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

As seen on Vogue

Your guide to harnessing the powers of plant hormones and the answer to the controversial question of whether it’s safe to eat soy.

 

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.

 

Ema Taylor, a naturopath and nutritionist who specialises in supporting women’s hormone health and reproductive issuess, suggests that 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,” Taylor says. “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. However, phytoestrogens can actually help regulate our oestrogen levels up or down,” says Taylor.

 

Phytoestrogens have a weak affinity for our oestrogen receptor sites and their action in the body depends on the level of oestrogen we have,” she explains. “In other words, phytoestrogens can gently increase the amount of oestrogen in our body if we are low, or gently decrease the amount of oestrogen in our body if we have too much.”

“Phytoestrogens have been shown to support pre and post menopausal women that are experiencing a decline in endogenous estrogen production. Consuming phytoestrogens is much safer than hormone replacement therapy.”

Some other benefits of eating good quality soy include the fact that phytoestrogens may also help reduce LDL cholesterol, decrease cardiovascular conditions and reduce symptoms associated with oestrogen deficit conditions (including menopausal symptoms, osteoporosis, neurodegenerative disorders and skin aging) — although more definitive research is required, adds Taylor.

 

Another thing to keep in mind is that the therapeutic action of any food is largely dependent on how well it is absorbed and distributed around our body, and some research suggests we need certain intestinal bacteria to convert soy isoflavones (a type of phytoestrogen) into more potent isoflavone equol. “These bacteria are believed to be present in one in three women, which may explain the variance in reported data on the health benefits of soy,” says Taylor.

 

As for what type of soy we should be eating? It’s 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 soy bean milk. Other phytoestrogen rich foods to include flax seeds, sesame seeds, sunflower seeds, almonds, oats, barley, legumes, clover, 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 Taylor says it is estimated about 70 per cent of the isoflavones in whole soy beans 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, she adds.

Some research has also found links between diseases (endocrine disruption, cancer, oxidative stress, damage to gut microbiome and increased pressure on detoxification pathways) and genetically engineered soy crops that have been sprayed with toxic substances, and it has been suggested a high intake of soy supplementation may play a role in behavioural problems and endocrine dysfunction.

 

So how much soy is enough? Western diets only include about 1-5mg of soy daily which is significantly lower than Asian diets which include 20-80mg of soy per day. However, like most things in life, consistency is key. Taylor says the beneficial effects of soy are more convincing when soy has been consumed throughout life rather than just before menopause and absorption rates increase when the intake is divided throughout the day.

“All foods should be eaten in moderation, so dividing your phytoestrogen intake throughout the day and including different sources is likely to be beneficial for your health,” she says.

Written by Jody Scott