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.
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.
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.]
Can you imagine dairy-free milk without a nut or oat? An Israeli start-up is using precision fermentation to create animal-free milk “indistinguishable from the real thing.”
Imagindairy’s technology recreates the whey and casein proteins found in a mammal’s milk. The fermentation time is quick at 3-5 days, and the final product mimics the taste and texture of traditional dairy milk, without cholesterol or GMOs. The product is expected to be in stores in the next two years.
“Many food products are produced in fermentation, including enzymes, probiotics and proteins,” says Eyal Afergan, co-founder and CEO of Imagindairy. He emphasized how safe the product is. “In fact, on the contrary, fermentation process produces a cleaner product which is antibiotic free and reduces the exposure to a potential milk borne pathogens.”
Read more (Food Navigator)
Investments in alternative protein hit their highest level in 2020: $3.1 billion, double the amount invested from 2010-2019. Over $1 billion of that was in fermentation-powered protein alternatives.
It’s a time of huge growth for the industry — the alternative protein market is projected to reach $290 billion by 2035 — but it represents only a tiny segment of the larger meat and dairy industries.
Approximately 350 million metric tons of meat are produced globally every year. For reference, that’s about 1 million Volkswagen Beetles of meat a day. Meat consumption is expected to increase to 500 million metric tons by 2050 — but alternative proteins are expected to account for just 1 million.
“The world has a very large demand for meat and that meat demand is expected to go up,” says Zak Weston, foodservice and supply chain manager for the Good Food Institute (GFI). Weston shared details on fermented alternative proteins during the GFI presentation The State of the Industry: Fermentation for Alternative Proteins. “We think the solution lies in creating alternatives that are competitive with animal-based meat and dairy.”
Why is Alternative Protein Growing?
Animal meat is environmentally inefficient. It requires significant resources, from the amount of agricultural land needed to raise animals, to the fertilizers, pesticides and hormones used for feed, to the carbon emissions from the animals.
Globally, 83% of agricultural land is used to produce animal-based meat, dairy or eggs. Two-thirds of the global supply of protein comes from traditional animal protein.
The caloric conversion ratios — the calories it takes to grow an animal versus the calories that the animal provides when consumed — is extremely unbalanced. It takes 8 calories in to get 1 calorie out of a chicken, 11 calories to get 1 calorie out of a pig and 34 calories to get 1 calorie out of a cow. Alternative protein sources, on the other hand, have an average of a 1:1 calorie conversion. It takes years to grow animals but only hours to grow microbes.
“This is the underlying weakness in the animal protein system that leads to a lot of the negative externalities that we focus on and really need to be solved as part of our protein system,” Weston says. “We have to ameliorate these effects, we have to find ways to mitigate these risks and avoid some of these negative externalities associated with the way in which we currently produce industrialized animal proteins.”
What are Fermented Alternative Proteins?
Alternative proteins are either plant-based and fermented using microbes or cultivated directly from animal cells. Fermented proteins are made using one of three production types: traditional fermentation, biomass fermentation or precision fermentation.
“Fermentation is something familiar to most of us, it’s been used for thousands and thousands of years across a wide variety of cultures for a wide variety of foods,” Weston says, citing foods like cheese, bread, beer, wine and kimchi. “That indeed is one of the benefits for this technology, it’s relatively familiar and well known to a lot of different consumers globally.”
- Traditional fermentation refers to the ancient practice of using microbes in food. To make protein alternatives, this process uses “live microorganisms to modulate and process plant-derived ingredients.” Examples are fermenting soybeans for tempeh or Miyoko’s Creamery using lactic acid bacteria to make cheese.
- Biomass fermentation involves growing naturally occurring, protein-dense, fast-growing organisms. Microorganisms like algae or fungi are often used. For example, Nature’s Fynd and Quorn …mycelium-based steak.
- Precision fermentation uses microbial hosts as “cell factories” to produce specific ingredients. It is a type of biology that allows DNA sequences from a mammal to create alternative proteins. Examples are the heme protein in an Impossible Foods’ burger or the whey protein in Perfect Day’s vegan dairy products.
Despite fermentation’s roots in ancient food processing traditions, using it to create alternative proteins is a relatively new activity. About 80% of the new companies in the fermented alternative protein space have formed since 2015. New startups have focused on precision fermentation (45%) and biomass fermentation (41%). Traditional fermentation accounts for a smaller piece of the category (14%). There were more than 260 investors in the category in 2020 alone.
“It’s really coming onto the radar for a lot of folks in the food and beverage industry and within the alternative protein industry in a very big way, particularly over the past couple of years,” Weston says. “This is an area that the industry is paying attention too. They’re starting to modify working some of its products that have traditionally maybe been focused on dairy animal-based dairy substrates to work with plant protein substrates.”
Can Alternative Protein Help the Food System?
Fermentation has been so appealing, he adds, because “it’s a mature technology that’s been proven at different scales. It’s maybe different microbes or different processes, but there’s a proof of concept that gives us a reason to think that that there’s a lot of hope for this to be a viable technology that makes economic sense.”
GFI predicts more companies will experiment with a hybrid approach to fermented alternative proteins, using different production methods.
Though plant-based is still the more popular alternative protein source, plant-based meat has some barriers that fermentation resolves. Plant-based meat products can be dry, lacking the juiciness of meat; the flavor can be bean-like and leave an unpleasant aftertaste; and the texture can be off, either too compact or too mushy.
Fermented alternative proteins, though, have been more successful at mimicking a meat-like texture and imparting a robust flavor profile. Weston says taste, price, accessibility and convenience all drive consumer behavior — and fermented alternative proteins deliver in these regards.
And, compared to animal meat, alternative proteins are customizable and easily controlled from start to finish. Though the category is still in its early days, Weston sees improvements coming quickly in nutritional profiles, sensory attributes, shelf life, food safety and price points coming quickly.
“What excites us about the category is that we’ve seen a very strong consumer response, in spite of the fact that this is a very novel category for a lot of consumers,” Weston says. “We are fundamentally reassembling meat and dairy products from the ground up.”
Is there a connection between a happy gut and a healthy heart? The University of North Florida Department of Nutrition and Dietetics is conducting a study to determine what impact a diet rich in fermented vegetables has on cardiovascular disease and markers of inflammation.
Participants will be placed in two groups — the first consumes their regular diet for eight weeks, then receives fermented vegetables at the end of the study. The second will eat a half cup of fermented vegetables every day for eight weeks.
“These studies are the only way nutritionists can determine if certain foods can help with prevention and/or treatment of common health problems faced by our community, such as cardiovascular disease,” says Dr. Andrea Arikawa, associate professor at the university.
Read more (University of North Florida)
A new peer-reviewed study from researchers at the University of Illinois and Ohio State University found 66% of commercial kefir products overstated probiotic count and “contained species not included on the label.”
Kefir, widely consumed in Europe and the Middle East, is growing in popularity in the U.S. Researchers examined the bacterial content of five kefir brands. Their results, published in the Journal of Dairy Science, challenge the “probiotic punch” the labels claim.
“Our study shows better quality control of kefir products is required to demonstrate and understand their potential health benefits,” says Kelly Swanson, professor in human nutrition in the Department of Animal Sciences and the Division of Nutritional Sciences at the University of Illinois. “It is important for consumers to know the accurate contents of the fermented foods they consume.”
Probiotics in fermented products are listed in colony-forming units (CFUs). The more probiotics, the greater the health benefit.
According to a news release from the University of Illinois: “Most companies guarantee minimum counts of at least a billion bacteria per gram, with many claiming up to 10 or 100 billion. Because food-fermenting microorganisms have a long history of use, are non-pathogenic, and do not produce harmful substances, they are considered ‘Generally Recognized As Safe’ (GRAS) by the U.S. Food and Drug Administration and require no further approvals for use. That means companies are free to make claims about bacteria count with little regulation or oversight.”
To perform the study, the researchers bought two bottles of each of five major kefir brands. Bottles were brought to the lab where bacterial cells were counted and bacterial species identified. Only one of the brands studied had the amount of probiotics listed on its label.
“Just like probiotics, the health benefits of kefirs and other fermented foods will largely be dependent on the type and density of microorganisms present,” Swanson says. “With trillions of bacteria already inhabiting the gut, billions are usually necessary for health promotion. These product shortcomings in regard to bacterial counts will most certainly reduce their likelihood of providing benefits.”
The news release continues:
When the research team compared the bacteria in their samples against the ones listed on the label, there were distinct discrepancies. Some species were missing altogether, while others were present but unlisted. All five products contained, but didn’t list, Streptococcus salivarius. And four out of five contained Lactobacillus paracasei.
Both species are common starter strains in the production of yogurts and other fermented foods. Because those bacteria are relatively safe and may contribute to the health benefits of fermented foods, Swanson says it’s not clear why they aren’t listed on the labels.
Although the study only tested five products, Swanson suggests the results are emblematic of a larger issue in the fermented foods market.
“Even though fermented foods and beverages have been important components of the human food supply for thousands of years, few well-designed studies on their composition and health benefits have been conducted outside of yogurt. Our results underscore just how important it is to study these products,” he says. “And given the absence of regulatory scrutiny, consumers should be wary and demand better-quality commercial fermented foods.”
Thanks to lactic acid — which kills harmful bacteria during fermentation — fermented foods are arguably among the safest foods that humans eat. But if critical errors are made, there is the risk of food safety hazards.
“When we talk about fruit and vegetable ferments, there is a very long history of microbial safety with traditionally fermented fruits and vegetables,” says Erin DiCaprio, extension specialist at University of California, Davis, Department of Food Science and Technology. “While outbreaks associated with fermented fruits and vegetables are rare, vegetable and fruit fermentation is not without risk.”
DiCaprio, a food safety expert, detailed proper food safety protocols during a webinar for EATLAC, a UC Davis project putting scientific knowledge and research behind fermentation. DiCaprio shared two documented instances of fermented foods causing a foodborne illness, both from small-scale batches of kimchi. But she emphasized that, when all food safety concerns are mitigated, fermented foods do not pose a risk.
“From the food microbiology standpoint, bacteria really are the most important group of microorganisms because bacteria, certain types of bacteria, are a food safety concern,” she adds. “There are many different types of bacteria that contribute to food spoilage and, of course, there are specific types of bacteria that are used beneficially for fermentation.”
What happens during fermentation that makes food safe? Lactic acid bacteria are created, which convert sugars into lactic acid, acetic acid and CO2. Those antimicrobial compounds help fight off pathogens, competing with other microbes for nutrition sources.
Biological hazards — bacteria, viruses and parasites that can cause foodborne illnesses — are the biggest concerns. Botulism, E. coli and salmonella are the main hazards for fermented foods. Botulism can form in oxygen-free conditions if a fermentation is not successful and acid levels are too low. E. coli and salmonella form when sanitation practices are not followed.
“Commercially, when someone is developing a valid fermentation process, they are typically going to be looking to see that sufficient acid is produced during fermentation, to inactivate some of these acid tolerant (bacteria),” DiCaprio says. “Our traditional vegetable fermentations — things like fermented cucumber, sauerkraut, kimchi — they’ve all been shown to produce sufficient acid to inactivate the sugar toxin producing e-coli, so from a safety standpoint, sufficient acid production is the critical control point for ensuring the safety of a fermented fruit or vegetable. “
There are seven critical factors to keep a ferment safe:
- High-quality, raw ingredients. “If there are a high number of spoilage microorganisms to start with, it will be really difficult for the lactic acid bacteria to dominate the fermentation,” DiCaprio says.
- Research-based recipe. Following a tested recipe ensures the proper balance of ingredients to keep the food safe.
- Proper sanitation. Cleaning of all utensils and surfaces ensures no pathogens will contaminate the food. This mitigates cross-contamination risk, too.
- Preparation of ingredients. Food particles should be uniform in size, either cut in small slices or shredded. Smaller pieces release more water and nutrients, promoting the growth of lactic acid bacteria.
- Salt concentration. Lactic acid bacteria thrive in a salt brine. The key amount: anywhere from 1-15% salt brine by weight of the ferment.
- Appropriate temperature. A temperature between 65-75 degrees fahrenheit is ideal to keep spoilage microorganisms at bay.
- Adequate time. “It takes a while for significant acid to be produced, so be patient and follow the directions in the recipe,” DiCaprio advises. Most fruit and vegetable ferments take 3-6 weeks to be completed.
Scientists in Russia and Egypt have developed a functional drink that’s been proven to combat anemia and malnutrition. The juice is made from beet extract, milk and probiotic bacterial strains. The scientists developed a quinoa bread, too. The goal is to keep the beverage and bread affordably priced and get them offered at grocery stores internationally.
“One should bear in mind that we are not creating a medicine, but a natural, functional food product,” said Sobhi Ahmed Azab Al-Suhaimi, professor in the Department of Technology at South Ural State University (SUSU) in Russia. “However, this juice can make up for the lack of iron, zinc, manganese and calcium in the body. One serving of the drink will contain the whole rate [sic] of minerals. Its carbohydrate content is low. Fermented juice will help to overcome anemia and to improve digestion due to probiotics.”
Scientists at SUSU worked with scientists at the University of Alexandria in Egypt. Their findings were published in the Journal of Food Processing and Preservation and Plants.
Read more (Phys.org)
Microbes that coexist on plants influence a crop’s size, shape, color, flavor and yield. What would these microbes do in microgravity? The International Space Station (ISS) is testing to find these results.
Flight engineer Shannon Walker (pictured) shows sample bags collected for the Grape Juice Fermentation in Microgravity Aboard ISS study. Astronauts will observe the fermentation process, measuring microbial differences. Back on earth, a matching, control sample is being observed in an environmental control chamber that mimics the ISS ambient temperature. The space and earth samples then will be analyzed for changes. Both flight and ground control samples are analyzed post-investigation for genetic change.
Read more (NASA)