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Research seeds: Chilli

In this article, we discuss the paper ‚ÄúHealthy Subjects Differentially Respond to Dietary Capsaicin Correlating with Specific Gut Enterotypes‚ÄĚ

Plant name and species

Chilli peppers (Capsicum frutescens L)

research seeds chilli

Aim of study

The aim of the study was to assess the effect of dietary capsaicin, a spicy molecule found in chilli peppers on the metabolic and immune profiles of people. The study also investigated how capsaicin affects gut microbes in healthy adults.

Study method

12 healthy people were given a weight maintenance diet for 6 weeks. They were then given 0, 5, 0, and 10 mg/d of capsaicin from chilli powder.

In the first week, participants were not given any chilli powder. After that they were given 5 mg/d of capsaicin for 2 weeks, then a 2-week high capsaicin intervention (10 mg/d) with a week in between where they had no chilli extract. 

At the end of each period, anthropometric and basal metabolism measurements were taken. 

The metabolic rate of patients (how much energy the body burns) was measured, as was their appetite. They also took blood and faecal samples. A daily questionnaire was also completed which monitored their symptoms of bowel movement, flatulence, stool consistency and other discomforts. 

The blood and faecal samples were used to measure plasma metabolic and inflammatory markers as well as the gut microbial ecology of each subject.

Herbal preparation: Red chilli pepper powders (from Capsicum frutescens L) were used as the source of dietary CAP, which contained 1.05mg/g CAP, 0.58 mg/g dihydrocapsaicin and 0.12 mg/g nordihydrocapsaicin.

Sample size: 12 healthy patients were given the chilli extract.

Results of study

With regards to the microbiome, capsaicin supplement increased the Firmicutes/Bacteroidetes ratio and Faecalibacterium abundance. It also increased plasma levels of glucagon-like peptide 1 and gastric inhibitory polypeptide, and decreased plasma ghrelin levels.


Ghrelin is a gut hormone which affects appetite, and reducing ghrelin decreases appetite. Glucagon-like peptide 1 encourages the release of insulin, as does gastric inhibitory polypeptide. This helps us to metabolise sugar therefore affecting our metabolism.¬†Firmicutes and Bacteroidetes have gained much attention in recent years as they are thought to be two of the most influential bacteria in maintaining normal intestinal homeostasis. Some scientists deem them the ‚Äútwo most important bacterial phyla in the gastrointestinal tract‚ÄĚ (1). Therefore, capsaicin‚Äôs ability to increase their ratio in the gut is indicative of chillis’s positive effect on gut health.

Capsaicin is an isolated compound found in chilli and is administered here in high concentrations. Although capsaicin is naturally found in chilli, it is not normally present in such high levels. However, the chemical complexity of more traditional natural extracts means that there is a whole array of other medicinal compounds found that can contribute synergistically to both the therapeutic efficacy of the plant and its safety.


This study shows that chilli, specifically capsaicin which is one of the spicy compounds in chilli helps to improve the ratio of healthy bacteria in our gut and also improves metabolic parameters.

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