Scholarly Journal of Food andNutrition
DOI: 10.32474/SJFN.2020.03.000155

ISSN: 2638-6070

Short Communication

Low COVID-19 Infection and Mortality inRice Eating Countries
Shaw Watanabe1* and Kazumoto Inuma2
1Life science Promoting Association, Asia Pacific Clinical Nutrition Society, Japan

2

Ricetech Corporation, Japan*Corresponding author: Shaw Watanabe, Life science Promoting Association, Asia Pacific Clinical Nutrition Society, Tokyo, Japan
Received:

Published:

June 15, 2020

June 25, 2020

Abstract
The relationship between rice consumption and the cumulative number of COVID-19/1000000 at June 6, 2020 was examined
after compilation of data from 19 major countries on 5 continents. A strong negative correlation with a coefficient of determinationof 0.59 was found. On the contrary, wheat consumption showed the positive correlation. This suggests that resistance to SARS-CoV-2
infection is influenced by the nature of staple foods. This is compatible with previous findings indicating that rice eaters have a
specific profile of intestinal microbiota, which strengthens the innate immunity to virus infection. Lower infection rates in Asia thanin the West appear to be partly due to dietary differences. Improvements in agricultural policies and eating habits, especially thepromotion of the use of brown rice food and rice bran, should be part of the national strategies to counter the COVID-19 pandemic.

Keywords: COVID-19; Innate Immunity; Rice; Brown Rice; Wheat

Introduction“Let food be thy medicine and medicine be thy food.” This quote
is attributed to Hippocrates in ancient Greece. The idea of a link
between medicine and food stems from the concept of common
grounds for illness, health, and diets. This thinking permeates
all popular cultures, fitting in very nicely with an historicalphenomenon. Recently, this concept has broadened our scientifichorizon, and appears to apply to the case of COVID-19 infection as
well [1]. Staple foods of the world are roughly divided into thosemade from rice and or wheat. Rice is popularly used in Asia, andwheat is used in Europe and America. To test the hypothesisthat dietary differences play a role in the immunity to COVID-19
infection, we looked for a possible correlation between riceconsumption, and SARS-CoV-2 virus infection and mortality.

Methods, Data and Statistical Analysis

Country data on the daily incidence of cases and deaths (per1 million inhabitants) caused by COVID-19 are publicly available[2,3]. The reference data were set at June 6, 2020. For correlation

Copyright © All rights are reserved by Shaw Watanabe.

analysis, we selected a sample of 19 representative countries,
distributed over 5 continents (Table 1). Of these countries, 18 aremembers of the G20 (Group of Twenty). Additional data from Spain
was adopted. For the same countries, per capita consumption ofrice and wheat (kg/year) were taken as independent variables. The
source of food data is [worldfood.apionet.or.jp/web/9-1.htm]/jt,and data of 1998 were used [4]. The two variables were subjected
to regression analysis after common logarithmic transformation.
Correlations were calculated by the least square’s method by IBMSPSS ver.24.
Table 1: Selected countries by continent, and COVID-19
incidence as of June 6, 2020.
North/Central/SouthAmerica:
Europe:Asia:
Africa/Middle East/
Australia:

Canada, USA, Mexico, Argentina.

United Kingdom, France, Italy, Germany,Spain, Russia.

China, Japan, India, Indonesia, South Korea,South Africa, Turkey, Saudi Arabia, andAustralia.

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Volume 3 - Issue 1Relationship between Per Capita Rice Consumption andCumulative Number of COVID-19 Patients by Country
Figure 1 shows the rice consumption per capita (kg/year) on
the horizontal axis and the number of COVID-19 infected people permillion population on the vertical axis. Both axes are logarithmic.
The coefficient of determination is 0.592, confirming a negative
correlation. The mortality rate shows a weaker correlation (0.44)
than the number of infected people, because the mortality data
is independently affected by medical care and other conditions(Figure 2).

Copyrights @ Shaw Watanabe, et al.

correlation in contrast to the rice consumption. The correlation
with wheat consumption is positive, quite contrary to rice, but
the coefficient of determination is 0.49, which is smaller than Rice
(Figure 3).

Figure 3: Scatter plot of wheat consumption by country
and the number of COVID-19 patients. Y-axis; Number of
COVID-19 patients/million, X-axis; wheat consumption/capita kg/year.

Discussion and Conclusion
Figure 1: Scatter plots between number of COVID-19
patients and rice consumption per capita. Y-axis; Numberof COVID-19 patients/million, X-axis; rice consumption/capita kg/year.

Figure 2: The scatter plot between the number of deaths
per one million population and rice consumption percapita. Y-axis; Number of COVID-19 deaths/million,X-axis; rice consumption/capita kg/year.

Correlation between Wheat Consumption and theNumber of COVID-19 Cases
The correlation between the number of COVID-19 patients andthe wheat consumption (kg/year) by country shows the positive

The magnitude of the new coronavirus epidemic varies greatly
from country to country. Why is the Japanese population lessfrequently infected? Why are there so many cases in America?
Why are the situations of Asia and Europe so different? It seems
that there has never been a model that can answer these questions
consistently. We proposed a hypothesis that the high proportion ofsIgA deficiency among Caucasians would be one explainable factor[1]. This time we conducted a statistical analysis by scatter plotof the correlation between staple food and coronavirus infection.
The coefficients of determination between the number of infected
people or the number of deaths, and rice consumption showednegative correlations of 0.59 and 0.44, respectively. Moreover,there was a positive correlation with wheat consumption. Sucha big contrast could cover the effects of many other confounding
factors, and strongly support the importance of innate immunity
based on rice foods. These results suggest that rice eaters havean intestinal environment characterized by a special microbiota
composition, whereby secreted short chain fatty acids stabilize
the innate immunity by T17/Treg balance [5,6]. It appears that theAsian-type meal centered on rice and fish provides more resistanceto virus infection than the Western-type meal centered on breadand meat. Among rice foods, it has been known that ingestion ofbrown rice and rice bran contributes greatly to health [7]. Thesemethods could be employed for population-based prevention of thesecond wave COVID-19 pandemic in developed countries, and thosestill spared from the spread of corona virus infection in developing
countries [8,9].

Citation: Shaw Watanabe, Kazumoto Inuma. Low COVID-19 Infection and Mortality in Rice Eating Countries. Scho J Food & Nutr. 3(1)2020. SJFN.MS.ID.000155. DOI: 10.32474/SJFN.2020.03.000155.

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Acknowledgement
The authors deeply appreciate Dr. Philippe Calain for his sincere
discussion and editing of this manuscript.

References

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COVID-19 Pneumonia. Int J Fam Med Prim Care 1(3): 1011-1014.

2. Idogawa M, Tange S, Nakase H, Tokino T Interactive Web-based Graphsof Coronavirus Disease 2019 Cases and Deaths per Population byCountry, Clinical Infectious Diseases, ciaa500, https://doi.org/10.1093/
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3. Word wide daily incidence of infection by the new coronavirus.
Department of Medical Genome Sciences, Research Institute for Frontier
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4. Ito S (2020) Per capita consumption of rice, wheat and corn in the world
and their changes. Kyushu University. Faculty of Agriculture. World Food
Statistics and Graphics. worldfood.apionet.or.jp/web/9-1.htm.
This work is licensed under Creative
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5. Hirakawa A, Aoe S, Watanabe S, Hisada T, Mocizuki J, et al. (2019) The
nested study on the intestinal microbiota in GENKI Study with specialreference to the effect of brown rice eating. J Obes Chronic Dis 3(1): l113.

6. Furusawa Y, Obata Y, Fukuda S, Endo T, Nakato G, et al. (2013)
Commensal microbe-derived butyrate induces the differentiation ofcolonic regulatory T cells. Nature 504(7480): 446-450.
7. Watanabe S, Hirakawa A, Mizuno S, Wakino S, Adachi K (2020) Whatshould we eat for healthy longevity? Necessity of tailor-made nutrition.
Acta Scientific Nutritional Health 4(3): 01-05
8. Watanabe S (2020) MicroRNA opens up a new world for nutrition
research. Acta Scientific Nutritional Health 4(1): 38-39.

9. Editor’s note. Leaving lockdown means understanding immune
responses to the virus. Science and Technology, 2020. https://www.
economist.com/science-and-technology/
2020/05/02/leavinglockdown-means-understanding-immune-responses-to-the-virus

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Citation: Shaw Watanabe, Kazumoto Inuma. Low COVID-19 Infection and Mortality in Rice Eating Countries. Scho J Food & Nutr. 3(1)2020. SJFN.MS.ID.000155. DOI: 10.32474/SJFN.2020.03.000155.

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