Dietary habits affected the levels of "everlasting chemicals" in the body
The authors of the new study, in their own words, filled an important gap and were the first to study food sources of per- and polyfluoroalkyl substances in two independent cohorts of young people. As a result, they were able to compile a list of the most harmful foods in terms of PFASs and find out where it is healthier to eat - at home or in restaurants.
Researchers from the University of Southern California, the Icahn School of Medicine at Mount Sinai, Emory University, Children's Hospital Los Angeles and the University of Colorado at Boulder (USA) set out to find out whether diet and food are associated with changes in the concentrations of "perpetual chemicals" in the blood of young people. The results are published in the journal Environment International.
Per- and polyfluoroalkyl substances (PFAS), a group of synthetic organofluorine compounds that act as pollutants and are fraught with negative health effects, are called "perpetual chemicals". PFASs have been found in household items such as non-stick cookware, food packaging, water repellents and stain removers. Due to their structure, these substances have a long half-life and persist in the environment for many years, entering and accumulating in the bodies of humans, other mammals, fish, and shellfish, among others.
"PFASs are detected in more than 98% of the United States population 12 years of age and older. These chemicals have a structure similar to fatty acids, giving them the ability to provoke hormonal disturbances associated with lipid metabolism and inflammation. Per- and polyfluoroalkyl substances are associated with many adverse health effects, including increased risk of certain cancers (e.g., liver cancer), impaired glucose homeostasis, type 2 diabetes and obesity, which are among the leading causes of death in the United States," the researchers recalled.
Maintaining a healthy lifestyle from a young age, which involves proper nutrition, reduces the likelihood of developing chronic diseases later in life. Therefore, identifying the factors that influence exposure to PFASs is important to reduce their levels in young bodies. It is diet that accounts for most of the exposure to per- and polyfluoroalkyl substances (except for people who work with them), so that is what the US health professionals focused on.
The sample included 124 young adults between 17 and 22 years old (mean age 19.8 years, 84% were overweight), mostly Hispanic, who participated in the Children's Health Study (CHS) between 2011 and 2018. The researchers also used data on 604 participants in the NHANES national survey (mean age 19.1 years, 53% were male, 48% were overweight), which has been assessing the health and nutritional status of the US population since 1999.
The new research paper took into account information from 2013-2014, 2015-2016, and 2017-2018. The results of tests to determine levels of six PFASs (perfluorodecanoic acid, perfluoronanoic and perfluorohexanesulfonic acids, perfluorooctanesulfonic acid, perfluorooctanoic acid and perfluoroheptanesulfonic acid), as well as weekend and weekday dietary data were available. In addition, all volunteers completed questionnaires on age, sex, parental background and education.
Having analysed all the data, at baseline the health professionals recorded higher levels of PFAS in the blood of people who were fond of tea (both sweetened and unsweetened), pork, sports drinks, nut and sunflower oils, crisps, bottled water, but at the same time consumed little whole fruit, fruit juices, pasta, fried potatoes, soft drinks, porridge, nuts and seeds, sugar and tap water.
The most significant association was with tea consumption (plus one serving correlated with a 24.8 per cent increase in perfluorohexanesulfonic acid, 16.17 per cent increase in perfluoroheptanesulfonic acid and 12.6 per cent increase in perfluorooctanoic acid) and pork (plus one serving was associated with a 13.4 per cent increase in perfluorooctanoic acid). From the second cohort, the researchers identified hot dogs and processed meats.
In contrast, one extra serving of sugar reduced perfluorooctanoic acid levels by 18.9 per cent and perfluorohexanesulfonic acid levels by 13.9 per cent. Tap and bottled water showed no significant association with PFAS concentrations in the NHANES survey.
Where people ate was also found to be important: frequent consumption of food cooked at home was associated with lower concentrations of perfluorooctanesulfonic acid, by 0.9 per cent at the start of the study and 1.6 per cent thereafter. Burritos, fajitas, tacos, Chips, and pizza, for example, were associated with lower PFAS levels if they were prepared at home, but higher levels if these meals were from fast-food restaurants and cafes. The same was true for hamburgers and perfluorodecanoic acid (the home-cooked version lowered its concentration by 22.2 per cent).
"To our knowledge, this is the first study to examine the association between food and concentrations of perfluoroalkyl chemicals. <...> The results showed that both certain foods and the place where they are prepared may be reflected in PFAS exposure. Taken together, this may provide a basis for the development of dietary interventions," the authors of the article summarised.