One of the protein sources for people who eat a predominantly plant based diet are soy products, mainly tofu.
I see many negative comments regarding tofu, especially related to an increase risk of breast cancer. So I went on a mission to research some medical papers and find out if this is true or not. (I eat quite a lot of tofu and many of my clients do too)
What is tofu?
Also known as bean curd, tofu is prepared by coagulating soy milk and then pressing the resulting curds into blocks.
There are many varieties and it can be silken, soft, firm or extra firm.
Oestrogens vs Phytoestrogens
Oestrogen is a female sex hormone. It is needed for:
-the menstrual cycle
-maintaining normal cholesterol levels
Now, this hormone has positive effects in some tissues and negative in others. For example, a lot of oestrogen is good for your bones, but can increase the risk of breast cancer.
Ideally, we would like our body to be a bit more selective.(In medical terms that is called a “selective oestrogen receptor modulator”).
For example, when oestrogen goes to the bones, they open the doors and windows to let it. They throw a party for it ! But when it goes to the breasts for example, they are a bit more reserved. Sort of, you come in for tea, have a biscuit and then off you go!
Unfortunately our body does not work like that and oestrogen is not a very polite hormone.
Now, phytoestrogen is a substance that occurs naturally in plants (and soy) and it appears to be extremely polite. Soy seems to lower the risk of breast cancer (come in, have tea and then go on your merry way) and also reduces menopausal hot flushes (let’s have a party! stay the night!)
Some chemicals in soy (called isoflavones) can reduce blood vessels inflammation.
One study found that supplementing with 80 mg of isoflavones per day for 12 weeks improved blood flow by 68% in people who were at risk of stroke.
Taking 50 grams of soy protein per day is also associated with improved blood fats and an estimated 10% lower risk of heart disease.
It seems that exposure to soy during childhood and adolescence may be most protective, but that’s doesn’t mean that intake later in life is not beneficial.
Research shows that women who eat soy products at least once a week have a 48–56% lower risk of breast cancer.
Digestive System Cancer
In one study, tofu was linked to a 61% lower risk of stomach cancer in men.
Another study reported 59% lower risk in women.
Isoflavones can reduce blood sugar levels and insulin levels. They also improve insulin sensitivity.
Soy consumption and especially tofu, has many more benefits.
Also, many more studies need to be done to understand even better the role of those foods in our health, in preventing, stoping or reversing certain diseases.