Plant-based RG-I ingredient may support immune function, modulate the microbiota: Study

By Stephen Daniells

- Last updated on GMT

© Filkina Natalia / Getty Images
© Filkina Natalia / Getty Images

Related tags immune support Gut microbiota carrot bell peppers Upcycling

Pectin-derived rhamnogalacturonan-I (RG-I) polysaccharides from bell pepper and carrot may stimulate the immune system and modulate the gut microbiota, says a new study from Europe.

Data published in Nutrients​ indicated that RG-I from bell pepper and carrot offered similar immune- and microbiota modulatory potential in vitro, while a proof-of-concept trial in humans showed that RG-I from bell pepper (bpRG-I) was well tolerated and enhanced innate immune responsiveness.

“RG-I enriched extracts prime innate immune responses and display a dual mode of action by exerting (1) an immunomodulatory effect on phagocytosis, a biomarker previously shown in some studies with ginseng-PS to be associated with protective effects against respiratory infections, and (2) a microbiota modulatory effect, with concomitant enhanced production of SCFA [short chain fatty acids],” ​wrote the researchers.


The ingredients are being developed and commercialized by Netherlands-based NutriLeads. The privately held company was founded in 2012 and is and backed by investors including Icos Capital, Goeie Grutten, DSM Venturing, Oost NL, SHIFT Invest and Thuja Capital.

The company’s lead ingredient, BeniCaros, is extracted from carrot pomace, which itself is a side stream from carrot juice production. This ingredient is expected to be available in the US for the formulation of dietary supplements and functional foods in the second half of 2021.

Commenting on the publication and the expected impact of the findings, Ruud Albers, PhD, CEO of NutriLeads, said: “We are delighted to share these new data, demonstrating the immunomodulatory effects of plant-based RG-I, which have the potential to bring health benefits to us all. We are particularly pleased that we can successfully derive RG-I from sustainable and widely available sources.

“Due to the pandemic, immune health is even higher on the agenda than ever before, and we believe that this research shows that dietary supplementation with RG-I from specific food crops is ideally suited to support immune function and modulate the microbiota.”

Indeed, demand for dietary supplements and functional food and beverage products with immune health properties sky-rocketed in 2020 after years of steady growth. The global immune health supplements market alone was estimated to be worth US$ 16.32 billion in 2019 and is expected to reach USD 29.40 billion by 2027, according to Fortune Business Insights​.

“We are well advanced with generating additional evidence showing the immune benefits of carrot-derived RG-I and are working together with Food and Food Supplement companies to deliver these benefits to consumers in the second half of 2021,” ​added Albers.

Study details

RG-I are natural, plant-derived polysaccharides that interact with the gut bacteria and the host innate immune system. For the new study, the researchers tested RG-I from bell pepper (Capsicum annuum​) and carrot (Daucus carota​), which were identified as the key immunostimulatory substances using activity-guided fractionation.

For the in vitro​ study, the researchers measured phagocytosis activity, the secretion of cytokines in Peripheral Blood Mononuclear Cells (PBMC) and Whole Blood obtained from healthy donors, and assessed the impact on the gut microbiome using the colonic incubation methods developed by ProDigest.

The in vitro results showed that both bpRG-I and cRG-I stimulated phagocytosis, and both stimulated comparable levels of a range of cytokines in a dose-dependent manner, including TNF-alpha, IL-10, IL-6 and IL1beta.

The colonic incubation showed that “bpRG-I and cRG-I extracts induced a shift in microbiota composition over 48 h leading to an increase in the proportional abundance of Bacteroidetes and concomitant decrease in Firmicutes and Proteobacteria as compared to the base medium,” ​wrote the researchers.

“At the family level, this was mainly driven by elevated relative levels of Bacteroidaceae, and reduced levels of Lachnospiraceae and Enterobacteriaceae.

Since both sources of RG-I led to comparable results, the researchers focused on the bell pepper extract for a human proof of concept study, which showed the ingredient was well tolerated and enhanced innate immune responsiveness in vivo​.

“These results provide an important step towards testing the efficacy of RG-I from bell pepper or carrot in a fully powered respiratory infection trial in humans,” ​concluded the researchers.

The researchers were affiliated with: Suze Consulting (The Netherlands); IMcoMET BV (The Netherlands); Glykos Finland Oy (Finland); Unilever, Foods Innovation Centre (The Netherlands); Rijk Zwaan (The Netherlands); ProDigest BV (Belgium); Analyze & Realize GmbH (Germany); Nutrileads BV (The Netherlands); and Wageningen University (The Netherlands).

Source: Nutrients
“Development of an Affordable, Sustainable and Efficacious Plant-Based Immunomodulatory Food Ingredient Based on Bell Pepper or Carrot RG-I Pectic Polysaccharides”
Authors: S. McKay et al​.

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