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.
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)
Chr. Hansen, a global bioscience supplier of ingredients, has developed Vega Culture Kits, a new line of probiotic starter cultures that can be used to create plant-based yogurt. “Vegurt,” a shortening of vegan or vegetarian yogurt, is the name being used for this non-dairy product. This term was created in reaction to the European Parliament’s current debate over whether plant-based products can use dairy-related terms like yogurt and milk.
“Vegurt seemed a catchy and suitable category name compared to having to sprain our tongues calling them ‘fermented plant-based alternatives to dairy yogurt,’” said Dr. Ross Critenden, senior director for commercial development at Chr. Hansen.
The Vega Culture Kits are designed to “robustly ferment” any dairy-free plant base, like nuts, cereals, legumes or seeds. The Vega Culture will appear as “culture” on ingredient lists, in the same way that dairy yogurts include “culture” when cultures or probiotic strains are added.
Read more (Food Navigator)
Fermentation saved the human diet, argues Krish Ashok, author of Masala Lab: The Science of Indian Cooking. He calls fermentation strategic rotting. The discovery of fire was key to the human’s survival as they learned to cook meat, but fermentation allowed civilization to create bread and alcohol, turn milk into yogurt and preserve a harvest through the winter.
“Fast forward a few millennia, and we have mastered fermentation to the point where we can pick and choose microbes with precision and generate complex flavours in the bargain,” Ashok writes. Pictured, his charming drawings illustrate microbes used in fermentation.
Read more (Mint Lounge)
When Julie Smolyansky began working at her family’s Lifeway Foods business, her father advised her: “Don’t talk about the bacteria. People in America freak out about the bacteria on their food.” So when Lifeway became the first company in the U.S. to put “probiotic” on a label in 2003, it wasn’t a big surprise when customers began calling, asking for the company’s non-probiotic version of kefir.
Americans have come a long way. Consumers today search for the “live, cultured” label on fermented dairy, and gut health is a critical component of the modern diet. Smolyansky and Raquel Guajardo, author/educator, shared their thoughts on kefir during the TFA webinar The Many Sides of Kefir.
“Fermented foods were not part of the American diet, and the way that kefir and fermented foods in general were used in other parts of the world from Asian to Eastern Europe to even India and Mexico, these cultures all have fermented foods as one of their pillars as their foods sources and their health and wellness cultures,” Smolyansky says. “It wasn’t until immigration from all these other countries that we started talking about kimchi or kefir or lassi or you name your cultured kind of special food.”
In the U.S., the average person consumes 9-10 cups of fermented dairy a year. Contrast that statistic with Europe, where the average consumption is 28 cups a month.
“When you’re born consuming it and you’ve developed that taste palette, then it’s very easy to play in the space and have a diet that’s very rich in probiotics and kefir and all sorts of other fermented foods,” Smolyansky says, adding that the situation is changing in the U.S. Now, “people are hungry for it, they want it, once they learn about it, once they taste it, they fall in love with it, they’re hooked.”
Lifeway’s kefir’s sales have soared. The company was valued at $12 million when Smolyansky took over in 2002 — now it’s valued into the hundreds of millions. And even more customers have found kefir during the COVID-19 pandemic, as they adopt healthier lifestyles.
Guajardo has seen her online classes increase during COVID. The Mexico-based educator co-authored the book “Kombucha, Kefir, and Beyond” with Alex Lewin, TFA advisory board member, who moderated the webinar.
“People say ‘You’re crazy, why do you teach what to do at home what you can buy in the supermarket?’ But my business has been growing that way,” she says, adding that health benefits are the main selling point for her classes. “Why would people buy sauerkraut or kefir if you’re not explaining the benefits?”
Dairy Kefir vs. Water Kefir
Guajardo, who makes both dairy kefir and water kefir (also known as tibicos) stresses that the grains used to make each are “totally different.” Kefir grains are living bacteria and yeast microorganisms clumped together with milk proteins and sugars. They are gelatinous and white, almost like cottage cheese. Water kefir grains are also made from living bacteria and yeast microorganisms, but they’re clumped together with sugar and have a translucent, crystal-like appearance.
“Water kefir” is not the appropriate term, Guajardo and Smolyansky agree, instead calling it by its traditional Mexican name, tibicos. And they feel that using kefir or tibicos grains in coconut or almond milk and calling it kefir is also inappropriate. Smolyansky favors using a description like cultured coconut milk or beverage, but not kefir.
The National Dairy Council and Codex Alimentarius, the international food code, both state kefir is a fermented dairy product made from the milk of a lactating mammal. Smolyansky points to the many peer-reviewed studies on kefir, verifying it is full of probiotics and nutrients. Water kefir and non-dairy kefir have not been studied, and can’t guarantee the same health benefits.
“Just by throwing the name onto anything and just bastardizing the definition, we completely dilute any of the research that’s ever been done [on kefir], it would dilute the history, the folklore. So we are very passionate about protecting the name,” Smolyansky says. “My ancestors made sure that kefir survived for 2,000 years, and it’s critical that we don’t dilute it now that it’s having a moment, now that it’s popular.”
Smolyansky’s family emigrated to the United States from the then Soviet Union in the late ‘70s. Her father, Michael, began Lifeway Foods in Chicago in 1986.
“We have to respect the standards and what these definitions mean or it will be the Wild West and people won’t know what they’re buying,” she adds. She shares the labelling of ice cream as an example — ice cream is considered dairy while non-dairy products have other names, like sorbet, gelato or non-dairy frozen dessert.
Can Kefir Grow Like Yogurt?
Yogurt has paved the way for kefir to expand its consumer base in the U.S. Both are fermented dairy products with tangy tastes. But for kefir to achieve widespread, mainstream adoption like yogurt, significant education is needed. Thousands of peer-reviewed studies prove kefir contains a higher concentration of probiotics than yogurt — and a wider range of beneficial bacteria. For kefir to grow, this message needs to reach consumers.
“It’s a different set of microbes,” Lewin says. “Kefir is fermented with yeast and yogurt isn’t. Kefir has a larger family of microbes.”
Smolyansky is passionate that kefir cannot be compared to the products of the major. yogurt companies.
“The yogurt produced in the United States is so over-produced and so over-pasteurized that there’s practically nothing living in it after it’s been processed,” she says. “It’s one of the biggest problems with yogurt in the U.S.”
Lifeway regularly sends their products to be tested for probiotics, measuring Colony Forming Units (CFUs), the active microorganisms in a food product. Smolyansky says eating probiotics is critical in a germ-phobic, antibody-heavy society, where we’re over-sanitizing due to the coronavirus pandemic.
“If our bodies aren’t fighting an outside kind of pathogen, it starts to fight itself,” she says. “One of the ways to counteract this disruption in our microflora is by the use and the introduction of consistently replenishing microflora including diversity of bacteria, a variety of food sources that offer bacteria, the diversity and kind [of bacteria] is always the king. It makes for great food environments in the gut.”
Do probiotic supplements deliver the same benefits as fermented foods? Dr. Gail Cresci says to be leery of prebiotic and probiotic pills.
“There are challenges to keeping microbes viable in encapsulated tablets,” says Cresci, director of Nutrition Research for the Cleveland Clinic’s Department of Pediatric Gastroenterology, Hepatology and Nutrition. “It’s also very, very important to know that each strain of bacteria is not the same as the next. For example, lactobacillus has hundreds of different strains, and each one may behave differently. People like to use supplements because they like to think one size fits all, but it doesn’t.”
“Take in prebiotics and probiotics through food sources. Yogurt with added probiotic bacterial strains is much better to consume than supplements also because as it’s been waiting for you to eat it, it’s been producing more beneficial metabolites. When you eat it, you get all that.”
Read more (American Heart Association/U.S. News & World Report)
After Dr. Bob Hutkins finished a presentation on fermented foods during a respected nutrition conference, the first audience question was from someone with a PhD in nutrition: “What are fermented foods?”
“I thought ‘Doesn’t everyone know what fermentation is?’ I realized, we do need a definition. Those of us that work in this field know what we’re talking about when we say fermented foods, but even people trained in foods do not understand this concept,” says Hutkins, a professor of food science at the University of Nebraska-Lincoln. He presented The New Definition of Fermented Foods during a webinar with TFA.
Hutkins was part of a 13-member interdisciplinary panel of scientists that released a consensus definition on fermented foods. Their research, published this month in Nature Reviews Gastroenterology & Hepatology, defines fermented foods as: “foods made through desired microbial growth and enzymatic conversions of food components.”
“We needed a definition that conveyed this simple message of a raw food turning into a fermented food via microorganisms,” Hutkins says. “It brings some clarity to many of these issues that, frankly, people are confused about.”
David Ehreth, president and founder of Alexander Valley Gourmet, parent company of Sonoma Brinery (and a TFA Advisory Board member), agreed that an expert definition was necessary.
“As a producer, and having started this effort to put live culture products on the standard grocery shelf, I started doing it as a result of unique flavors that I could achieve through fermentation that weren’t present in acidified products,” Ehreth says. “Since many of us put this on our labels, we should be paying close attention to what these folks are doing, since they are the scientific backbone of our industry.”
Hutkins calls fermented foods “the original shelf-stable foods.” They’ve been used by humankind for over thousands of years, but have mushroomed in popularity in the last 15. Fermented foods check many boxes for hot food trends: artisanal, local, organic, natural, healthy, flavorful, sustainable, innovative, hip, funky, chic, cool and Instagram-worthy.
Nutrition, Hutkins hypothesizes, is a big driver of the public’s interest in fermentation. He noted that Today’s Dietitian has voted fermented foods a top superfood for the past four years.
Evidence to make bold claims about the health benefits of fermentation, though, is lacking. Hutkins says there is observational and epidemiological evidence. But randomized, human clinical trials — “the highest evidence one can rely on” — are few and small-scale for fermented foods.
Hutkins shared some research results. One study found that Korean elders who regularly consume kimchi harbor lactic acid bacteria (LAB) in their GI tract, providing compelling evidence that LAB survives digestion and reaches the gut. Another study of cultured dairy products, cheese, fermented vegetables, Asian fermented products and fermented drinks found that most contain over 10 million LAB per gram.
Still, the lack of credible studies is “a barrier we have to get past,” Hutkins says. There are confirmed health benefits with yogurt and kefir, but this research was funded by the dairy industry, a large trade group with significant resources.
“I think there’s enough evidence — most of it through these associated studies — to warrant this statement: fermented foods, including those that contain live microorganisms, should be included as part of a healthy diet.”
By August, any manufacturer labeling their fermented or hydrolyzed foods or ingredients “gluten-free” must prove that they contain no gluten, have never been through a process to remove gluten, all gluten cross-contact has been eliminated and there are measures in place to prevent gluten contamination in production.
The FDA list includes these foods: cheese, yogurt, vinegar, sauerkraut, pickles, green olives, beers, wine and hydrolyzed plant proteins. This category would also include food derived from fermented or hydrolyzed ingredients, such as chocolate made from fermented cocoa beans or a snack using olives.
Read more (JD Supra Legal News)
In the latest issue of Popular Science, a creative infographic illustrates “the wonderful world of fermented foods on one delicious chart.” It represents “a sampling of the treats our species brines, brews, cures, and cultures around the world,” and is particularly interesting as it shows mainstream media catching on to fermentation’s renaissance. Fermentation fit with the issue’s theme of transformation in the wake of the pandemic.
Read more (Popular Science)
Fermented dairy foods have been shown to lower the risk of chronic diseases, inflammation and weight gain. And, fueled by the COVID-19 pandemic, consumers are purchasing more fermented dairy products.
“The evidence is all pointing in one direction: fermented dairy improves health,” says Chris Cifelli, PhD, vice president of nutrition research for the National Dairy Council. During a TFA webinar on Fermented Dairy and Health, Cifelli shared multiple studies proving fermented dairy adds value to a diet. “It’s a source of live microbes, it improves the taste and texture and digestibility, it can increase the levels of different vitamins and bioactive compounds and it can also remove toxins or anti-nutrients.”
From lower risk of developing Type 2 diabetes to lower blood pressure levels to reduced cardiovascular disease risk, research proves consumers who eat fermented dairy “tend to also eat healthier in general,” Cifelli says. “Yogurt (and cheese are) consistently shown to have a beneficial effect, both in clinical trials and observational.”
Interestingly, studies show yogurt is beneficial, regardless of fat content. Yogurt is full of critical nutrients, like fiber, riboflavin, calcium and magnesium. This “halo of health” surrounding yogurt has driven a recent sales surge.
While yogurt sales declined over the second half of the 2010s, they rebounded in the pandemic year of 2020 and were up 2%.
“Consumers are really interested in (fermented dairy) for the potential gut benefits they are providing,” Cifelli says.
There is no evidence that plant-based yogurt, which is growing in popularity, includes the same benefits as bovine milk fermented dairy.
Kefir sales are on the rise;, too, are also growing. gGlobally, itkefir is expected to reach $1.84 billion in sales by 2027. Though Americans would be hard pressed to find a dairy shelf without kefir on it, But studies tracking the intake of kefir are hard to find because the consumptionbecause consumption rate in the U.S. is still low. Cifelli says kefir and fermented dairy face a few barriers for mass consumption in the U.S.
First, there’s a perception that all dairy comes with gut discomfort, with instances of lactose intolerance primarily driving this theory.
“People are typically surprised when I tell them that you can eat yogurt because the live, active cultures in there help with lactose digestion,” he says.
Second, consumers are nervous about hormones coming from cow products. But, Cifelli notes, all food has hormones.
Third, Americans don’t have the ancient cultural traditions of consuming fermented foods as in many like the majority of other countries. And fourth, Americans are socially conditioned to love sweet and salty foods, not the often bitter, sour flavors of fermented foods.
“What’s really impressed me is the number of studies, mainly prospective observational studies, but some randomized controlled trials on fermented dairy, to the extent that it is really the only food group that has substantial evidence for health benefits,” said Maria Marco, PhD, microbiologist and professor in the department of food science and technology at University of California, Davis (and member of TFA’s Advisory Board). Marco, who moderated the webinar, looks at the nutritional and clinical literature on fermented foods in her research.
Cifelli said this is because, in the U.S., milk and cheese have been actively consumed and studied for decades. The bulk of yogurt research is only from the last 20 years. Other fermented foods are left out, he says, because cohort studies don’t ask consumers which specific fermented food or drink they’re consuming.
“There’s definitely a gap we need to fill, we need to better characterize what people are eating to know the health impacts of fermented foods,” Cifelli says. “Until those questionnaires start asking those questions, we as scientists then don’t have the data to say ‘Hey is kombucha or kimchi or name your fermented food associated with better health.’”