- Researchers have previously determined the link between fiber intake and health status.
- Once the bacteria are metabolized, fiber promotes a healthy gut microbiome.
- A recent study found that an increase in fiber intake for 2 weeks significantly changes the gut microbiome.
Researchers have found that increasing fiber intake for 2 weeks can significantly change the human intestinal microbiome, including increasing the types of bacteria that break down fiber.
However, the number of short-chain fatty acids (SCFA) has not increased. SCFA is the result of bacteria breaking down fiber, and they have multiple functions in the body.
For example, SCFA is used as
The research, published in the journal MicrosystemTo further study the fiber intake, the relationship between intestinal bacteria and SCFA laid the foundation.
Fiber plays an important role in human health. For example, recent reviews of various meta-analysis found that people who consume the most fiber can significantly reduce the chance of death due to cardiovascular events.
However, in the United States, only one in ten people consume the recommended amount of fiber.
According to Dr. co-director of the University of California, Irvine (UCI) microbiome program, associate professor of biochemistry and molecular biology Katrine Whiteson, he is co-author of the study:
“The lack of fiber intake in industrialized countries makes our gut microbes hungry, which may have an important impact on health. This may be related to the increase in colorectal cancer, autoimmune diseases, and even the decline in vaccine efficacy and the response to cancer immunotherapy. .”
The small intestine cannot digest fiber. Instead, according to the authors of this study, it enters the colon, where microbes can break down fiber.
This process leads to SCFA. Experts believe that they are important for a series of factors that affect a person’s health.
The authors of this study hope to study the relationship between the short-term increase in dietary fiber, the composition of the gut microbiome and the presence of SCFA.
To investigate, the researchers conducted a study involving 26 undergraduates studying biology courses at UCI and their teachers.
In the first week, the participants had a normal diet and provided three stool samples for analysis.
In the second week, the participants started on a high-fiber diet. They use fitness apps to track their nutritional intake, with a goal of consuming 40 grams (g) of fiber per day. In order to help, the researchers provide them with 10 meals a week, these meals come from a variety of different plants, high in fiber.
In the third week, encourage participants to increase their fiber intake to 50 grams per day. During this week, participants provided three more stool samples.
According to the teaching assistant graduate student Andrew Oliver of the course, “Students increase their fiber intake by an average of 25 grams per day, but the fiber intake before the intervention varies greatly.”
By the end of the study, some students had to reduce their daily weight from zero to 50 grams. All of us are obsessed with the fiber content of the food we eat. “
The researchers then analyzed the samples using DNA sequencing to identify the composition of the bacteria. They use gas chromatography to measure SCFA.
The researchers found that after dietary intervention, the composition of the participant’s gut microbiome changed about 8%.
This is mainly due to the increase in known fiber-decomposing bacteria, including Bifidobacterium, Bacteroides, with Prevotella.
However, the researchers did not find a statistically significant increase in SCFA. They speculated that this may be because the stool sample cannot accurately represent the level of SCFA in the intestine, and the level of SCFA in the intestine is mainly found in the intestinal cell wall.
The researchers also suggested that the two-week intervention may not be long enough to observe any difference in SCFA.
Dr. Whiteson said: “We hope to carry out longer dietary fiber interventions to study how fiber supports the gut microbiome and promotes health.”
“During a pandemic, when we need immune health and a healthy vaccine response, we encourage everyone to consider plant diversity in the diet and add some beans, berries and avocados where possible.”