Time to change
Compared to Asian diets, those of us eating a Western style diet consume significantly less soy. As it’s not one of our traditional staples, we don’t really think to incorporate it into our meal plans except, perhaps, in the form of salt-laden soy sauce. As a result, our intake of dietary isoflavones averages at just 2mg to 5mg per day.
In Japan, where soy products such as miso, natto, tofu and tempeh are dietary staples, the intake of isoflavones is much greater at between 50mg to 100mg per day. This is one of the main reasons why it’s thought that women who follow a traditional Asian diet do not experience significant menopausal symptoms such as hot flushes or night sweats.
So what exactly is soy?
Soy beans contain plant hormones known as isoflavones; when eaten, these are broken down by bowel bacteria to release the active forms which provide health benefits. Some people with the highest level of probiotic bacteria (e.g. Lactobacilli, Bifidobacteria) are able to further convert the soy isoflavone, daidzein, into a more powerful oestrogen, called equol.
Although the activity of soy isoflavones at oestrogen receptors is weaker than human oestrogen, they provide a significant hormone boost to help offset menopausal symptoms. As a bonus, soy isoflavones also boost the production of collagen protein in the skin, helping to improve elasticity and hydration and minimise signs of skin ageing. Preliminary research suggests that dietary isoflavones may also help to protect skin against sun damage and reduce wrinkle formation. If you’re concerned about your bone health or cholesterol, consuming soy can have benefits for those, too.
Cooking up a rainbow
Good sources of soy isoflavones include soy milk and yogurt, tofu, miso, tempeh and edamame beans. These can easily be added to meals, while frozen soy beans can be added to soups, stews, and casseroles.
Other nutritious sources of plant hormones include chickpeas, broad beans, lentils, sweet potato, Chinese leaves such as pak choy and kohlrabi, as well as nuts (especially peanuts and pistachios) and seeds.
Other soy sauces
Soy isoflavone supplements are one of the most useful supplements for women approaching the menopause, or experiencing perimenopausal symptoms. The usual recommended dose is 40mg to 100mg soy isoflavones a day.
Soy – dictionary corner:
1. Natto: A food native to Japan made of fermented soybeans. It’s typically eaten for breakfast.
2. Tofu: Also known as bean curd, derived from soya. It can be soft, firm or extra firm. Try it in a curry.
3. Miso: Also made from fermented soy beans, this is a traditional Japanese seasoning. Try it in soup.
4. Tempeh: A fermented soy product originating from Indonesia. Try it in chilli con (or non) carne.
If you have a history of breast cancer, always follow your own doctor’s advice about whether or not to take isoflavone supplements.
Evidence suggests they are protective but different doctors have different opinions.