Polyphenols and your gut

We often talk about fibre when it comes to good gut health. Whether we’re talking about supporting bowel health, feeding your good gut bacteria, or improving the regularity of your bowels, fibre is often at the heart of the conversation (and for good reason)! However, there are also non-nutrients called polyphenols found in plant foods that are almost never talked about but are a big part of the picture when it comes to the health-promoting properties of plant foods. Research has shown that over 90% of the polyphenols found in berries reach the colon (passing the small intestine) and can interact with the microbiota where they exert their effects [1]. Let’s take a look at how polyphenols interact with the gut.

Anti-bacterial

Polyphenols are anti-bacterial can prevent bacterial overgrowth in the gut. They have been shown to selectively inhibit the growth of pathogenic bacteria, such as the flavonoids found in red wine or the anthocyanins found in raspberries [2].

Anti-inflammatory

Polyphenols have also been shown to have an anti-inflammatory effect in the gut, through increasing the amounts of gut microbes that produce butyrate and other short chain fatty acids [1]. Butyrate provides many health benefits including strengthened immunity and having a cardioprotective effect. Additionally, our gut microbiota can enhance the bioavailability of polyphenols and convert them to bioavailable metabolites [3].

Prebiotic-like effects

They have also been shown to have a prebiotic-like effect, where they help good bacteria to flourish. A study found that 4-weeks of freeze-dried strawberry powder (one of the richest sources of polyphenols) led to significant changes in certain good gut microbes that are associated with health and longevity [4].

Gut-brain axis

Through the above-mentioned mechanisms, polyphenols appear to also indirectly support brain health via the gut brain axis. By inhibiting bacterial overgrowth and enhancing the bioavailability of benefiting compounds, polyphenols may support brain health [5]. Studies have shown that berries may reduce cognitive fatigue, improve cognitive performance, and may slow cognitive decline [6].

A Final Word

There is growing research on the health benefits of polyphenols, including their effects on the gut microbiota. We suggest including plenty of polyphenol-rich foods in your diet to support your gut health, such as blueberries, raspberries, blackberries, strawberries, extra virgin olive oil and coffee!

References

[1] Komarnytsky S, Wagner C, Gutierrez J, Shaw OM. Berries in Microbiome-Mediated Gastrointestinal, Metabolic, and Immune Health. Curr Nutr Rep. 2023 Mar;12(1):151-166. doi: 10.1007/s13668-023-00449-0. Epub 2023 Feb 4. PMID: 36738429.

[2] Makarewicz M, Drożdż I, Tarko T, Duda-Chodak A. The Interactions between Polyphenols and Microorganisms, Especially Gut Microbiota. Antioxidants (Basel). 2021 Jan 28;10(2):188. doi: 10.3390/antiox10020188. PMID: 33525629; PMCID: PMC7911950.

[3] Plamada D, Vodnar DC. Polyphenols-Gut Microbiota Interrelationship: A Transition to a New Generation of Prebiotics. Nutrients. 2021 Dec 28;14(1):137. doi: 10.3390/nu14010137. PMID: 35011012; PMCID: PMC8747136.

[4] Ezzat-Zadeh Z, Henning SM, Yang J, Woo SL, Lee RP, Huang J, Thames G, Gilbuena I, Tseng CH, Heber D, Li Z. California strawberry consumption increased the abundance of gut microorganisms related to lean body weight, health and longevity in healthy subjects. Nutr Res. 2021 Jan;85:60-70. doi: 10.1016/j.nutres.2020.12.006. Epub 2020 Dec 5. PMID: 33450667.

[5] Travica N, D'Cunha NM, Naumovski N, Kent K, Mellor DD, Firth J, Georgousopoulou EN, Dean OM, Loughman A, Jacka F, Marx W. The effect of blueberry interventions on cognitive performance and mood: A systematic review of randomized controlled trials. Brain Behav Immun. 2020 Mar;85:96-105. doi: 10.1016/j.bbi.2019.04.001. Epub 2019 Apr 15. PMID: 30999017.

[6] Whyte AR, Cheng N, Butler LT, Lamport DJ, Williams CM. Flavonoid-rich mixed berries maintain and improve cognitive function over a 6 h period in young healthy adults. Nutrients 2019. https://doi.org/10.3390/nu11112685.