in each group who have been drinking tea or coffee daily and the participants who were daily eating leaf vegetables, root vegetables, fermented foods, herbs and spices, beans and peas, and other foods such as mushrooms and olives.

Figure 6

Discrepancy from expected values in the chi-square test results - comparison among the “Did not get COVID” group of each country. The colors indicate where the observed values were higher than the expected values (smaller to larger discrepancy indicated by pink to red color) and where the observed values were lower than the expected values (smaller to larger discrepancy indicated by light to dark blue). Gray color indicates there were no or negligible discrepancies.

Figure 7

Median of the self-reported time (days) until recovery of “Not tested” and “Tested positive” group participants (A) and tables showing statistical differences of pairwise comparisons of the “Not tested” (B) and “Tested positive” (C) groups. (D) Reports on the dates the participants contracted COVID-19 (“Not tested” and “Tested positive” group combined).

Figure 8

Daily consumption of foods in each country. (A) Food categories that showed high percentages of daily consumption in India and Japan. (B) Food categories that showed high percentages of daily consumption in Japan than other countries. (C) Food categories that showed higher percentages of daily consumption in India than other countries. India and Japan are highlighted by squares.