MedicalResearch.com Interview with:
Gang Liu, PhD
Postdoctoral Research Fellow
Department of Nutrition
Harvard T.H. Chan School of Public Health
MedicalResearch.com: What is the background for this study? What are the main findings?
Response: Although many approaches can be used to achieve a short-term weight loss, maintenance of weight loss has become a key challenge for sustaining long-term benefits of weight loss. Accumulating evidence has suggested that certain environmental compounds may play an important role in weight gain and obesity development.
The potential endocrine-disrupting effects of perfluoroalkyl substances (PFASs), which are extensively used in many industrial and consumer products including food packaging, paper and textile coatings, and non-stick cookware, have been demonstrated in animal studies, but whether PFASs may interfere with body weight regulation in humans is largely unknown.
In a 2-year POUNDS Lost randomized clinical trial that examined energy-restricted diets on weight changes, baseline plasma concentrations of major PFASs were measured among 621 overweight and obese participants aged 30-70 years. Body weight was measured at baseline, 6, 12, 18, and 24 months. Resting metabolic rate (RMR) and other metabolic parameters, including glucose, lipids, thyroid hormones, and leptin, were measured at baseline, 6, and 24 months.
We found that higher baseline levels of PFASs were significantly associated with a greater weight regain, primarily in women. On average, women in the highest tertile of PFASs regained 1.7-2.2 kg more body weight than women in the lowest tertile. In addition, higher baseline plasma PFAS concentrations, especially perfluorooctanesulfonic acid (PFOS) and perfluorononanoic acid (PFNA), were significantly associated with greater decline in RMR during the first 6 months and less increase in RMR during weight regain period.
MedicalResearch.com: What should readers take away from your report?
Response: Our study suggests that PFAS may interfere with body weight regulation. Given that PFASs are ubiquitous in consumer products (such as fast-food wrappers and non-stick pans) and could also been found in contaminated drinking water and seafood, the public should pay attention to these potential exposure sources.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: The mechanisms need to be elucidated to interpret the findings that higher baseline PFASs, especially PFOS and PFNA, were associated with changes in RMR, which is a major determinant of weight maintenance. In addition, whether the 5 major PFASs might have different biological mechanisms and perhaps exert additive or synergistic effects also warrants further exploration.
MedicalResearch.com: Is there anything else you would like to add?
Response: Although the production of PFOS and PFOA in the United States has largely been phased out, the production of other PFASs, such as PFNA, may continue or even increase, especially in developing countries. Given the persistence of these PFASs in the environment and the human body, their potential adverse effects remain a public health concern.
This research was supported by NIH grants from the National Institute for Environmental Health Sciences (ES022981, ES021372, and ES021477), the National Heart, Lung, and Blood Institute (HL073286), and the General Clinical Research Center, National Institutes of Health (RR-02635). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Citations: Liu G, Dhana K, Furtado JD, Rood J, Zong G, Liang L, et al. (2018) Perfluoroalkyl substances and changes in body weight and resting metabolic rate in response to weight-loss diets: A prospective study. PLoS Med 15(2): e1002502. https://doi.org/10.1371/journal.pmed.1002502
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