Are you looking for the benefits of fermented food to see if you want to add them to your diet? Would it be better to increase fiber intake instead? Well, you’re in luck, a paper published last year looked at this very topic.
Unfortunately, you often won’t get the full picture of a study from social media or the popular press. Accuracy doesn’t necessarily sell as well as brief and headline-grabbing.
It doesn’t help that people on social media pick a side and only report what supports their bias. And many just skim the abstract and don’t bother reading the whole paper.
So when this paper was disseminated last year, many got the wrong idea. There were benefits of fermented food but not by increasing fiber. In fact, fermented foods increased diversity of the microbiome AND decreased multiple inflammatory markers.
However, a higher fiber diet improved neither diversity nor inflammation. Many took this to mean that you can ignore fiber altogether.
So it’s an open and shut case? Fermented foods are yea and high fiber diets are nay, right? Not so fast.
In fact, this paper likely shows us that there is a proper order to implement these 2 separate dietary factors to optimize their effects.
Benefits of fermented foods may promote benefits of high fiber
The basics of this study were straightforward. Participants either increased their daily fiber intake by 20g/day or increased fermented food intake by 6 servings/day. And they were largely successful at doing so over the 10-week intervention.
The results in the fermented foods group showed increased microbiome diversity and a decrease in inflammation. Furthermore, in addition to seeing higher prevalence of bacteria from the fermented foods, other microbes increased as well.
In the high fiber group, there was an increase in enzymes that degrade fiber. However, there were no changes in inflammation or microbiome diversity. At least not in the group as a whole.
Interestingly, if you stratify the group by microbiome diversity at the beginning of the study, we see some trends. Those who had low diversity at the beginning of the study saw increased inflammation from a high fiber diet.
However, as diversity increased, inflammation decreased. Those with moderate diversity saw a small drop in inflammation, and those with high diversity saw a big decrease.
What this study tells us
Though this study is pretty small(N=18), it gives us some pretty cool insight. In order to get the immune benefits of a high fiber diet, a more diverse microbiome is necessary.
Interestingly, they found increased stool carbohydrate in the high fiber group. This indicates the group as a whole lacked the microbiome to yield the benefits of increased fiber intake. Their microbiome simply didn’t ferment the fiber.
In addition to decreasing inflammation, one of the primary benefits of fermented food was an increase in microbiome diversity. Therefore, it makes sense that increasing fermented food intake before increasing fiber intake may expedite the process of increasing fiber intake.
Therefore, this paper doesn’t indicate that there is no benefit to increasing your fiber intake. It supports the notion that there is a proper order to the introduction of fermented and high fiber foods if your microbiome diversity is low.
Start with the fermented food, then slowly increase fiber intake. If you already have high diversity, the order probably doesn’t matter.
Wondering why they used foods rather than supplements? We covered why fermented and high fiber foods trump supplements in a Youtube video you can check out here:
There’s also a wonderful podcast with 2 of the authors of this study. They cover the results as well as what constitutes a fermented food as well as some of the tricks companies use to make a food seem fermented when it’s not.
Check that out here: