Consuming beneficial bacteria together with the dietary fiber and oligosaccharides that they use as food is said to be good to maintain a healthy gut.
Many people may already eat fermented foods such as natto (fermented soybeans) as a source of beneficial bacteria, but only few people are probably aware of the importance of dietary fiber.
It is known that beneficial bacteria that are part of the gut flora ferment dietary fibers they take up to produce short-chain fatty acids, which are good for the body. These short-chain fatty acids make the intestinal environment more acidic, in turn creating an even better environment for the beneficial bacteria to live in.
Among the different types of short-chain fatty acids, butyric acid, produced by butyric acid bacteria, is considered to be particularly beneficial to the body.
How the gut flora and in particular butyric acid bacteria change in healthy adults who consume the dietary fiber-rich BARLEYmax®︎ was studied by Dr. Kazunari Kaneko of the Department of Pediatrics at Kansai Medical University. This article explains the results of this study.
The following article was written by Dr. Kazunari Kaneko, Professor and Vice Chancellor of the Department of Pediatrics, Kansai Medical University.
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Author
Dr. Kazunari Kaneko
Professor and Vice Chancellor, Department of Pediatrics, Kansai Medical University. Doctor of Medicine.
Dr. Kaneko is a board member of various pediatric academic societies in Japan, including the Japan Pediatric Society, the Japanese Society for Pediatric Nephrology, the Japanese Society on Enuresis, and the Japanese Society of Pediatric Urology. He is board certified in pediatrics and certified by the Japanese Society of Pediatric Urology. He is an expert in general pediatrics, pediatric nephrology and intestinal bacteriology.
As many as 100 trillion bacteria live in our intestines, forming what is called the gut flora (or intestinal flora). Among these are beneficial bacteria that have a positive effect on the human body, harmful bacteria that produce toxic substances, and opportunistic bacteria that magnify the effects of whichever other bacteria dominate. The balance of these bacteria is important for the health of the body. In a healthy adult, the gut flora consists of about 20% beneficial bacteria, 10% harmful bacteria, and 70% opportunistic bacteria. An imbalance in this intestinal flora is called dysbiosis and is associated with various diseases.
What are butyric acid bacteria?
Beneficial bacteria such as Lactobacillus and BB-12 Bifidobacterium produce short-chain fatty acids (butyric acid, acetic acid, propionic acid, etc.) that are essential for maintaining good health. In addition to the better-known Lactobacillus and BB-12 Bifidobacterium, butyric acid bacteria are also considered beneficial bacteria. Butyric acid bacteria is the general name for bacteria that produce a short-chain fatty acid called butyric acid by fermenting and breaking up dietary fiber they take up in the intestines. This butyric acid produced by butyric acid bacteria has various health benefits. Specifically, butyric acid is a source of energy for the large intestine, inhibits the growth of harmful bacteria that produce toxic substances, and creates a favorable intestinal environment for beneficial bacteria such as lactic acid bacteria and bifidobacteria to live in. Butyric acid is important to maintain a good intestinal environment and prevent the gut flora from falling into a state of disbiosis. In fact, our research team at the Department of Pediatrics, Kansai Medical University, reported that the percentage of butyric acid bacteria in the intestinal flora was low in children with food allergies and diseases such as idiopathic nephrotic syndrome1,2).
Butyric acid bacteria and how to get more butyric acid
So how can we increase the amount these important beneficial butyrate bacteria in our gut flora? Consuming barley, which is rich in dietary fiber, has been reported to have a positive effect on the gut flora of Japanese people3). We therefore hypothesized that daily consumption of BARLEYmax®︎, which contains twice the amount of fiber and four times the amount of resistant starch of normal barley, might efficiently increase the number of Butyric acid bacteria and set out to study this question with the cooperation of Teijin Limited. We asked 18 healthy adults (12 men and 6 women, median age 35.9 years) to consume 40 g of granola containing BARLEYmax®︎ 20.4 g (including 5.6 g of dietary fiber and 0.68 g of resistant starch) once a day, at least four times a week, for four weeks. Stool samples were collected before the start, after the four weeks, and one month after the end of BARLEYmax®︎ intake, and bacterial genes in the stool were analyzed by next-generation sequencing to determine the percentage (%) of butyric acid bacteria in the gut flora. We also measured the concentration of short-chain fatty acids (butyric acid, acetic acid, and propionic acid) in the stool using high-performance liquid chromatography. As shown in Figure 1, the median percentage of butyric acid bacteria was 5.9% (interquartile range 2.4-6.8) before BARLEYmax®︎ intake, which increased to 8.2% (interquartile range 3.7-10.8) after the four weeks. However, one month after the end of BARLEYmax®︎ intake, the percentage dropped back to 5.4% [interquartile range 2.3-9.0], below the baseline level.
Change of butyric acid bacteria ratio with BARLEYmax®︎ intake
As shown in Figure 2, concentrations of short-chain fatty acids (butyric acid, acetic acid, and propionic acid) in the stool also increased during the four weeks of BARLEYmax®︎ intake, but returned to baseline levels one month after the end of intake. From this we learned that while there were some differences between individual study participants, daily consumption of BARLEYmax®︎ increased the ratio of butyric acid bacteria and the amount of short-chain fatty acids in the intestine over as long as four weeks, but that these returned to original levels after one month when BARLEYmax®︎ was not consumed anymore4).
Changes in stool concentrations of short-chain fatty acids with BARLEYmax®︎ intake
Our research team is now investigating whether daily consumption of BARLEYmax can improve the symptoms of children with food allergies, whose gut flora often shows symptoms of dysbiosis.
Summary
Daily consumption of the fiber-rich functional barley BARLEYmax®︎ can increase the ratio of beneficial butyric acid bacteria in the gut flora and also increase the amount of butyric acid and other short-chain fatty acids that are important to maintaining good health. However, the effect is likely limited to the period during which BARLEYmax®︎ is consumed. As with everything in life, “persistence is the key” also in looking after your health.
References
1: Tsuji S, Suruda C, Hashiyada M, Kimata T, Yamanouchi S, Kitao T, Kino J, Akane A, Kaneko K. Gut Microbiota Dysbiosis in Children with Relapsing Idiopathic Nephrotic Syndrome. Am J Nephrol. 2018;47(3):164-170. doi: 10.1159/000487557. Epub 2018 Mar 13. PMID: 29533950.
2: Yamagishi M, Akagawa S, Akagawa Y, Nakai Y, Yamanouchi S, Kimata T, Hashiyada M, Akane A, Tsuji S, Kaneko K. Decreased butyric acid-producing bacteria in gut microbiota of children with egg allergy. Allergy. 2021 Jul;76(7):2279-2282. doi: 10.1111/all.14795. Epub 2021 Jun 2. PMID: 33650199.
3: Matsuoka T, Hosomi K, Park J, Goto Y, Nishimura M, Maruyama S, Murakami H, Konishi K, Miyachi M, Kawashima H, Mizuguchi K, Kobayashi T, Yokomichi H, Kunisawa J, Yamagata Z. Relationships between barley consumption and gut microbiome characteristics in a healthy Japanese population: a cross-sectional study. BMC Nutr. 2022 Mar 14;8(1):23. doi: 10.1186/s40795-022-00500-3. PMID: 35287729; PMCID: PMC8919566.
4: Akagawa S, Akagawa Y, Nakai Y, Yamagishi M, Yamanouchi S, Kimata T, Chino K, Tamiya T, Hashiyada M, Akane A, Tsuji S, Kaneko K. Fiber-Rich Barley Increases Butyric Acid-Producing Bacteria in the Human Gut Microbiota. Metabolites. 2021 Aug 22;11(8):559. doi: 10.3390/metabo11080559. PMID: 34436500; PMCID: PMC8399161.
Dr. Kazunari Kaneko
Professor and Vice Chancellor, Department of Pediatrics, Kansai Medical University. Doctor of Medicine.
Graduated from Niigata University School of Medicine in 1984, passed the national medical examination in 1984 and joined the Department of Pediatrics at Juntendo University. Graduated from Juntendo University Graduate School in 1989. Went to England in the same year to study at the Department of Nephrology, Children’s Hospital, London, England for two years. Appointed as lecturer at the Department of Pediatrics, Juntendo University School of Medicine in 1998, as assistant professor at the Department of Pediatrics, Juntendo University Urayasu Hospital in 2003, and as head of the Department of Pediatrics, Kansai Medical University in 2005. Serves as Vice Chancellor of Kansai Medical University since 2021.
Dr. Kaneko is a board member of various pediatric academic societies in Japan, including the Japan Pediatric Society, the Japanese Society for Pediatric Nephrology, the Japanese Society on Enuresis, and the Japanese Society of Pediatric Urology. He is board certified in pediatrics and certified by the Japanese Society of Pediatric Urology. He is an expert in general pediatrics, pediatric nephrology and intestinal bacteriology.