A report published in “Applied and Environmental Microbiology” discussess the ability to metabolize complex sugar molecules from cranberries by Bifidobacterium longum.
Bifidobacterium longum supspecies longum, which is one of the good guys in our gut flora is typically present in adults. Infants are mainly colonized by the variant Bifidobacterium longum supsp. infantis, which enables them to metabolize human milk.
The good news is that B. longum can metabolize complex sugar molecules found in cranberries (the molecules are called xyloglucans). Worded more precisely, even though our human cells are not able to break down these molecules, the gut flora, with the species mentioned above, can. This is advantageous not only for us as we get to break down the ‘waste products’, which we can, but it is also beneficial for other good microbes in our gut flora, who use those products as fuel for growth as well.
The researchers put B. longum on a restrictive diet of only xyloglucans and looked at what would happen (i.e. survive or die). In short, the tested B longum subsp longum didn’t mind and grew as fast as it would on glucose, but could not use the molecules to the same efficiency as it would on glucose (its biomass was only moderately increased compared to glucose).
In contrast the tested B longum subsp infantis did not grow on this medium at all.
How did other species fare?
- Lactobacillus plantarum did even better than B. longum in terms of growth, survival, but had a slower growth rate
- L. johnsonii
B.longum metabolizes the xyloglucans via the bifid shunt. The bifid shunt is the name of the process that leads to the degradation of sugars into acetate and lactate in a theoretical 1:5 ratio. With the restrictive diet of xyloglucans (i.e. no glucose), that ratio went up for B longum (2.5).
During degradation of xyloglucans, the formate:lactate ratio went up to 2.5:0.3 (vs 0.05:0.05 when using glucose).
In addition, the resulting metabolites from crude cranberry extract benefitted other microbes in the gut, providing more fuel (and hence more thriving) for them
For further information, please have a look at the full publication!
Cheers! 🙂