Hi @ipekg ! welcome to the forum 
It’s great to hear that you’ve been using Plenny Shake Active as your main food and that it helps you towards your fitness goals.
The association between cancer and soy stems from the fact that soy contains isoflavones, which are a form of phytoestrogen. Studies have shown that there is a correlation between breast cancer and high levels of the human hormone estrogen. But, the phytoestrogens in soy are way weaker than human estrogen, meaning that they do not have the same effect on our bodies. Some doctors might suggest women with a family history of estrogen-sensitive breast cancer shouldn’t take soy supplements until there are more clinical studies on the matter (if this is your case, please consult with your doctor). However, it’s important to remember that there’s no evidence that soy or isoflavones actually increase the risk of cancer or have negative effects on people with cancer. Moreover, isoflavones supplements are used due to their antioxidant effect and even anti-cancer effects
Soy protein isolate contains more isoflavones than other soy foods. We made the calculation for you. A Plenny Shake Active portion would have approximately 5.8mg of isoflavonoids (between soy flour and protein isolate). If you consume two shakes per day, that would be 11.6mg per day. Some studies suggest that consuming foods rich in isoflavones might be beneficial.
This meta-analysis looked at several studies that were done on Asian populations and Asian Americans. They found that Asian populations consuming more soy isoflavones had a 29% lower risk of getting breast cancer compared to the Asian Americans that consumed way less.
Observational studies have shown that western populations tend to consume low levels of soy isoflavones (average 0.3mg/day) and there is not an overall reduced risk of breast cancer (or any other cancer vs people that consume soy on a daily basis). Moreover, it is believed that long-term exposure to isoflavones may be necessary to lower the risk of developing breast cancer later in life. In a 7-year study, British women were followed to evaluate if a moderate intake of 10.8 mg/day during adulthood could decrease the risk of developing breast cancer, as compared to a low intake of 0.23 mg/day, but there was no positive effect.
In the case of prostate cancer, soy consumption may be beneficial in men at a high risk of progressing to advanced prostate cancer. Additionally, there is a study in which men consuming SPI for 6 months didn’t have any change in the biomarkers for prostate cancer. And in the case of thyroid function, there is no evidence of changes in thyroid activity.
Another concern that might come from soy protein isolate is regarding its production: the solvents used in the extraction and maybe heavy metals concentration in the final product. To ensure that our products are safe and high-quality, we not only require quality analysis from our suppliers, but we also conduct laboratory analyses of our meal range to be sure that they meet all the safety and quality standards that are required for products in the European Union.
We hope this helps you to ease your mind a bit 
