栄養障害と治療のジャーナル

概要

栄養学会議 2015: クウェートの大学生女性の急性期におけるイヌリン繊維摂取の食欲感覚と食物摂取への影響: ランダム化二重盲検プラセボ対照試験 - ユニス A サルメアン - 生命科学大学

ユニス・A・サルメアン

動物実験では、発酵性繊維であるイヌリンがエネルギー摂取量の減少と体重減少をもたらすことが示されています。この研究は、イヌリン補給が食欲プロファイルと食物摂取に及ぼす影響を一致させることを目的とします。クウェート大学から登録された40人の大学生時代（20.3±3.7歳（平均±SD））の女性を、二重盲検法でイヌリン飲料（1日16 gを330 mlの水に溶解）または330 mlの水（プラセボ）に無作為に割り当てました。両方の飲料は等カロリーで、同一の不透明な水のボトルに入った人工香料が加えられました。飲料は7日間（順応期）毎日摂取され、8日目の摂食実験中に視覚的アナログスケール（VAS）を使用して食欲プロファイルが報告されました。絶食したボランティアは、一日中さまざまな時点でVASによって管理されました。2つのグループ間に年齢または体重に有意差はありませんでした。プラセボ群は、繊維群と比較して、昼食時に有意に多くのエネルギーを消費しました (670±174 kcal 対 554±217 kcal、p<0.05)。VAS スコアは、プラセボ群はイヌリン群と比較して、午前中に食欲が有意に高く (p<0.05)、この食欲は少なくとも 2 時間 45 分間有意に持続したことを示しました。プラセボ群は、一日の早い時間に空腹感と食欲が急激に高まり、その期間中の満腹感と満足度の評価も有意に低下しました (p<0.05)。

 

As reviewed before, previous studies suggest that fiber can affect hunger and/or satiety favorably, leading to reduced energy intake. Several animal studies have suggested that consumption of fermentable fibers can increase GLP-1 and proglucagon expression and improve glucose homeostasis. However, to our information, very few, mostly non homogeneous studies with adjustable fiber dosage investigated the impact of ITFs or inulin supplementation on appetite, hunger sensations, and food intake in the adult population. In our study, when participants consumed 16 g/day of ITFs in the morning, the average ratings in their ‘desire to eat’, ‘hunger’, and ‘prospective food consumption’ were significantly lower compared to the control group. In calculation, the fiber group recounted higher ‘fullness’ grades before lunch, signifying a possible impact from the fiber. However, because the adaptation period was a free-living phase, it is difficult to conclude that the observed benefits, although suggested, are due solely to the ITFs since the amount of food consumed from breakfast to lunch is unknown. However, looking at the data from the test day, where settings and food intake were controlled, it appears that consuming 16 g of ITFs in the morning lowered the desire to eat, hunger, and the interest in food consumption, and enhanced fullness and satisfaction for much longer compared to placebo. This is consistent with the findings of Cani et al, who found that 16 g of ITFs promoted satiety in healthy humans.

The impacts on appetite of the participants was thanks to ITF consumption since both groups consumed equal amounts of energy at breakfast (235 ± 18 kcal vs 230 ± 16 kcal) and were housed in exact conditions with minimal physical disturbances. The lingering impact of the ITFs on appetite sensations can explain why the fiber group has consumed 21% fewer calories from food at lunch, since most sensations favorably varies until 155 min post-breakfast, and shortly before lunch is served at 200 min. It is worth noting that the reduced consumption of food by the fiber group meant that they had more time to interact at the table during lunch, which may have led to a pattern of increased liquid consumption, a naturally anticipated response when liquids accompany meals. It would have been more ideal to provide water in place of juice, considering that liquid calories are less likely to elicit a precise dietary compensation response because swallowing does not trigger the internal satiety signal that masticating does.

One reason for previous studies failing to show a positive impact of fiber supplementation on VAS domains could be the use of inhomogeneous subject populations, in particular, a wider physiological age difference. Harrold included subjects with age ranges from 18–65, 1–64, and 20–60 years, respectively. The innate physiological response and magnitude of appetite and energy regulation complexes for older and younger people can be quite different. Anorexigenic signals in older adults prevail over orexigenic signals, contributing to prolonged satiety and inhibition of hunger, which can easily affect VAS reporting in a mixed population of wide physiological age ranges. It is, therefore, suggested that more homogeneous subject populations be used when investigating the impact of fiber on appetite and energy regulation. We designed our study to be practically homogeneous; thus, we enrolled college-age females, which may explain the agreement found in our study with that of Cani et al., where fiber intake had a big impact on satiety in 21–39-year-old participants.

Another probable reason for the contradiction of the results of preceding studies may be the dissimilar doses of ITFs used. The study by Karalus et al. testified no momentous benefits on craving ratings or weight of supplementing the diet with 10 g ITF fiber. The likely explanation for this is often the low fiber doses utilized in the study. The 10 g dose of ITFs isn't likely to supply any marked impact on appetite and hunger sensations. The 16 g of inulin used in our study is likely to be an effective dose to produce meaningful change in appetite sensations, as this amount has been shown to produce favorable changes in appetite sensations, and in appetite-related hormones and peptides.

Our statistics propose an influence on weightiness in the short term. After a week of supplementation, the fiber group saw no significant increase in body weight compared to its baseline, but the control group had a significant increase from its baseline. This is consistent with the findings of Parnell and Reimer, where supplementation with ITFs resulted in a significant reduction in weight in the fiber group while the control group experienced a significant weight gain.

Participants consuming the fiber reported a higher incidence of bloating and flatulence, which was anticipated. Although the incidence was higher among fiber consumers, the fiber was tolerated as no dropouts were reported as a result of supplement use.

In conclusion, dietary supplementation with 16 g/day of ITF fiber in the morning was found to reduce hunger, desire to eat, and prospective food consumption, and to increase fullness and satiety in acute settings, leading to reduced food intake at lunch. These consequences propose that ITF fiber is potentially a useful assistant dietary supplement for curbing appetite and possibly aiding weight management.

Biography

ユニス・サルミアンはクウェート大学栄養学部の教員です。サルミアン博士はカリフォルニア州立大学で食品科学と栄養学の学士号を取得し、その後フロリダ大学で人間栄養学の修士号と博士号を取得しました。現在の研究対象は、医療栄養療法における繊維とプレバイオティクスの役割、特に慢性腎臓病のさまざまな結果と関連バイオマーカーに対する添加繊維の役割の調査です。また、繊維とプレバイオティクスが健康、ウェルネス、生活の質の促進に果たす役割の調査にも力を入れています。

この研究の一部は、2015 年 10 月 26 日から 28 日まで米国イリノイ州シカゴで開催された第 4 回国際栄養会議および展示会で発表されました。