Health & Wellbeing

Fermented vs. high-fiber diet microbiome study delivers surprising results

Fermented vs. high-fiber diet ...
A ten-week trial found fermented food diet improved microbiome diversity and reduced inflammatory biomarkers while a high-fiber diet had little effect
A ten-week trial found fermented food diet improved microbiome diversity and reduced inflammatory biomarkers while a high-fiber diet had little effect
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A ten-week trial found fermented food diet improved microbiome diversity and reduced inflammatory biomarkers while a high-fiber diet had little effect
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A ten-week trial found fermented food diet improved microbiome diversity and reduced inflammatory biomarkers while a high-fiber diet had little effect

Investigating the relationship between diet, gut bacteria and systemic inflammation, a team of Stanford University researchers has found just a few weeks of following a diet rich in fermented foods can lead to improvements in microbiome diversity and reductions in inflammatory biomarkers.

The new research pitted a high-fiber diet against a diet with lots of fermented food. Thirty-six healthy adults were recruited and randomly assigned one of the two diets for 10 weeks.

“We wanted to conduct a proof-of-concept study that could test whether microbiota-targeted food could be an avenue for combatting the overwhelming rise in chronic inflammatory diseases,” explains Christopher Gardner, co-senior author on the new study.

Blood and stool samples were collected before, during, and after the dietary intervention. Over the course of the trial the researchers saw levels of 19 inflammatory proteins drop in the fermented food cohort. This was alongside increases in microbial diversity in the gut and reduced activity in four types of immune cells.

Perhaps most significantly, these changes were not detected in the group tasked with eating a high-fiber diet. Erica Sonnenburg, another co-senior author on the study, says this discordancy between the two cohorts was unexpected.

“We expected high fiber to have a more universally beneficial effect and increase microbiota diversity,” she says. “The data suggest that increased fiber intake alone over a short time period is insufficient to increase microbiota diversity.”

One hypothesis raised in the study to explain the different responses to the two diets is that fiber-induced microbiota diversity increases can take longer to manifest than fermented food-induced changes. Several biomarker changes were noted in the fiber diet cohort, including altered short-chain fatty acid production and increased stool microbial protein density. The researchers note these are indications high-fiber diets can remodel gut microbial populations but potentially at a slower rate than fermented foods.

“It is possible that a longer intervention would have allowed for the microbiota to adequately adapt to the increase in fiber consumption,” notes Sonnenburg. “Alternatively, the deliberate introduction of fiber-consuming microbes may be required to increase the microbiota’s capacity to break down the carbohydrates.”

Perhaps the biggest takeaway from this new study is the rapid immune and microbiome changes induced by the fermented diet and the consistency of responses across the whole cohort. Justin Sonnenburg, another researcher working on the project called the findings a “stunning” demonstration of how a small dietary change in healthy adults can influence microbial diversity and subsequent immune activity.

The next step for the researchers will be to move to animal studies and explore what specific mechanisms are mediating these dietary-induced changes. Plus, the researchers are also curious about whether a combined high-fiber and fermented food diet enhances these responses.

“There are many more ways to target the microbiome with food and supplements, and we hope to continue to investigate how different diets, probiotics and prebiotics impact the microbiome and health in different groups,” says Justin Sonnenburg.

The new study was published in the journal Cell.

Source: Stanford Medicine

12 comments
12 comments
Nick Arrizza
Clearly this is an encouraging finding but something we probably already knew intuitively; after all adding new microbes with fermented foods is instantaneous where as growing a new microbiome with high fibre foods takes time. My question is, if the fermented food is only transient and a normal Western diet low in fibre is continued will this diversity sustain itself or will it degenerate to its previous state? In other words a high fibre diet although taking longer to establish a diverse microbiome will also help to sustain it in the long run. So, yes, kick start your new microbiome with fermented plants and sustain it with a high fibre whole plant based diet. But didn't we already know this?
c2cam
@Nick - well put, my thoughts as well.
guzmanchinky
What constitutes fermented foods? Pickles and such? I need to look into this...
lon4
If fermented grapes count I have a very diverse bioome now!
Dreadalus
from med.stanford.edu, "...foods such as yogurt, kefir, fermented cottage cheese, kimchi and other fermented vegetables, vegetable brine drinks, and kombucha tea..."

Vegetable brine drinks? That seems pretty hardcore.
Karmudjun
NIce Job Rich - an excellent synopsis with the absence of extremely important supportive information that I have lifted from the Stanford page:
"Eating foods such as yogurt, kefir, fermented cottage cheese, kimchi and other fermented vegetables, vegetable brine drinks, and kombucha tea led to an increase in overall microbial diversity, with stronger effects from larger servings."
Clearly certain fermented grapes have health benefits, as do pickles, but where lay or non-medical people take this without the list above is absurd to inane. Personally I am all the above except for fermented cottage cheese & kimchi. But I can let "food be my medicine" or exercise a "healthy lifestyle diet" as Hippocrates wrote.
Calcfan
Articles like this should include the quantities of foods and a list of them.
Gary
One serving of fermented foods were defined as the following: kombucha, yogurt, kefir, buttermilk, kvass = 6 oz, kimchi, sauerkraut, other fermented veggies = 1/4 cup, vegetable brine drink = 2 oz. Broad categories of fermented foods were grouped into cottage cheese, kefir, kombucha, vegetable brine drinks, vegetables, yogurt, other foods, and other drinks.
Tristan P
Yes Ion4, I've also quite a diverse range of fermented plants in my diet. Fermented grapes. Fermented grain. Fermented barley. Even fermented sugar cane. I should live to 100!
greg heil
i suspect microbiomic diversity is very specific. One needs fermented food supplements for each food type one consumes... Eg Natto for beans, KimChi/Kraut for Vegy fibers, Yoghourt for sweets and milks. Personally i look for and consume a variety of fermented foods including Kefir, Kombucha ... a continuous stream keeps the good DNA tools in and the baddies are crowded out.