A UK scientist has developed a database of biomarkers to measure the effects of plant hormones, found in soy and other fibres, on humans.
The information, which will be freely available to researchers worldwide, may help prove how phytoestrogens influence the treatment of breast cancer, one of the leading causes of death among women in developed countries.
Previous research has linked a high intake of phytoestrogens to lower risk of cancer in women, attributed partly to the effect they have on lowering natural production of oestrogen. But these studies have not been properly validated or tested on humans, only on rats or mice.
The new database, developed over a three-year period by Dr Margaret Ritchie from the University of St Andrews in Scotland, validates the foods containing phytoestrogens. It can now be used to investigate the effects of human exposure to these compounds.
"So far, nobody in the world can accurately monitor human exposure to phytoestrogens, or how people respond to such exposure. This is a major breakthrough and a massive step forward," said Ritchie.
Phytoestrogens are found in around 300 foods, including many fruits and vegetables, sunflower and sesame seeds and rye, but in highest quantities in soybeans. But until now there has been no biomarker, a long-term reliable measurement, for their effects. Ritchie worked with Professor John Cummings, a biomarker expert at Dundee's Ninewells Hospital, to identify and validate several suitable biomarkers of phytoestrogen exposure.
"It was a case of going back to basics. It's amazing that no-one has developed a biomarker of phytoestrogen exposure before," she said.
Dr Ritchie enlisted almost 90 healthy, cancer-free women aged between 18 and 81, to keep a food diary for up to six months. They also supplied the researcher with over 500 blood, urine and diet samples so that she could measure exposure to phytoestrogens. Some men were included in the research to prove that the biomarkers were reliable regardless of gender.
The database - which will be made freely available to researchers across the world via the University of St Andrews' website - is already being used in an Edinburgh-based prostate cancer study.
Dr Ritchie has presented her research at conferences in Scotland, the US, Germany and Ireland this year and will publish the results an upcoming issue of theBritish Journal of Nutrition. The research is also currently under review by the European Journal of Clinical Nutrition and the new Journal of Evidence-Based Integrative Medicine.