Whole oats better than isolated components for gut health

Posted on Thu, 11 Apr 19

Isolated prebiotics and polyphenols are sold as gut health supplements, but an intriguing study suggests that whole, unrefined food sources may sometimes be better.  

Whole grain oats consumed as porridge or oatmeal has been shown to have a prebiotic effect, quickly boosting the metabolic activity of healthy gut bacteria. 

The prebiotic effect of oats could be due to key components, in particular unique types of fibres such as β-glucans or polyphenols. But an experimental study aiming to find the prebiotic factor in oats discovered that the sum is greater than its parts. 

After separating β-glucan and polyphenols from oats a research team compared their weight matched prebiotic effects to whole oats on human faecal bacteria composition and metabolism.  

Interestingly, it was the whole oats that had changed gut microbial composition and increased bifidobacteria, whereas isolated β-glucan or polyphenols given at a matched dose did not have the same effect. 

Furthermore, the whole oats increased proliferation of a specific bacteria called Bifidobacterium adolescentis which has the ability to synthesize and secrete the neuroactive substance γ-aminobutyric acid (GABA) and has been associated with disease prevention. 

Although β-glucans and polyphenols did have some unique effects, increasing the phylum Bacteroidetes and Enterobacteriaceae respectively. 

“In conclusion, our study has shown that oat bran as a complex food matrix beneficially increases the number of B. adolescentis and the amount of short chain fatty acid production,” commented the study investigators. “In contrast, a matched dose of the isolated bioactive compounds, β-glucan and other polyphenols did not show any effect on the abundance of Actinobacteria.”

References: 

Kristek A, Wiese M, Heuer P, et al. Oat bran, but not its isolated bioactive β-glucans or polyphenols, have a bifidogenic effect in an in vitro fermentation model of the gut microbiota. Br J Nutr. 2019 Mar;121(5):549-559.