Inulin

Inulin is a naturally occurring fructose polysaccharide found in the roots and rhizomes of several plants. Chemically, inulin is an unbranched polysaccharide belonging to the class of fructans. It is composed of 30–35 fructose units linked by β-1,2-glycosidic bonds. It is used in the cosmetic industry in skincare and hair care formulations.1,2 In skincare formulations it is added for its prebiotic activity. With its humectant properties, it provides skin the needed hydration and strengthens the skin barrier through skin microbiota primarily. It reduces the growth of bad bacteria in favor of friendly microorganisms naturally present on the skin.  only organisms with inulinase enzymes can metabolize inulin which is present in the skin microbiome. Due to this, inulin acts as a prebiotic and only feeds select protective organisms that in turn provide food for others, thus supporting the microbiota and protecting the Integrity of the Skin Microbiota from Preservatives while nourishing it. It is also known to have antioxidant activity and hence scavenges the free radicals formed due to the stress-induced damage to the skin. Inulin can be extracted from a variety of plant sources but the content of inulin present and the efficacy of the inulin depends on the source of extraction.

It favors good bacteria over bad bacteria. The outermost layer of the skin is the microbial layer, the skin microbiota. Staphylococcus epidermis, one of the dominant skin-associated bacteria produces several antimicrobial compounds and proteases that can limit the formation of biofilms by pathogenic species.3,4,5 It acts as a shield preventing the entry of pathogenic bacteria. Colonizing the skin with Staphylococcus epidermis remodels the skin immunity by inducing IL-17a+ CD8+ T cells that migrate to the epidermis, enhance the immunity, and limits pathogen invasion.7,8Numerous studies suggest that the skin microbiome is intricately involved in a wide range of molecular and cellular processes within the skin and beyond.9,10Thus, the nutrients that play an important role in shaping the individual differences in microbial signature ultimately contribute to health and diseases.

It maintains a balance of skin microbiota. The skin microbiome layer is exposed to a variety of factors UV light, preservatives used in day-to-day cosmetics, and environmental pollutants that disrupt and damage the skin microbiota.9,10Usage of prebiotics have numerous beneficial effects.11Clinical studies have proven Inulin’s function as a prebiotic resulting in the growth and maintenance of skin microbiota.11Having a healthy well-balanced skin microbiome will result in better hydration of the skin. Clinical studies done using 0.1% of hyaluronic acid and 1.5% Inulin have shown that the subjects who used inulin had better hydration compared to hyaluronic acid.14

The inulin used in Trouvaille product line has been categorized as the most innovative ingredient to improve skin barrier function and has protective and restructuring effects on the skin. It exhibits vitamin D3 like activity and hence improves hydration levels and strengthens the skin barrier. Clinical studies done on 50 women have proven that in a time period of 14 to 28 days there is improved skin hydration and skin barrier. Transepidermal water loss was reduced and an improved microrelief was observed over a 28-day period. An another independent study has shown that it even counteracts the damage caused due to the preservatives used in the cosmetics and outperforms hylauronic acid in hydration efficiency.12,13,14

 

Figure-1. UV-induced effects on the skin and potential treatment strategies using microbes, proor pre-biotics.8

 

References:

  1. Distant Site Effects of Ingested Prebiotics. Nutrients 2016, 8, 523.
  2. Inulin as an effectiveness and safe ingredient in cosmetics. P Journal of Chemical Technology, 21, 1, 44-49.
  3. Antimicrobial action is provided by phenol-soluble modulins derived from Staphylococcus epidermiis, a normal resident of the skin. J. Invest.Dermatol. 130, 192–200,2010.
  4. Prebiotic Combinations Effects on the Colonization of Staphylococcal Skin Strains. Microorganisms, 2020 Dec 24;9(1):37.
  5. Potential of Skin Microbiome, Pro- and/or Pre-Biotics to Affect Local Cutaneous Responses to UV Exposure. Nutrients 2020, 12, 1795.
  6. Commensal-dendritic-cell interaction specifies a unique protective skin immune signature. Nature 2015, 520, 104–108.
  7. Commensal microbiota modulate gene expression in the skin. Microbiome 2018, 6, 20.
  8. Skin Microbiome Modulates the Effect of Ultraviolet Radiation on Cellular Response and Immune Function. iScience 2019, 15, 211–222.
  9. Photoprotective effects of galacto-oligosaccharide and/or Bifidobacterium longum supplementation against skin damage induced by ultraviolet irradiation in hairless mice. Int. J. Food Sci. Nutr. 2015, 66, 923–930.
  10. The human skin microbiome. Nat. Rev. Microbiol.. 2018, 16, 143–155.
  11. Inulin-Type Prebiotics – A Review: Part, Alternative Medicine Review Volume 13, Number 4 2008.
  12. Cichorium intybus root extract: A “vitamin D-like” active ingredient to improve skin barrier function. May 20, Journal of Dermalogical Treatment 28(1):1-4.
  13. Characterization of oily mature skin by biophysical and skin imaging techniques, February 2018. Skin Research and Technology 24(3).
  14. Prebiotics: Are they weapons for preservatives? (cosmeticsbusiness.com).