The researchers disclosed in the journal Cell host microorganism on April 28, 2022 that the health benefits of dietary fiber vary from person to person and may depend on the precise fiber type and dosage "Our results show that the physiological, microbial and molecular effects of individual fibers are very different. In addition, the results show the attractive prospect of using targeted fibers mediated by microbiome to promote the development of health and systems biology in a predictable and personalized direction," said Michael Snyder, a geneticist at Stanford University School of Medicine and senior research author
A high fiber diet can reduce the risk of heart attack, stroke and cardiovascular disease. Their role is to lower cholesterol, and people who eat a westernized diet have healthier blood lipids. Dietary fiber is a carbohydrate that is selectively metabolized by intestinal microorganisms, but it is not digestible by humans in other aspects. Understanding how they affect the microbiome and thus human biochemistry and physiology is essential for the effective use of dietary fiber supplements to improve human health.
From a chemical point of view, fibers are diverse in length, branching, composition, solubility and other properties. "They are often studied as complex mixtures from plant sources," Snyder said. It is necessary to determine the harmless effects of individual fibers on the microbiome and establish relevant health biomarkers, preferably by testing different fibers in the same person. "
To meet this need, Snyder and his colleagues set out to understand how purified individual fiber components affected the same group of participants. The specific effects of LCI, which is commonly found in cereals, on the physiological structure of chicory roots and chicory roots were studied.
Using the knowledge of fecal metagenomics, plasma proteomics, metabolomics and lipomics, the researchers analyzed the serum cytokines and clinical value of 18 participants. "Fiber is associated with improved metabolic and cardiovascular health, but understanding the effects of individual fibers on microbial and metabolomic responses has not been studied using multiomic data sets," Snyder said
Participants consumed 10 grams of fiber per day in the first week, 20 grams per day in the second week and 30 grams per day in the third week. The results show that fiber and usually dose-dependent microbial and systemic responses. On average, ax consumption is associated with a significant reduction in low density lipoprotein (LDL) (known as bad cholesterol) and an increase in bile acids, which may contribute to the reduction of cholesterol. However, individual responses varied, and some participants had little change in cholesterol levels.
"Some high fiber foods have cholesterol lowering effects, and our research suggests that these reductions may be driven by individual components of the fiber combination in unrefined plant foods," Snyder said
At the same time, LCI is associated with a modest reduction in inflammatory markers and an increase in the abundance of bifidobacteria, a generally beneficial type of intestinal microorganisms known to produce healthy short chain fatty acids. But at the highest dose, inflammation and levels of a liver enzyme called alanine aminotransferase increased, suggesting that too much of this fiber may be harmful. Similarly, these potential negative reactions are different among different participants.
Two limitations of the study are its short duration and small number of participants. However, according to the authors, the study provides insights into the mechanism behind fiber-induced cholesterol reduction, reveals the harmful effects of high chrysanthemum powder consumption, and emphasizes the association between individual purified fibers and microbiome.
"Overall, our results show that the benefits of fiber depend on the type, dose and participants of fiber - a landscape of factors resulting from the interaction between fiber, intestinal microbiome and host. These results have important implications for personalized responses and interventions," Snyder said
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https://www.sciencedirect.com/science/article/pii/S1931312822001664?via%3Dihub