MINNEAPOLIS/ST. PAUL (07/24/2023) — Fermented foods have grown in popularity and are widely consumed, in part due to claims regarding their positive effect on digestive health. However, these claims lack sufficient scientific support, especially for lacto-fermented vegetables.
A team of University of Minnesota researchers set out to test these claims, by studying if frequent consumption of lacto-fermented vegetables, such as kimchi or kraut, had any effect on the trillions of bacteria that make up the gut microbiome.
Their findings were recently published in the journal Gut Microbiome.
To conduct their study, the researchers collected fecal samples of 23 people in the Twin Cities who frequently consumed at least one serving of plant-based fermented foods, five times a week for two years. This did not include dairy ferments. Their fecal microbiomes were studied and compared to those of 24 people who never or rarely consumed lacto-fermented vegetables or other fermented foods, and had not done so in the last two years.
The researchers conducted a thorough dietary examination of the participants before beginning the experiment and found both consumers of lacto-fermented foods and non-consumers started from a similar place in terms of overall diet quality. They determined the Healthy Eating Indexscore, a USDA measure of nutritional health, and found both groups were close to the national average score for adults, which is 58 out of 100. Lacto-fermented vegetable consumers were slightly higher at 59 out of 100, and non-consumer had a slightly lower score of 55 out of 100.
The researchers found:
- Potentially probiotic bacteria and fungi likely derived from the lacto-fermented vegetables were found in the feces of some individuals regularly consuming fermented foods.
- Regular consumption of lacto-fermented vegetables may stimulate bacteria with the potential to produce butyrate, a compound in the gut that is widely known for its positive effects on health.
Lacto-fermented vegetables have a significantly greater effect on some of the functions performed by microorganisms in the gut and on the nutrients that our microbiome uses to perform functions with potentially key effects on health. This is demonstrated by the observation that regular consumers showed a greater diversity of fecal metabolites (small gut nutrients) and greater production of microbial nutrients with known positive effects on health such as acetate and propionate (short chain fatty acids).
“Our findings support existing research showing that fermented foods, in this case, lacto-fermented vegetables, benefit the gut microbiome and metabolome in people consuming a typical Western diet," said lead author Kylene Guse, a postdoctoral researcher at the University of South Dakota, formerly with the U of M.
However, these microbiome-mediated benefits should be tested by taking repeated snapshots of a person’s microbiome over time, and assessing if consumption can improve specific health issues in humans.
“Our findings have implications for health prevention strategies based on the healing power of healthy foods,” said Andres Gomez, an assistant professor in the Department of Animal Science. “In the future, we need to test a potential positive effect of consuming lacto-fermented vegetables in subjects with specific diseases with a known microbiome connection, such as cancer, obesity or autoimmune disease, among others.”
The team is currently assessing how they can expand community health and science literacy on the potential benefits of consuming fermented vegetables and how the gut microbiome is an important component for health maintenance. They are also testing the effect of consuming other fermented foods — specifically kombucha — in addressing mental health issues, as associations emerge between gut microbes and brain function
This research was supported by the Office of Community Engagement to Advance Research and Community Health (CEARCH) of the Clinical and Translational Science Institute (CTSI) at the University of Minnesota and the University of Minnesota’s Agricultural Research, Education, Extension and Technology Transfer Program.
About the College of Food, Agricultural and Natural Resource Sciences
The University of Minnesota’s College of Food, Agricultural and Natural Resource Sciences (CFANS) strives to inspire minds, nourish people, and sustainably enhance the natural environment. CFANS has a legacy of innovation, bringing discoveries to life through science and educating the next generation of leaders. Every day, students, faculty, and researchers use science to address the grand challenges of the world today and in the future. CFANS offers an unparalleled expanse of experiential learning opportunities for students and the community, with 12 academic departments, 10 research and outreach centers across the state, the Minnesota Landscape Arboretum, the Bell Museum of Natural History, and dozens of interdisciplinary centers. Learn more at cfans.umn.edu.
FAQs
Certain fermented foods contain probiotics such as Lactobacillus and Bifidobacterium species, which can help increase the beneficial bacteria in the gut. These types of bacteria aid the breakdown of complex carbohydrates, synthesis of vitamins, and produce beneficial compounds including short-chain fatty acids (SCFAs).
Are fermented vegetables good for your gut? ›
Regular consumption of lacto-fermented vegetables may stimulate bacteria with the potential to produce butyrate, a compound in the gut that is widely known for its positive effects on health.
What does fermentation do for your gut? ›
The good bacteria in fermented foods (probiotics) may improve digestion, boost immunity, promote a healthy weight and more. Lisa Valente is a registered dietitian and former senior digital nutrition editor for EatingWell.
What are 3 health benefits from eating fermented foods? ›
As a result, fermented foods provide many health benefits such as anti-oxidant, anti-microbial, anti-fungal, anti-inflammatory, anti-diabetic and anti-atherosclerotic activity.
How long does fermented food take to help your gut? ›
Stanford researchers discover that a 10-week diet high in fermented foods boosts microbiome diversity and improves immune responses.
How often should you eat fermented vegetables? ›
We advocate eating fermented foods three times per day, as snacks or with meals. It's the consistent introduction of these live culture fermented foods to your microbiome that creates the most gut health benefits. And what's more, eating a variety of different fermented foods is key.
What is the healthiest fermented food? ›
Fermented Foods for Gut Health
- Miso (refrigerated)
- Pickles (in salt, not vinegar)
- Sauerkraut (choose refrigerated)
- Kimchi.
- Kombucha (no sugar)
- Other probiotic drinks (no sugar), like beet Kvass, apple cider.
- Various other cultured products.
- You can also easily make fermented vegetables, such as sauerkraut at home!
In alphabetical order, the best vegetables for fermenting include cabbage, carrots, cauliflower, cucumbers, garlic, kohlrabi, peppers, radishes, snap beans and turnips.
What are the disadvantages of fermented foods? ›
However, some people might experience severe side effects after consuming fermented foods.
- Bloating. The most common reaction to fermented foods is a temporary increase in gas and bloating. ...
- Headaches and migraines. ...
- Histamine intolerance. ...
- Food-borne illness. ...
- Infection from probiotics. ...
- Antibiotic resistance.
One of the downsides of fermentation is that it products a lactic acid byproduct that can harm the cell temporarily.
Here are seven foods high in probiotics:
- Yogurt. Yogurt is made by culturing milk with bacteria that produce lactic acid, such as Lactobacillus bulgaricus and Streptococcus thermophilus, although more strains can also be added. ...
- Buttermilk. ...
- Cottage Cheese. ...
- Tempeh. ...
- Sauerkraut. ...
- Miso Soup.
Fermented foods containing probiotic bacteria and fungi can enhance the immune system, improve gastrointestinal health, and lower the risk of developing various inflammatory diseases.
What happens when you first start eating fermented foods? ›
Fermented foods can cause gas and bloating, even in a healthy individual. This is because you are introducing more microbes into your system, and happy microbes produce gas when fed the right diet, aka a healthy balanced diet including plenty of fibre rich foods.
Can you eat too much fermented food? ›
Fermented foods are considered safe for most people. However, some individuals may experience side effects. Due to the high probiotic content of fermented foods, the most common side effect is an initial and temporary increase in gas and bloating ( 32 ).
Should you eat fermented food on an empty stomach? ›
All said, fermented foods do have the potential to plenty of good for your gut, but if you deal with digestive issues or sensitivities, it may be best to consume them in moderation and not on an empty stomach.
Is it better to take probiotics or eat fermented foods? ›
There are two ways to get more good bacteria into your gut: fermented foods and dietary supplements. Fermented foods are the most natural source. Probiotic supplements, which are typically sold over the counter, are reserved to treat specific ailments as suggested by your doctor, and not recommended for everyday use.
What are the most nutritious vegetables to ferment? ›
- Cabbage. Cabbage is the perfect vegetable for fermentation, and not without good reason! ...
- Carrots. Carrots can be used in all kinds of fermentations, but they also shine on their own! ...
- Beets. Beets are great for fermentation! ...
- Tomatoes. Managing the abundance of tomatoes in the fall… ...
- Cauliflower. ...
- Green Beans. ...
- Celery. ...
- Hot Peppers.
Fermentation increases the nutritional value of food, the bioavailability of nutrients, and the enzyme concentration, in addition to neutralizing several toxic substances. Contrary to canned vegetables, fermented vegetables retain all their nutrients and vitamins.
