Phytoestrogens are naturally occurring plant-based compounds that mimic oestrogen in the body. Oestrogen is a hormone and, in female adolescence, plays a role in the development of breasts, armpit hair, pubic hair and, up until the menopause, controls a woman’s periods. A diet rich in phytoestrogen foods has been found to be beneficial in combating some symptoms caused by fluctuating oestrogen levels, such as those experienced during the early stages of the menopause. But how truly effective are they at reducing symptoms such as hot flushes? And, more importantly, how safe are they when eaten or taken as a food supplement?
How phytoestrogens work
When phytoestrogens enter the body, the body’s oestrogen receptors treat them as if they were oestrogen. When we eat foods that contain phytoestrogens, such as isoflavones found in foods like soy milk and red clover, they have a similar effect to naturally occurring oestrogen. However, be warned that phytoestrogens do not bind to oestrogen receptors as firmly as oestrogen produced by the body, so their effects may be weaker.
Foods rich in phytoestrogen
Nuts and seeds: flaxseeds, sunflower seeds, sesame seeds, almonds and walnuts
Fruits: apples, carrots, pomegranates, strawberries, cranberries and grapes
Vegetables: yams, lentils, alfalfa sprouts, mung beans and sprouts
Soy products: soybeans, tofu, tempeh, miso soup and miso paste
Herbs: red clover, licorice root and hops
Liquids: coffee, bourbon, beer, red wine, olive oil and jasmine oil
Grains: oats, barley and wheat germ
Phytoestrogens and the reduction of hot flushes
Studies demonstrating the effectiveness of isoflavones in the management of hot flushes have been inconsistent. A Cochrane review back in 2013 concluded that some trials reported a slight reduction in hot flushes with phytoestrogen-based treatments such as food supplements. However, the review concluded that there was no beneficial effect over placebo when assessing the frequency of hot flushes. Then a 2014 study found phytoestrogens did reduce the frequency of hot flushes in menopausal women without any side effects. This study suggests that eating a diet high in phytoestrogen or taking food supplements can have similar effects to taking Hormone Replacement Therapy (HRT).
The safety of phytoestrogens instead of HRT
Studies show that phytoestrogens may provide similar benefits to that of synthetic oestrogen used in HRT when reducing the frequency of hot flushes. However, this may not mean that they are any safer than taking synthetic HRT itself. Phytoestrogens act in a similar way and may carry the same risks. A 2010 study found that high levels of soy in a woman’s diet can lead to reduced ovarian function. This is particularly true in premenopausal women during their reproductive years, when these decreases could have the greatest effect. Another study in 2011 considered phytoestrogens to be endocrine disrupters, indicating that they have the potential to cause other adverse health effects.
While reading around the subject of phytoestrogen, I came across a lot of contradictory information. I struggled to find any clarity on whether consuming phytoestrogens in high levels is actually beneficial or harmful to women experiencing hot flushes due to the menopause. This would suggest to me that more research is needed to fully understand how phytoestrogens work – and that may be because the answer is complex. It may depend on age, health status and even the presence or absence of specific gut microflora. If you are considering eating a diet rich in phytoestrogen or taking food supplements, be aware that, like any other natural diet or product, it can have interactions with other drugs, such as Warfarin, and adverse effects like any medicines. To be safe, I would speak with your doctor or dietician or nutritional therapist before you increase phytoestrogen through diet or food supplements.