By naturopath Jessie Denmeade
There has been a lot of misunderstanding about phytoestrogens over the years. Most of this misunderstanding is based on outdated information about how hormone receptors work, information that was developed in the 80s and 90s.
Let’s start with how hormones work in our body. Hormones (like neurotransmitters and many other nature chemicals) communicate with the cells in our bodies via receptor sites. These receptor sites are like locks, and the hormones are the keys, eliciting the hormone reaction. Only cells that have the corresponding receptor sites can be affected by hormones.
There are two main types of oestrogen receptor sites in our bodies, alpha and beta-receptor sites. When an alpha-receptor site is triggered, it has a proliferative, pro-inflammatory action (which is what we associate as the negatives of oestrogen such as oestrogen dependant cancers). When a beta-receptor site is triggered, it has an anti-proliferative and anti-inflammatory action. The oestrogens that our body makes (endogenous oestrogens), can bind with both alpha and beta-receptors. At different stages of our oestrogens breakdown, they will have a greater affinity with either alpha or beta (this is why healthy liver and bowel function are so important to healthy oestrogen balance). But ultimately, our endogenous oestrogens will bind to both receptor sites.
“Xenoestrogens” are synthetic chemicals found in plastics, pesticides, preservatives etc., that imitate oestrogen. However, xenoestrogens only trigger alpha-receptor site, which is why they are linked oestrogenic cancers and the ‘negatives’ of oestrogen. “Phytoestrogens” are natural plant chemicals that only trigger beta-receptor sites. However, they are able to bind to alpha-receptor site, but not trigger them. This makes the phytoestrogens protective against the pro-inflammatory and proliferative actions of other forms of oestrogen by blocking up the alphas making them inaccessible and unable to be triggered.
A diet high in phytoestrogens can help protect us from some of the dangers of plastics and toxins in our environment, as well as some of the less favourable actions of our naturally produced endogenous oestrogens. The foods highest in phytoestrogens tend to be legumes (especially soy) and flax seeds, however many fruits and vegetables including broccoli, peaches, carrots, berries and garlic, as well as sesame seeds and nuts, provide great sources of phytoestrogens.
There is accumulating evidence to suggest that phytoestrogens confer health benefits relating to cancer, osteoporosis, cardiovascular disease and menopause. These findings are consistent with the epidemiological evidence showing favourable correlations between lower rates of certain cancers, osteoporotic fractures, cardiovascular disease incidents and menopausal symptoms, among populations that consume diets traditionally high in soy products (for instance, Japan).
I wanted to explain these differences to dispel some of the common misunderstandings about phytoestrogens. I have met women who think they shouldn’t eat soy because they’ve had breast cancer, and men who won’t touch soy because they’re worried about growing breast tissue, and I want to make clear that these are not things to worry about. Our primitive understanding of oestrogen functions in the human body has been responsible for many misgivings about certain food types. But we now have the science to work through them.
So enjoy your soy and don’t be shy about legumes. My main concern around dietary soy is the amount of GMO soy that is on the market. But as long as you choose organically grown products, or check packaging for labels clearly stating that it’s made with non-GMO ingredients, then there is nothing to worry about.