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ORIGINAL RESEARCH article

Front. Nutr.
Sec. Nutrition and Metabolism
Volume 11 - 2024 | doi: 10.3389/fnut.2024.1487859
This article is part of the Research Topic Functional Foods for Metabolic Health View all 10 articles

Dietary soy protein reverses obesity-induced liver steatosis and alters fecal microbial composition independent of isoflavone level

Provisionally accepted
Reza Hakkak Reza Hakkak 1*Soheila Korourian Soheila Korourian 1Wei Li Wei Li 1Beverly Spray Beverly Spray 2Nathan Twaddle Nathan Twaddle 3Christopher Randolph Christopher Randolph 1Elisabet Børsheim Elisabet Børsheim 1Michael S. Robeson Michael S. Robeson 1
  • 1 University of Arkansas Medical Center, Little Rock, United States
  • 2 Arkansas Children's Research Institute (ACRI), Little Rock, Arkansas, United States
  • 3 National Center for Toxicological Research (FDA), Jefferson, Arkansas, United States

The final, formatted version of the article will be published soon.

    Non-alcoholic fatty liver disease (NAFLD)Metabolic dysfunction-associated steatotic liver disease (MASLD) is a major public health concern that is exacerbated by the obesity pandemic. Dietary interventions have the potential to alleviate obesity-associated NAFLDMASLD through variable mechanisms, including optimizing the gut microbiota. Previously, we reported that soy protein concentrate (SPC) with low or high levels of isoflavone (LIF or HIF) protected young obese Zucker rats from developing liver steatosis. The current study was designed to test whether SPC-LIF and SPC-HIF diets would reverse liver steatosis and alter fecal microbial composition in adult obese Zucker rats with existing steatosis. Six-week-old male obese Zucker rats (n = 2826) were fed a casein control diet (CAS) for 8 weeks and 7 rats were randomly selected and sacrificed to confirm liver steatosis. The remaining rats were randomly assigned to receive CAS, SPC-LIF, or SPC-HIF diet (n = 6 -7/group) for an additional 10 weeks. Compared to CAS diet, feeding SPC-LIF and SPC-HIF diets resulted in significantly lower liver weight, liver steatosis score, and liver microvesicular score (p < 0.05), but did not lead to difference in body weight, liver macrovesicular score, serum ALT, or serum AST. Isoflavone levels (e.g. LIF vs. HIF) did not affect any of these measurements except in the SPC-HIF group, which had an additional decrease in liver weight (p < 0.05) compared to the SPC-LIF group. The SPC-HIF group also had significantly higher levels of allthe aglycone forms of daidzein, genistein, and equol as well as theand total levels of daidzein, genistein, and equol compared to SPC-LIF or CAS diet fed rats (p < 0.05). The distribution of microbial communities based on measures of beta diversity of both SPC-LIF and SPC-HIF groups were significantly different to that of the CAS group (p ≤ 0.005). Conversely, aAlpha-diversity did not differ between any of the groups. When tTakenTaken together, dietary soy protein can reverse liver steatosis in adult Zucker rats, and the reversal of steatosis is accompanied by alterations in gut microbial composition.

    Keywords: Obesity, Non-alcoholic fatty liver disease, Soy Protein, isoflavone level, microbiota, Zucker rats

    Received: 28 Aug 2024; Accepted: 09 Oct 2024.

    Copyright: © 2024 Hakkak, Korourian, Li, Spray, Twaddle, Randolph, Børsheim and Robeson. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Reza Hakkak, University of Arkansas Medical Center, Little Rock, United States

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