Jornal de Distúrbios Nutricionais e Terapia

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Congresso de Nutrição 2015: O impacto do consumo de fibras de inulina nas sensações de apetite e ingestão de alimentos em situações agudas em mulheres em idade universitária no Kuwait: Um estudo randomizado, duplo-cego e controlado por placebo - Younis A Salmean - Faculdade de Ciências da Vida

Younis A Salmean

Estudos em animais mostraram que a inulina, uma fibra fermentável, resulta em redução da ingestão de energia e perda de peso. Este estudo visa comparar o efeito da suplementação de inulina no perfil de apetite e ingestão de alimentos. 40 mulheres em idade universitária (20,3 ± 3,7 anos (média ± DP)) matriculadas na Universidade do Kuwait foram randomizadas de forma duplo-cega para uma bebida de inulina (16 g/dia em 330 ml de água) ou 330 ml de água (placebo). Ambas as bebidas eram isocalóricas e aromatizadas artificialmente em garrafas de água opacas idênticas. As bebidas foram tomadas diariamente por 7 dias (era de adaptação) e Escalas Visuais Analógicas (VAS) foram usadas para relatar perfis de apetite no 8º dia durante um laboratório de alimentação. Voluntários em jejum foram gerenciados pela VAS em vários pontos de tempo durante todo o dia. Não houve diferença significativa em idade ou peso entre os dois grupos. O grupo placebo gastou significativamente mais quantidades de energia no almoço quando comparado ao grupo de fibras (670±174 kcal vs. 554±217 kcal, p<0,05). As pontuações VAS indicaram que o grupo placebo teve um desejo significativamente maior por comida pela manhã em comparação ao grupo inulina (p<0,05) e esse desejo permaneceu significativo por pelo menos 2 horas e 45 minutos. O grupo placebo obteve um aumento acentuado na fome e no desejo de comer alimentos no início do dia e também experimentou classificações de saciedade e satisfação significativamente mais fracas durante esse período (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

Younis Salmean é um membro do corpo docente do Departamento de Nutrição da Universidade do Kuwait. O Dr. Salmean se formou na California State University com um diploma de bacharel em Ciência dos Alimentos e Dietética, e posteriormente obteve um mestrado e doutorado na University of Florida em Nutrição Humana. Seus interesses de pesquisa atuais se concentram em examinar o papel da fibra e dos prebióticos na terapia nutricional médica, especificamente o papel das fibras adicionadas em vários resultados da doença renal crônica e biomarcadores relacionados. Ele também está focado em examinar o papel que a fibra e os prebióticos podem desempenhar na promoção da saúde, bem-estar e qualidade de vida.

Este trabalho foi parcialmente apresentado na 4ª Conferência e Exposição Internacional sobre Nutrição, realizada de 26 a 28 de outubro de 2015 em Chicago, Illinois, EUA.