How did this hypothesis come about?
Soybeans are rich in molecules called "isoflavones" which has weak estrogen properties and has been used for years as a "natural" remedy for hot flashes in menopausal women. It is a known fact that many male transgenders take estrogen (not soy) to stimulate breast growth. Therefore, someone has decided to put 2 and 2 together and come up with the hypothesis that soy causes rise of estrogen, which causes man boobs. Is it true? Btw, in case you are wondering there is a scientific / medical term for man boobs and its called gynecomastia. Yup - didn't know that.
The fact is, this is a myth and there is no medical or scientific evidence to support this hypothesis. In 2004, an Italian study of kids raised on soy protein formula showed no gynecomastia, no early puberty, no changes in their bones and definitely no signs of screwed up hormones. In fact soy has been enjoyed by the world for thousands of years. So until there is scientific evidence of soy causing gynecomastia, all this is just another myth - like the myth that doing leg raises actually targets your lower abs. Of course if you were to surf hardcore body building sites, you will notice that soy based protein gets a really bad name. But most of the time, these are just opinions without any scientific proof.
So what actually causes gynecomastia? Here are some of the causes based on medical science:
- Malnutrition and recovery from malnutrition can create a hormonal environment that is man boob friendly
- Disorders in the male sex organ (testicles) which may be caused by genetics, aging, trauma, infection, aging
- Other conditions that can promote altered hormonal environment such as chronic renal failure or hyperthyroidism.
- Certain drugs and medications overdose - please check with your doctor on this.
But isn't soy protein less effective for building muscle compared to whey protein?
Says who? I noticed lots of these comments on hardcore bodybuilding sites. Here is the truth on that as well. Several studies have been done to assess muscle gain in individuals using soy protein, whey protein and egg protein. The results - There was absolutely no difference between the three. Supporters of whey protein like to site BV (Biological value) as an indicator for the quality of protein. Unfortunately, BV is as outdated as BMI. Today most scientists use a different rating to score the quality of protein. Its called the PDCAAS--Protein Digestibility Corrected Amino Acid Score. The highest possible score or rating is 1, meaning the highest and best quality protein for human consumption. Soy scores a 1 just like whey protein. So is whey still superior to soy? I can't see how.
I am a big supporter of soy based protein because i am lactose intolerant, and for years i trained without using any protein supplement at all. Today i use a soy based protein supplement because it just takes the guess work out of nutrition. For me, my soy based protein supplement gives a high protein content (80% of it is protein) without the unnecessary calories. Now who wouldn't want that? And like i shared earlier, from that protein shake, i can make it into a weight gainer or even a meal replacement shake. I do hope this post has shed some light on soy protein and busted the myth that many people have with regards to soy protein.
So if you have been consuming loads of soy based products like tofu, soy milk and tempe, don't worry. You don't need to go down to Victoria Secret to check out their latest collection of bras. The fact is, soy protein does NOT cause man boobs. As usual, look forward to hearing your comments.