- On June 8, 2017
As mentioned in the first blog of this series, Soya and your health: Overview, there have been several studies that have indicated that a regular intake of soya foods may help prevent hormone-related cancers such as breast cancer, prostate cancer, and colon cancer.
Hormone-related cancers are suspected to be oestrogen induced. For many years now, oestrogen has been a suspected carcinogen as there has been strong epidemiological evidence that links the hormone to cancers such as breast, endometrial and uterine cancers. The school of thought is that when the body produces an excess of oestrogen the more likely a hormone related cancer will appear – because oestrogen fuels the growth of the cancer cells.
The internet is full of many myths, and one is that you shouldn’t eat soya if you’re at risk for hormone-related cancer. This is because soya has had a bad rap because of its isoflavones. These plant-based chemicals are similar in structure to that of oestrogen, so there was some fear that soya could act as oestrogen in the body and in turn, would stimulate the cancer cells. But then you see headlines and other articles suggesting soya protects you against the disease. Should you avoid these foods or not?
Lower rates of breast and prostate cancer in some Asian countries led researchers to investigate the link between eating whole soy foods and the prevention of hormone-related cancers. Soya is being eaten, in its traditional forms, from a very young age in Asian countries. In one study, where more than 73 000 Chinese women were observed, researchers found that those who ate at least 13 grams of soya protein a day were 11% less likely to develop breast cancer than those who consumed less than five grams a day.
There have been several large, human studies that have shown that a diet high is soya does not increase the chance of hormone-related cancers but rather, consistently shows that compared with women that do not eat soya, women that regularly consume soya do have a lower risk of developing hormone-related cancers. Whilst the studies have only been observational (so they cannot conclusively prove that soya protects against hormone-related cancers) the studies are reassuring that soya products do not increase the cancer risk.
As part of a healthy diet, whole soya products, like soya flour and soya mince, are safe. The research that has been conducted on soya and hormone-related cancers have only looked at whole soya products. Soya dietary supplements such as soya pills and isoflavones-enriched powders should be avoided.