How purple tea enhances GLP-1 signaling to support TMAO reduction

Purple tea, derived from the vibrant Camellia sinensis​ plant, is celebrated for its striking color, unique flavor, and potential health benefits.​

Rich in anthocyanins, this remarkable varietal plays a critical role in addressing metabolic health challenges by targeting harmful biomarkers like trimethylamine-N-oxide (TMAO). Emerging research from Vidya highlights the innovative potential of this tea in the dietary supplement landscape, particularly its ability to reduce TMAO biomarkers, which are essential to regulate the glucagon-like peptide-1 (GLP-1) receptor.

Purple tea, developed by the Tea Research Foundation of Kenya (TRFK), has a wide variety of polyphenols compared to other popular teas, such as green tea. Purple tea contains not only polyphenolic compounds commonly found in green tea, such as epigallocatechin gallate (EGCG) and epicatechin gallate (ECG), but also anthocyanidins (malvidin, pelargonidin, and cyanidin 3-O-galactoside) and 1,2-di-O-galloyl- 4,6-O-(S)-hexahydroxydiphenoyl-β-D-glucose (GHG), a hydrolyzable tannin.

“Purple tea extract presents novel ingredient opportunities to boost the intake of these critical compounds and support lower TMAO biomarkers that positively influence the GLP-1 pathway,” says Aleksander Richards, Director of Clinical Research and Development at Vidya.

Purple tea’s role in metabolic health ​

Vidya, a leading global manufacturer of biotics and herbal extracts, is introducing a new purple tea extract, Porelis^TM​, with compelling research that sheds light on how an ingredient with naturally high anthocyanin levels may help address contributing factors for metabolic disorders, such as high TMAO biomarkers.

With evidence supporting its efficacy, purple tea is positioned to redefine nutritional strategies for managing common inflammatory response issues related to problems in metabolic health. Research by Vidya builds on a human clinical trial by Shimoda, H. et al., showing that purple tea improves obesity parameters compared to baseline, including BMI, body fat mass index, and body weight.²​

In 2024, a double-blind, randomized, placebo-controlled, cross-over study, a daily intake of 250mg of Porelis, standardized to 3% GHG, demonstrated significant inhibition in TMAO biomarkers by 12% and a statistically significant reduction in body weight and BMI compared to placebo.¹​

Figure 1: In a study with Porelis, TMAO levels were significantly reduced in plasma fasting levels from baseline (173.86 +/- 5.94ng/mL) to the end of the study (155.15 +/- 10.60, ng/mL).¹​​​

Research that examines the gut microbiome and digestive pathways in the liver and gut shows that dysregulation of TMAO is apparent in metabolic health issues, including diabetes and obesity. The metabolite TMAO is synthesized from trimethylamine (TMA), a metabolite of various precursors, mainly choline and carnitine.

The recent uptick in the use of GLP-1 agonist drugs for metabolic disorders opens avenues to explain how high TMAO levels impair glucose tolerance by blocking the hepatic insulin signaling pathway, causing systemic inflammation in adipose tissue and accelerating the development of metabolic disorders.

One factor in this disruption is inadequate short-chain fatty acids (SCFAs), including acetate, propionate, and butyrate. Short-chain fatty acids from anthocyanins enhance the release of propionate-upregulated peptide YY (PYY) and GLP-1 peptides, which reduces TMAO levels.

Further examination is underway to confirm Porelis’ mechanism of action; however, it is well-known that anthocyanins positively influence gut microbiota and inhibit the growth of TMA-producing bacterial strains in the gut with the aid of these SCFAs.¹ ​

This strongly suggests that Porelis has the potential to remodel gut microbiota and increase the uptake of SCFAs, reducing the overproduction of TMAO.

• The Vidya study shows Porelis was well-tolerated by human test subjects.¹​
• BMI decreased from baseline (27.92 +/- 1.72 kg/m²​) to the end of the study (27.22 +/- 1.90 kg/m²​).
• TMAO levels were reduced in plasma fasting levels from baseline (173.86 +/- 5.94ng/mL) to the end of the study (155.15 +/- 10.60, ng/mL).
• Porelis’ proprietary bioactive extract consists of standardized 3-5% of 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-β-D-glucose (GHG).
• This ingredient and supporting research are evidence that plant polyphenols may exert prebiotic properties that modulate gut microbiota and inhibit the growth of TMAO-producing bacterial strains.
• Anthocyanins in Porelis have antioxidant and anti-inflammatory properties that support gut microbiota and healthy metabolic processes.
• Purple tea provides catechins and epicatechin metabolites that act as potent scavengers of free radicals and support healthy mitochondrial function.

Despite their importance to human health, intake of anthocyanins is currently limited among adults. China is the only country with proposed levels of 50mg/day for anthocyanins.³ ​Ingestion of anthocyanins in Italy is the highest among Western countries from red-blue fruits and vegetables and wine in the Mediterranean diet, with men 64.9mg/day and women 44.1mg/day. NHANES data estimates anthocyanin intake in the US to be ∼11.6 ± 1.1 mg/d for individuals aged ≥20 y, which is lower than necessary to gain health benefits.³​

The dramatic rise of GLP-1 drug prescriptions is a significant indicator that metabolic disorders are a growing worldwide health challenge. As anthocyanin intake and TMAO circulating concentrations are better understood, ingredients like Porelis purple tea extract will open new avenues for developing products that use functional ingredients to support healthy metabolic reactions thanks to an abundance of anthocyanins.

Vidya looks forward to sharing upcoming Porelis published research and educating the ingredient sector on the importance of this exciting new product for metabolic health.

References​

1.​ Vidya, 2024, A Double Blind, Placebo-Controlled, Randomized, Crossover Study to Evaluate the Effectiveness, Safety and Tolerability Of Porelis on Weight Management in Overweight Subject
2. ​Shimoda, H.; et al. Purple Tea and Its Extract Suppress Diet-induced Fat Accumulation in Mice and Human Subjects by Inhibiting Fat Absorption and Enhancing Hepatic Carnitine Palmitoyltransferase Expression.​ Int J Biomed Sci. ​2015;11(2):67-75.
3.​ Wallace, T.C.; et al. Anthocyanins.​ Adv Nutr. 2015 Sep 15;6(5):620-2.

Additional references​

da Silva, TBV.; et al. Purple tea: chemical characterization and evaluation as inhibitor of pancreatic lipase and fat digestion in mice. Food Funct. 2023;14(3):1761-1772. Published 2023 Feb 6.

Kilel, EC.; et al. Green tea from purple leaf coloured tea clones in Kenya- their quality characteristics. Food Chem​. 2013;141(2):769-775.

Sandoval-Ramírez, B.A.; et al. The health benefits of anthocyanins: an umbrella review of systematic reviews and meta-analysesof observational studies and controlled clinical trials. Nutr Rev​. 2022;80(6):1515-1530. 

Chen, M.L.; et al. Resveratrol Attenuates Trimethylamine-N-Oxide (TMAO)-Induced Atherosclerosis by Regulating TMAO Synthesis and Bile Acid Metabolism via Remodeling of the Gut Microbiota. mBio​. 2016;7(2):e02210-15.

Annunziata, G.; et al. Effects of Grape Pomace Polyphenolic Extract (Taurisolo®) in Reducing TMAO Serum Levels in Humans: Preliminary Results from a Randomized, Placebo-Controlled, Cross-Over Study. Nutrients​. 2019;11(1):139. 

Pastor-Villaescusa, B.; et al. Polyphenols in Obesity and Metabolic Syndrome. [Updated 2018 Oct 05]. In: Editor(s): Amelia Marti del Moral, Concepción María Aguilera García, Obesity: Oxidative Stress and Dietary Antioxidants. 2018, Pages 213- 239. Academic Press. 

Rochoń, J.; et al. Role of gut-liver axis and glucagon-like peptide-1 receptor agonists in the treatment of metabolic dysfunction-associated fatty liver disease. World J Gastroenterol​ 2024; 30(23): 2964-2980.

Gonçalves, A.C.; Dietary Effects of Anthocyanins in Human Health: A Comprehensive Review. Pharmaceuticals (Basel)​. 2021;14(7):690. Published 2021 Jul 18.