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ARS Home » Southeast Area » Little Rock, Arkansas » Microbiome and Metabolism Research Unit » Research » Publications at this Location » Publication #329484
Title: Impact of dietary fibers on nutrient management and detoxification organs: Gut, liver, and kidneys

Author
item Kieffer, Dorothy
item MARTIN, ROY - University Of California
item Ferruzzi, Mario

Submitted to: Advances in Nutrition
Publication Type: Review Article
Publication Acceptance Date: 7/26/2016
Publication Date: 11/15/2016
Citation: Kieffer, D., Martin, R.J., Adams, S.H. 2016. Impact of dietary fibers on nutrient management and detoxification organs: Gut, liver, and kidneys. Advances in Nutrition. 7(6):1111-1121. doi:10.3945/an.116.013219.

Interpretive Summary: Increased dietary fiber (DF) intake elicits a wide range of health benefits, not just locally in the gut, but throughout the body. While this has been known for many years, it remains largely unknown what mechanisms are involved, and how types of DF and differ in their effects. This review article provides a unique perspective by exploring the effects of DF on three key nutrient management organs: gut, liver and kidney. Dietary fibers can greatly alter the gut milieu by impacting the gut microbiome (i.e., intestinal bacteria), which in turn influences the gut barrier, immune and hormone responses, and nitrogen cycling and microbial metabolism. These gut-associated changes can then alter the physiology and biochemistry of the body's tissues through signals carried from the gut and into the bloodstream. An emerging opportunity is to identify which signals are most important, i.e., to clarify the specific factors emanating from the gut in response to DF. These include metabolites only made by bacteria and not one’s own body (aka, xenometabolites), peptides or bioactive food components made available through the actions of the gut microbes. New technologies are currently being leveraged to fully identify these factors, and to link them to actions at the cellular level to determine which dietary fibers are most effective in fostering human health.

Technical Abstract: Increased dietary fiber (DF) intake elicits a wide range of physiological effects, not just locally in the gut, but systemically. Dietary fibers can greatly alter the gut milieu by impacting the gut microbiome, which in turn influences the gut barrier, gastrointestinal immune and endocrine responses, and nitrogen cycling and microbial metabolism. These gut-associated changes can then alter the physiology and biochemistry of the body's other main nutrient management and detoxification organs—the liver and kidneys. Determining the molecular mechanisms by which DF alters (patho)physiology of the gut, liver and kidneys has been challenging for several reasons: the heterogeneous nature of DF, differences in resident gut microbiota that influence efficacy of fiber supplementation, variation in study design including population (i.e., healthy vs. unhealthy, neonates-to-adults), dose, duration, type of fiber supplementation, and background diet (i.e., high vs low fat). A further challenge has been to identify the specific factors emanating from the gut in response to DF, which signal to or impact the physiology of the liver and kidneys. These may include microbial-derived xenometabolites, peptides or bioactive food components made available by gut microbes, inflammation signals, and gut hormones. The intent of this review is to summarize how DF alters the gut milieu to specifically impact intestinal, liver and kidney functions, and to discuss the potential local and systemic signaling networks that are involved.