The NFI Technical University of Denmark looked at five possible alternatives with a chemical structure similar to BPA.
BPA, bisphenol B (BPB), bisphenol E (BPE), bisphenol F (BPF), bisphenol S (BPS) and 4-cumylphenol (HPP) were analysed.
“All test compounds caused the same qualitative effects on estrogen receptor and androgen receptor activity, and most of the alternatives exhibited potencies within the same range as BPA,” said the researchers.
They said other studies have found BPS in canned soft drinks and BPB in canned tomatoes, drinks and beers.
Denmark banned BPA in food contact materials for children aged 0-3 in 2010. The ban was labelled as “temporary” but will remain in place until studies show that low doses do not have an impact on development of the nervous system or the behaviour of rats, according to the government.
Findings show that bisphenol B, E, F, S and 4-cumylphenol have similar potential to cause endocrine disruption.
Anna Kjerstine Rosenmai, from the division of Toxicology and Risk Assessment at NFI, said the safety of any alternative needs to be considered before it is used.
“If the compounds are of a similar structure you might suspect the same effect but you cannot be sure and sometimes you get surprised so we wanted to see whether there were similar effects,” she told FoodQualityNews.com.
“We wanted to investigate similar compounds but varied a bit to represent different chemical structures, like a longer chain in the middle of the compound to see if that made a difference.
“We would like to investigate other end points and other compounds that are not BPA analogues, like other chemicals that may be present in food packaging materials.”
Rosenmai added that next steps could include validation in animal studies.
“I would like to extend the testing to other relevant cell-based toxicological studies or animal studies because there are not necessarily similar effects in an animal model,” she said.
“We want to urge the need for finding safer alternatives and to give further awareness to take safety into consideration before alternatives are chosen.”
The toxicological study used seven in vitro assays and QSAR modelling.
The five compounds tested showed estrogenic effects, blocked the receptor for male sex hormones, and affected sex hormone synthesis.
Mixed potential of BPS
BPS had the lowest estrogenic and antiandrogenic activity, but had high efficacy on progestagen levels. The remaining BPA alternatives had toxicological profiles that were generally similar.
Progestagen levels increased with exposure to BPB, BPE, BPF, BPS, and HPP; however BPA and BPB did not increase levels significantly in the majority of the experiments.
Testosterone, androstenedione and DHEA levels generally decreased with exposure to the test compounds.
However; DHEA did not change with HPP exposure and increased in level with BPB exposure.
BPA and BPE showed the most potent effect on androgens levels compared to the remaining test compounds
The National Food Institute is also investigating BPA-like compounds in plastics and paper.
Source: Toxicological Sciences
Online ahead of print, doi: 10.1093/toxsci/kfu030
“Are structural analogues to bisphenol A safe alternatives”
Authors: Anna Kjerstine Rosenmai, Marianne Dybdahl, Mikael Pedersen, Barbara Medea Alice van Vugt-Lussenburg, Eva Bay Wedebye, Camilla Taxvig and Anne Marie Vinggaard