Soy & Menopause: Is it beneficial? Are there any risks?
Many people in the community are confused about the conflicting information regarding soy products, particularly when it comes to breast cancer risk or recurrence and particularly in women experiencing menopause. So in order to reassure women of the efficacy of soy products for menopausal symptoms, the latest evidence for risk of soy needs to be addressed.
For many years breast cancer survivors have been told to avoid soy due to the foods phytoestrogen content. The theory being that phytoestrogens may stimulate the growth of cancer promoting cells. This was due to the lack of evidence and research so it was better to be cautious and rule it out. However, in the last few years there have been many studies for a total of 10,000 women, who have found that including whole soy foods (with the emphasis on whole) does not increase the risk or, recurrence of breast cancer. Studies have actually concluded that increasing soy consumption decreases risk of recurrence and increases mortality.
The Shanghai breast cancer survival study results published in the JAMA 2009, was a large population study of 5,042 women with a history of breast cancer. The conclusion of the 3-4 year study was that: high soy food intake and tamoxifen use may be comparable on breast cancer outcomes.
The problem today is that most processed food contains soy in the form of soy oil, soy lecithin, soy flour or soy protein. Soy is one of the biggest cash crops in America and the food industry is keen to market all soy as a health product. Tofu, tempeh, soy milk and miso are the traditional uses of soy, not the fillers that are used in processed food many of which are produced by GM farmers. Traditionally all soy food was eaten fermented.
Soy contains phytoestrogens which are non-steroidal and are of plant origin. The evidence in efficacy for menopausal symptoms shows as benefits in short and long term memory, mental flexibility, fluency and planning. The other advantage is a reduction in the dreaded hot flushes. This evidence is from 19 trials and 36 publications, based on an average intake of 54mg per day of soy. Hot flushes over a period of 12 months showed a reduction of 20% compared with placebo.
In order to give you an idea of how much soy this is:
- Textured soy protein ¼ cup = 62mg
- Roasted soy nuts, ¼ cup = 60mg
- Tempeh ½ cup = 35mg
- Tofu- ½ cup 35mg
- Soy milk, 1 cup =20-30mg
Interesting research shows that only 7 % of women in Japan suffer from hot flushes and night sweats, and its mainly due to their high plant based diet, lean protein and of course dietary fermented soy and whole soy products.
In the past all the evidence for the risk of soy isoflavone and the proliferation of breast cancer was based on rodent studies, it has now been proposed by several eminent researchers that the metabolism of isoflavone in rodents is not equivalent to that in humans. Soy beans are by far the most concentrated form of isoflavone, but it is not the only one. Evidence from the U.S shows that 45% of isoflavone are ingested from beans and peas, 25% from tea and coffee, 10% from nuts and 5% from grains.
When choosing soy milk or soy products check the label. Some milks have vegetable oils and sugars added. Go for the whole bean option and when buying tofu or tempeh organic is best. Bon soy is the best tasting soy milk and recently I have spotted it in Woolworths, it is free of vegetable oils, but unfortunately a little more expensive. Coles stocks frozen edamame beans (young soy beans in the pod, to be steamed).
So if you are suffering from menopausal symptoms, such as ‘brain fog”, night sweats, hot flushes, poor memory add a little soy in the right form of course!