The National Health and Nutrition Examination Survey (NHANES) is a program of studies designed to assess the health and nutritional status of adults and children in the United States. The survey is unique in that it combines interviews and physical examinations. Even more unique is that one report stemming from the survey and reported on in the International Journal of Obesity, indicates that the environmental pollutants trapped in fat cells could be released back into circulation when people shed a lot of weight.
According to data collected from over 1,000 adult participants over the age of 40, serum concentrations of six persistent organic pollutants were significantly correlated with weight change. Although the cross-sectional study design could not establish that weight loss itself led to the higher concentrations of circulating organic pollutants, the findings were consistent with such a mechanism, the researchers suggested.
"As persistent organic pollutants mainly bioaccumulate in adipose tissue, weight change can affect serum concentrations," they explained. The researchers suggested that such releases may account for some adverse outcomes seen in people undergoing large weight losses, including increased rates of cardiovascular disease, dementia and death.
These chemicals included trans-nonachlor, beta-hexachlorocyclohexane, PCB169, PCB180, 1,2,3,4,6,7,8-heptachlorodibenzo-p-dioxin, and 1,2,3,4,6,7,8-heptachlorodibenzofuran (HpCDF). It is possible that factors other than weight loss, which were not analyzed in the current study, were also associated with the serum pollutant levels. However, pending the outcome of future studies, the study also states that "researchers and clinicians need to consider lipophilic xenobiotics such as persistent organic pollutants that bioaccumulate in adipose tissue as well as obesity itself when they study or manage obesity issues because such xenobiotics may work against what we generally expect from weight loss or gain."