食物繊維が排便におよぼす影響

Effect of Dietary Fiber on Defecation

要旨

　健康な成人女性9名を対象にいかなるDF量を含む食事が快適な自然排便を促すかを検討した．20歳代の女性に必要な栄養所要量（1900～2000 Kcal／日）にDF 10g／日，20g／日，30g／日を調整した3種類の食事（DF食）を各々5日間に渡って全被験者に摂取させた．いずれのDF食から開始しても良いものとし，各DF食間には5日以上の日常食を入れさせた．

　DF量の増加にともなって排便量は増加し，特にDF 20g／日から30g／日に増すと飛躍的に増加した．排便回数もDF量の増加につれて回数は増え，排便のない日が少なくなった．通常便秘のない被験者はDF 20g／日でほぼ1日1回，DF 30g／日で1日1～2回の排便があったが，便秘者ではDF増加によって便通効果はあるものの反応は個々に異なった．便の硬度はDFの増加に伴って軟化する傾向を示した．また実験期間中の排便にともなう自覚的苦痛としては「残便感」「腹部膨満感」「排便時の肛門部痛」を認めた．これらの苦痛はDF20g／日で最も少なかったが，DF 10g／日と30g／日ではむしろ日常食より訴えが多くなった．著明に現れた苦痛はDF 10g／日と30g／日の「残便感」であった．また，DF 30g／日で全被験者が食事量の多さが苦痛であると訴えた．

　便通改善効果と自覚的苦痛の軽減を考慮すると本実験からは，快適な自然排便を促すDF量は20g／日が適当であると思われた．しかしDFに対する反応は個人によって異なると考えられるため，今後，更に詳細な検討が必要であろう．

Abstract

　Effect of dietary fiber (DF) to obtain a confortable defecation was investigated using nine adult female in health. Meals used in this study contained the recommended energy (1900-2000Kcal/ day) in females of twenties with the fixed nutritional composition. Meals were divided into four different types; meals containing uncalculated quantity of DF (conventional meal) and meals with three different quantities of DF (10g, 20g and 30g/day). All subjects took three different DF meals one after another for 5 days for each. Intervals of 5 days or more with conventional meals were placed between each DF meal. The volume of stool and the frequency of defecation were increased by DF intake in a dose dependent manner. A regular defecation was obtained by DF meals (1/day for 20g DF and 1-2/day for 30g DF). Subjects with the chronic constipation also responded to meals with DF although an individual difference was shown. A stool appeared to be softened by a relatively large quantity of DF (＞20g/day). A residual stool, abdominal full sensation, and anal pain on evacuation as accompanied symptoms with defecation were much less in meals containing DF 20g/day, while meals with DF 10g or 30g/day rather increased a symptom such as a residual stool compared with a conventional meal. In addition, all subjects complained an excess of volume of meals containing DF 30g/day. Concerning with effectiveness on bowel movement and accompanying symptoms, the present results suggest that meals containing DF 20g/day were the most suitable to obtain a confortable defecation. An individual difference in response to DF meal, however, requires a more detailed investigation.