October 10, 2016

expert reaction to review of the health effects of natural alternatives to oestrogen therapy

A review of published evidence on the health effects of plant-derived compounds (phytoestrogens) similar in structure to oestrogen is published in the British Journal of Pharmacology. The review reported that, when used as an alternative to hormone replacement therapy, phytostrogens had the potential for harmful effects which are not at this stage outweighed by the health benefits.

Prof. Mary Ann Lumsden, Senior Vice President of Strategic Development, Royal College of Obstetricians and Gynaecologists (RCOG), and Professor of Gynaecology & Medical Education, University of Glasgow, said:

“This is a thorough narrative review of phytoestrogens, which is welcomed. As was found in the NICE guideline on Menopause: diagnosis and management, it is very difficult to draw conclusions from the available literature since the studies are often small and are of variable quality.

“Although there is some evidence of benefit, it is inconsistent, therefore it is not possible to draw definitive conclusions from this study. Information on adverse effects is sparse and since these could be significant, it is difficult to compare risks and benefits at the moment. Further well conducted clinical trials are required.”

Prof. Edzard Ernst, Emeritus Professor of Complementary Medicine, University of Exeter, said:

“This is a thorough review of the current knowledge of the risks and benefits of phytoestrogens which are currently popular for all sorts of indications. It shows that the benefits are not all that well documented and probably small. The risks are potentially substantial but also far from established. Essentially, this means that there is much uncertainty about the value or otherwise of dietary supplements and foods containing phytoestrogens. The best advice therefore is to be very cautious and avoid the regular intake of phytoestrogens, particularly high dose supplements.”

Prof. Ashley Grossman, Emeritus Professor of Endocrinology, University of Oxford, & Society for Endocrinology spokesperson, said:

“There is a lot of interest in ‘natural’ oestrogens as replacement therapy in menopausal women, which have been considered to be safer and less prone to unwanted adverse effects. This class would especially include plant oestrogens or phyto-oestrogens. However, this review assesses all the evidence including the fact that such compounds may sometimes acts as anti-oestrogens, and concludes that it is difficult to give such ‘natural’ agents a clean bill of health. Natural compounds may have as many unwanted effects as synthetic products.”

Prof. Adam Balen, Chair of the British Fertility Society, said:

“This is a narrative literature review, which goes through the published papers (I’m not sure whether this is a fully comprehensive list of studies, although the fact it is peer-reviewed suggests that it probably) and indicates that phytoestrogens don’t really have any proven benefit and so on available evidence should not be recommended as an alternative to standard oestrogen/progestogen HRT for those women in whom it is indicated.”

‘The potential health effects of dietary phytoestrogens’ by Rietjens et al. published in British Journal of Pharmacology on Monday 10th September. 

Declared interests

Prof. Mary Ann Lumsden: “None at all apart from Chairing the NICE Guideline and being President of IMS, but no financial conflicts.”

Prof. Edzard Ernst: No conflicts of interest

Prof. Ashley Grossman: No conflicts of interest

Prof. Adam Balen: No conflicts of interest