To soy or not to soy: everything you need to know about phytoestrogens

Plant powered diets are big news and the benefits of eating mostly plants can not be underestimated. But there is one type of plant food that is more controversial than all the rest. It seems that everyone has an opinion on whether or not we should eat soy, and that is because it has been linked to thyroid issues, digestive problems and even breast cancer.

As a naturopath and nutritionist who supports women’s hormonal health at all stages of life, I suggest instead the question we should be asking is, what type of soy do we eat? It is important to understand there are different types and quality of soy products. Asian countries consume whole soybeans, with or without fermentation, whereas Western countries use higher amounts of processed soy, including soy proteins and supplements, which alters the nutrient profile and health properties considerably.

Soy is controversial because it contains plant hormones called phytoestrogens — compounds that have a similar structure to our natural sex hormone oestrogen. Phytoestrogens have been shown to support pre and post menopausal women that are experiencing a decline in endogenous estrogen production.

The phytoestrogens from plant foods fool the body into thinking it still has some oestrogen. The oestrogen receptors in your body ‘recognise’ and accept any substance that has a similar molecular structure to endogenous oestrogen. So where oestrogen would normally latch on, phytoestrogens fill their space. So, your brain says, ‘Hang on a minute! I have some oestrogen so I don’t need to have that hot flush now!’.

As for what type of soy we should be eating, it is important to choose carefully. Always aim for the whole food and look for organic whole soy products such as soybeans, tofu, miso, edamame, tempeh and whole soybean milk.

Other phytoestrogen rich foods to include are flax seeds, sesame seeds, sunflower seeds, almonds, walnuts, oats, barley, legumes, clover, mung beans, alfalfa and soybean sprouts.

There are many reasons to avoid genetically modified soy in processed foods and soy supplements -think soy protein isolate in protein powders – as it is estimated about 70 percent of the isoflavones in whole soybeans are lost during processing. The negative long-term health implications of eating genetically modified foods which have been sprayed with toxic herbicides are also still not completely understood.

So how much soy is enough?

The beneficial effects of soy during menopause are more convincing when soy has been consumed from your 40s onwards, and like most things, consistency is key. Research demonstrates that as little as 100 grams of tofu or 2 heaped dessert spoons of freshly ground linseeds every day can lessen hot flushes and improve vaginal dryness after six weeks of regular daily consumption.

The simplest way is to begin with those phytoestrogen foods you love to eat and work them into your everyday meals. If you love chickpeas swap them for the beef in your next curry. Add two heaped dessert spoons of freshly ground flaxseeds to your weekend smoothie or breakfast granola. Sprinkle alfalfa sprouts on your workday salads or enjoy a miso soup as a snack mid-afternoon. Add legumes to your soups. Swap the butter in your sandwich for tahini paste. Add flaxseed crackers to your Friday night cheese board or choose teriyaki tofu instead of chicken when eating out at your favourite Japanese. All easy ways to up the phytoestrogen content on your plate and use food as medicine in your very own kitchen!