Capsaicinoids and capsinoids. A potential role for weight management? A systematic review of the evidence

The therapeutic potential of typical plant-derived compounds for the management of metabolic disorders

Obesity and Type 2 diabetes are prevalent metabolic dysfunctions that present significant health challenges worldwide. Available cures for these ailments have constraints with accompanying unwanted effects that persistently exist. Compounds originated from plants have recently been introduced as hopeful remedies to treat metabolic disorders because of their diverse pharmacological activities. This detailed observation gives an introduction into the treatment capacity of plant-derived compounds regarding metabolic syndromes while analyzing various groups alongside their performance in this field despite unique mechanisms designed by nature itself. Interestingly, this study provides some examples including curcumin, resveratrol, quercetin, berberine, epigallocatechin gallate (EGCG), and capsaicin, which highlights potential therapeutic impacts for future testing. However, current clinical trials inspecting human studies investigating efficacies concerning metabolism challenge present limitations. Finally, the review weighs up bad reactions possibly inflicted after administering plant-originated materials though suggestive insights will be provided later. Above all, it outlines the chance to identify novel therapies encapsulated within natural substances based upon recent developments could hold significant promise toward managing misplaced metabolisms globally.

Spicy food consumption reduces the risk of ischaemic stroke: a prospective study

Previous studies revealed that consuming spicy food reduced mortality from CVD and lowered stroke risk. However, no studies reported the relationship between spicy food consumption, stroke types and dose–response. This study aimed to further explore the association between the frequency of spicy food intake and the risk of stroke in a large prospective cohort study. In this study, 50 174 participants aged 30–79 years were recruited. Spicy food consumption data were collected via a baseline survey questionnaire. Outcomes were incidence of any stroke, ischaemic stroke (IS) and haemorrhagic stroke (HS). Multivariable-adjusted Cox proportional hazard models estimated the association between the consumption of spicy food and incident stroke. Restricted cubic spline analysis was used to examine the dose–response relationship. During the median 10·7-year follow-up, 3967 strokes were recorded, including 3494 IS and 516 HS. Compared with those who never/rarely consumed spicy food, those who consumed spicy food monthly, 1–2 d/week and 3–5 d/week had hazard ratio (HR) of 0·914 (95 % CI 0·841, 0·995), 0·869 (95 % CI 0·758, 0·995) and 0·826 (95 % CI 0·714, 0·956) for overall stroke, respectively. For IS, the corresponding HR) were 0·909 (95 % CI 0·832, 0·994), 0·831 (95 % CI 0·718, 0·962) and 0·813 (95 % CI 0·696, 0·951), respectively. This protective effect showed a U-shaped dose–response relationship. For obese participants, consuming spicy food ≥ 3 d/week was negatively associated with the risk of IS. We found the consumption of spicy food was negatively associated with the risk of IS and had a U-shaped dose–response relationship with risk of IS. Individuals who consumed spicy food 3–5 d/week had a significantly lowest risk of IS.

UHPLC-qTOF-MS-Based Nontargeted Metabolomics to Characterize the Effects of Capsaicin on Plasma and Skin Metabolic Profiles of C57BL/6 Mice-An In vivo Experimental Study

Background

Capsaicin is the main compound found in chili pepper and has complex pharmacologic effects. This study aimed to elucidate the mechanism of the effect of capsaicin on physiological processes by analyzing changes in metabolites and metabolic pathways.

Methods

Female C57BL/6 mice were divided into two groups(n = 10/group) and fed with capsaicin-soybean oil solution(group T) or soybean oil(group C) for 6 weeks. Ultra-high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (UHPLC-qTOF-MS) based metabolomics was undertaken to assess plasma and skin metabolic profile changes and identify differential metabolites through multivariate analysis.

Results

According to the OPLS-DA score plots, the plasma and skin metabolic profiles in the group T and group C were significantly separated. In plasma, 38 significant differential metabolites were identified. KEGG pathway enrichment analysis revealed that the most significant plasma metabolic pathways included pyruvate metabolism and ABC transporters. In skin, seven significant differential metabolites were found. Four metabolic pathways with p values < 0.05 were detected, including sphingolipid metabolism, sphingolipid signaling pathway, apoptosis, and necroptosis.

Conclusion

These findings will provide metabolomic insights to assess the physiological functions of capsaicin and contribute to a better understanding of the potential effects of a capsaicin-rich diet on health.

A single dose of dihydrocapsiate does not improve neuromuscular performance in resistance-trained young adults: A randomised, triple-blinded, placebo-controlled, crossover trial

Capsinoids may exert ergogenic effects on resistance exercises. However, the acute effects of capsinoids on neuromuscular performance in humans are unknown. Here, we aimed to investigate the acute effects of dihydrocapsiate on lower- and upper-body neuromuscular performance parameters in resistance-trained individuals. 25 young adults (n = 6 women; age = 26 ± 3 years; body mass index = 24.3 ± 2.8 kg/m2) with ≥ 1-year resistance training experience were included in this triple-blind (participants, intervention researchers, and data analysts were blinded), placebo-controlled, crossover study. Lower- and upper-body ballistic strength (countermovement jump [CMJ] height and bench press throw [BPT] peak velocity), maximum dynamic strength (estimated 1 repetition maximum in squat and bench press [BP]), and strength-endurance (mean set velocity [squat] and number of repetitions to failure [bench press]) were assessed in 2 independent sessions (≥7 days separation). Participants ingested 12 mg of dihydrocapsiate or placebo 30 min before each trial. We found no significant differences between dihydrocapsiate and placebo conditions in ballistic strength, (CMJ height 33.20 ± 8.07 vs 33.32 ± 7.85 cm; BPT peak velocity 2.82 ± 0.77 vs 2.82 ± 0.74 m/s) maximal dynamic strength (estimated squat 1RM: 123.76 ± 40.63 vs 122.66 ± 40.97 kg; estimated BP 1RM: 99.47 ± 43.09 vs 99.60 ± 43.34 kg), and strength-endurance (squat mean set velocity 0.66 ± 0.07 vs 0.66 ± 0.05 m/s; number BP repetitions to failure 13.00 ± 3.56 vs 13.00 ± 4.78) (all P ≥ 0.703). We conclude that dihydrocapsiate does not acutely improve neuromuscular performance in trained young adults.

Dietary Intake of Capsaicin and Its Association with Markers of Body Adiposity and Fatty Liver in a Mexican Adult Population of Tijuana

Background: Capsaicin (CAP) is the main chemical component responsible for the pungency (burning pain) of the chili plant (capsicum spp.), whose metabolic functions include energy balance and fatty acid oxidation. The aim of this study is to analyze the association of dietary capsaicin consumption with markers of adiposity and fatty liver in a Mexican adult population. Methods: This cross-sectional/analytical study recruited 221 subjects aged 18 to 65 years who were resident in the city of Tijuana, Baja California, Mexico. The daily CAP intake was analyzed through a validated chili/CAP consumption questionnaire. Anthropometric and biochemical measurements were performed following standardized protocols. Adjusted Pearson's correlations were applied to analyze the association of CAP with adiposity and fatty liver markers. Results: In this study, the daily average consumption of CAP was 152.44 mg. The dietary CAP consumption positively correlated with BMI (r = 0.179, p = 0.003), hip circumference (r = 0.176, p = 0.004) and body adiposity index (r = 0.181, p = 0.001. Likewise, the daily CAP intake positively correlated with hepatic steatosis index (r = 0.158, p = 0.004), fatty liver index (r = 0.141, p = 0.003) and lactate dehydrogenase (r = 0.194, p = 0.016) after statistical settings. Conclusions: The results of this study suggest positive associations between dietary CAP consumption and the markers of body adiposity and fatty liver in a Mexican adult population.

Anti-Obesity Drug Delivery Systems: Recent Progress and Challenges

Obesity has reached an epidemic proportion in the last thirty years, and it is recognized as a major health issue in modern society now with the possibility of serious social and economic consequences. By the year 2030, nearly 60% of the global population may be obese or overweight, which emphasizes a need for novel obesity treatments. Various traditional approaches, such as pharmacotherapy and bariatric surgery, have been utilized in clinical settings to treat obesity. However, these methods frequently show the possibility of side effects while remaining ineffective. There is, therefore, an urgent need for alternative obesity treatments with improved efficacy and specificity. Polymeric materials and chemical strategies are employed in emerging drug delivery systems (DDSs) to enhance therapy effectiveness and specificity by stabilizing and controlling the release of active molecules such as natural ingredients. Designing DDSs is currently a top priority research objective with an eye towards creating obesity treatment approaches. In reality, the most recent trends in the literature demonstrate that there are not enough in-depth reviews that emphasize the current knowledge based on the creation and design of DDSs for obesity treatment. It is also observed in the existing literature that a complex interplay of different physical and chemical parameters must be considered carefully to determine the effectiveness of the DDSs, including microneedles, for obesity treatment. Additionally, it is observed that these properties depend on how the DDS is synthesized. Although many studies are at the animal-study stage, the use of more advanced DDS techniques would significantly enhance the development of safe and efficient treatment approaches for obese people in the future. Considering these, this review provides an overview of the current anti-obesity treatment approaches as well as the conventional anti-obesity therapeutics. The article aims to conduct an in-depth discussion on the current trends in obesity treatment approaches. Filling in this knowledge gap will lead to a greater understanding of the safest ways to manage obesity.

The effects of capsaicin intake on weight loss among overweight and obese subjects: a systematic review and meta-analysis of randomised controlled trials

Animal studies have shown that capsaicin plays a positive role in weight management. However, the results in human research are controversial. Therefore, the present systematic review and meta-analysis aimed to evaluate the effect of capsaicin on weight loss in adults. We searched PubMed, Embase, China Biomedical Literature Database (CBM), Cochrane library and clinical registration centre, identifying all randomised controlled trials (RCT) published in English and Chinese to 3 May 2022. A random-effect model was used to calculate the weighted mean difference (WMD) and 95 % CI. Heterogeneity between studies was assessed by the Cochran Q statistic and I-squared tests (I 2 ). Statistical analyses were performed using STATA version 15.1. P-values < 0·05 were considered as statistically significant. From 2377 retrieved studies, fifteen studies were finally included in the meta-analyses. Fifteen RCT with 762 individuals were included in our meta-analysis. Compared with the control group, the supplementation of capsaicin resulted in significant reduction on BMI (WMD: -0·25 kg/m2, 95 % CI = -0·35, -0·15 kg/m2, P < 0·05), body weight (BW) (WMD: -0·51 kg, 95 % CI = -0·86, -0·15 kg, P < 0·05) and waist circumference (WC) (WMD: -1·12 cm, 95 % CI = -2·00, -0·24 cm, P < 0·05). We found no detrimental effect of capsaicin on waist-to-hip ratio (WMD: -0·05, 95 % CI = -0·17, 0·06, P > 0·05). The current meta-analysis suggests that capsaicin supplementation may have rather modest effects in reducing BMI, BW and WC for overweight or obese individuals.

Effects of spicy food consumption on overweight/obesity, hypertension and blood lipids in China: a meta-analysis of cross-sectional studies

BACKGROUND AND OBJECTIVES

Effect of spicy food consumption on health has attracted widespread attention in recent years. However, the relationships between spicy food intake and overweight/obesity, hypertension and blood lipid levels remain unclear. A meta-analysis of available observational studies was conducted in order to explore the associations.

METHODS

PubMed, Embase, Cochrane Library and Web of science databases were searched for studies published up to 10 August 2021 without language limitation. The fixed and random effects models were selected to aggregate the effect sizes and 95% confidence intervals (CIs) in this study.

RESULTS

A total of nine observational studies involving 189,817 participants were included. Results from this meta-analysis showed that the highest category of spicy food intake significantly increased the risk of overweight/obesity (pooled Odds Ratio (OR): 1.17; 95% CI: 1.07, 1.28; P < 0.001), compared with the lowest category of spicy food intake. Conversely, a remarkable negative association was observed between the highest category of spicy food intake and hypertension (pooled OR: 0.87; 95% CI: 0.81, 0.93; P = 0.307). In addition, the highest category of spicy food intake increased the level of low density lipoprotein cholesterol (LDL-C) (weighted mean difference (WMD): 0.21; 95% CI: 0.02, 0.39; P = 0.040), and reduced high density lipoprotein cholesterol level (HDL-C) (WMD: -0.06; 95% CI: -0.10, -0.02; P = 0.268) concentrations, but it was not related to total cholesterol (TC) (WMD: 0.09; 95% CI: -0.08, 0.26; P = 0.071) and triglyceride (TG) (WMD: -0.08; 95% CI: -0.19, 0.02; P = 0.333)] levels.

CONCLUSION

Spicy food intake may have a beneficial effect on hypertension, but adversely affect overweight/obesity, as well as blood lipid levels. However, the results should be interpreted cautiously because the present analyses were based on only observational studies and not intervention studies. More large and high-quality studies in different populations will be needed to verify these associations in the future.

Capsaicin: A Potential Treatment to Improve Cerebrovascular Function and Cognition in Obesity and Ageing

Impaired cognition is the primary symptom of dementia, which can lead to functional disability and reduced quality of life among an increasingly ageing population. Ageing is associated with increased oxidative stress, chronic low-grade systemic inflammation, and endothelial dysfunction, which reduces cerebrovascular function leading to cognitive decline. Chronic low-grade systemic inflammatory conditions, such as obesity, exacerbate this decline beyond normal ageing and predispose individuals to neurodegenerative diseases, such as dementia. Capsaicin, the major pungent molecule of chilli, has recently demonstrated improvements in cognition in animal models via activation of the transient receptor potential vanilloid channel 1 (TRPV1). Capsaicin-induced TRPV1 activation reduces adiposity, chronic low-grade systemic inflammation, and oxidative stress, as well as improves endothelial function, all of which are associated with cerebrovascular function and cognition. This review examines the current literature on capsaicin and Capsimax, a capsaicin supplement associated with reduced gastrointestinal irritation compared to capsaicin. Acute and chronic capsaicin treatment can improve cognition in animals. However, studies adequately assessing the effects of capsaicin on cerebrovascular function, and cognition in humans do not exist. Capsimax may be a potentially safe therapeutic intervention for future clinical trials testing the effects of capsaicin on cerebrovascular function and cognition.

Thermogenic Brown Fat in Humans: Implications in Energy Homeostasis, Obesity and Metabolic Disorders

In mammals including humans, there are two types of adipose tissue, white and brown adipose tissues (BATs). White adipose tissue is the primary site of energy storage, while BAT is a specialized tissue for non-shivering thermogenesis to dissipate energy as heat. Although BAT research has long been limited mostly in small rodents, the rediscovery of metabolically active BAT in adult humans has dramatically promoted the translational studies on BAT in health and diseases. It is now established that BAT, through its thermogenic and energy dissipating activities, plays a role in the regulation of body temperature, whole-body energy expenditure, and body fatness. Moreover, increasing evidence has demonstrated that BAT secretes various paracrine and endocrine factors, which influence other peripheral tissues and control systemic metabolic homeostasis, suggesting BAT as a metabolic regulator, other than for thermogenesis. In fact, clinical studies have revealed an association of BAT not only with metabolic disorders such as insulin resistance, diabetes, dyslipidemia, and fatty liver, but also with cardiovascular diseases including hypertension and atherosclerosis. Thus, BAT is an intriguing tissue combating obesity and related metabolic diseases. In this review, we summarize current knowledge on human BAT, focusing its patho-physiological roles in energy homeostasis, obesity and related metabolic disorders. The effects of aging and sex on BAT are also discussed.

Spicy food consumption is associated with abdominal obesity among Chinese Han population aged 30-79 years in the Sichuan Basin: a population-based cross-sectional study

BACKGROUND

Few animal experiments and volunteer-based intervention studies have showed a controversial effect of spicy foods on abdominal obesity. We aimed to examine the association between spicy food frequency, spicy flavor, and abdominal obesity among Chinese Han population in the Sichuan Basin which area eating spicy foods relatively often.

METHODS

A cross-sectional analysis was conducted using the Sichuan Basin baseline data from the China Multi-Ethnic Cohort (CMEC) study, including data from electronic questionnaires, anthropometric measurements and blood sample collection. A total of 40,877 adults (22,503 females) aged 30-79 years were included in the final analysis. Multivariable logistic regression yielded adjusted odds ratios (ORs) and 95% confidence intervals (CIs) for abdominal obesity associated with the strength of spicy flavor and frequency of spicy food intake.

RESULTS

The prevalence of daily spicy food eating was 47.3% in males and 52.7% in females, the percentages of abdominal obesity were 52.3%, 48.8%, 51.6% and 55.5% in the spicy food intake subgroups of never, 1-2 days/week, 3-5 days/week and 6-7 days/week, respectively. Compared with males who never consumed spicy food, the adjusted ORs (95% CIs) in the 1-2 days/week, 3-5 days/week and 6-7 days/week subgroups were 1.21 (1.09, 1.34), 1.35 (1.21, 1.51), and 1.35 (1.25, 1.47), respectively (P_trend < 0.001). The corresponding odds ratios for females were 0.95 (0.87, 1.05), 1.14 (1.03, 1.26), and 1.25 (1.16, 1.35), respectively (P_trend < 0.001). Similarly, compared with no spicy flavor, the adjusted ORs (95% CIs) of mild, middle, and strong spicy strength for abdominal obesity in males were 1.27 (1.17, 1.38), 1.51 (1.37, 1.67), and 1.36 (1.11, 1.67) respectively (P_trend < 0.001). The corresponding odds ratios for females were 1.14 (1.06, 1.23), 1.27 (1.15, 1.40), and 1.32 (1.06, 1.65), respectively (P_trend < 0.001).

CONCLUSIONS

The data indicated that spicy food consumption was a risk factor for abdominal obesity among Chinese adult population in the Sichuan Basin. The results need to be approved by large cohort studies.

Dihydromyricetin ameliorates diet-induced obesity and promotes browning of white adipose tissue by upregulating IRF4/PGC-1α

BACKGROUND

Promoting the browning of white adipose tissue (WAT) is a promising approach for the treatment of obesity and related comorbidities because it increases energy expenditure. In this study, we investigated whether Dihydromyricetin (DHM), a flavonoid component, could ameliorate diet-induced obesity through promoting the browning of WAT.

METHODS

Male C57BL/6 J mice were received a high-fat diet (HFD) to induce obesity and subsequently were treated with DHM (100 mg/kg/day) or vehicle for 4 weeks. The effects of DHM on weight reduction and metabolic phenotype improvement were observed in the mice. The expression of genes and protein involved in browning of WAT were assessed in inguinal WAT (iWAT) of the mice. Then, the effect of DHM on the inducing browning program was verified in adipocytes differentiated from stromal vascular fraction (SVF) cells of mouse iWAT. Finally, the mechanism by which DHM improves the browning of WAT was explored using RNA-seq and luciferase reporter assay.

RESULTS

We find that DHM reduces body weight, decreases WAT mass, improves glucose and lipid metabolic disorders, and ameliorates hepatic steatosis in diet-induced obese (DIO) mice. Further studies show that DHM induces WAT browning, which is manifested by increased expression of uncoupling protein 1 (UCP1) and peroxisome proliferator-activated receptor gamma coactivator (PGC)-1α and enhanced mitochondrial activity in iWAT and primary adipocytes. In addition, we also find that DHM enhances interferon regulatory factor 4 (IRF4) expression, which is a key transcriptional regulator of PGC-1α.

CONCLUSION

Our findings identify that DHM prevents obesity by inducing the browning of WAT through the upregulation of IRF4/PGC-1α, which may have potential therapeutic implications for the treatment of obesity.

Dietary Supplements for Weight Management: A Narrative Review of Safety and Metabolic Health Benefits

Dietary supplements for weight management include myriad ingredients with thermogenic, lipotropic, satiety, and other metabolic effects. Recently, the safety of this product category has been questioned. In this review, we summarize the safety evidence as well as relevant clinical findings on weight management and metabolic effects of six representative dietary supplement ingredients: caffeine, green tea extract (GTE), green coffee bean extract (GCBE), choline, glucomannan, and capsaicinoids and capsinoids. Of these, caffeine, GTE (specifically epigallocatechin gallate [EGCG]), and choline have recommended intake limits, which appear not to be exceeded when used according to manufacturers’ instructions. Serious adverse events from supplements with these ingredients are rare and typically involve unusually high intakes. As with any dietary component, the potential for gastrointestinal intolerance, as well as possible interactions with concomitant medications/supplements exist, and the health status of the consumer should be considered when consuming these components. Most of the ingredients reviewed also improved markers of metabolic health, such as glucose, lipids, and blood pressure, although the data are limited for some. In summary, weight management supplements containing caffeine, GTE, GCBE, choline, glucomannan, and capsaicinoids and capsinoids are generally safe when taken as directed and demonstrate metabolic health benefits for overweight and obese people.

Development and Validation of an HPLC Method for Simultaneous Determination of Capsaicinoids and Camphor in Over-the-Counter Medication for Topical Use

A reverse-phase high-performance liquid chromatography method was developed to determine and quantify capsaicin (trans-8-methyl-N-vanillyl-6- nonenamid), dihydrocapsaicin (8-methyl-N-vanillylnonanamide), and camphor (trimethylbicyclo[2.2.1]heptan-2-one). It is applicable in analyses of over-the-counter (OTC) medications for topical use and raw materials such as chili pepper oleoresin. Chromatographic separation was carried out on a C18 column using an isocratic flow of the mobile phase containing acetonitrile and ultrapure water in a ratio of 2:3, with pH adjusted to 3.2 using glacial acetic acid, and a flow rate of 1.5 mL/min. The concentration of the eluting compounds was monitored by a diode-array detector at a wavelength of 281 nm. The method was evaluated for several validation parameters, including selectivity, accuracy (confidence intervals < 0.05%), repeatability, and intermediate precision. The limit of detection (LOD) was determined to be 0.070 µg/mL for capsaicin, 0.211 µg/mL for dihydrocapsaicin, and 0.060 µg/mL for camphor. The limit of quantification (LOQ) was determined to be 0.212 µg/mL for capsaicin, 0.640 µg/mL for dihydrocapsaicin, and 0.320 µg/mL for camphor. Linearity was set in the range of 2.5–200 µg/mL for capsaicin and dihydrocapsaicin and 25–2000 µg/mL for camphor. The suggested analytical method can be used for quality control of formulated pharmaceutical products containing capsaicinoids, camphor, and propolis.

Interventions associated with brown adipose tissue activation and the impact on energy expenditure and weight loss: A systematic review

BACKGROUND

Brown adipose tissue (BAT) plays a role in modulating energy expenditure. People with obesity have been shown to have reduced activation of BAT. Agents such as β-agonists, capsinoids, thyroid hormone, sildenafil, caffeine, or cold exposure may lead to activation of BAT in humans, potentially modulating metabolism to promote weight loss.

METHODS

We systematically searched electronic databases for clinical trials testing the effect of these agents and cold exposure on energy expenditure/thermogenesis and the extent to which they may impact weight loss in adults.

RESULTS

A total of 695 studies from PubMed, Web of Science, and Medline electronic databases were identified. After the removal of duplicates and further evaluation, 47 clinical trials were analyzed. We observed significant heterogeneity in the duration of interventions and the metrics utilized to estimate thermogenesis/energy expenditure. Changes observed in energy expenditure do not correlate with major weight changes with different interventions commonly known to stimulate thermogenesis. Even though cold exposure appears to consistently activate BAT and induce thermogenesis, studies are small, and it appears to be an unlikely sustainable therapy to combat obesity. Most studies were small and potential risks associated with known side effects of some agents such as β-agonists (tachycardia), sibutramine (hypertension, tachycardia), thyroid hormone (arrhythmias) cannot be fully evaluated from these small trials.

CONCLUSION

Though the impact of BAT activation and associated increases in energy expenditure on clinically meaningful weight loss is a topic of great interest, further data is needed to determine long-term feasibility and efficacy.

Signaling Targets Related to Antiobesity Effects of Capsaicin: A Scoping Review

The search for new antiobesogenic agents is increasing because of the current obesity pandemic. Capsaicin (Caps), an exogenous agonist of the vanilloid receptor of transient potential type 1 (TRPV1), has shown promising results in the treatment of obesity. This scoping review aims to verify the pathways mediating the effects of Caps in obesity and the different methods adopted to identify these pathways. The search was carried out using data from the EMBASE, MEDLINE (PubMed), Web of Science, and SCOPUS databases. Studies considered eligible evaluated the mechanisms of action of Caps in obesity models or cell types involved in obesity. Nine studies were included and 100% (n = 6) of the in vivo studies showed a high risk of bias. Of the 9 studies, 66.6% (n = 6) administered Caps orally in the diet and 55.5% (n = 5) used a concentration of Caps of 0.01% in the diet. In vitro, the most tested concentration was 1 μM (88.9%; n = 8). Capsazepine was the antagonist chosen by 66.6% (n = 6) of the studies. Seven studies (77.8%) linked the antiobesogenic effects of Caps to TRPV1 activation and 3 (33.3%) indicated peroxisome proliferator-activated receptor (PPAR) involvement as an upstream connection to TRPV1, rather than a direct metabolic target of Caps. The main secondary effects of Caps were lower weight gain (33.3%; n = 3) or loss (22.2%; n = 2), greater improvement in lipid profile (33.3%; n = 3), lower white adipocyte adipogenesis (33.3%; n = 3), browning process activation (44.4%; n = 4), and higher brown adipocyte activity (33.3%; n = 3) compared with those of the control treatment. Some studies have shown that PPAR agonists modulate TRPV1 activity, and no study has evaluated the simultaneous antagonism of these 2 receptors. Consequently, further studies are necessary to elucidate the role of each of these signaling molecules in the antiobesogenic effects of Caps.

Capsaicin and Its Effects on Body Weight

Capsaicin is a bioactive compound found in the fruits (i.e., peppers) of the plant genus Capsicum, which is widely used in many cultures. Besides many health effects of this compound, it can also be effective in body weight control through various mechanisms such as regulating lipolysis in adipocytes, increasing the feeling of satiety, stimulating energy expenditure, and reducing energy intake. This study investigated capsaicin and its effects on body weight control. In clinical studies, the amount of capsaicin affecting body weight loss differ. Longitudinal and randomized controlled studies are needed to explain the effects of capsaicin on body weight control.Key teaching points• Capsaicin can decrease hunger through hormones in the gastrointestinal tract.• Capsaicin can increase energy expenditure through brown adipose tissue.• Capsaicin can increase lipolysis in white adipose tissue.• More comprehensive studies are needed to clarify this issue.

The effect of herbs and spices on risk factors for cardiometabolic diseases: a review of human clinical trials

Herbs and spices are recommended to increase flavor and displace salt in the diet. Accumulating evidence suggests herbs and spices may improve risk factors for cardiometabolic diseases. In this narrative review, an overview of evidence from human clinical trials examining the effect of herbs and spices on risk factors for cardiometabolic diseases is provided. Human clinical trials examining supplemental doses of individual spices and herbs, or the active compounds, have yielded some evidence showing improvements to lipid and lipoprotein levels, glycemic control, blood pressure, adiposity, inflammation, and oxidative stress. However, cautious interpretation is warranted because of methodological limitations and substantial between-trial heterogeneity in the findings. Evidence from acute studies suggests intake of mixed herbs and spices as part of a high-saturated fat, high-carbohydrate meal reduces postprandial metabolic impairments, including lipemia, oxidative stress, and endothelial dysfunction. Limited studies have examined the postprandial metabolic effects of incorporating mixed herbs and spices into healthy meals, and, to our knowledge, no trials have assessed the effect of longer-term intake of mixed herbs and spices on risk factors for cardiometabolic diseases. To inform evidence-based guidelines for intake of herbs and spices for general health and cardiometabolic disease risk reduction, rigorously conducted randomized controlled trials are needed, particularly trials examining herb and spice doses that can be incorporated into healthy dietary patterns.

Sweet pepper and its principle constituent capsiate: functional properties and health benefits

Capsiate is a non-pungent analogue of capsaicin. It belongs to the family of capsinoids which are esters of vanillyl alcohol with fatty acids while capsaicin belongs to the family of capsaicinoids that are amides of vanillylamine with a variety of branched-chain fatty acids. While capsaicin is extensively reported for plethora of pharmacological actions, capsiate remains much less explored. Extracted from various species of Capsicum plant, the molecule has also been chemically synthesized via a number of synthetic and enzymatic routes. Based on its action on transient receptor potential vanilloid subfamily member 1 receptors, recent research has focused on its potential roles in treatment of obesity, metabolic disorders, cancer, cardiovascular disorders and gastro-intestinal disorders. Its toxicity profile has been reported to be much safe. The molecule, however, faces the challenge of low aqueous solubility and stability. It has been commercialized for its use as a weight loss supplement. However, the therapeutic potential of the compound which is much beyond boosting metabolism remains unexplored hitherto. This comprehensive review summarizes the studies demonstrating the therapeutic potential of capsiate in various pathological conditions. Discussed also are potential future directions for formulation strategies to develop efficient, safe and cost-effective dosage forms of capsiate to explore its role in various disease conditions. The databases investigated include Cochrane library, Medline, Embase, Pubmed and in-house databases. The search terms were "capsiate," "capsinoids," "thermogenesis," and their combinations. The articles were screened for relevance by going through their abstract. All the articles pertaining to physicochemical, physiological, pharmacological and therapeutic effects of capsiate have been included in the manuscript.

Effect of Capsinoids Supplementation on Fat Oxidation and Muscle Glycogen Restoration During Post-exercise Recovery in Humans

BACKGROUND

Capsinoids (CSN), the novel non-pungent capsaicin analogs have been reported to promote metabolic health and exercise tolerance. However, the effect of CSN on fat oxidation and changes in skeletal muscle glycogen levels during post-exercise recovery has not been investigated in humans.

PURPOSE

We examined the effect of CSN supplementation on energy reliance, glycogen resynthesis and molecular proteins in the skeletal muscle of young adults during post-exercise recovery.

METHODS

In this crossover-designed study, nine healthy adult male volunteers (aged 21.4±0.2 years, BMI 21.9±1.3 kg/m2) completed a 60-min cycling exercise at 70% VO2max. Participants consumed either CSN (12 mg, single dosage) or placebo capsules with a high-carbohydrate meal (2 g carb/kg bodyweight) immediately after exercise. Biopsied muscle samples (vastus lateralis), blood, and gaseous samples were obtained during 3h postexercise recovery period.

RESULTS

We found that oral CSN supplementation right after exercise significantly altered the energy reliance on fat oxidation during recovery. This was evidenced by lower respiratory exchange ratio (RER) and higher fat oxidation rate in CSN trial. Despite this, acute CSN dosage does not contribute in enhancing the glycogen replenishment in skeletal muscle during 3h recovery. We identified no significant differences in postprandial glucose and insulin area under the curve in both trials. Western blot data showed an increased muscle GLUT4 expression, but no significant response of p-Akt/Akt ratio with CSN during post-exercise recovery.

CONCLUSION

Our findings conclude that acute CSN intake could change energy reliance on fat oxidation but is unable to enhance muscle glycogen resynthesis during post-exercise recovery. Thus, ergogenic properties of CSN in relevance to muscle glycogen restoration following exercise needs to be further investigated in young adults.

Oxidative Stress, Plant Natural Antioxidants, and Obesity

Oxidative stress is important in the pathophysiology of obesity, altering regulatory factors of mitochondrial activity, modifying the concentration of inflammation mediators associated with a large number and size of adipocytes, promoting lipogenesis, stimulating differentiation of preadipocytes to mature adipocytes, and regulating the energy balance in hypothalamic neurons that control appetite. This review discusses the participation of oxidative stress in obesity and the important groups of compounds found in plants with antioxidant properties, which include (a) polyphenols such as phenolic acids, stilbenes, flavonoids (flavonols, flavanols, anthocyanins, flavanones, flavones, flavanonols, and isoflavones), and curcuminoids (b) carotenoids, (c) capsaicinoids and casinoids, (d) isothiocyanates, (e) catechins, and (f) vitamins. Examples are analyzed, such as resveratrol, quercetin, curcumin, ferulic acid, phloretin, green tea, Hibiscus Sabdariffa, and garlic. The antioxidant activities of these compounds depend on their activities as reactive oxygen species (ROS) scavengers and on their capacity to prevent the activation of NF-κB (nuclear factor κ-light-chain-enhancer of activated B cells), and reduce the expression of target genes, including those participating in inflammation. We conclude that natural compounds have therapeutic potential for diseases mediated by oxidative stress, particularly obesity. Controlled and well-designed clinical trials are still necessary to better know the effects of these compounds.

Correlation of Chillies Capsaicinoids Contents with their Cytotoxic Effects against Hepatocarcinoma Cells

BACKGROUND AND OBJECTIVE

Chillies are delicious spices that are used extensively. Capsaicinoids, the major constituents of chillies with reported anti-cancer effects, have been determined with non-specific colorimetric methods. A rapid and reproducible method for extraction and quantification of the major chillies capsaicinoids; capsaicin, dihydrocapsaicin (DHC) and nordihydrocapsaicin (n-DHC), was reported, moreover study of their cytotoxic activity.

MATERIALS AND METHODS

This study has covered the extraction of capsaicinoids from red and green-colored chillies followed by their quantification using HPLC-UV method after validation. Furthermore, the correlation of capsaicinoids contents with their in vitro hepatocarcinoma cytotoxicity was represented by Pearson's correlation coefficient.

RESULTS

Capsaicinoids contents are ranged from 1219.88-15098.67 ng mg-1 of Dried Extract (DE). Capsaicin exhibits the lowest IC50 when compared to doxorubicin (9.201±0.91 and 16.1±0.82 μg mL-1, respectively). The exhibited activities of methanol extracts of red and green-colored chillies (IC50 = 20.21±1.72 and 16.02±0.69 μg mL-1, respectively) may attribute to their excessive contents of capsaicinoids (6975.42 and 15098.67 ng mg-1 DE, respectively). Capsaicin and n-DHC contents have a negative correlation with cytotoxic activity.

CONCLUSION

Green-colored chillies were found to be more cytotoxic in comparison with red-colored chillies that may be relative to their high content of capsaicinoids. The present investigation suggests that capsaicinoids contents correlate with cytotoxic activity.

The effect of Capsaicinoids or Capsinoids in red pepper on thermogenesis in healthy adults: A systematic review and meta-analysis

The outcomes of the earlier trials are controversial concerning the effect of Capsaicinoids/Capsinoids on thermogenesis. We carried out this systematic review and meta-analysis to examine the effect of Capsaicinoids/Capsinoids on thermogenesis indices including resting metabolic rate (RMR) and respiratory quotient (RQ) in healthy adults. An electronic literature search was conducted between 1990 and 2019, using the following databases: PubMed, Web of Sciences, Scopus, Cochrane Central Register of Controlled Trials, and EMBASE. Placebo-controlled clinical trials were considered as eligible papers. Effect sizes were pooled using weighted mean difference (WMD), with a random-effects model. Of the 4,092 articles, 13 studies were included in the meta-analysis. Pooled effect sizes revealed that compared with placebo, Capsaicinoids/Capsinoids significantly increased RMR (WMD: 33.99 Kcal/day, 95% CI: 15.95, 52.03; I² : 0%, p = .94), energy expenditure, and fat oxidation. It also significantly lessened RQ (WMD: -0.01, 95% CI: -0.02, -0.01; I² : 5.4%, p = .39) and carbohydrate oxidation. Moreover, intervention in capsule form for longer duration had a more considerable influence on RMR than comparative groups. We observed moderate improvement in RMR, RQ, and fat oxidation following supplementation with Capsaicinoids/Capsinoids. However, further high-quality studies are required to clarify the thermogenic properties of Capsaicinoids/Capsinoids.

Current Evidence to Propose Different Food Supplements for Weight Loss: A Comprehensive Review

The use of food supplements for weight loss purposes has rapidly gained popularity as the prevalence of obesity increases. Navigating through the vast, often low quality, literature available is challenging, as is providing informed advice to those asking for it. Herein, we provide a comprehensive literature revision focusing on most currently marketed dietary supplements claimed to favor weight loss, classifying them by their purported mechanism of action. We conclude by proposing a combination of supplements most supported by current evidence, that leverages all mechanisms of action possibly leading to a synergistic effect and greater weight loss in the foreseen absence of adverse events. Further studies will be needed to confirm the weight loss and metabolic improvement that may be obtained through the use of the proposed combination.

An Examination of a Novel Weight Loss Supplement on Anthropometry and Indices of Cardiovascular Disease Risk

PURPOSE

This study examined whether adding Dichrostachys glomerata (DG; 300 mg/d) to thermogenic supplements with (DG + C) and without (DG) caffeine and other nutrients affects weight loss, changes in body composition, and/or markers of health.

METHODS

Sixty-eight participants (female, 54%) were grouped in a double-blind, parallel, stratified random, placebo-controlled manner to supplement their diet with a placebo, DG, or DG + C for 12 weeks while maintaining their normal diet and physical activity. Diet, physical activity, body weight, body composition, anthropometric measures, resting energy expenditure, fasting blood samples, and questionnaires were obtained at 0, 4, 8, and 12 weeks and analyzed using general linear models with repeated measures. Data are reported as mean (±SD) and change from baseline (mean, 95% confidence interval) for weeks 4, 8, and 12, respectively, with p values showing changes from baseline.

RESULTS

DG treatment promoted significant but minor reductions in fat mass (-0.56 [-1.02, -0.14], p = 0.01; -0.63 [-1.23, -0.02], p = 0.04; -0.71 [-1.47, 0.09] kg, p = 0.08) and percent body fat (-0.46 [-0.96, -0.04], p = 0.07; -0.63 [-1.16, -0.10], p = 0.02; -0.78 [-1.45, 0.07] %, p = 0.03). There was some evidence that DG + C increased resting energy expenditure, decreased hunger, increased satiety, and improved sleep quality (diminished in DG + C). No other significant effects were observed.

CONCLUSIONS

Ingestion of thermogenic supplements containing DG (300 mg/d) with and without caffeine and other nutrients in overweight but otherwise healthy participants who did not alter diet or physical activity promoted clinically insignificant changes in body weight and composition.

Safety assessment of a fenugreek dietary fiber-based formulation of capsaicinoids-rich red chili (Capsicum annum) extract (Capsifen®): Acute and sub-chronic studies

Despite the promising health beneficial effects (thermogenic, lipolytic, hypotriglyceridemic, hypocholesterolemic, anti-inflammatory and anticancer) of capsaicinoids-rich red chili pepper, commonly known as cayenne pepper (Capsicum annum or Capsicum frutescence), its consumption at physiologically relevant dosage is always hampered by the pungency and stomach discomforts. The present study examined the safety of a pungency-masked and sustained release food-grade formulation of capsaicinoids-rich red chili pepper extract using fenugreek derived galactomannan soluble dietary fiber (Capsifen®). The safety was assessed by oral acute (300, 2000, 5000 mg/kg b. wt. for 14 days) and subchronic (250, 500 and 1000 mg/kg b. wt.) toxicity studies in Wistar rats. None of the group of animals belonging to both acute and subchronic treatments did produce any adverse events in feeding behavior, urine analysis, and in hematology/biochemical parameters when compared to the control. However, a decrease in body weight was observed among 500 and 1000 mg/kg b. wt. treated groups. The terminal autopsy did not reveal any alterations in relative organ weight except for the high dose treated group, where an increase in liver and kidney weight was observed. Histopathology of all the animals was normal. Thus, the Low-observed-adverse-effect level (LOAEL) of Capsifen was determined for 500 mg/kg b. wt. /day.

Polymeric Carriers for Controlled Drug Delivery in Obesity Treatment

The global rise in the prevalence of obesity and affiliated metabolic syndrome poses a significant threat to human health. Various approaches, including bariatric surgery and pharmacotherapy, have been used in the clinical setting for obesity treatment; however, these conventional options remain ineffective and carry risks of adverse effects. Therefore, treatments with higher efficacy and specificity are urgently required. Emerging drug delivery systems use polymeric materials and chemical strategies to improve therapeutic efficacy and specificity through stabilization and spatiotemporally controlled release of antiobesity agents. In this review, we provide insights into current treatments for obesity with a focus on recent developments of polymeric carriers for enhanced antiobesity drug delivery.

Development of a Novel Anti-Obesity Compound with Inhibiting Properties on the Lipid Accumulation in 3T3-L1 Adipocytes

Background:

Obesity as a developing global challenge can be characterized by increase in adipocyte number and size arising from adipogenesis. Control of adipogenesis, as a potential strategy, can prevent and manage obesity. So far, the effectiveness of herbal medicine and active ingredients therapies for obesity and metabolic syndrome treatment has been investigated. In this study, a novel combination of berberine, catechin, and capsaicin was developed, and their effect on 3T3-L1 adipocytes was investigated.

Methods:

The effect of active ingredient on the cell viability was assessed by MTT assay. Adipocytes were treated with various concentrations of berberine (3 and 6.25 μM), catechin (6.25 and 12.5 μM), and capsaicin (6.25 and 12.5 μM) alone and in combination.

Results:

All active ingredients did not affect the cell viability by MTT assay at different concentrations. The dual and triple combinations of three active ingredients showed excellent potential as anti-obese without any toxicity. The inhibitory effect of berberine, catechin, and capsaicin on the differentiation of 3T3-L1 preadipocytes was found to be dose-dependent. These results indicate that catechin in both doses may have a stronger effect than the two other active ingredients on the intracellular lipid accumulation. Also, the triple combination of the aforementioned ingredients showed better responses than their dual combination.

Conclusion:

This work is the first report to simultaneously investigate these three active ingredients in a single, dual, and triple formats. The berberine, catechin, and capsaicin co-treatment inhibits the adipogenesis during the differentiation process. This compound can be a prospective therapy for obesity and relevant diseases such as dyslipidemia.

Association of the frequency of spicy food intake and the risk of abdominal obesity in rural Chinese adults: a cross-sectional study

OBJECTIVES

Recent data relating to the association between spicy food intake frequency and abdominal obesity are limited, especially in low-income areas. Therefore, the study explored the relationship between spicy food intake frequency and abdominal obesity, and assessed the role of energy intake as a mediator of these associations in a rural Chinese adult population.

DESIGN

Cross-sectional study.

SETTING

Rural Chinese adult population.

PARTICIPANTS

Subjects from Henan Rural Cohort Study (n=28 773).

PRIMARY OUTCOME MEASURES

The effects of spicy food intake frequency on abdominal obesity were analysed by restricted cubic spline and logistic regression, and the mediation effect was analysed using the bootstrap method.

RESULTS

The adjusted percentages of abdominal obesity were 47.32%, 51.93%, 50.66% and 50.29% in the spicy food intake subgroups of never, 1-2 day/week, 3-5 day/week and 6-7 day/week, respectively. An inverse U-shaped association was found between spicy food intake frequency and abdominal obesity (p<0.01). Compared with subjects who never consumed spicy food, the adjusted ORs (95% CIs) in the 1-2 day/week, 3-5 day/week and 6-7 day/week subgroups were 1.186 (1.093, 1.287), 1.127 (1.038, 1.224) and 1.104 (1.044, 1.169), respectively. Furthermore, the increased odd of abdominal obesity related to more frequent spicy food intake was mediated by higher fat energy intake; the direct and indirect effects were 1.107 (1.053, 1.164) and 1.007 (1.003, 1.012), respectively.

CONCLUSIONS

The data indicated that spicy food intake increased the risk of abdominal obesity, and fat energy intake may be a mediator of this association in rural Chinese populations. Clarifying the mechanisms will facilitate the development of novel preventive and therapeutic approaches for abdominal obesity.

TRIAL REGISTRATION NUMBER

ChiCTR-OOC-15006699.

Appetite-Suppressing and Satiety-Increasing Bioactive Phytochemicals: A Systematic Review

The prevalence of obesity is increasing worldwide. Bioactive phytochemicals in food supplements are a trending approach to facilitate dieting and to improve patients' adherence to reducing food and caloric intake. The aim of this systematic review was to assess efficacy and safety of the most commonly used bioactive phytochemicals with appetite/hunger-suppressing and/or satiety/fullness-increasing properties. To be eligible, studies needed to have included at least 10 patients per group aged 18 years or older with no serious health problems except for overweight or obesity. Of those studies, 32 met the inclusion criteria, in which 27 different plants were tested alone or as a combination, regarding their efficacy in suppressing appetite/hunger and/or increasing satiety/fullness. The plant extracts most tested were derived from Camellia sinensis (green tea), Capsicum annuum, and Coffea species. None of the plant extracts tested in several trials showed a consistent positive treatment effect. Furthermore, only a few adverse events were reported, but none serious. The findings revealed mostly inconclusive evidence that the tested bioactive phytochemicals are effective in suppressing appetite/hunger and/or increasing satiety/fullness. More systematic and high quality clinical studies are necessary to determine the benefits and safety of phytochemical complementary remedies for dampening the feeling of hunger during dieting.

Culinary herbs and spices: what can human studies tell us about their role in the prevention of chronic non-communicable diseases?

Culinary herbs and spices (CHS) are known primarily as flavour enhancers, and it is now well established that they possess bioactive properties that indicate that these foods may have a role to play in the prevention of non-communicable chronic diseases (CNCDs). Human studies are now beginning to provide insights into the significance of the potential health benefits of CHS in a dietary context, particularly concerning their antioxidant and anti-inflammatory properties and their impact on glucose homeostasis, appetite and the consumption of low/reduced fat, salt and sugar foods. However, these studies have also identified a number of factors that are very pertinent to furthering understanding of how CHS can be used for the maintenance of health and the prevention of CNCDs. The challenge for the next phase of studies will be how to incorporate, successfully, these factors into study methodology for investigating the preventative benefits of these foods. © 2019 Society of Chemical Industry.

Virus-induced gene silencing in chili pepper by apple latent spherical virus vector

Apple latent spherical virus (ALSV) can infect a variety of crops, usually without inducing symptoms. Partial gene sequences can be introduced into ALSV vectors for the induction of virus-induced gene silencing (VIGS). These features are beneficial for the estimation of gene functions in plants, with relatively concise experimental manipulations. Given that the infectability of chili peppers (Capsicum spp.) by ALSV was unknown, an ALSV infectivity test was performed on the highly pungent Capsicum chinense cultivar 'Habanero'. The chili pepper plants were not infected after rub-inoculation with a crude homogenate of ALSV-infected Chenopodium quinoa leaves, whereas inoculating them with a concentrated ALSV virus preparation caused an infection. Inoculation with an ALSV RNA preparation by gold particle bombardment resulted in high infection rates (about 90%). The infection was systemic and the infected plants were symptomless. For the induction of VIGS, 201-nucleotide fragments of the putative aminotransferase (pAMT) gene were introduced into the ALSV vector. These ALSV vectors infected 80-90% of RNA-inoculated chili pepper seedlings. Expression of pAMT-mRNA was repressed in the placenta of immature fruit of infected plants. The silencing of pAMT in the infected plants caused a substantial decrease in capsaicin content and a concomitant moderate accumulation of the non-pungent bioactive metabolite capsiate in these plants. These results showed that ALSV could be used to study gene functions by VIGS and to enhance capsiate accumulation in chili pepper through genetic modification.

Development of Capsaicin Loaded Hydrogel Beads for In vivo Lipid Lowering Activities of Hyperlipidemic Rats

Objective:

The presence of capsaicin in the diet has been revealed to enhance energy expenditure and it has been used in anti-obesity therapy. The present work investigated the potential antihyperlipidemic effect of capsaicin loaded hydrogel beads on hyperlipidemic rats. Hydrogels are three dimensional, hydrophilic, polymeric networks capable of imbibing large amounts of water or biological fluids.

Methods:

Capsaicin loaded hydrogel beads were prepared by the ionotropic gelation method using Aluminium Chloride (AlCl₃) as a cross-linking agent. The characterization of hydrogel beads was carried out by X-ray Diffraction (XRD), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopic (SEM) analysis.

Results:

The surface morphology revealed that the prepared beads were spherical in shape. XRD and DSC study of the hydrogel beads revealed that the drug was homogeneously dispersed in the hydrogel matrix. The beads showed pH sensitive behavior and when the medium pH was changed from 1.2 to 7.4, the capsaicin release was considerably increased. 100mg/kg body weight of Triton was injected intraperitoneally in rats to induce hyperlipidemia and it showed elevated levels of serum cholesterol and triglyceride. Capsaicin loaded hydrogel beads were administered to normal and hyperlipidemic rats for 7 days and the prepared hydrogel beads were significantly reduced high lipid profile in comparison to free capsaicin.

Conclusion:

The results clearly demonstrated that hydrogel beads can be used as a potential carrier for delivery of capsaicin to reduce lipid profile.

Small molecules for fat combustion: targeting obesity

Obesity is increasing in an alarming rate worldwide, which causes higher risks of some diseases, such as type 2 diabetes, cardiovascular diseases, and cancer. Current therapeutic approaches, either pancreatic lipase inhibitors or appetite suppressors, are generally of limited effectiveness. Brown adipose tissue (BAT) and beige cells dissipate fatty acids as heat to maintain body temperature, termed non-shivering thermogenesis; the activity and mass of BAT and beige cells are negatively correlated with overweight and obesity. The existence of BAT and beige cells in human adults provides an effective weight reduction therapy, a process likely to be amenable to pharmacological intervention. Herein, we combed through the physiology of thermogenesis and the role of BAT and beige cells in combating with obesity. We summarized the thermogenic regulators identified in the past decades, targeting G protein-coupled receptors, transient receptor potential channels, nuclear receptors and miscellaneous pathways. Advances in clinical trials were also presented. The main purpose of this review is to provide a comprehensive and up-to-date knowledge from the biological importance of thermogenesis in energy homeostasis to the representative thermogenic regulators for treating obesity. Thermogenic regulators might have a large potential for further investigations to be developed as lead compounds in fighting obesity.

The Immunomodulatory and Anti-Inflammatory Role of Polyphenols

This review offers a systematic understanding about how polyphenols target multiple inflammatory components and lead to anti-inflammatory mechanisms. It provides a clear understanding of the molecular mechanisms of action of phenolic compounds. Polyphenols regulate immunity by interfering with immune cell regulation, proinflammatory cytokines' synthesis, and gene expression. They inactivate NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and modulate mitogen-activated protein Kinase (MAPk) and arachidonic acids pathways. Polyphenolic compounds inhibit phosphatidylinositide 3-kinases/protein kinase B (PI3K/AkT), inhibitor of kappa kinase/c-Jun amino-terminal kinases (IKK/JNK), mammalian target of rapamycin complex 1 (mTORC1) which is a protein complex that controls protein synthesis, and JAK/STAT. They can suppress toll-like receptor (TLR) and pro-inflammatory genes' expression. Their antioxidant activity and ability to inhibit enzymes involved in the production of eicosanoids contribute as well to their anti-inflammation properties. They inhibit certain enzymes involved in reactive oxygen species ROS production like xanthine oxidase and NADPH oxidase (NOX) while they upregulate other endogenous antioxidant enzymes like superoxide dismutase (SOD), catalase, and glutathione (GSH) peroxidase (Px). Furthermore, they inhibit phospholipase A2 (PLA2), cyclooxygenase (COX) and lipoxygenase (LOX) leading to a reduction in the production of prostaglandins (PGs) and leukotrienes (LTs) and inflammation antagonism. The effects of these biologically active compounds on the immune system are associated with extended health benefits for different chronic inflammatory diseases. Studies of plant extracts and compounds show that polyphenols can play a beneficial role in the prevention and the progress of chronic diseases related to inflammation such as diabetes, obesity, neurodegeneration, cancers, and cardiovascular diseases, among other conditions.

Hesperidin and capsaicin, but not the combination, prevent hepatic steatosis and other metabolic syndrome-related alterations in western diet-fed rats

We aimed to assess the potential effects of hesperidin and capsaicin, independently and in combination, to prevent the development of obesity and its related metabolic alterations in rats fed an obesogenic diet. Three-month-old male Wistar rats were divided into 5 groups: Control (animals fed a standard diet), WD (animals fed a high fat/sucrose (western) diet), HESP (animals fed a western diet + hesperidin (100 mg/kg/day)), CAP (animals fed a western diet + capsaicin (4 mg/kg/day)), and HESP + CAP (animals fed a western diet + hesperidin (100 mg/kg/day) + capsaicin (4 mg/kg/day)). Hesperidin and capsaicin were administered by gavage. Capsaicin decreased body fat gain and prevented insulin resistance, whereas hesperidin showed little effect on body fat gain and no apparent effects on insulin resistance. No additive effects were observed with the combination. Capsaicin and hesperidin, separately, improved blood lipid profile, diminished hepatic lipid accumulation, and prevented non-alcoholic steatohepatitis in western diet-fed rats, but the combination showed lower effects. Hesperidin alone, and to a lesser extent capsaicin or the combination, displayed hypotensive effects in western diet-fed rats. In conclusion, capsaicin and hesperidin, separately, exhibit health beneficial effects on metabolic syndrome-related alterations in western diet-fed rats, but the effects are mitigated with the combination.

Spicy food and self-reported fractures

BACKGROUND & AIMS

Population-based evidence that suggests health effects of spicy consumptions on fracture was scant. The study aimed to explore the association of spicy food intake with self-reported history of fractures in the Chinese populations.

METHODS

Data was drawn from the baseline survey of a large cohort study conducted in China between 2004 and 2008. A total of 512,891 adults (including 302,632 females) were included. Frequency, strength and duration of spicy food consumption were assessed using a survey questionnaire. Fracture history was self-reported based on physician's diagnoses. Multivariate logistic regression models stratified by socio-economic factors, body mass index and other lifestyle factors were performed adjusting for potential confounders.

RESULTS

The prevalence of daily spicy food intake was 30.32% in males and 29.90% in females. The adjusted odds ratios for fractures were 1.04 (95% CI: 1.01-1.07) for those who ate spicy food occasionally, 1.10 (95% CI: 1.05-1.16) for those who ate one or two days a week, 1.15 (95% CI: 1.09-1.20) for three to five days a week, and 1.12 (95% CI: 1.07-1.17) for daily consumers, compared to participants who never ate spicy food. Participants who ate weak spicy food (OR: 1.10, 95% CI: 1.14-1.23), moderate spicy food (OR: 1.11, 95% CI: 1.06-1.15) and strong spicy food (OR: 1.18, 95% CI: 1.12-1.25) were more strongly associated with self-reported history of fracture. In addition, the strengths of associations were consistently stronger with the duration of spicy food exposure. In stratified analyses, the strength of such an association appeared stronger in rural areas (OR: 1.14, 95% CI: 1.09-1.20) than urban (OR: 1.09, 95% CI: 1.05-1.12). The correlation was consistently stronger in males than in females.

CONCLUSIONS

Among Chinese adults, a positive cross-sectional association between the level of spicy food intake and history of fractures was found in both sexes.

Combination of Capsaicin and Hesperidin Reduces the Effectiveness of Each Compound To Decrease the Adipocyte Size and To Induce Browning Features in Adipose Tissue of Western Diet Fed Rats

We explored the potential of hesperidin and capsaicin, separately and in combination, to induce white adipose tissue (WAT) browning and to help body weight management in Western diet-fed rats. Adult male Wistar rats were fed for 8 weeks with Western diet and treated daily with hesperidin (100 mg/kg/day), capsaicin (4 mg/kg/day), hesperidin (100 mg/kg/day) + capsaicin (4 mg/kg/day), or the vehicle. Hesperidin and capsaicin separately, but not (or to a lesser extent) the combination, resulted in a decreased size of adipocytes and induced emergence of multilocular brown-like adipocytes positive for UCP1 and CIDEA in retroperitoneal WAT. Expression levels of browning markers, such as Prdm16, in inguinal WAT also increased with capsaicin treatment compared with the vehicle (145% ± 17% vs 92% ± 21%, P < 0.05), but no significant effects were found with the combination (106% ± 12%). Thus, the combination of both bioactives reduces the effectiveness of each compound to decrease the adipocyte size and induce WAT browning.

Capsaicinoids supplementation decreases percent body fat and fat mass: adjustment using covariates in a post hoc analysis

BACKGROUND

Capsaicinoids (CAPs) found in chili peppers and pepper extracts, are responsible for enhanced metabolism. The objective of the study was to evaluate the effects of CAPs on body fat and fat mass while considering interactions with body habitus, diet and metabolic propensity.

METHODS

Seventy-five (N = 75) volunteer (male and female, age: 18 and 56 years) healthy subjects were recruited. This is a parallel group, randomized, double-blind, placebo controlled exploratory study. Subjects were randomly assigned to receive either placebo, 2 mg CAPs or 4 mg CAPs dosing for 12 weeks. After initial screening, subjects were evaluated with respect to fat mass and percent body fat at baseline and immediately following a 12-week treatment period. The current study evaluates two measures of fat loss while considering six baseline variables related to fat loss. Baseline measurements of importance in this paper are those used to evaluate body habitus, diet, and metabolic propensity. Lean mass and fat mass (body habitus); protein intake, fat intake and carbohydrate intake; and total serum cholesterol level (metabolic propensity) were assessed. Body fat and fat mass were respectively re-expressed as percent change in body fat and change in fat mass by application of formula outcome = (12-week value - baseline value) / baseline value) × 100. Thus, percent change in body fat and change in fat mass served as dependent variables in the evaluation of CAPs. Inferential statistical tests were derived from the model to compare low dose CAPs to placebo and high dose CAPs to placebo.

RESULTS

Percent change in body fat after 12 weeks of treatment was 5.91 percentage units lower in CAPs 4 mg subjects than placebo subjects after adjustment for covariates (p = 0.0402). Percent change in fat mass after 12 weeks of treatment was 6.68 percentage units lower in Caps 4 mg subjects than placebo subjects after adjustment for covariates (p = 0.0487).

CONCLUSION

These results suggest potential benefits of Capsaicinoids (CAPs) on body fat and fat mass in post hoc analysis. Further studies are required to explore pharmacological, physiological, and metabolic benefits of both chronic and acute Capsaicinoids consumption.

TRIAL REGISTRATION

ISRCTN10458693 'retrospectively registered'.

Sex-dependent difference in the association between frequency of spicy food consumption and risk of hypertension in Chinese adults

PURPOSE

The aim of our study was to explore the association between frequency of spicy food consumption and risk of hypertension in Chinese adults.

METHODS

Data were extracted from the 2009 wave of the China Health and Nutrition Survey, consisting of 9273 apparently healthy adults. Height, weight, and blood pressure (BP) were measured and diet was assessed with three consecutive 24-h recalls in combination with a weighed food inventory. Frequency of spicy food consumption and degree of pungency in spicy food consumption were self-reported. Hypertension was defined as systolic BP (SBP) ≥ 140 mmHg and/or diastolic BP (DBP) ≥ 90 mmHg, or having known hypertension. Multilevel mixed-effects models were constructed to estimate changes in SBP and DBP levels as well as risk of hypertension.

RESULTS

Higher frequency of spicy food consumption was significantly associated with lower SBP and DBP levels and lower risk of hypertension in female participants after adjustment for potential confounders (all P trend < 0.05) and cluster effects at different levels (individual, community, and province). Compared with female participants who did not eat spicy food, the adjusted odds ratios of hypertension were 0.740 (95% CI 0.569, 0.963; P = 0.025) in female participants who consumed usually, and 0.760 (95% CI 0.624, 0.925; P = 0.006) in female participants who ate spicy food with moderate pungency. There was no significant association of spicy food consumption with hypertension in male participants.

CONCLUSIONS

Frequency of spicy food consumption was inversely associated with risk of hypertension in female, but not male adults.