Capsaicin and capsiate could be appropriate agents for treatment of obesity: A meta-analysis of human studies

Multiple effects of spicy flavors on neurological diseases through the intervention of TRPV1: a critical review

The spicy properties of foods are contributed by various spicy flavor substances (SFs) such as capsaicin, piperine, and allicin. Beyond their distinctive sensory characteristics, SFs also influence health conditions and numerous studies have associated spicy flavors with disease treatment. In this review, we enumerate different types of SFs and describe their role in food processing, with a specific emphasis on critically examining their influence on human wellness. Particularly, detailed insights into the mechanisms through which SFs enhance physiological balance and alleviate neurological diseases are provided, and a systematic analysis of the significance of transient receptor potential vanilloid type-1 (TRPV1) in regulating metabolism and nervous system homeostasis is presented. Moreover, enhancing the accessibility and utilization of SFs can potentially amplify the physiological effects. This review aims to provide compelling evidence for the integration of food flavor and human health.

Capsiate ameliorates secondary hyperparathyroidism by improving insulin sensitivity and inhibiting angiogenesis

Secondary hyperparathyroidism has a significant impact on the overall well-being of the body. Capsiates, known for their antioxidant and metabolic properties, have emerged as a promising alternative treatment for secondary hyperparathyroidism. This study aims to evaluate the effects and mechanisms of capsiates in the treatment of secondary hyperparathyroidism. To achieve our research objectives, we conducted a study on patients' serum and examined changes in metabolic markers using serum metabolomics. We induced secondary hyperparathyroidism in rat through dietary intervention and divided them into four groups. The first group, referred to as the Parathyroid Hormone (PTH) group, received a low-calcium and high-phosphate diet (0.2% calcium, 1.2% phosphorus). The second group served as the control group, receiving a standard phosphate and calcium diet (0.6% calcium, 0.6% phosphorus). The third group, called the capsiates group, consisted of rat from the control group treated with capsiates (intraperitoneal injection of 2 mg/kg capsiates for 2 weeks after 2 weeks of dietary intervention). The fourth group was the capsiates-treated PTH group. Subsequently, we conducted ribose nucleic acid (RNA) sequencing on parathyroid gland cells and evaluated serum thyroxine levels, oxidative stress, expression of proteins associated with vascular neogenesis, measurement of SOD, GSH and 3-nitrotyrosine, micro-CT and histological staining. The serum metabolomic data revealed a significant decrease in capsiate levels in the secondary hyperparathyroidism group. Administration of capsiates to PTH rat resulted in increased calcium levels compared to the PTH group. Additionally, the PTH + Capsiates group showed significantly lower levels of PTH and phosphate compared to the PTH group. The PTH group exhibited a notable increase in the quantity and size of mitochondria compared to the control group. Following capsiates administration to the PTH group, there was a significant reduction in the number of mitochondria and length of microvilli, but an increase in the size of mitochondria compared to the PTH group. Sequencing analysis revealed that vascular endothelial growth factor (VEGF) and Vascular Endothelial Growth Factor Receptor 1 (VEGFR1) play crucial roles in this process. Vascular-related variables and downstream signalling were significantly elevated in hyperthyroidism and were alleviated with capsaicin treatment. Finally, combining capsiates with the PTH group improved bone mineral density, Tb.N, BV.TV, Cs.Th, Tt.Ar, OPG, Ob.TV and Oc.TV, as well as the mineral apposition rate, but significantly decreased Tb.Sp and Receptor Activator for Nuclear Factor-κ B Ligand (RANKL) compared to the PTH group. The findings suggest that capsiates can improve secondary hyperparathyroidism and ameliorated osteoporosis outcomes by inhibiting angiogenesis and reducing oxidative stress.

Ten weeks of Capsicum annuum L. extract supplementation did not change adipose tissue-derived hormones, appetite, body composition, and muscle strength when combined with resistance training in healthy untrained men: A clinical trial study

Capsiate (CAP) is a nonpungent capsaicin analog (Capsicum annuum L. extract) that has been studied as a potential antiobesity agent. However, the interaction between chronic CAP supplementation and resistance training is not clear. The purpose of this study was to examine the changes in adipose tissue-derived hormones, body composition, appetite, and muscle strength after 10 weeks of resistance training, combined with chronic CAP supplementation in healthy untrained men. We hypothesized that CAP could induce higher benefits when combined with resistance training after 10 weeks of intervention compared to resistance training alone. Twenty-four young men (age, 22.0 ± 2.9) were randomized to either capsiate supplementation (CAP = 12 mg/day) or placebo (PL), and both groups were assigned to resistance training. Body composition, leptin and adiponectin concentrations, subjective ratings of appetite, energy intake, and exercise performance were assessed at before and after 10 weeks of progressive resistance training. There was a significant increase in body mass (P < .001), fat-free mass (CAP: 58.0 ± 7.1 vs. post, 59.7 ± 7.1 kg; PL: pre, 58.4 ± 7.3 vs. post, 59.8 ± 7.1 kg; P < .001), resting metabolic rate (CAP: pre, 1782.9 ± 160.6 vs. post, 1796.3 ± 162.0 kcal; PL: pre, 1733.0 ± 148.9 vs. post, 1750.5 ± 149.8 kcal; P < .001), maximal strength at 45 leg press (P < .001) and bench press (P < .001) in both groups, but no significant (P > .05) supplementation by training period interaction nor fat mass was observed. For subjective ratings of appetite, energy intake, leptin, and adiponectin, no significant effect of supplementation by training period interaction was observed (P > .05). In conclusion, 10 weeks of resistance training increased total body weight, muscle mass, and maximum strength in healthy untrained men; however, CAP supplementation (12 mg, 7 days per week) failed to change adipose tissue-derived hormones, appetite, body composition and muscle strength in this population. Registered under Brazilian Registry of Clinical Trials (RBR-8cz9kfq).

Natural compounds as obesity pharmacotherapies

Obesity has become a serious global public health problem, affecting over 988 million people worldwide. Nevertheless, current pharmacotherapies have proven inadequate. Natural compounds have garnered significant attention due to their potential antiobesity effects. Over the past three decades, ca. 50 natural compounds have been evaluated for the preventive and/or therapeutic effects on obesity in animals and humans. However, variations in the antiobesity efficacies among these natural compounds have been substantial, owing to differences in experimental designs, including variations in animal models, dosages, treatment durations, and administration methods. The feasibility of employing these natural compounds as pharmacotherapies for obesity remained uncertain. In this review, we systematically summarized the antiobesity efficacy and mechanisms of action of each natural compound in animal models. This comprehensive review furnishes valuable insights for the development of antiobesity medications based on natural compounds.

Anti-obesity Properties of Phytochemicals: Highlighting their Molecular Mechanisms against Obesity

Obesity is a complex, chronic and inflammatory disease that affects more than one-third of the world's population, leading to a higher incidence of diabetes, dyslipidemia, metabolic syndrome, cardiovascular diseases, and some types of cancer. Several phytochemicals are used as flavoring and aromatic compounds, also exerting many benefits for public health. This study aims to summarize and scrutinize the beneficial effects of the most important phytochemicals against obesity. Systematic research of the current international literature was carried out in the most accurate scientific databases, e.g., Pubmed, Scopus, Web of Science and Google Scholar, using a set of critical and representative keywords, such as phytochemicals, obesity, metabolism, metabolic syndrome, etc. Several studies unraveled the potential positive effects of phytochemicals such as berberine, carvacrol, curcumin, quercetin, resveratrol, thymol, etc., against obesity and metabolic disorders. Mechanisms of action include inhibition of adipocyte differentiation, browning of the white adipose tissue, inhibition of enzymes such as lipase and amylase, suppression of inflammation, improvement of the gut microbiota, and downregulation of obesity-inducing genes. In conclusion, multiple bioactive compounds-phytochemicals exert many beneficial effects against obesity. Future molecular and clinical studies must be performed to unravel the multiple molecular mechanisms and anti-obesity activities of these naturally occurring bioactive compounds.

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 Foods of Mesoamerican Origin in Adipose Tissue and Liver-Related Metabolism

Adipose tissue and liver metabolism play a key role in maintaining body homeostasis; therefore, their impairment conduces a pathological state. Nowadays, occidental lifestyle is a common etiological issue among a variety of chronic diseases, while diet is a unique strategy to prevent obesity and liver metabolism impairment and is a powerful player in the treatment of metabolic-related diseases. Mesoamerican foods are rich in bioactive molecules that enhance and improve adipose tissue and liver performance and represent a prophylactic and therapeutic alternative for disorders related to the loss of homeostasis in the metabolism of these two important tissues.

Are We Ready to Recommend Capsaicin for Disorders Other Than Neuropathic Pain?

Capsaicin, a lipophilic, volatile compound, is responsible for the pungent properties of chili peppers. In recent years, a significant increase in investigations into its properties has allowed the production of new formulations and the development of tools with biotechnological, diagnostic, and potential therapeutic applications. Most of these studies show beneficial effects, improving antioxidant and anti-inflammatory status, inducing thermogenesis, and reducing white adipose tissue. Other mechanisms, including reducing food intake and improving intestinal dysbiosis, are also described. In this way, the possible clinical application of such compound is expanding every year. This opinion article aims to provide a synthesis of recent findings regarding the mechanisms by which capsaicin participates in the control of non-communicable diseases such as obesity, diabetes, and dyslipidemia.

The Effect of Capsaicin on Growth Performance, Antioxidant Capacity, Immunity and Gut Micro-Organisms of Calves

Capsaicin is the active ingredient of the red pepper plant of the genus Capsicum. The aim of this study was to investigate the effects of different doses of capsaicin on growth performance, antioxidant capacity, immunity, fecal fermentation parameters and gut microbial composition in nursing calves. Twenty-four newborn Holstein calves were randomly assigned to three treatment groups, which each consisted of eight calves. The milk replacer was supplemented with 0, 0.15 or 0.3 mL/d of capsaicin in each of the three treatment groups. During the 4-week experiment, intake was recorded daily, body weight and body size parameters were measured at the beginning and end of the trial and serum samples and rectal fecal samples were collected at the end of the trial to determine serum parameters, fecal fermentation parameters and fecal microbiome compartments. The results showed that both doses of capsaicin had no negative effect on the growth performance or the fecal fermentation parameters of calves, and the higher dose (0.3 mL/d) of capsaicin significantly improved the antioxidant capacity and immunity of calves. The calves in the high-dose capsaicin-treated group had lower fecal scores than those recorded in the control group. High doses of capsaicin increased glutathione antioxidant enzyme, superoxide dismutase, immunoglobulin A, immunoglobulin G, immunoglobulin M and interleukin-10 levels and decreased malondialdehyde and bound bead protein levels. In addition, capsaicin regulated the gut microbiota, reducing the abundance of diarrhea-associated bacteria, such as Eggerthella, Streptococcus, Enterococcus and Enterobacteriaceae, in the gut of calves in the treated group. Therefore, high doses of capsaicin can improve the antioxidant and immune capacity of calves without affecting growth performance, as well as improve the gut microbiological environment, which enables the healthy growth of calves.

The gut microbiota metabolite capsiate regulate SLC2A1 expression by targeting HIF-1α to inhibit knee osteoarthritis-induced ferroptosis

Ferroptosis is an iron-dependent cell death that has been found to aggravate the progression of osteoarthritis (OA) and gut microbiota- OA axis refers to the bidirectional information network between the gut microbiota and OA, which may provide a new way to protect the OA. However, the role of gut microbiota-derived metabolites in ferroptosis-relative osteoarthritis remains unclear. The objective of this study was to analyze the protective effect of gut microbiota and its metabolite capsiate (CAT) on ferroptosis-relative osteoarthritis in vivo and in vitro experiments. From June 2021 to February 2022, 78 patients were evaluated retrospectively and divided into two groups: The health group (n = 39) and the OA group (n = 40). Iron and oxidative stress indicators were determined in peripheral blood samples. And then in vivo and in vitro experiments, a surgically destabilized medial meniscus (DMM) mice model was established and treated with CAT or Ferric Inhibitor-1 (Fer-1). Solute Carrier Family 2 Member 1 (SLC2A1) short hairpin RNA (shRNA) was utilized to inhibit SLC2A1 expression. Serum iron was increased significantly but total iron binding capacity was decreased significantly in OA patients than healthy people (p < 0.0001). The least absolute shrinkage and selection operator clinical prediction model suggested that serum iron, total iron binding capacity, transferrin, and superoxide dismutase were all independent predictors of OA (p < 0.001). Bioinformatics results suggested that SLC2A1, Metastasis-Associated Lung Adenocarcinoma Transcript 1 (MALAT1), and HIF-1α (Hypoxia Inducible Factor 1 Alpha)-related oxidative stress signaling pathways play an important role in iron homeostasis and OA. In addition, gut microbiota 16s RNA sequencing and untargeted metabolomics were used to find that gut microbiota metabolites CAT in mice with osteoarthritis were negatively correlated with Osteoarthritis Research Society International (OARSI) scores for chondrogenic degeneration (p = 0.0017). Moreover, CAT reduced ferroptosis-dependent osteoarthritis in vivo and in vitro. However, the protective effect of CAT against ferroptosis-dependent osteoarthritis could be eliminated by silencing SLC2A1. SLC2A1 was upregulated but reduced the SLC2A1 and HIF-1α levels in the DMM group. HIF-1α, MALAT1, and apoptosis levels were increased after SLC2A1 knockout in chondrocyte cells (p = 0.0017). Finally, downregulation of SLC2A1 expression by Adeno-associated Virus (AAV) -SLC2A1 shRNA improves osteoarthritis in vivo. Our findings indicated that CAT inhibited HIF-1a expression and reduced ferroptosis-relative osteoarthritis progression by activating SLC2A1.

Capsicum annuum L. and its bioactive constituents: A critical review of a traditional culinary spice in terms of its modern pharmacological potentials with toxicological issues

Capsicum annuum L., commonly known as chili pepper, is used as an important spice globally and as a crude drug in many traditional medicine systems. The fruits of C. annuum have been used as a tonic, antiseptic, and stimulating agent, to treat dyspepsia, appetites, and flatulence, and to improve digestion and circulation. The article aims to critically review the phytochemical and pharmacological properties of C. annuum and its major compounds. Capsaicin, dihydrocapsaicin, and some carotenoids are reported as the major active compounds with several pharmacological potentials especially as anticancer and cardioprotectant. The anticancer effect of capsaicinoids is mainly mediated through mechanisms involving the interaction of Ca²⁺ -dependent activation of the MAPK pathway, suppression of NOX-dependent reactive oxygen species generation, and p53-mediated activation of mitochondrial apoptosis in cancer cells. Similarly, the cardioprotective effects of capsaicinoids are mediated through their interaction with cellular transient receptor potential vanilloid 1 channel, and restoration of calcitonin gene-related peptide via Ca²⁺ -dependent release of neuropeptides and suppression of bradykinin. In conclusion, this comprehensive review presents detailed information about the traditional uses, phytochemistry, and pharmacology of major bioactive principles of C. annuum with special emphasis on anticancer, cardioprotective effects, and plausible toxic adversities along with food safety.

Gender-specific effects of capsiate supplementation on body weight and bone mineral density: a randomized, double-blind, placebo-controlled study in slightly overweight women

INTRODUCTION

Overweight and obesity are highly prevalent conditions associated with premature morbidity and mortality worldwide. Capsiate, a nonpungent analogue of capsaicin, binds to TRP vanilloid 1 (TRPV1) receptor, which is involved in adipogenesis, and could be effective as a weight-lowering agent.

METHODS

Eighteen slightly overweight women were enrolled in this randomized, double-blind, placebo-controlled study. Nine patients were included in the capsiate intervention group and received 9 mg/day of capsinoids and 9 patients received placebo for 8 weeks. All patients underwent weight and waist circumference assessment before and after treatment. Body composition and bone mineral density (BMD) were also detected by dual-energy X-ray absorptiometry (DXA).

RESULTS

Fourteen patients completed the study. The treatment with capsiate or placebo for 8 weeks was not associated with significant changes in weight or waist circumference. After treatment, there was a significant improvement in BMD values measured at the spine in the capsiate group (1.158 vs 1.106 g/cm², + 4.7%; p = 0.04), but not in the group treated with placebo. Similarly, the capsiate group showed a 9.1% increase (p = 0.05) in the adipose tissue and an 8.5% decrease in lean mass measured at the supraclavicular level, whereas these changes were not statistically significant in the placebo group.

CONCLUSIONS

Treatment with capsiate for 8 weeks led to negligible changes in body weight in a small sample of slightly overweight women, but our findings suggest a potential effect of capsaicin on bone metabolism in humans.

Unravelling the Therapeutic Potential of Nano-Delivered Functional Foods in Chronic Respiratory Diseases

Chronic inflammation of the respiratory tract is one of the most concerning public health issues, as it can lead to chronic respiratory diseases (CRDs), some of which are more detrimental than others. Chronic respiratory diseases include chronic obstructive pulmonary disease (COPD), asthma, lung cancer, and pulmonary fibrosis. The conventional drug therapies for the management and treatment of CRDs only address the symptoms and fail to reverse or recover the chronic-inflammation-mediated structural and functional damage of the respiratory tract. In addition, the low efficacy and adverse effects of these drugs have directed the attention of researchers towards nutraceuticals in search of potential treatment strategies that can not only ameliorate CRD symptoms but also can repair and reverse inflammatory damage. Hence, there is a growing interest toward investigating the medicinal benefits of nutraceuticals, such as rutin, curcumin, zerumbone, and others. Nutraceuticals carry many nutritional and therapeutic properties, including anti-inflammatory, antioxidant, anticancer, antidiabetic, and anti-obesity properties, and usually do not have as many adverse effects, as they are naturally sourced. Recently, the use of nanoparticles has also been increasingly studied for the nano drug delivery of these nutraceuticals. The discrete size of nanoparticles holds great potential for the level of permeability that can be achieved when transporting these nutraceutical compounds. This review is aimed to provide an understanding of the use of nutraceuticals in combination with nanoparticles against CRDs and their mechanisms involved in slowing down or reversing the progression of CRDs by inhibiting pro-inflammatory signaling pathways.

Phenol-Rich Botanicals Modulate Oxidative Stress and Epithelial Integrity in Intestinal Epithelial Cells

Botanicals are mainly known for their role as antimicrobials and anti-inflammatories. Thus, the dual purpose of the study was to verify the antioxidant potential of the tested botanicals and to evaluate their possible modulation of intestinal barrier integrity. As the effects of various phenol-rich extracts were screened, the human Caco-2 cell line was determined to be most suitable for use as the in vitro model for the intestinal epithelium. The tested botanicals, all approved as feed additives, are ginger essential oil, tea tree oil, grape seed extract, green tea extract, olive extract, chestnut extract, pomegranate extract, thyme essential oil, and capsicum oleoresin. The cells were treated with incremental doses of each botanical, followed by measurements of transepithelial electrical resistance (TEER), gene expression of tight junctions (TJs), and reactive oxygen species (ROS). The results showed how different phenol-rich botanicals could modulate barrier functions and oxidative stress in different ways. Interestingly, all the botanicals tested exerted an antioxidant potential by dropping the cytoplasmatic ROS, while the beneficial effect was exerted at different concentrations for each botanical. Our data support the role of plant extracts and essential oils in controlling gut barrier function and in reducing the negative effects of oxidative stress in intestinal epithelial cells, thereby supporting gut barrier functionality.

Both caffeine and Capsicum annuum fruit powder lower blood glucose levels and increase brown adipose tissue temperature in healthy adult males

Using a combination of respiratory gas exchange, infrared thermography, and blood glucose (BGL) analysis, we have investigated the impact of Capsicum annuum (C. annuum) fruit powder (475 mg) or caffeine (100 mg) on metabolic activity in a placebo controlled (lactose, 100 mg) double-blinded three-way cross-over-design experiment. Metabolic measurements were made on day 1 and day 7 of supplementation in eight adult male participants (22.2 ± 2 years of age, BMI 23 ± 2 kg/m², x̅ ± SD). Participants arrived fasted overnight and were fed a high carbohydrate meal (90 g glucose), raising BGL from fasting baseline (4.4 ± 0.3 mmol/L) to peak BGL (8.5 ± 0.3 mmol/L) 45 min after the meal. Participants consumed the supplement 45 min after the meal, and both caffeine and C. annuum fruit powder restored BGL (F _(8,178) = 2.2, p = 0.02) to near fasting levels within 15 min of supplementation compared to placebo (120 min). In parallel both supplements increased energy expenditure (F _{(2, 21)} = 175.6, p < 0.001) over the 120-min test period (caffeine = 50.74 ± 2 kcal/kg/min, C. annuum fruit = 50.95 ± 1 kcal/kg/min, placebo = 29.34 ± 1 kcal/kg/min). Both caffeine and C. annuum fruit powder increased supraclavicular fossa temperature (F _(2,42) = 32, p < 0.001) on both day 1 and day 7 of testing over the 120-min test period. No statistical difference in core temperature or reference point temperature, mean arterial pressure or heart rate was observed due to supplementation nor was any statistical difference seen between day 1 and day 7 of intervention. This is important for implementing dietary ingredients as potential metabolism increasing supplements. Together the results imply that through dietary supplements such as caffeine and C. annuum, mechanisms for increasing metabolism can be potentially targeted to improve metabolic homeostasis in people.

Vanillin reduction in the biosynthetic pathway of capsiate, a non-pungent component of Capsicum fruits, is catalyzed by cinnamyl alcohol dehydrogenase

Capsicum fruits synthesize capsaicin from vanillylamine, which is produced from vanillin in a reaction catalyzed by a putative aminotransferase (pAMT). Capsiate, a non-pungent compound that is structurally similar to capsaicin, is synthesized from vanillyl alcohol rather than vanillylamine. Vanillyl alcohol is possibly generated by the enzymatic reduction of vanillin, but the enzyme responsible for this reaction is unknown. In the present study, we revealed that the vanillin reductase in the capsiate biosynthetic pathway is cinnamyl alcohol dehydrogenase (CAD), which is an enzyme involved in lignin synthesis. The reduction of vanillin to vanillyl alcohol was greater in the mature red fruit placental extract than in the immature green fruit placental extract. This reduction was suppressed by both N-(O-hydroxyphenyl) sulfinamoyltertiobutyl acetate, a specific inhibitor of CAD, and ethylenediaminetetraacetic acid, a metalloenzyme inhibitor. The CaCAD1 transcript levels in the placenta were higher in the red fruits than in the green fruits. A recombinant CaCAD1 protein obtained using an Escherichia coli expression system reduced vanillin to vanillyl alcohol. This reaction was suppressed by the CAD inhibitors. These results strongly suggest that CAD is the enzyme that catalyzes the reduction of vanillin to vanillyl alcohol during capsiate biosynthesis. Syntenic analyses indicated that genes encoding CAD and capsaicin synthase (Pun1) involved in capsiate biosynthesis were acquired before the pAMT gene during the evolution of the family Solanaceae. This raises the possibility that in the genus Capsicum, the capsiate biosynthetic pathway emerged before the pAMT-encoding gene was acquired as the final trigger for capsaicin biosynthesis.

Capsaicin for Weight Control: “Exercise in a Pill” (or Just Another Fad)?

Medical management of obesity represents a large unmet clinical need. Animal experiments suggest a therapeutic potential for dietary capsaicin, the pungent ingredient in hot chili peppers, to lose weight. This is an attractive theory since capsaicin has been a culinary staple for thousands of years and is generally deemed safe when consumed in hedonically acceptable, restaurant-like doses. This review critically evaluates the available experimental and clinical evidence for and against capsaicin as a weight control agent and comes to the conclusion that capsaicin is not a magic “exercise in a pill”, although there is emerging evidence that it may help restore a healthy gut microbiota.

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.

Transdermal Photothermal-Pharmacotherapy to Remodel Adipose Tissue for Obesity and Metabolic Disorders

Despite the increasing prevalence of obesity, the current medications, which act indirectly on the central nervous system to suppress appetite or on the gastrointestinal tract to inhibit fat absorption, suffer from poor effectiveness and side effects. Here, we developed a transdermal mild photothermal therapy directly acting on the root of evil (subcutaneous white adipose depot) to induce its ameliorating remodeling (browning, lipolysis, and apoptosis), based on the injectable thermoresponsive hydrogel encapsulated with copper sulfide nanodots. Further, combining pharmaceutical therapy with codelivery of mirabegron leads to a strong therapeutic synergy. This method not only ensures high effectiveness and low side effects due to localized and targeted application but also remotely creates significant improvements in systemic metabolism. Specifically, as compared to the untreated group, it totally inhibits obesity development in high-fat-diet fed mice (15% less in body weight) with decreased masses of both subcutaneous (40%) and visceral fats (54%), reduced serum levels of cholesterol (54%)/triglyceride (18%)/insulin (74%)/glucose (45%), and improved insulin sensitivity (65% less in insulin resistance index). This self-administrable method is amenable for long-term home-based treatment. Finally, multiple interconnected signaling pathways are revealed, providing mechanistic insights to develop effective strategies to combat obesity and associated metabolic disorders.

Bulk Process for Enrichment of Capsinoids from Capsicum Fruit

Various methods to synthesize capsinoids (the nonpungent analogs of capsaicinoids) from precursor molecules have been reported. Capsinoids are also naturally present, at typically low concentrations, in the fruit of many Capsicum species and genotypes. However, they are also present in the fruit of select genotypes at high concentrations. The fruit of high-capsiate genotypes represents a commercial source of these compounds. To date, no method has been published that efficiently extracts and purifies capsinoids from Capsicum fruit in a rapid and simple bulk process. This study evaluated the efficacy of various organic solvents for the extraction of capsinoids from dried Capsicum annuum fruit. Among the organic solvents evaluated, pentane appeared to provide a good combination of both recovery and purity. A subsequent liquid/liquid extraction step, utilizing pentane and acetonitrile, resulted in 26.3 % (wt/wt) capsiate and 19.4 % (wt/wt) dihydrocapsiate for a combined capsinoids yield of 45.7 % (wt/wt). A third step, involving a rapid hp20ss chromatography column using a water/acetonitrile gradient, resulted in a combined capsinoids yield of 96.6 % (wt/wt).

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.

Acute Response to Capsiate Supplementation at Rest and during Exercise on Energy Intake, Appetite, Metabolism, and Autonomic Function: A Randomized Trial

OBJECTIVE

The purpose of the present study was to examine the effect of capsiate supplementation on energy intake, self-reported appetite-related sensations, energy expenditure, fat oxidation, and autonomic parameters with and without an exercise intervention.

METHODS

Thirteen healthy men completed four randomized trials: two trials for the control condition (without exercise), one with capsiate supplementation (CTRL_cap) and one with a placebo (CTRL_pla), and two trials for the exercise condition, one with capsiate supplementation (EX_cap) and one with placebo (EX_pla). Exercise sessions were performed 150 min after the consumption of a standardized breakfast, and supplementation 115 min after consumption of breakfast. An ad libitum buffet was offered 200 min following the completion of the standardized breakfast, and energy intake (EI) and relative energy intake (REI) (relative energy intake = energy intake - energy expenditure related to exercise) were evaluated.

RESULTS

There were no significant effects on EI, self-reported appetite sensations, fat oxidation, and energy expenditure. REI was reduced in conditions involving EX when compared to CTRL. A low-frequency to high-frequency ratio for heart rate variability was higher in CTRL_cap (1.6 ± 1.1) vs. CTRL_pla (1.2 ± 0.9) (p = 0.025; d = 0.39).

CONCLUSION

Acute capsiate supplementation combined with aerobic exercise has limited effects on the examined variables (EI, REI, fat oxidation, energy expenditure, and autonomic parameters), while changes in the autonomic nervous system function in the absence of exercise may have occurred without influencing other variables.

CLINICAL TRIAL REGISTRATION

ensaiosclinicos.gov.br number, RBR-5pckyr https://ensaiosclinicos.gov.br/rg/RBR-5pckyr.

Chronic capsiate supplementation increases fat-free mass and upper body strength but not the inflammatory response to resistance exercise in young untrained men: a randomized, placebo-controlled and double-blind study

BACKGROUND

Acute capsaicinoid and capsinoid supplementation has endurance and resistance exercise benefits; however, if these short-term performance benefits translate into chronic benefits when combined with resistance training is currently unknown. This study investigated changes of chronic Capsiate supplementation on muscular adaptations, inflammatory response and performance in untrained men.

METHODS

Twenty untrained men were randomized to ingest 12 mg Capsiate (CAP) or placebo in a parallel, double-blind design. Body composition and performance were measured at pre-training and after 6 weeks of resistance training. An acute resistance exercise session test was performed pre and post-intervention. Blood samples were collected at rest and post-resistance exercise to analyze Tumor necrosis factor- (TNF-), Soluble TNF- receptor (sTNF-r), Interleukin-6 (IL-6) and Interleukin-10 (IL-10).

RESULTS

Exercise and CAP supplementation increased fat-free mass in comparison to baseline by 1.5 kg (P < 0.001), however, the majority of the increase (1.0 kg) resulted from an increase in total body water. The CAP change scores for fat-free mass were significantly greater in comparison to the placebo (CAP ∆%= 2.1 ± 1.8 %, PLA ∆%= 0.7 ± 1.3 %, P = 0.043) and there was a significant difference between groups in the bench press exercise (P = 0.034) with greater upper body strength change score for CAP (∆%= 13.4 ± 9.1 %) compared to placebo (∆%= 5.8 ± 5.2 %), P = 0.041. CAP had no effect on lower body strength and no supplementation interactions were observed for all cytokines in response to acute resistance exercise (P > 0.05).

CONCLUSION

Chronic Capsiate supplementation combined with resistance training during short period (6 weeks) increased fat-free mass and upper body strength but not inflammatory response and performance in young untrained men.

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.

Characteristics of spicy food consumption and its relation to lifestyle behaviours: results from 0.5 million adults

This study aimed to describe the characteristics and lifestyle differences of spicy food consumption in 0.5 million adults. Participants were recruited from 2004 to 2008 in the baseline research of the CKB study. Higher frequency and stronger pungency degree in spicy food positively correlated with preference for salty taste, eating snacks/deep-fried foods, tea/alcohol drinking and tobacco smoking. Among weekly tea/alcohol drinkers and current regular smokers, participants with a higher frequency of spicy food consumption or preference for stronger pungency degree were more likely to prefer strong tea, drink alcohol exceed the healthy amount, drink alcohol in the morning every day, smoke ≥ 40 cigarettes per day, consume a larger amount of tea leaves, alcohol and cigarettes each day, and start habitual tea/alcohol drinking or smoking at an earlier age. Differences existed in lifestyle factors related to major chronic diseases according to spicy food consumption frequency and pungency degree among the Chinese population.

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.

Dietary supplementation of transient receptor potential vanilloid-1 channel agonists reduces serum total cholesterol level: a meta-analysis of controlled human trials

Abnormal cholesterol level is a major risk factor in the development of atherosclerosis, which is a fundamental derangement in cardiovascular diseases. Any efforts should be undertaken to lower blood cholesterol levels. Among dietary interventions, capsaicinoid supplementation is also considered as a novel cholesterol-lowering approach, but human studies concluded contradictory results about its effectiveness. The present meta-analysis aimed at determining the effects of capsaicinoids on serum lipid profile in humans. We searched the PubMed, EMBASE, and CENTRAL databases from inception to February 2021. We included 10 controlled studies, which involved 398 participants. We found that dietary capsaicinoid supplementation alone or in combination with other substances significantly (p = 0.004 and 0.001, respectively) reduced serum total cholesterol level compared to controls with an overall standardized mean difference of -0.52 (95% confidence interval: -0.83, -0.21). Capsaicinoids also decreased low-density lipoprotein level significantly (p = 0.035), whereas no effect was observed on serum levels of high-density lipoprotein and triglycerides. Our findings provide novel quantitative evidence for the efficacy of dietary capsaicin supplementation in lowering serum total cholesterol and low-density lipoprotein levels in humans. To validate our conclusion, further randomized controlled trials in a diverse population of adult humans receiving dietary capsaicinoid supplementation are warranted.

Antibacterial properties of capsaicin and its derivatives and their potential to fight antibiotic resistance - A literature survey

Antibiotic resistance is endangering public health globally and gives reason for constant fear of virtually intractable bacterial infections. Given a limitation of novel antibiotic classes brought to market in perspective, it is indispensable to explore novel, antibiotics-independent ways to fight bacterial infections. In consequence, the antibacterial properties of natural compounds have gained increasing attention in pharmacological sciences. We here performed a literature survey regarding the antibacterial effects of capsaicin and its derivatives constituting natural compounds of chili peppers. The studies included revealed that the compounds under investigation exerted i.) both direct and indirect antibacterial properties in vitro depending on the applied concentrations and the bacterial strains under investigation; ii.) synergistic antibacterial effects in combination with defined antibiotics; iii.) resistance-modification via inhibition of bacterial efflux pumps; iv.) attenuation of bacterial virulence factor expression; and v.) dampening of pathogen-induced immunopathological responses. In conclusion, capsaicin and its derivatives comprise promising antimicrobial molecules which could complement or replace antibiotic treatment strategies to fight bacterial infections. However, a solid basis for subsequent clinical trials requires future investigations to explore the underlying molecular mechanisms and in particular pharmaceutical evaluations in animal infection models.

Extraction, purification, bioactivity and pharmacological effects of capsaicin: a review

Capsaicin (trans-8-methyl-N-vanillyl-6-nonenamide), a well-known vanilloid, which is the main spicy component in chili peppers, showing several biological activities and the potential applications range from food flavorings to therapeutics. Traditional extraction of capsaicin by organic solvents was time-consuming, some new methods such as aqueous two-phase method and ionic liquid extraction method have been developed. During past few decades, an ample variety of biological effects of capsaicin have been evaluated. Capsaicin can be used in biofilms and antifouling coatings due to its antimicrobial activity, allowing it has a promising application in food packaging, food preservation, marine environment and dental therapy. Capsaicin also play a crucial role in metabolic disorders, including weight loss, pressure lowing and insulin reduction effects. In addition, capsaicin was identified effective on preventing human cancers, such as lung cancer, stomach cancer, colon cancer and breast cancer by inducing apoptosis and inhibiting cell proliferation of tumor cells. Previous research also suggest the positive effects of capsaicin on pain relief and cognitive impairment. Capsaicin, the agonist of transient receptor potential vanilloid type 1 (TRPV1), could selectively activate TRPV1, inducing Ca²⁺ influx and related signaling pathways. Recently, gut microbiota was also involved in some diseases therapeutics, but its influence on the effects of capsaicin still need to be deeply studied. In this review, different extraction and purification methods of capsaicin, its biological activities and pharmacological effects were systematically summarized, as well as the possible mechanisms were also deeply discussed. This article will give an updated and better understanding of capsaicin-related biological effects and provide theoretical basis for its further research and applications in human health and manufacture development.

Capsiate Intake with Exercise Training Additively Reduces Fat Deposition in Mice on a High-Fat Diet, but Not without Exercise Training

While exercise training (ET) is an efficient strategy to manage obesity, it is recommended with a dietary plan to maximize the antiobesity functions owing to a compensational increase in energy intake. Capsiate is a notable bioactive compound for managing obesity owing to its capacity to increase energy expenditure. We aimed to examine whether the antiobesity effects of ET can be further enhanced by capsiate intake (CI) and determine its effects on resting energy expenditure and metabolic molecules. Mice were randomly divided into four groups (n = 8 per group) and fed high-fat diet. Mild-intensity treadmill ET was conducted five times/week; capsiate (10 mg/kg) was orally administered daily. After 8 weeks, resting metabolic rate and metabolic molecules were analyzed. ET with CI additively reduced the abdominal fat rate by 18% and solely upregulated beta-3-adrenoceptors in adipose tissue (p = 0.013) but did not affect the metabolic molecules in skeletal muscles. Surprisingly, CI without ET significantly increased the abdominal fat rate (p = 0.001) and reduced energy expenditure by 9%. Therefore, capsiate could be a candidate compound for maximizing the antiobesity effects of ET by upregulating beta-3-adrenoceptors in adipose tissue, but CI without ET may not be beneficial in managing obesity.

Capsaicinoid and Capsinoids as an Ergogenic Aid: A Systematic Review and the Potential Mechanisms Involved

CONTEXT

Capsaicinoids and capsinoids (CAP) are natural substances found primarily in chili peppers and other spicy foods that agonize the transient receptor potential vanilloid-1 in the mouth, stomach, and small intestine. Several studies have shown CAP to be a potential antiobesity agent and to exhibit an analgesic effect in both rodents and humans. However, there is no scientific consensus about the effects of CAP on physical exercise performance and its physiological mechanisms of action.

PURPOSE

This systematic review aimed to better elucidate the effects of CAP compounds as ergogenic aids and to discuss underlying mechanisms of action by which this supplement may potentially enhance endurance performance and muscular strength.

CONCLUSIONS

Among 22 studies included in the review, 14 examined the effects of capsaicinoid or capsinoid compounds on endurance and resistance exercise performance in animals, with 9 studies showing benefits on performance. In humans, 8 studies were included: 3 demonstrated significant acute endurance benefits and 2 showed acute resistance exercise performance benefits compared with a placebo condition. Therefore, while more mechanistic studies are necessary to confirm these outcomes in humans, the available scientific literature appears to suggest that these compounds could be considered an effective nutritional strategy to improve exercise performance.

Effects of Capsicum annuum supplementation on the components of metabolic syndrome: a systematic review and meta-analysis

Metabolic syndrome (MetS) has increasingly gained importance as the main risk factor for cardiovascular diseases and type II diabetes mellitus. Various natural compounds derived from plants are associated with beneficial effects on the incidence and progression of MetS. This study aimed to evaluate the effects of Capsicum annuum on factors related to MetS by assessing randomized controlled trials (written in English). We searched the online databases of PubMed, Embase, Google scholar, and Cochrane Library up to April 2020. 'Patient/Population, Intervention, Comparison and Outcomes' format was used to determine whether intervention with C. annuum supplementation compared with placebo supplementation had any effect on the components of MetS among participants. We considered standardized mean differences (SMD) with 95% confidence intervals (CI) as effect size measures using random-effects model. Analysis of the included 11 studies (n = 609) showed that C. annuum supplementation had significant effect on low density lipoprotein-cholesterol [SMD = - 0.39; 95% CI - 0.72, - 0.07; P = 0.02; prediction interval, - 1.28 to 0.50] and marginally significant effect on body weight [SMD = - 0.19; 95% CI - 0.40, 0.03; P = 0.09]. However, larger and well-designed clinical trials are needed to investigate the effects of C. annuum on MetS.

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.

Effect of mild-intensity exercise training with capsiate intake on fat deposition and substrate utilization during exercise in diet-induced obese mice

Purpose

While the anti-obesity effects of exercise and capsiate are well-observed individually, the effect of exercise with capsiate intake has not been systematically explored yet. Therefore, the purpose of this study is to investigate whether the anti-obesity effects of exercise training can be further enhanced by capsiate intake.

Methods

8-week-old male mice were divided into 3 groups (n = 8 per group): sedentary group (SED; nontrained), exercise-trained group (EXE) and exercisetrained group with 10 mg/kg of capsiate intake (EXE+CAP). All mice were offered high-fat diet and water ad libitum. The mild-intensity treadmill training was conducted 5 times a week for 8 weeks. After 8 weeks, metabolism during exercise and abdominal fat weight were measured.

Results

Body weight and the rate of total abdominal fat were significantly less in EXE+CAP than in SED but not between EXE and SED. The average of respiratory exchange rate during exercise was significantly much lower in EXE+SED (p = 0.003) compared to the difference between EXE and SED (p = 0.025). Likewise, the fat oxidation during exercise was significantly much higher in EXE+SED (p = 0.016) compared to the difference between EXE and SED (p = 0.045). Then, the carbohydrate oxidation during exercise was significantly much lower in EXE+SED (p = 0.003) compared to the difference between EXE and SED (p = 0.028).

Conclusion

In conclusion, the anti-obesity functions of exercise training can be further enhanced by capsiate intake by increasing fat oxidation during exercise. Therefore, we suggest that capsiate could be a candidate supplement which can additively ameliorate obesity when combined with exercise.

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.

Effects and mechanisms of edible and medicinal plants on obesity: an updated review

In recent years, obesity has become a global public health issue. It is closely associated with the occurrence of several chronic diseases, such as diabetes and cardiovascular diseases. Some edible and medicinal plants show anti-obesity activity, such as fruits, vegetables, spices, legumes, edible flowers, mushrooms, and medicinal plants. Numerous studies have indicated that these plants are potential candidates for the prevention and management of obesity. The major anti-obesity mechanisms of plants include suppressing appetite, reducing the absorption of lipids and carbohydrates, inhibiting adipogenesis and lipogenesis, regulating lipid metabolism, increasing energy expenditure, regulating gut microbiota, and improving obesity-related inflammation. In this review, the anti-obesity activity of edible and medicinal plants was summarized based on epidemiological, experimental, and clinical studies, with related mechanisms discussed, which provided the basis for the research and development of slimming products. Further studies should focus on the exploration of safer plants with anti-obesity activity and the identification of specific anti-obesity mechanisms.

A Critical Review on the Role of Food and Nutrition in the Energy Balance

The mass media has increasingly frequently suggested to the general population that specific foods or nutritional schemes are able to affect both human metabolism and energy expenditure, thus facilitating weight loss. This critical review is aimed at assessing available evidence on the roles of nutrients, food and dietary regimens in energy intake and energy expenditure. We queried the National Library of Medicine, the Cochrane Library, Excerpta Medica dataBASEand the Cumulative Index to Nursing and Allied Health Literature database, and a search strategy was performed by using database-specific subject headings and keywords. We found that available scientific evidence on these topics is scarce, and that the limited number of available studies often have poor methodological quality. Only a few foods show beneficial effects on metabolism and energy expenditure, as the human energy balance is complex and multifactorial. Finally, microbiota may interfere with the intake, use and expenditure of energy in the human body. Conclusive evidence is still lacking, and, at present, it is not possible to identify a food or a diet with a significant impact on human energy expenditure.

Capsaicin—the major bioactive ingredient of chili peppers: bio-efficacy and delivery systems

The mechanisms of bio-efficacy of capsaicin and delivery systems with enhanced bioavailability were reviewed.

Assessment of Pharmacology, Safety, and Metabolic activity of Capsaicin Feeding in Mice

Capsaicin (CAP) activates transient receptor potential vanilloid subfamily 1 (TRPV1) to counter high-fat diet (HFD)-induced obesity. Several studies suggest that CAP induces the browning of white adipocytes in vitro or inguinal white adipose tissue (iWAT) in vivo. However, there is a lack of data on the dose-response for CAP to inhibit HFD-induced obesity. Therefore, we first performed experiments to correlate the effect of various doses of CAP to prevent HFD-induced weight gain in wild-type (WT) mice. Next, we performed a subchronic safety study in WT mice fed a normal chow diet (NCD ± CAP, 0.01% in NCD) or HFD ± CAP (0.01% in HFD) for eight months. We analyzed the expression of adipogenic and thermogenic genes and proteins in the iWAT from these mice, conducted histological studies of vital organs, measured the inflammatory cytokines in plasma and iWAT, and evaluated liver and kidney functions. The dose-response study showed that CAP, at doses above 0.001% in HFD, countered HFD-induced obesity in mice. However, no difference in the anti-obesity effect of CAP was observed at doses above 0.003% in HFD. Also, CAP, above 0.001%, enhanced the expression of sirtuin-1 and thermogenic uncoupling protein 1 (UCP-1) in the iWAT. Safety analyses suggest that CAP did not cause inflammation. However, HFD elevated plasma alanine aminotransferase and creatinine, caused iWAT hypertrophy and hepatic steatosis, and CAP reversed these. Our data suggest that CAP antagonizes HFD-induced metabolic stress and inflammation, while it does not cause any systemic toxicities and is well tolerated by mice.

Properties of capsaicin and its utility in veterinary and human medicine

The main aim of this paper was to show the variety of capsaicin's properties. Capsaicin is an active component of plants of the Capsicum genus, and is known for its pungency. Capsaicin is used in the food, pharmaceutical and cosmetic industries. Additional properties of capsaicin have been demonstrated, including pain relief, weight loss, body thermoregulation, and antioxidant, antimicrobial and anticancer activities. Studies of capsaicin's effects on the human and animal organism need to be continued, with special emphasis on new applications.

Binding Efficacy and Thermogenic Efficiency of Pungent and Nonpungent Analogs of Capsaicin

(1) Background: Capsaicin, a chief ingredient of natural chili peppers, enhances metabolism and energy expenditure and stimulates the browning of white adipose tissue (WAT) and brown fat activation to counter diet-induced obesity. Although capsaicin and its nonpungent analogs are shown to enhance energy expenditure, their efficiency to bind to and activate their receptor—transient receptor potential vanilloid subfamily 1 (TRPV1)—to mediate thermogenic effects remains unclear. (2) Methods: We analyzed the binding efficiency of capsaicin analogs by molecular docking. We fed wild type mice a normal chow or high fat diet (± 0.01% pungent or nonpungent capsaicin analog) and isolated inguinal WAT to analyze the expression of thermogenic genes and proteins. (3) Results: Capsaicin, but not its nonpungent analogs, efficiently binds to TRPV1, prevents high fat diet-induced weight gain, and upregulates thermogenic protein expression in WAT. Molecular docking studies indicate that capsaicin exhibits the highest binding efficacy to TRPV1 because it has a hydrogen bond that anchors it to TRPV1. Capsiate, which lacks the hydrogen bond, and therefore, does not anchor to TRPV1. (4) Conclusions: Long-term activation of TRPV1 is imminent for the anti-obesity effect of capsaicin. Efforts to decrease the pungency of capsaicin will help in advancing it to mitigate obesity and metabolic dysfunction in humans.

Troglitazone activates TRPV1 and causes deacetylation of PPARγ in 3T3-L1 cells

Published research suggests that activation of transient receptor potential vanilloid subfamily 1 (TRPV1) enhances the expression and deacetylation of peroxisome proliferator-activated receptor gamma (PPARγ) to cause browning of white adipose tissue. Here, we show that TRPV1 activation by capsaicin significantly prevents high fat diet-induced obesity in mice. This is associated with an increase in the expression and deacetylation of PPARγ in the epididymal fat of these mice. Consistent with the TRPV1 activation in vivo, overexpression of TRPV1 enhanced the PPARγ and other thermogenic genes in cultured 3T3-L1 preadipocytes. To determine the interaction between TRPV1 and PPARγ signaling, we analyzed the effect of Troglitazone (Trog; a thiazolidinedione derivative and an agonist of PAARγ) treatment on cultured 3T3-L1 cells. Trog enhanced the expression of TRPV1, PPARγ and thermogenic proteins in undifferentiated 3T3-L1 cells but not in differentiated cells. Acute application of Trog stimulated a robust Ca²⁺ influx into 3T3-L1 cells and TRPV1 inhibition by capsazepine prevented this. More interestingly, Trog or capsaicin treatment caused the deacetylation of PPARγ in 3T3-L1 cells and inhibition of TRPV1 or Sirtuin 1 - prevented this. Our data suggest a novel effect of Trog to induce PPARγ deacetylation by activating TRPV1. This research has a significant implication on the role of TRPV1 and PPARγ signaling in the browning of white adipose tissue.

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'.

Molecular mechanisms of the anti-obesity effect of bioactive ingredients in common spices: a review

The mechanisms of the anti-obesity effects of bioactive compounds in common spices in adipocytes, animal models and human participants have been reviewed.

Diversity effect of capsaicin on different types of skeletal muscle

Capsaicin is a major pungent content in green and red peppers which are widely used as spice, and capsaicin may activate different receptors. To determine whether capsaicin has different effects on different types of skeletal muscle, we applied different concentrations (0, 0.01, and 0.02%) of capsaicin in the normal diet and conducted a four-week experiment on Sprague-Dawley rats. The fiber type composition, glucose metabolism enzyme activity, and different signaling molecules' expressions of receptors were detected. Our results suggested that capsaicin reduced the body fat deposition, while promoting the slow muscle-related gene expression and increasing the enzyme activity in the gastrocnemius and soleus muscles. However, fatty acid metabolism was significantly increased only in the soleus muscle. The study of intracellular signaling suggested that the transient receptor potential vanilloid 1 (TRPV1) and cannabinoid receptors in the soleus muscle were more sensitive to capsaicin. In conclusion, the distribution of TRPV1 and cannabinoid receptors differs in different types of muscle, and the different roles of capsaicin in different types of muscle may be related to the different degrees of activation of receptors.

Involvement of thermosensitive TRP channels in energy metabolism

To date, 11 thermosensitive transient receptor potential (thermo-TRP) channels have been identified. Recent studies have characterized the mechanism of thermosensing by thermo-TRPs and the physiological role of thermo-TRPs in energy metabolism. In this review, we highlight the role of various thermo-TRPs in energy metabolism and hormone secretion. In the pancreas, TRPM2 and other TRPs regulate insulin secretion. TRPV2 expressed in brown adipocytes contributes to differentiation and/or thermogenesis. Sensory nerves that express TRPV1 promote increased energy expenditure by activating sympathetic nerves and adrenaline secretion. Here, we first show that capsaicin-induced adrenaline secretion is completely impaired in TRPV1 knockout mice. The thermogenic effects of TRPV1 agonists are attributable to brown adipose tissue (BAT) activation in mice and humans. Moreover, TRPA1- and TRPM8-expressing sensory nerves also contribute to potentiation of BAT thermogenesis and energy expenditure in mice. Together, thermo-TRPs are promising targets for combating obesity and metabolic disorders.