Appetite 73 (2014) 183–188

Contents lists available at ScienceDirect

Appetite journal homepage: www.elsevier.com/locate/appet

Research review

Could capsaicinoids help to support weight management? A systematic review and meta-analysis of energy intake data q S. Whiting a, E.J. Derbyshire a,⇑, B. Tiwari b a b

School of Healthcare Science, John Dalton East Building, Oxford Road, Manchester M1 5GD, United Kingdom Teagasc Food Research Centre, Ashtown, Dublin 15, Ireland

a r t i c l e

i n f o

Article history: Received 2 July 2013 Received in revised form 8 October 2013 Accepted 5 November 2013 Available online 15 November 2013 Keywords: Capsaicinoids Capsaicin Chilli Chili Weight management Energy intake

a b s t r a c t Objective: Capsaicinoids are a group of chemicals naturally occurring in chilli peppers with bioactive properties that may help to support weight management. The aim of the present study was to conduct a meta-analysis investigating the potential effects of capsaicinoids on energy intake, to clarify previous observations and form evidence-based conclusions about possible weight management roles. Methods: Medical databases (Medline, Web of Knowledge and Scopus) were systematically searched for papers. Search terms were: ‘capsaicin’ or ‘red pepper’ or ‘chilli’ or ‘chili’ with ’satiety’ or ‘energy intake’. Of the seventy-four clinical trials identified, 10 were included, 8 of which provided results suitable to be combined in analysis (191 participants). From the studies, 19 effect sizes were extracted and analysed using MIX meta-analysis software. Results: Data analysis showed that capsaicinoid ingestion prior to a meal reduced ad libitum energy intake by 309.9 kJ (74.0 kcal) p < 0.001 during the meal. Results, however, should be viewed with some caution as heterogeneity was high (I2 = 75.7%). Study findings suggest a minimum dose of 2 mg of capsaicinoids is needed to contribute to reductions in ad libitum energy intake, which appears to be attributed to an altered preference for carbohydrate-rich foods over foods with a higher fat content. Conclusions: Meta-anlysis findings suggest that daily consumption of capsaicinoids may contribute to weight management through reductions in energy intake. Subsequently, there may be potential for capsaicinoids to be used as long-term, natural weight-loss aids. Further long-term randomised trials are now needed to investigate these effects. Ó 2013 Elsevier Ltd. All rights reserved.

Contents Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Identification of relevant studies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Inclusion and exclusion criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Data extraction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Statistical analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

183 184 184 184 184 184 184 185 187

Introduction

q Acknowledgements: The authors would like to acknowledge the support of Manchester Metropolitan University for funding this research. Conflict of interest statement: There are no conflicts of interest. ⇑ Corresponding author. E-mail address: [email protected] (E.J. Derbyshire).

0195-6663/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.appet.2013.11.005

The plant of the genus capsicum produces a fruit (chilli pepper) with unique bioactive compounds (Kwon et al., 2011). The fruit contains a group of chemicals known as capsaicinoids, the most abundant and well known being capsaicin. Capsaicin, along with dihydrocapsaicin, makes up around 90% of capsaicinoids found in a typical chilli pepper (Meghvansi et al., 2010). These compounds are responsible for the fruit’s ‘pungent’ flavour sensation that has

184

S. Whiting et al. / Appetite 73 (2014) 183–188

made it popular in culinary cultures around the world (Hursel & Westerterp-Plantenga, 2010). This sensation occurs as capsaicinoids bind to the same group of nociceptors (namely the transient receptor potential cation channel subfamily V member 1 (TRPV1), also known as the ‘capsaicin receptor’) which lead to the sensation of pain from heat and acid (Sanatombi & Sharma, 2008). In recent years, the fruit’s bioactive effects have become of increasing interest within the field of health research (Luo, Peng, & Li, 2011). Clinical trials suggest capsaicinoids may have anti-cancer (Yang et al., 2010), anti-inflammatory (Choi et al., 2011) and antioxidant properties (Henning et al., 2011), while they have been used for pain relief for some time (Szallasi, Cruz, & Geppetti, 2006). Many of these effects are due to the actions of capsaicinoids on the TRPV1 which is found in tissues throughout the body and is the subject of current research (Gunthorpe & Szallasi, 2008). There is also accumulating evidence that capsaicinoid compounds may help to support weight loss (Ludy, Moore, & Mattes, 2012). Evidence from intervention trials in humans suggests daily consumption of capsaicinoids may increase energy expenditure by around 30 per cent for an hour (Yoshioka et al., 1995) and lipid oxidation by around 20% (Lejeune, Kovacs, & Westerterp-Plantenga, 2003). A number of human intervention trials have also investigated capsaicinoids’ ability to regulate energy intake, although findings have generally been contradictory (Whiting, Derbyshire, & Tiwari, 2012). For example, one study found significant reductions in ad libitum energy intake of 24 subjects after consuming a capsaicinoid invention prior to a meal, compared to a placebo (Westerterp-Plantenga, Smeets, & Lejeune, 2005). However, another trial found no reduction in energy intake in 36 participants during a 4-week intervention with fresh chillies compared with a control diet (Ahuja, Robertson, Geraghty, & Ball, 2007). As the effects of capsaicinoids on energy intakes can be difficult to establish from one meal, one trial investigated the effects of hot spices on energy intake and appetite after participants received five meals of fixed portion sizes, served with or without five hot spices followed by a buffet (Reinbach, Martinussen, & Moller, 2010). While hot spices were not found to significantly affect energy intake, the ingestion of hot spices appeared to induce changes in sensory specific desires e.g. an increased desire for sweet foods after ingesting chilli. While pharmacological solutions have been created to help people control appetite, a number of medications (such as sibutramine, fenfluramine and dexfenfluramine) have been withdrawn from the market due to harmful cardiovascular side-effects and the options for treatment with drugs are currently limited (McGavigan & Murphy, 2012). Capsaicinoids have therefore the potential to be an innovative approach in terms of helping people trying to manage their weight; however, patent legislation provides little monetary incentive for the pharmaceutical industry to develop a plant compound for a medical application. Thus this present article sets out to combine findings from studies investigating inter-relationships between capsaicinoid ingestion and energy intake using a meta-analytical approach and form evidence-based conclusions about possible weight management roles.

Methods Identification of relevant studies Studies were identified by searching Web of Knowledge, PubMed and Scopus (1990-Present). The initial search was performed in June 2012 and updated in May 2013. The following search terms were used in all databases: ‘capsaicin’ ‘red pepper’’, ‘chilli’, ‘chili’. These four terms were each combined (using Boolean ‘AND’) with ‘energy intake’ and ‘satiety’. Trials were initially selected based on their abstract; full content was then reviewed to determine final inclusion.

Inclusion and exclusion criteria Inclusion was based on the following criteria: Human, randomised, intervention trials, in English using ‘healthy’ volunteers, compared to themselves or to a matched control group. Healthy meant participants were free of disease, but included overweight and obese participants. Duplicate results were removed, along with studies that did not investigate capsaicinoids’ effect on appetite and those where the intervention included other bioactive ingredients (such as green tea and caffeine). The remaining studies were reviewed to establish an appropriate effect size that could be extracted and analysed. The most commonly occurring measure (change in energy intake) was chosen and studies that did not feature this measure were excluded. Data extraction Data extracted from the papers included: number of participants, gender, age, BMI, ethnicity, study type, dosage, the intervention used and study duration (Table 1). The studies’ authors and year of publication were also recorded. Effect sizes were then extracted for analysis, including mean energy intakes (in kJ) for control and intervention groups, along with standard deviations. Statistical analysis Both random and fixed effects models were used to estimate combined mean differences, although the random effects model is theoretically preferable in this case. The fixed effects model assumes the effect size is the same for each study (Borenstein, 2009). However, due to differences in study design (such as dosage, timing of intervention and population size) this is unlikely to be the case for the trials used in this analysis. All statistical analyses were performed using MIX software version 2.0 (Bax, Yu, Ikeda, Tsuruta, & Moons, 2006). The analysis was carried out according to PRISMA guidelines (Moher, Liberati, Tetzlaff, & Altman, 2010). Results A total of 74 clinical trials were identified from the database searches. Fifty-five trials were excluded for being duplicates and a further 9 were excluded for methodological reasons (as listed in Fig. 1), leaving a total of 10 trials. The 10 studies investigated the role of capsaicinoids on weight management in relation to effects on energy intake, hunger and hormone levels. Studies assessing ad libitum energy intake after a capsaicinoid intervention were most common, and were therefore used in the main analysis. Two papers were then excluded as they did not measure energy intake (see Fig. 1), leaving a final total of 8 studies (with 191 participants) which were included in the meta-analysis (see Table 2 for assessment of risk of bias). Most of the selected studies followed this design: after randomisation, participants would consume a capsaicinoid intervention or placebo, followed by a test meal consumed at a research site. The participants would consume food ad libitum until full and the remaining food would then be weighed to calculate energy intake. The only exception to this was one study which used 4 weeks of chilli supplementation (added to meal by the participant at home) in addition to participants’ normal diet and 4 weeks of a control diet (Ahuja et al., 2007). Two trials investigated capsaicinoids effects on over and under eating; one featured 3 weeks of positive energy balance and 3 weeks of negative energy balance, prior to each test meal (Reinbach, Smeets, Martinussen, Moller, & Westerterp-Plantenga, 2009). The other trial simulated these conditions by using high fat or high

185

S. Whiting et al. / Appetite 73 (2014) 183–188 Table 1 Key characteristics and findings of the studies featured in the analysis. Author

Sample size

Gender

Ethnicity

Mean BMI

Mean age

Study type

Dose (mg)

Intervention

Length

Key finding

Yoshioka et al. (1999)(a) Yoshioka et al. (1999)(b) Yoshioka et al. (2004) WesterterpPlantenga et al. (2005) Ahuja et al. (2007) Reinbach et al. (2009) Reinbach et al. (2010)

13

Female

Asian

21.9

26

Randomised, placebo control

30

Meal with dried chilli

Single meal

Non-significant reduction in EI

10

Male

Caucasian

23.7

33

Randomised, placebo control

18

2 Meals

Significant reduction in EI (p < 0.05)

16

Male

Asian

25.6

22

Randomised, double blind, placebo control

0.2, 3

Appetiser with dried chilli Chilli soup or capsules

Single meal

Non-significant reduction in EI

24

Mixed

Caucasian

25.0

35

Randomised, double blind, placebo control, crossover

2.25

Juice with chilli or chilli capsules

4 Days

Significant reduction in EI (p < 0.05), stronger effect with oral exposure

36

Mixed

Mixed

26.4

46

Randomised, placebo control, crossover Randomised, placebo control, crossover

33/ day 2.5

Preserved chilli Chilli capsules

4 weeks 6 weeks

Non-significant reduction in EI

Ludy and Mattes (2011)

*

No effect on EI

27

Mixed

Caucasian

22.2

29.6

40

Male and Female Intervention groups. Mixed

Caucasian

24.6

22.4

Randomised, placebo control, crossover

0.4

Appetiser with chilli

10 Meals*

No effect on EI

Mixed

23.0

22.6

Randomised, double blind, placebo control, crossover

3.6

Chilli capsules

6 meals

Significant reduction in EI (p < 0.05), observed only in non-chilli eaters

25

Key: EI – Energy Intake. Trials both featured 5 different bioactive interventions, only the capsaicinoid intervention was featured in this analysis.

*

Table 2 Assessment of the risk of bias of all trials included in the analysis. Study

Protocol described

Yoshioka et al. (1999)(a) Yoshioka et al. (1999)(b) Yoshioka et al. (2004) Westerterp-Plantenga et al. (2005) Ahuja et al. (2007) Reinbach et al. (2009) Reinbach et al. (2010) Ludy and Mattes (2011)

+ + + + + + + +

Key: + = Low risk of bias;

Specified inclusion criteria

+ + + + +

Sample size calculation

+

Blinding n/a n/a + + n/a + n/a +

Randomisation

Completeness of data

+ + + + + +

+ + + + + + + +

= High risk of bias; n/a = means blinding not possible due to chilli’s ‘spicy’ sensation.

carbohydrate meals as test meals (Yoshioka et al., 1999). Both trials found reductions in energy intake under both conditions. Another trial measured the effect of the hedonistic impact of capsaicinoids by using two different interventions, one capsules and one a spicy tomato juice (Westerterp-Plantenga et al., 2005). They observed a decrease in energy intakes under both conditions, but particularly after capsaicanoid ingestion (P < 0.05). As shown in Table 1 capsaicanoid dosages in the trials ranged from 0.4 mg to 33 mg and study length ranged from single meals to a four week intervention, which may account for differences in study findings. The meta-analysis assessed the change in energy intake following the consumption of capsaicinoid interventions compared with placebos. The combined effect size showed that consuming capsaicinoids caused statistically significant reductions in ad libitum energy intake of 309.9 kJ (74.0 kcal) per meal (as shown in Fig. 2; forest plot), under the random effects model, with a 95% confidence interval of 481.5–138.3 kJ (115.0–33.0 kcal) and P < 0.001. The analysis indicated high heterogeneity, I2 = 75.7%. To investigate this heterogeneity further, a number of subgroup analyses were performed. The variables analysed were: ethnicity, study group size, intervention type (food or supplement), trial length, the timing of the intervention compared to the test meal

and dosage. The BMI and age of participants were also considered, however, these were similar across all trials (average BMI range 21.9–25.6, average age range 22–46), so were considered unlikely to have an impact. To see which variables may have impacted on the heterogeneity, the effect observed in different sub-groups were compared and the following P-values were calculated: Asian vs. Caucasian P = 0.70, less than 20 participants vs. more than 20 participants P = 0.83, food intervention vs. supplement P = 0.16, single meal intervention vs. multiple day intervention P = 0.83, intervention given immediately prior to meal vs. several hours before P = 0.40, dosage less than 1 mg vs. more than 1 mg P < 0.001.

Discussion The results suggest adding capsaicinoids to the diet could have a beneficial effect for weight management, by reducing energy intake; caution should be applied to this result however, due to the high heterogeneity. A reduction of around 309.9 kJ (74 kcal) per meal, repeated three times a day may have the potential to lead to beneficial weight loss. A calorie imbalance of 2100 kJ (500 kcal) per day is often suggested as ideal for weight loss (Stern et al.,

186

S. Whiting et al. / Appetite 73 (2014) 183–188

Literature Search (n=74) Databases: PubMed, Web of Knowledge Limits: Clinical trials, Humans, English

Duplicates Removed (n=55)

Articles screened on basis of title and abstract

Included (n=10)

Excluded (n=9) No investigation into appetite (n=7) Used multiple bioactive chemicals in intervention (n=2)

Articles screened for appropriate effect size

Included (n=8)

Excluded (n=2) Did not investigate energy intake (n=2)

Fig. 1. A flow diagram detailing the literature search, with exclusions and inclusions.

2004), although smaller imbalances can also lead to weight loss and improved health outcomes (Hill, 2006). The results of the sub-groups analysis suggest that some of the heterogeneity is a result of the different dosages used in the trials. No other significant difference was observed between the other sub-groups, suggesting they were not impacting on the heterogeneity. Comparing the lowest dosage trials (75%), this indicates that the trials may have large variations in study design. Some degree of statistical heterogeneity is inevitable due to clinical and methodological diversity, which always occurs in a meta-analysis (Higgins, Thompson, Deeks, & Altman, 2003). None of the studies reported issues with compliance of the capsaicinoid intervention, this is likely due to the short nature of most of the trials and because a number of the studies determined a hedonically acceptable maximum dose prior to the intervention (Ahuja et al., 2007; Ludy & Mattes, 2011; Westerterp-Plantenga et al., 2005; Yoshioka et al., 2004). Indeed participants in one trial reported that ingestion of higher dosages over a long period would not be possible due to capsaicinoids’ overpowering flavour and increases in gastric motility (dosage for this trial was 33 mg/day in a predominantly Caucasian population) (Ahuja et al., 2007). Compliance was a problem in a 3 month trial using capsaicinoid supplements, with a higher dosage (135 mg/day) (Lejeune et al., 2003). To counteract this, a number of investigations have been performed with capsinoids, a non-pungent group of compounds, originating from the pepper cultivar CH-19 sweet. This group of chemicals seem to have many similar effects on the body as capsaicinoids, but without the spicy sensation in the mouth. Much of the work in this area has focused on changes in energy expenditure (Galgani & Ravussin, 2010; Snitker et al., 2009) and fat oxidation (Josse et al., 2010; Lee, Li, Zerlin, & Heber, 2010) rather than appetitive effects, so analysis is not included in this paper. Whether a reduction in energy intake could be maintained long term is not clear from the studies in this analysis, as most of the

trials were short term. The trial with the longest intervention period, lasting 4 weeks, found no difference in energy intake between control and intervention groups (Ahuja et al., 2007). Two studies took into account whether participants were regular consumers of spicy foods prior to the trial, however results were contrasting. One trial finding a significant reduction in energy intake among regular consumers (Westerterp-Plantenga et al., 2005), the other finding a significantly reduction in energy intake only in non-regular consumers (Ludy & Mattes, 2011). What is considered regular consumption may vary greatly around the world, with average daily chilli consumption levels much higher among Asian populations (2.5–8 g) than American and European populations (0.05–0.5 g) (Gonlachanvit, 2010). It is not clear from these studies what the ideal dose of capsaicinoids to reduce energy intake would be as unfortunately, there were not enough results from the trials to produce an informative dose response curve. Doses varied from 0.4 mg (Reinbach et al., 2010) to 33 mg (Yoshioka et al., 1999). The sub-group analysis suggested there was minimal effect for dosages less than 2 mg of capsaicinoids (energy intake increase of 35.4 kJ (8.4 kcal) p = 0.74), whereas dosages greater than 2 mg produced a significant effect (energy intake decrease of 372.0 kJ (88.9 kcal) p < 0.001). It should also be noted that there does not seem to be an agreed analytical standard for reporting dosages of capsaicinoids, with some researchers using Scoville heat units and others mg/g, which can make accurate comparisons more difficult. There is evidence for several potential pathways for the mechanism of action for capsaicinoids effect on energy intake. Firstly, it seems capsaicinoids may affect stomach and intestinal hormones that have an influence on appetite. A recent study found increased levels of GLP-1 (p < 0.05) and decreased levels of ghrelin (effect not significant, p = 0.07) after a capsaicinoid containing lunch, compared to a placebo lunch (Smeets & Westerterp-Plantenga, 2009). Ghrelin is a hormone that potently stimulates hunger, weight gain and growth hormone production (Castañeda, Tong, Datta, Culler, & Tschöp, 2010). GLP-1 appears to be a regulator of appetite and food intake, along with stimulating insulin secretion (Holst, 2007) and may slow gastric emptying (Horner, Byrne, Cleghorn, Naslund, & King, 2011). Secondly, capsaicinoids may influence appetite through stimulation of the sympathetic nervous system (SNS). It has been well established that capsaicinoids stimulate the SNS, causing the release of catecholamines (Hursel & Westerterp-Plantenga, 2010). This effect is caused by activation of the TRPV1 calcium channel, of which capsaicin is a potent agonist (Tominaga & Tominaga, 2005). Indeed the release of catecholamines, has been the mechanism of action for some appetite suppressant drugs such as Sibutramine (Adan, Vanderschuren, & E la Fleur, 2008). The release of these ‘fight or flight’ hormones causes a reduction in appetite and thereby food intake (Clapham, Arch, & Tadayyon, 2001). Adipose tissue maybe influencing this process, as a study found the effects of capsinoids (non-pungent capsaicinoid analogs) only occurs in participants with brown adipose tissue (Yoneshiro, Aita, Kawai, Iwanaga, & Saito, 2012). Thirdly, capsaicinoids seem to have an influence on food choice. It was observed that the effects on energy intake were stronger when trial participants received oral exposure to capsaicinoids (Westerterp-Plantenga et al., 2005) and there was a preference for carbohydrate-rich foods over fat-rich foods (Westerterp-Plantenga et al., 2005; Yoshioka et al., 1999, 2004). Capsaicinoids stimulate TRPV1 receptors in the mouth, which generate a sensation of heat or pain; it is likely this occurs by activation of neurons in the orbitofrontal cortex. Capsaicin has been shown to stimulate neurons in this region of the brain (Kadohisa, Rolls, & Verhagen, 2004), where a short-term, sensory-specific control of appetite and eating is implemented (Rolls, 2004b). This is an important area

S. Whiting et al. / Appetite 73 (2014) 183–188

187

Fig. 2. A forest plot showing effect size of capsaicin vs. placebo for all studies. An effect of 0 represents no difference in energy intake, an effect of 0 represent an increase in energy intake.

of the brain for the convergence of representations of the taste, smell, sight, and mouth feel of food (Rolls, 2004a) and also provides representations of the reward value of taste, smell, and flavour (Kadohisa et al., 2004). Therefore, capsaicinoids maybe having an influence on the sensory and reward properties of foods and thereby influencing energy intake. It should be noted that research and understanding in this area is still developing and much of the research has been with non-human primate brains. To further understand capsaicinoids’ potential role in weight management, it would be informative for any future research to explore: (1) whether these effects are maintained in the long-term or whether desensitisation does occurs and effectiveness is reduced, particularly if several doses a day are maintainable and safe in the long term; (2) it would be helpful to know if capsaicinoid interventions could be used successfully in combination with other weight management strategies such as reduced energy intake and/ or increased physical activity; (3) different dosages levels at which capsaicinoids are effective at influencing energy intake and the palatability of such dosages to different population groups. Achieving results with hedonically acceptable dosage may be to be a barrier to successful usage, particularly in Caucasians and (4) how capsaicinoids could be successfully incorporated into the diet, particularly for population groups with a low habitual intake. In summary, this meta-analysis supports our hypothesis that capsaicinoids could play a role in weight management alongside exercise and dietary measures. The overall result of this analysis should be viewed with some caution however, as the I2 statistic implied high heterogeneity, with sub-group analysis suggesting differences in trial design. The analysis provides a more definitive answer as to whether capsaicinoids influence energy intake and

appetite, giving an indication of the size of the effect and minimum level of dosage required. The extent of the effect on energy intake is relatively small and therefore long term intake would be required to produce a beneficial effect. It may also be the case that several doses a day are needed to produce substantial effects; this may mean that capsaicinoids would need to be taken in the form of a supplement, as their strong sensory effect means most people would be unwilling to eat chillies with every meal. But combined with capsaicinoids’ effect on energy intake and lipid oxidation observed in other research (Ludy et al., 2012; Whiting et al., 2012) there is potential for development of a natural weight loss aid, particularly as there are a lack of pharmaceutical options. Evidence also suggests capsaicinoids have a synergistic effect on weight loss when used with other bioactive ingredients, especially catechins from green tea (Belza, Frandsen, & Kondrup, 2007; Reinbach et al., 2009).

References Adan, R. A. H., Vanderschuren, L. J. M. J., & E la Fleur, S. (2008). Anti-obesity drugs and neural circuits of feeding. Trends in Pharmacological Sciences, 29(4), 208–217. Ahuja, K. D., Robertson, I. K., Geraghty, D. P., & Ball, M. J. (2007). The effect of 4-week chilli supplementation on metabolic and arterial function in humans. European Journal of Clinical Nutrition, 61(3), 326–333. Bax, L., Yu, L. M., Ikeda, N., Tsuruta, H., & Moons, K. G. (2006). Development and validation of MIX. Comprehensive free software for meta-analysis of causal research data. BMC Medical Research Methodology, 6, 50. Belza, A., Frandsen, E., & Kondrup, J. (2007). Body fat loss achieved by stimulation of thermogenesis by a combination of bioactive food ingredients. A placebocontrolled, double-blind 8-week intervention in obese subjects. International Journal of Obesity, 31(1), 121–130.

188

S. Whiting et al. / Appetite 73 (2014) 183–188

Borenstein, M. (2009). Introduction to meta-analysis. Chichester, U.K.: John Wiley & Sons. Castañeda, T. R., Tong, J., Datta, R., Culler, M., & Tschöp, M. H. (2010). Ghrelin in the regulation of body weight and metabolism. Frontiers in Neuroendocrinology, 31(1), 44–60. Choi, S. E., Kim, T. H., Yi, S. A., Hwang, Y. C., Hwang, W. S., Choe, S. J., et al. (2011). Capsaicin attenuates palmitate-induced expression of macrophage inflammatory protein 1 and interleukin 8 by increasing palmitate oxidation and reducing c-Jun activation in THP-1 (human acute monocytic leukemia cell) cells. Nutrition Research, 31(6), 468–478. Clapham, J. C., Arch, J. R. S., & Tadayyon, M. (2001). Anti-obesity drugs. A critical review of current therapies and future opportunities. Pharmacology & Therapeutics, 89(1), 81–121. Galgani, J. E., & Ravussin, E. (2010). Effect of dihydrocapsiate on resting metabolic rate in humans. The American Journal of Clinical Nutrition, 92(5), 1089–1093. Gonlachanvit, S. (2010). Are rice and spicy diet good for functional gastrointestinal disorders? Journal of Neurogastroenterology and Motility, 16(2), 131–138. Gunthorpe, M. J., & Szallasi, A. (2008). Peripheral TRPV1 receptors as targets for drug development. New molecules and mechanisms. Current Pharmaceutical Design, 14(1), 32–41. Henning, S. M., Zhang, Y., Seeram, N. P., Lee, R. P., Wang, P., Bowerman, S., et al. (2011). Antioxidant capacity and phytochemical content of herbs and spices in dry, fresh and blended herb paste form. International Journal of Food Sciences and Nutrition, 62(3), 219–225. Higgins, J. P., Thompson, S. G., Deeks, J. J., & Altman, D. G. (2003). Measuring inconsistency in meta-analyses. BMJ, 327(7414), 557–560. Hill, J. O. (2006). Understanding and addressing the epidemic of obesity. An energy balance perspective. Endocrine Reviews, 27(7), 750–761. Holst, J. J. (2007). The physiology of glucagon-like peptide 1. Physiological Reviews, 87(4), 1409–1439. Horner, K. M., Byrne, N. M., Cleghorn, G. J., Naslund, E., & King, N. A. (2011). The effects of weight loss strategies on gastric emptying and appetite control. Obesity Reviews. An Official Journal of the International Association for the Study of Obesity, 12(11), 935–951. Hursel, R., & Westerterp-Plantenga, M. S. (2010). Thermogenic ingredients and body weight regulation. International Journal of Obesity, 34(4), 659–669. Josse, A. R., Sherriffs, S. S., Holwerda, A. M., Andrews, R., Staples, A. W., & Phillips, S. M. (2010). Effects of capsinoid ingestion on energy expenditure and lipid oxidation at rest and during exercise. Nutrition & Metabolism, 7, 65. Kadohisa, M., Rolls, E. T., & Verhagen, J. V. (2004). Orbitofrontal cortex. Neuronal representation of oral temperature and capsaicin in addition to taste and texture. Neuroscience, 127(1), 207–221. Kwon, K.-T., Uddin, M. S., Jung, G.-W., Sim, J.-E., Lee, S.-M., Woo, H.-C., et al. (2011). Solubility of red pepper (Capsicum annum) oil in near- and supercritical carbon dioxide and quantification of capsaicin. Korean Journal of Chemical Engineering, 28(6), 1433–1438. Lee, T. A., Li, Z., Zerlin, A., & Heber, D. (2010). Effects of dihydrocapsiate on adaptive and diet-induced thermogenesis with a high protein very low calorie diet. A randomized control trial. Nutrition & Metabolism, 7, 78. Lejeune, M. P., Kovacs, E. M., & Westerterp-Plantenga, M. S. (2003). Effect of capsaicin on substrate oxidation and weight maintenance after modest bodyweight loss in human subjects. The British Journal of Nutrition, 90(3), 651–659. Ludy, M.-J., & Mattes, R. D. (2011). The effects of hedonically acceptable red pepper doses on thermogenesis and appetite. Physiology & Behavior, 102(3-4), 251–258. Ludy, M.-J., Moore, G. E., & Mattes, R. D. (2012). The effects of capsaicin and capsiate on energy balance. Critical review and meta-analyses of studies in humans. Chemical Senses, 37(2), 103–121. Luo, X. J., Peng, J., & Li, Y. J. (2011). Recent advances in the study on capsaicinoids and capsinoids. European Journal of Pharmacology, 650(1), 1–7. McGavigan, A. K., & Murphy, K. G. (2012). Gut hormones. The future of obesity treatment? British Journal of Clinical Pharmacology, 74(6), 911–919.

Meghvansi, M. K., Siddiqui, S., Khan, M. H., Gupta, V. K., Vairale, M. G., Gogoi, H. K., et al. (2010). Naga chilli. A potential source of capsaicinoids with broadspectrum ethnopharmacological applications. Journal of Ethnopharmacology, 132(1), 1–14. Moher, D., Liberati, A., Tetzlaff, J., & Altman, D. G. (2010). Preferred reporting items for systematic reviews and meta-analyses. The PRISMA statement. International Journal of Surgery, 8(5), 336–341. Reinbach, H. C., Martinussen, T., & Moller, P. (2010). Effects of hot spices on energy intake, appetite and sensory specific desires in humans. Food Quality and Preference, 21(6), 655–661. Reinbach, H. C., Smeets, A., Martinussen, T., Moller, P., & Westerterp-Plantenga, M. S. (2009). Effects of capsaicin, green tea and CH-19 sweet pepper on appetite and energy intake in humans in negative and positive energy balance. Clinical Nutrition, 28(3), 260–265. Rolls, E. T. (2004a). The functions of the orbitofrontal cortex. Brain and Cognition, 55(1), 11–29. Rolls, E. T. (2004b). Smell, taste, texture, and temperature multimodal representations in the brain, and their relevance to the control of appetite. Nutrition Reviews, 62(11 Pt 2), S193–204. discussion S224–141. Sanatombi, K., & Sharma, G. J. (2008). Capsaicin content and pungency of different capsicum spp. Cultivars. Notulae Botanicae Horti Agrobotanici Cluj-Napoca, 36(2), 89–90. Smeets, A., & Westerterp-Plantenga, M. (2009). The acute effects of a lunch containing capsaicin on energy and substrate utilisation, hormones, and satiety. European Journal of Nutrition, 48(4), 229–234. Snitker, S., Fujishima, Y., Shen, H., Ott, S., Pi-Sunyer, X., Furuhata, Y., et al. (2009). Effects of novel capsinoid treatment on fatness and energy metabolism in humans. Possible pharmacogenetic implications. The American Journal of Clinical Nutrition, 89(1), 45–50. Stern, L., Iqbal, N., Seshadri, P., Chicano, K. L., Daily, D. A., McGrory, J., et al. (2004). The effects of low-carbohydrate versus conventional weight loss diets in severely obese adults. One-year follow-up of a randomized trial. Annals of Internal Medicine, 140(10), 778–785. Szallasi, A., Cruz, F., & Geppetti, P. (2006). TRPV1. A therapeutic target for novel analgesic drugs? Trends in Molecular Medicine, 12(11), 545–554. Tominaga, M., & Tominaga, T. (2005). Structure and function of TRPV1. Pflugers Archiv. European Journal of Physiology, 451(1), 143–150. Westerterp-Plantenga, M. S., Smeets, A., & Lejeune, M. P. (2005). Sensory and gastrointestinal satiety effects of capsaicin on food intake. International Journal of Obesity, 29(6), 682–688. Whiting, S., Derbyshire, E., & Tiwari, B. K. (2012). Capsaicinoids and capsinoids. A potential role for weight management? A systematic review of the evidence. Appetite, 59(2), 341–348. Yang, Z.-H., Wang, X.-H., Wang, H.-P., Hu, L.-Q., Zheng, X.-M., & Li, S.-W. (2010). Capsaicin mediates cell death in bladder cancer T24 cells through reactive oxygen species production and mitochondrial depolarization. Urology, 75(3), 735–741. Yoneshiro, T., Aita, S., Kawai, Y., Iwanaga, T., & Saito, M. (2012). Nonpungent capsaicin analogs (capsinoids) increase energy expenditure through the activation of brown adipose tissue in humans. The American Journal of Clinical Nutrition, 95(4), 845–850. Yoshioka, M., Imanaga, M., Ueyama, H., Yamane, M., Kubo, Y., Boivin, A., et al. (2004). Maximum tolerable dose of red pepper decreases fat intake independently of spicy sensation in the mouth. The British Journal of Nutrition, 91(6), 991–995. Yoshioka, M., Lim, K., Kikuzato, S., Kiyonaga, A., Tanaka, H., Shindo, M., et al. (1995). Effects of red-pepper diet on the energy metabolism in men. Journal of Nutritional Science and Vitaminology, 41(6), 647–656. Yoshioka, M., St-Pierre, S., Drapeau, V., Dionne, I., Doucet, E., Suzuki, M., et al. (1999). Effects of red pepper on appetite and energy intake. The British Journal of Nutrition, 82(2), 115–123.

Could capsaicinoids help to support weight management? A systematic review and meta-analysis of energy intake data.

Capsaicinoids are a group of chemicals naturally occurring in chilli peppers with bioactive properties that may help to support weight management. The...
480KB Sizes 0 Downloads 0 Views