A diet high in fermented foods increases microbiome diversity, lowers inflammation, and improves immune response, according to researchers at Stanford University’s School of Medicine.The groundbreaking results were published in the journal Cell.

In the clinical trial, healthy individuals were fed for 10 weeks, a diet either high in fermented foods and beverages or high in fiber. The fermented diet — which included yogurt, kefir, cottage cheese, kimchi, kombucha, fermented veggies and fermented veggie broth — led to an increase in overall microbial diversity, with stronger effects from larger servings.

“This is a stunning finding,” says Justin Sonnenburg, PhD, an associate professor of microbiology and immunology at Stanford. “It provides one of the first examples of how a simple change in diet can reproducibly remodel the microbiota across a cohort of healthy adults.”

Researchers were particularly pleased to see participants in the fermented foods diet showed less activation in four types of immune cells. There was a decrease in the levels of 19 inflammatory proteins, including interleukin 6, which is linked to rheumatoid arthritis, Type 2 diabetes and chronic stress. 

“Microbiota-targeted diets can change immune status, providing a promising avenue for decreasing inflammation in healthy adults,” says Christopher Gardner, PhD, the Rehnborg Farquhar Professor and director of nutrition studies at the Stanford Prevention Research Center. “This finding was consistent across all participants in the study who were assigned to the higher fermented food group.”

Microbiota Stability vs. Diversity

Continues a press release from Stanford Medicine News Center: By contrast, none of the 19 inflammatory proteins decreased in participants assigned to a high-fiber diet rich in legumes, seeds, whole grains, nuts, vegetables and fruits. On average, the diversity of their gut microbes also remained stable. 

“We expected high fiber to have a more universally beneficial effect and increase microbiota diversity,” said Erica Sonnenburg, PhD, a senior research scientist at Stanford in basic life sciences, microbiology and immunology. “The data suggest that increased fiber intake alone over a short time period is insufficient to increase microbiota diversity.”

Justin and Erica Sonnenburg and Christopher Gardner are co-authors of the study. The lead authors are Hannah Wastyk, a PhD student in bioengineering, and former postdoctoral scholar Gabriela Fragiadakis, PhD, now an assistant professor of medicine at UC-San Francisco.

A wide body of evidence has demonstrated that diet shapes the gut microbiome which, in turn, can affect the immune system and overall health. According to Gardner, low microbiome diversity has been linked to obesity and diabetes.

“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,” Gardner said.

The researchers focused on fiber and fermented foods due to previous reports of their potential health benefits. High-fiber diets have been associated with lower rates of mortality. Fermented foods are thought to help with weight maintenance and may decrease the risk of diabetes, cancer and cardiovascular disease.

The researchers analyzed blood and stool samples collected during a three-week pre-trial period, the 10 weeks of the diet, and a four-week period after the diet when the participants ate as they chose.

The findings paint a nuanced picture of the influence of diet on gut microbes and immune status. Those who increased their consumption of fermented foods showed effects consistent with prior research showing that short-term changes in diet can rapidly alter the gut microbiome. The limited changes in the microbiome for the high-fiber group dovetailed with previous reports of the resilience of the human microbiome over short time periods.

Designing a suite of dietary and microbial strategies

The results also showed that greater fiber intake led to more carbohydrates in stool samples, pointing to incomplete fiber degradation by gut microbes. These findings are consistent with research suggesting that the microbiome of a person living in the industrialized world is depleted of fiber-degrading microbes.

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

In addition to exploring these possibilities, the researchers plan to conduct studies in mice to investigate the molecular mechanisms by which diets alter the microbiome and reduce inflammatory proteins. They also aim to test whether high-fiber and fermented foods synergize to influence the microbiome and immune system of humans. Another goal is to examine whether the consumption of fermented foods decreases inflammation or improves other health markers in patients with immunological and metabolic diseases, in pregnant women, or in older individuals.

“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,” Justin Sonnenburg said.

Other Stanford co-authors are Dalia Perelman, health educator; former graduate students Dylan Dahan, PhD, and Carlos Gonzalez, PhD; graduate student Bryan Merrill; former research assistant Madeline Topf; postdoctoral scholars William Van Treuren, PhD, and Shuo Han, PhD; Jennifer Robinson, PhD, administrative director of the Community Health and Prevention Research Master’s Program and program manager of the Nutrition Studies Group; and Joshua Elias, PhD.

Researchers from the nonprofit research center Chan-Zuckerberg Biohub also contributed to the study. Here’s the complete press release from Stanford Medicine News Center.

Forty years after the U.S. Food and Drug Administration (FDA) released its first legal definition of yogurt, the government agency has now updated that standard of identity. But, according to the International Dairy Foods Association (IDFA), this new final rule is so outdated and out-of-touch with yogurt makers that popular products could be removed from grocery store shelves. The IDFA, which represents the nation’s dairy manufacturing industry, submitted an 87-page formal objection to the FDA.

“The result is a yogurt standard that is woefully behind the times and doesn’t match the reality of today’s food processing environment or the expectations of consumers,” says Dr. Joseph Scimeca, senior vice president of IDFA’s Regulatory and Scientific Affairs. 

The IDFA is particularly concerned that the FDA crafted its final rule using comments made when the agency first pitched the guideline 12 years ago. Scimeca continues: “the final rule is already out of date before it takes effect…as if technology has not progressed or as if the yogurt making process itself has been trapped in amber like a prehistoric fossil.”

The revised standard does not include IDFA’s recommended revisions.

Read more (IDFA)

More Than One SCOBY?

A SCOBY is the gelatinous bacteria colony central to making kombucha. But did you know there are four different types of SCOBY? Scientists at Oregon State University spent the past four years researching the microorganisms that contribute to the tea fermentation that produces kombucha. The results of their work were published in the journal Microorganisms.

SCOBY is a challenging mystery to many kombucha brewers. Little is known about how SCOBY impacts flavor. The OSU scientists aim to help kombucha brewers make a more consistent product. 

“Without having a baseline of which organisms are commonly most important, there are too many variables to try and think about when producing kombucha,” says Chris Curtin, an assistant professor of fermentation microbiology at OSU. “Now with this research we can say there are four main types of SCOBY. If we want to understand what contributes to differences in kombucha flavors we can narrow that variable to four types as opposed to, say, hundreds of types.”

Curtin and doctoral student Keisha Harrison used DNA sequencing to evaluate the microorganisms in 103 SCOBYs used by kombucha brewers (primarily ones in North America). The four SCOBY types each use different combinations of yeast and bacteria.

Read more (Oregon State University)

Natural winemaking is moving mainstream, as more viticulturists preach the importance of soil health and shun traditional herbicides. “Where does natural wine finish and conventional wine start? These days, it’s hard to tell,” reads an article in Vinepair. Though the vast majority of global wine production still relies on conventional methods, the virtues of natural winemaking are helping change the industry.

“While it used to be rare for wines to be fermented with wild yeast — allowing the microbes present on the grapes to carry out fermentation — this is now much more common. And conventional producers have been prompted to question their use of additives such as sulfur dioxide. In fact, many aspects of winemaking that were championed by natural wine folk have now become much more common, even replacing some of the triumphs of more heavy-handed methods. As more producers trend away from making big, international-style reds with dark color, sweet fruit, high alcohol, and obvious new oak character, extracting less color and tannin for lighter-style reds is gaining popularity.”

 Read more (Vinepair)

Natto Stops Covid-19?

Natto — the sticky, slimy fermented soybeans, commonly eaten in Japan inhibits infection by the coronavirus, according to the Tokyo University of Agriculture and Technology (TUAT). Researchers found that natto contains extracts that break down proteins on the surface of the coronavirus, preventing it from infecting cells. 

Their results, published in the journal Biochemical and Biophysical Research Communications, note further studies are needed to determine if there are antiviral properties in the food. But the trial found natto also limited infection by Bovine herpesvirus-1 (BHV-1), a cause of outbreaks of respiratory disease in cattle around the world.

Important to note: the study was funded by Takano Foods Co., Ltd., a Japanese company that makes natto commercially.

Read more (Biochemical and Biophysical Research Communications)

Researchers with the USDA have found that fermented cucumber pickles contain more of the naturally-occurring gamma-aminobutyric acid (GABA) than do their acidified counterparts. Results of this study of commercially-available pickles were recently published in the Journal of Food Composition and Analysis.

GABA works as a neurotransmitter in the brain. It has been scientifically proven that GABA, when consumed in foods or supplements, reduces blood pressure, improves decision making, reduces anxiety and boosts immunity. 

Fermented cucumber pickles undergo a lactic acid fermentation, whereas acidified cucumber pickles are submerged in an acidic brine. The fermented pickles with the most GABA were made in a low-salt fermentation, and the products were prepared for direct consumption. GABA content also was found to remain stable during storage for fermented cucumbers.

“Worldwide, people are interested in consuming fermented foods as part of a healthy lifestyle. Most often, we associate the healthfulness of fermented foods with probiotic microbes. But many fermented foods contain few to no microbes when consumed,” said Jennifer Fideler Moore, North Carolina State University graduate research assistant and one of the study co-authors, in a USDA-ARS press release. “Our research shows that the health-promoting potential of lactic acid fermented cucumbers reaches far beyond the world of probiotics. This opens the door to more research into health-promoting compounds made during fermentation of fruits and vegetables.”

Adds Suzanne Johanningsmeier, study co-author and USDA Agricultural Research Service (USDA-ARS) Research Food Technologist: “Fruits and vegetables are made up of thousands of unique molecules. These molecules rule the flavor, texture, and nutritional value, but it is difficult to study them in such complex systems. To tackle this problem, we use advanced analytical chemistry techniques like mass spectrometry to study food molecules and figure out the best food processing methods for improved quality of fruit and vegetable products.”

[Johanningsmeier presented further details of the study during a TFA webinar.]

Farming with Beer Waste

In a  study published in Frontiers in Sustainable Food Systems, researchers detail how they have created an eco-friendly pesticide using beer bagasse (spent beer grains), rapeseed cake (byproduct of oil extraction from seeds) and fresh cow manure. 

Chemical pesticides have been proven harmful to the environment, damaging soil and water. Pesticides are also easily consumed, and many studies link their use to multiple diseases and birth defects. Researchers from the Neiker Basque Institute for Agricultural Research and Development in Spain hope that farmers will use these organic byproducts from beer production to kill parasites, preserve healthy soil and increase crop yields. 

Read more (Frontiers Science News)

Can Microbes Eat Plastic?

Scientists found that rumen microbes, which ferment feed in a cow’s stomach and produce fatty acids, can also break down plastics, including the common polyethylene terephthalate (PET) used in food and drink packaging. Rumen microbes are found in the rumen of cows, the largest compartment of their stomach.

These researchers hope to determine the specific enzymes used by the microbes  in this process, then genetically engineer the microbes to produce them in large quantities that  could then be used at an industrial scale. The study, conducted by the University of Natural Resources and Life Sciences in Vienna, is published in the journal Frontiers in Bioengineering and Biotechnology.

This is not the first bacterium found to consume plastic. Ideonella sakaiensis, in enzymes secreted by some marine organisms and in certain fungi — and used in sake fermentation — also breaks down PETs. 

Read more (Live Science)

Picturing Traditional Sake

Hoping to spur interest in traditional sake, a Japanese producer has published a picture book What is Sake? that takes readers on a tour of their sake facility. Suigei Brewing Co., based in the western city of Kochi, uses the book to  detail how sake is made. The bilingual book includes English translations. 

The president of Suigei Brewing Co., Hirokuni Okura, notes Japan’s sake culture is gradually being forgotten. He said he desires to “have both adults and children view sake, an element of Japanese food culture, as something close to them.”

The book’s illustrator, Misae Nagai, featured all 53 employees of Suigei in her charming illustrations.

Read more (The Mainichi)

Dunkin’ Kombucha

Move over, Dunkin’ Coffee. The chain known for its coffee and donuts is branding itself into new territory — kombucha. Dunkin’ is the first chain restaurant (to TFA’s knowledge) to make their own kombucha. They are testing their new Dunkin’ Kombucha —  made in two flavors, Fuji Apple Berry and Blueberry Lemon — in select restaurants in the Albany, N.Y., and Charlotte, N.C., markets. 

According to their release, “Dunkin’ continues to democratize delicious by testing kombucha for the first time.” In any case, this test is further evidence of the fermented tea’s increased popularity as an alternative to soda.

Read more (Dunkin’)