Estrogenic Activities of Food Supplements and Beers as Assessed by a Yeast Bioreporter Assay

ABSTRACT

Mounting evidence of the effects of endocrine-disrupting chemicals (EDCs) in humans has led to assaying a vast array of food items (processed or packaged) as possible sources of human exposure to estrogens. In this study, we investigated the current situation in this respect of different food supplements and beer brands. Eleven food supplements and 24 beer brands were obtained from Helsinki, Finland. Sample preparation was carried out by established methods while estrogenic activities were assessed by a yeast bioluminescent assay, using two recombinant yeast strains (Saccharomyces cerevisiae BMAEREluc/ERα and S. cerevisiae BMA64/luc). All the food supplements as well as 81% of the beer samples tested were found to be estrogenic, with estradiol equivalent concentrations of food supplements and beer brands ranging from 7.5 to 11.5 µg/ml and from below detection limits to 43.6 ng/ml, respectively. The estrogenic activities detected in beer samples were not dependent on the beer's alcoholic content, the country of production, or the size of the production brewery. The results of our study imply that both food supplements and beers can be a significant source of human exposure to estrogens. Therefore, further studies and regular surveillance are warranted.

KEYWORDS:

• beer
• bioassay
• endocrine-disrupting chemicals
• estrogenic activity
• food supplements
• isoflavones
• isoxanthohumol
• phytoestrogens

Acknowledgments

We are grateful to Hannu Kause for his insightful contributions and for providing us with the majority of beer brands, including the hops-free control beer.

Declaration of interest

The authors declare no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Additional information

Notes on contributors

Iyekhoetin Matthew Omoruyi

Dr. Iyekhoetin Matthew Omoruyi is a faculty member and researcher in the Department of Biological Sciences, Faculty of Science, Benson Idahosa University, Nigeria. He obtained his P.hD. in Public Health Microbiology and Toxicology from the University of Helsinki (UH), Finland, and was a member of Prof. Raimo Pohjanvirta's research group, in UH between 2011 and 2015. His research currently focuses on the mutagenic and oestrogenic activites of a wide range of matrix as well as on the molecular epidemiology and distribution of toxigenic and pathogenic genes in selected microorganisms.

Raimo Pohjanvirta

Professor Raimo Pohjanvirta is a professor of Toxicology, in the Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, Finland. his research is on the toxicity mechanism of dioxin (TCDD), the physiological and toxicological effects of the AH receptor as well as the estrogenic activity and genotoxicity of foodstuffs.