Comparison of seasonal variation in the fasting respiratory quotient of young Japanese, Polish and Thai women in relation to seasonal change in their percent body fat

Tomoko Morinaka,Yoshiaki Sone,Joanna Bajerska,Luksana Makonkawkeyoon,Jan Jeszka,Malgorzata Wozniewicz,Naoko Hirota,Porn-Ngarm Limtrakul,Shoko Kumagai

doi:10.1186/1880-6805-31-10

Abstract

BackgroundFrom the viewpoint of human physiological adaptability, we previously investigated seasonal variation in the amount of unabsorbed dietary carbohydrates from the intestine after breakfast in Japanese, Polish and Thai participants. In this investigation we found that there were significant seasonal variations in the amount of unabsorbed dietary carbohydrates in Japanese and Polish participants, while we could not find significant seasonal variation in Thai participants. These facts prompted us to examine seasonal variations in the respiratory quotient after an overnight fast (an indicator of the ratio of carbohydrate and fat oxidized after the last meal) with female university students living in Osaka (Japan), Poznan (Poland) and Chiang Mai (Thailand).MethodsWe enrolled 30, 33 and 32 paid participants in Japan, Poland and Thailand, respectively, and measurements were taken over the course of one full year. Fasting respiratory quotient was measured with the participants in their postabsorptive state (after 12 hours or more fasting before respiratory quotient measurement). Respiratory quotient measurements were carried out by means of indirect calorimetry using the mixing chamber method. The percent body fat was measured using an electric bioelectrical impedance analysis scale. Food intake of the participants in Osaka and Poznan were carried out by the Food Frequency Questionnaire method.ResultsThere were different seasonal variations in the fasting respiratory quotient values in the three different populations; with a significant seasonal variation in the fasting respiratory quotient values in Japanese participants, while those in Polish and Thai participants were non-significant. We found that there were significant seasonal changes in the percent body fat in the three populations but we could not find any significant correlation between the fasting respiratory quotient values and the percent body fat.ConclusionsThere were different seasonal variations in the fasting respiratory quotient values in the three different populations. There were significant seasonal changes in the percent body fat in the three populations but no significant correlation between the fasting respiratory quotient values and the percent body fat.

Highlights

From the viewpoint of human physiological adaptability, we previously investigated seasonal variation in the amount of unabsorbed dietary carbohydrates from the intestine after breakfast in Japanese, Polish and Thai participants
We only show the results of the food intake survey of the participants who participated in the Respiratory quotient (RQ) and the percent body fat measurements
We analyzed seasonal variations in the fasting RQ values, the percent body fat, body weight and nutrient intake by one-factor repeated measure analysis of variance followed by post hoc multiple comparison tests using the Bonferroni method in each country

Summary

Introduction

From the viewpoint of human physiological adaptability, we previously investigated seasonal variation in the amount of unabsorbed dietary carbohydrates from the intestine after breakfast in Japanese, Polish and Thai participants. There is a Japanese saying, ‘the autumn climate is so good that even horses get fat’ This means that the autumn harvest season, especially for the Japanese staple food (rice), is the time when people stockpile food in order to survive severe winters when food is less available. From a human evolutionary viewpoint, it is generally accepted that storage of energy-rich fats is more efficient in periods of food abundance so as to survive food shortages The function of this fat storage mechanism is to have a source of energy available for times when food is scarce or difficult to find, or when animals hibernate [1]. From the viewpoint of human nutritional evolution, it is very interesting to see that modern populations still have a physiological mechanism to control the seasonal change in fat accumulation as hibernant animals do, even though modern populations are surrounded by readily available energy-rich food throughout the year more so than ever before

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