A diet rich in fiber may decrease disease risks associated with perfluorooctane sulfonate (PFOS) exposure, according to researchers at the University of Kentucky. With funding from the NIEHS Superfund Research Program (SRP), the team investigated how dietary fiber may play a role in gut microbiota-liver metabolism interactions.

“We know that in humans, high fiber diets help protect against numerous diseases, such as cardiometabolic diseases, cancer, obesity, diabetes, and so forth,” said project leader Bernhard Hennig, Ph.D. “Many of these diseases are also linked to exposure to environmental pollutants or environmental insults, so the goal of this study was to see if fiber could also protect against environmentally-induced disease.”

The harms of PFOS

PFOS is part of a class of synthetic chemicals called per- and polyfluoroalkyl substances (PFAS), which are commonly used in water and oil repellents, food packaging, industrial processes, and firefighting foams. Although PFOS was phased out in the U.S. in the early 2000s, it can still be found in drinking water, groundwater, soil, and air.

“PFOS can induce liver damage, impact cholesterol balance, compromise heart health, and affect antibody production and overall immunity,” said lead researcher Pan Deng, Ph.D. “Exposure to PFOS is also associated with decreased thyroid function and other related illnesses.”

Benefits of a fiber-rich diet

Investigators at the University of Kentucky SRP Center were the first to learn that healthful nutrition and diets rich in fiber can counteract the adverse health effects of environmental pollutants. Specifically, the researchers studied how some components of diet can protect against the harmful health effects of polychlorinated biphenyls (PCBs), a contaminant linked to many inflammatory diseases, including cancer. They found that inulin — a soluble fiber found in vegetables — can decrease risk of cardiovascular disorders and reduce fat accumulation in the liver.

"We found that fiber can regulate lipid metabolism and immune function and protect the gut microbiome," Deng said. "These mechanisms play a protective role in the occurrence of inflammatory diseases and can help reduce the risk of obesity, heart disease, and diabetes."

Mitigating PFOS disruption

The researchers, led by Deng, investigated the role of different fibers — including inulin and pectin, another soluble fiber ― on PFOS-induced disruption of liver and gut health in mice. According to Deng, they further focused on PFOS because it is widely found in contaminated water and food.

Their results suggested that, compared with mice that were fed a standard diet, inulin- and pectin-fed mice were less susceptible to the metabolic outcomes of PFOS exposure, such as liver damage and lipid accumulation. Mice fed soluble fiber also had less PFOS in their plasma and in their livers and had higher expression of genes that protect against PFOS-induced atherosclerosis, or fat buildup in and on artery walls.

This research supports the potential of enriching diets with soluble fiber as a way to reduce disease risk in PFOS-exposed populations, according to the authors. However, more research is needed to understand the exact mechanisms involved in the preventative properties of dietary fiber against environmental insults.

According to Hennig, the team next plans to further understand how positive lifestyle changes, such as healthful nutrition and increased physical activity, will modify mechanisms of disease risks associated with PFAS exposure.

Citations:
Deng P, Durham J, Liu J, Zhang X, Wang C, Li D, Gwag T, Ma M, Hennig B. 2022. Metabolomic, lipidomic, transcriptomic, and metagenomic analyses in mice exposed to PFOS and fed soluble and insoluble dietary fibers. Environ Health Perspect 130(11):117003.

Hofe CR, Feng L. Zephyr D, Stromberg AJ, Henning B, Gaetke LM. 2014. Fruit and vegetable intake, as reflected by serum carotenoid concentrations, predicts reduced probability of polychlorinated biphenyl-associated risk for type 2 diabetes: National Health and Nutrition Examination Survey 2003-2004. Nutr Res 34(4):285−293.