Note: I first posted this as a comment in response to my “Milk does not cause cancer” post, which was a follow up to “That email about Chinese women not getting breast cancer has it wrong.”
It’s certainly true that Asian countries DO have a lower rate of prostate and breast cancer. But there are MANY, MANY, MANY differences between Western and Asian lifestyles aside from dairy consumption.
Without evidence, saying “Western people drink milk. Asian people don’t. Western people have higher rates of cancer than Asian people. Therefore drinking milk must cause cancer,” is a hypothesis. Without evidence, it’s just an idle conjecture.
Without evidence, you can’t conclude that there is a connection between those two things, any more than you can say “Western women are two inches taller, on average, than Asian women. Western women have higher rates of breast cancer. Therefore, height causes cancer.”
You can hypothesize that, but before you claim it to be true you have to test it and have evidence to back up your assertion. So exactly how would you test that? Well, you might ask these questions: Do tall Asian women have more breast cancer than short ones? Do short American women have less breast cancer than tall ones? Do tall women generally have more breast cancer than short women, regardless of race or geography? If the answer is no (and I am pretty sure it is, since I just made that up) then there goes your hypothesis. *Poof*
So what about the dairy-cancer hypothesis? Researchers have thoroughly investigated whether the difference in American and Asian breast cancer rates is related to dairy consumption. How? By asking these questions:
- Do Asian women who drink a lot of dairy have higher breast cancer rates than Asian women who drink little or no dairy?
- Do Western women who drink milk have a higher rate of breast cancer than those who don’t?
- Is there any relationship between dairy consumption and breast cancer in any population in any place on the globe?
In case after case, study after study, when researchers looked into these questions the answer was no. If anything, they found that consuming dairy gives women a very slight protective effect against breast cancer.
Conclusion: Science has thoroughly failed to find any evidence linking dairy consumption to breast cancer. There is no causative link. Dairy does not cause breast cancer.