Elsevier

Appetite

Volume 62, 1 March 2013, Pages 84-90
Appetite

Research report
Acute effects of a herb extract formulation and inulin fibre on appetite, energy intake and food choice

https://doi.org/10.1016/j.appet.2012.11.018Get rights and content

Abstract

The impact of two commercially available products, a patented herb extract Yerbe Maté, Guarana and Damiana (YGD) formulation and an inulin-based soluble fermentable fibre (SFF), alone or in combination, on appetite and food intake were studied for the first time in a double blind, placebo-controlled, cross-over design. 58 normal to slightly overweight women consumed a fixed-load breakfast followed 4 h later by an ad libitum lunch. They were administered YGD (3 tablets) and SFF (5 g in 100 ml water), YGD and water (100 ml), SFF and placebo (3 tablets) or water and placebo 15 min before meals. Appetite was assessed using visual analogue scales, and energy intake was measured at lunch. Significant reductions in food intake and energy intake were observed when YGD was present (59.5 g, 16.3%; 112.4 kcal, 17.3%) and when SFF was present (31.9 g, 9.1%; 80 kcal, 11.7%) compared with conditions were products were absent. The lowest intake (gram and kcal) was in the YGD + SFF condition. Significant reductions in AUC hunger and AUC desire to eat were also observed after YGD + SFF combination. The data demonstrate that YGD produces a robust short-term effect on caloric intake, an effect augmented by SFF. Caloric compensation for SFF indicates independent effects on appetite regulation.

Highlights

• A number of products in the consumer market are purported to affect appetite. • A mixed herbal product was found to acutely reduce intake. • The effects of the mixed herbal product were augmented by fermentable fibre. • Acute effects of fermentable fibre alone were less distinct. • Combination of treatments also reduced appetite (AUC analysis).

Introduction

The mechanisms underpinning appetite expression are a key target for products designed to control energy intake and marketed to suppress hunger or sustain fullness. The within-meal process of satiation and the post-meal end state of satiety are generated by the sensory, physical and chemical characteristics of the food consumed. The strength of these signals determines meal duration and meal size and/or the length of the post-meal interval before the next eating occasion (Blundell, 1991) and thus they are legitimate targets for appetite control. Many products available to the consumer, including herbal extracts and fermentable fibres, claim to affect appetite through impacting on such mechanisms but supporting evidence (‘proof of concept’) is limited.

Rodent studies and consumer data indicate that certain herbal extracts may have beneficial effects on appetite and weight control when used as supplements or food components (Ruxton & Gardner, 2005). One such product is a preparation containing extracts of Yerba Maté, Guarana and Damiana (YGD). Andersen and Fogh (2001) found that YGD induced significant weight loss over 45 days compared with control in overweight patients, reducing the time to perceived gastric fullness. YGD also significantly delayed gastric emptying. Consumer studies have also indicated the weight loss (self-reported) and appetite suppressing (retrospective measures) potential of YGD but most of these studies lacked control conditions (Ruxton, 2004, Ruxton et al., 2005, Ruxton et al., 2007). The suggested mechanism of action, based on three studies, is a post-meal delay in gastric emptying which may enhance satiation and strengthen early meal satiety (Andersen and Fogh, 2001, Savage et al., 1987, Schjoldager et al., 1989). However, with multiple potentially active components (Yerba Maté, Guarana and Damiana) the mechanisms of action for YGD on energy balance could be numerous. To date, the effects of YGD on human food intake and the flux of appetite between meals have yet to be demonstrated in an appropriate design.

Some fibre types increase satiation and early post-meal satiety through their high viscosity and bulking effects (Burton-Freeman, 2000). Others may affect longer-term appetite control through colonic fermentation and the production of Short Chain Fatty Acids (SCFAs; Bosch et al., 2009). Inulin and inulin-type fructans, mostly oligosaccharides or oligofructoses, stimulate colonic production of SCFAs (Guarner, 2005) with effects on food intake typically only reported after a duration sufficient for complete fermentation of the fibre to occur (Archer, Johnson, & Devereux, 2004) or after repeated dosing (Cani et al., 2006, Delzenne et al., 2005). Prolonged (3 weeks) treatment with inulin-type fructans has been shown to reduce plasma ghrelin levels and increase intestinal gene expression and secretion of glucagon-like peptide-1 (7–36) amide (GLP-1; Cani et al., 2004, Delzenne et al., 2005). Inulin may therefore reduce hunger and the consumption of palatable food via ghrelin mediated mechanisms (Egecioglu et al., 2010, Jerlhag et al., 2007) and/or strengthen satiety by a GLP-1 mediated delay of gastric emptying (Hellström et al., 2008, Roberfroid, 2007). However, despite plausible mechanisms, evidence for the effects of inulin and inulin-type fructans (acute or chronic), on human food intake, food choice, eating behaviour and subjective feelings of appetite remains equivocal (Archer et al., 2004, Peters et al., 2009). Nonetheless, we have recently observed acute effects of these fibre types on appetite ratings in preload designs (unpublished results). Although such acute studies are not sufficient to support satiety claims per se as evidence of prolonged efficacy is required, they do provide valuable proof-of-concept data.

The current study is the first to assess the acute impact of two products, both with purported effects on gastric emptying, appetite expression, caloric intake and food choice. A patented herb YGD formulation and an inulin-based soluble fermentable fibre (SFF) were tested alone and in combination. SFF used in this acute study (Fibresure) was selected based on previously observed effects on appetite (unpublished) in a study administering the same fibre prior to a fixed load meal. Products were given prior to a fixed load breakfast to determine if they strengthened post-meal satiety and prior to lunch to determine their effects on satiation. Based on existing data it was hypothesised that the products would (1) produce a significant reduction in food intake at a subsequent ad libitum test meal, (2) produce a specific reduction in the intake of high fat palatable foods at this meal and (3) impact on pre-and post-meal appetite ratings indicating enhanced satiety. Given the potential role of fermentation in the effects of the fibre on appetite, changes in appetite were observed for up to 8 h after the first dose. With the potential for additive or synergistic effects on gastric emptying it was also proposed that the observed effects on appetite would be enhanced through co-administration of these products. Such proof-of-concept studies are necessary prior to examining efficacy (enduring effects on appetite and weight control) and other consumer benefits in the intended populations.

The current study also adopted a new proposed standard in analysing appetite ratings. The AUC ANCOVA analysis has been proposed as superior to standard time by condition ANOVA analysis of VAS because the latter approach does not take into account that appetite ratings are a function of multiple time points which are not physiologically or statistically independent. Additionally this alternative approach negates the inflation of type 1 statistical errors which occurs with comparisons of multiple single time points and which can lead to inappropriate conclusions regarding product efficacy (Blundell et al., 2010).

Section snippets

Participants

A population of likely consumers of the products (normal and overweight women) were recruited to the study. Fifty-eight healthy women, aged 18–65, with a body mass index (BMI) between 18.5 and 29.9 kg/m2 completed the study. Volunteers were recruited by advertisement from the University of Liverpool and surrounding area of Merseyside in England. Individuals completed a standardised telephone or email assessment to determine their eligibility for the study. Those who were aged over 65, with a BMI

Test meals

A standard fixed-load breakfast (496 kcal) containing items typically consumed at this meal was dispensed to participants in all conditions. In addition to the fixed-load breakfast, at the first visit, participants were offered a hot drink of tea or coffee with additional milk (35 g) and sugar if desired. If requested, this drink had to be consumed on each subsequent visit. The ad libitum test lunch consisted of a selection of 12 cold items appropriate to the eating occasion and was designed to

Participants

In total 71 participants were screened, 62 were recruited and 58 completed the study. Nine participants were excluded, six as their BMI was >29.9, two due to medication they were currently taking and one as her BMI was <18. Of the four that were recruited to the study but did not complete it, three could not fit the visits around previous commitments and one could not be contacted after her first visit. Their data have been excluded from analysis. The demographic (age), and anthropometric

Discussion

The current study examined the effect of two commercially sold products, administered separately or together prior to a fixed load breakfast and an ad libitum lunch, on appetite and energy intake. The YGD product, currently marketed to normal and overweight consumers in the UK and US for weight management through appetite control, produced clear effects on food intake. This is the first time such effects have been reported. The SFF product, previously marketed in the UK and currently marketed

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    Acknowledgements: This work was supported by Natures Remedies Ltd., Amersham, UK. Jason C.G. Halford has also acted as a consultant for the company. Joanne A. Harrold and Jason C.G. Halford participated in the study design, in the analysis and interpretation of the data and writing of the manuscript. Joanne A. Harrold, Katy O’Shiel, Etaoin Quinn, Georgina M. Hughes, Emma J. Boyland and Nicola J. Williams were involved in performing the studies and writing the manuscript.

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