Soy confused? Me too. I can’t for the life of me work out where the hysteria around soy came from. To me, it is simple, whole foods that come from the earth, traditionally prepared/minimally processed, should be regarded as health-promoting. Especially those foods that have been consumed by healthy populations for centuries, and studied extensively. Yet somewhere along the way, we get thrown astray. Soy is definitely victim to ill-informed claims and scare tactics. It is time to set the record straight. The right types of soy are unequivocally, a healthful choice.
Soy does not contain oestrogen, but rather, phytoestrogens. Phytoestrogens are beneficial and adapt to what the individual needs, raising or lowering oestrogen levels accordingly. A large-scale study at a fertility centre demonstrated improved birth rates in females consuming soy and undergoing fertility treatment. Menopausal women dealing with hot flashes indeed find relief with soy products, according to this study. As mentioned, phytoestrogens adapt to what is required, and therefore soy does not interfere with male sex hormones. This study concluded that soy does not “exert feminizing effects on men at intake levels equal to and even considerably higher than are typical for Asian males.”
Phytoestrogens also act as antioxidants and have anti-proliferative properties to inhibit tumour growth. As such, research appears to support soy’s positive effect on preventing or slowing down the growth of cancer. Even amongst women with a history of breast cancer, soy food consumption has been significantly associated with decreased risk of death and recurrence. Other analyses have found that soy foods are protective against prostate cancer in men, as well as reduced colon cancer risk.
The beneficial isoflavones (types of phytoestrogens) in soy have been indicated as preventing the breakdown of bones. Whilst soy generally does contains less calcium than dairy, it does contain triple the amount of magnesium, a vital mineral for bone maintenance. Soy products also do not cause hypothyroidism and hypothyroid adults need not avoid soy foods. However, the isoflavones in soy may potentially reduce iodine availability, required for healthy thyroid hormone production. It is therefore suggested that people who consume soy might need slightly more iodine in their diets (which we can get from sea veggies like dulse and nori).
Finally, most soy foods contain fibre, which is essential for good digestion, preventing constipation and overall gut health. Whilst most meat has equivalent protein content, it contains zero fibre, and is therefore not a “package deal”, like tempeh and tofu are.
Soy sources to include and avoid:
Organic and non-GMO edamame and fermented sources such as tempeh, natto, miso, tamari (easiest to digest and assimilate). Whilst soy milk and tofu are more processed, organic varieties are not going to negatively impact your health and should not be feared. Soy protein isolates – broken down soy into highly processed ingredients contained within junk foods – are not part of a healthy diet and should be avoided, as all highly-processed foods should be.
As you can see, there is a lot of good evidence indicating the benefits of good quality soy foods in the diet. It is not necessarily a miraculous cure-all, but rather, not something to avoid should you wish to include it as part of a plant-rich varied diet. So go on, eat the tempeh, drink the miso!