One of the biggest myths about breast cancer that is still doing the rounds today is that underwired bras cause breast cancer. Instagram and TikTok are full of videos saying that they’re dangerous – that underwired bras cause dangerous toxins to build up in your breasts, that you should throw yours in the bin.
The reality is that this is nonsense. Underwired bras don’t cause breast cancer and I’m going to tell you why.
The myth started back in in 1995 with a widely debunked book called Dressed to Kill: The Link between breast cancer and bras by Sydney Ross Singer and Soma Grismaijer, a husband-and-wife anthropology team.
They claimed that if you wore an underwired bra for more than twelve hours a day, it would greatly increase your risk of getting breast cancer.
Their claim was based on a series of interviews with almost five thousand American women. Half of them had been diagnosed with breast cancer and half hadn’t. They observed that the women who wore a bra all day long were more likely to have breast cancer – now they had to explain why.
Remember that the authors weren’t doctors, they were anthropologists with no medical training. They came up with the idea that because underwired bras press on breast tissue, that would block the lymph system which would in turn lead to a build-up of toxins in the breasts, and that’s why women develop breast cancer.
In 2015 the conspiracy hit the headlines again when an osteopath called Dr Habib Sadeghi, not a doctor, wrote an article on Gwyneth Paltrow’s pseudoscience website, GOOP, saying that underwired bras are dangerous and that premenopausal women who did wear underwired bras had double the risk of getting breast cancer.
It almost sounds sensible, doesn’t it? After all, if it’s featured on GOOP and it’s in a book, and there are lots of influencers and bra manufacturers saying the same thing, then it must be true?
And if you’ve had breast cancer, like me, you might even think it’s your fault because you’ve been wearing an underwired bra for years.
Before I answer that, think about this. If underwired bras really did cause breast cancer, don’t you think they’d come with a health warning? Or that our parents / teachers / doctors would tell us not to wear them? That every bra would have a label saying it causes cancer, just like cigarettes?
The simple fact is that there is no evidence to prove that underwired bras cause breast cancer. So let’s debunk the myth once and for all.
Underwired bras don’t sit on breast tissue
The underwire of a well-fitting bra should sit beneath the breast, not on it. If it digs into your breast or leaves a mark at the end of the day, then your bra is too small for you.
Underwired bras don’t block lymph drainage
The lymph fluid in the breast travels up and out to the lymph nodes in the armpit, not down towards the underwire, so even if a bra was too small and the underwire did press on the very bottom edge of the breast, it is not going to affect lymph flow.
Lymph fluid doesn’t contain cancerous toxins
Lymph vessels in your breast drain the waste products of metabolism. This lymph fluid is filtered in your lymph nodes which trap or destroy anything harmful such as bacteria. The rest is reabsorbed back into the bloodstream where the liver and kidneys deal with them.
However, some chemicals like alcohol and nicotine, which are cancerous, are not found in lymph fluid. When you smoke and drink, they get absorbed into your bloodstream and can cause cancerous mutations in cells leading to the development of breast cancer.
Healthy people don’t get a build-up of toxins
Lifestyle magazines and websites love to talk about toxins – toxin build-up, toxin flushing, toxins poisoning the body. The tell us we need to detox – diets, enemas, fasting - so they can sell you products you don’t need. But as long as your liver and kidneys are working properly, your body will get rid of anything it doesn’t need automatically.
An observation is not the same as proof
Based on the interviews in the book, the authors cannot prove that the only reason some women had breast cancer and some didn’t was because they wore a bra for a longer period of time.
There were many things they didn’t account for, such as age, family history of breast cancer, alcohol consumption, activity levels and body mass, which have all been proven to increase your risk of getting breast cancer.
To prove that bras were the only reason, they would need to find a large group of identical women where the only difference between them was the length of time they wore a bra. It’s called a correlation, not a causation.
Here’s another example that’s easier to understand. What would you say if I told you that coffee causes lung cancer? You’d think I was mad. But this is how I would prove it. People who smoke get lung cancer, but people who smoke also drink coffee. Therefore, coffee causes lung cancer, not smoking.
But we know this is nonsense. Coffee doesn’t cause lung cancer, and bras don’t cause breast cancer. It’s bad research. And it’s scare-mongering.
So, is there any scientific evidence to prove that bras cause cancer?
There is only one proper study that looked at bra wearing patterns and cancer from 2014.
Over a thousand postmenopausal women with breast cancer were interviewed and compared to 500 women without breast cancer. There was no connection between the number of hours spent wearing a bra OR whether a woman wore an underwired bra.
Underwired bras can help with breast health by supporting the weight of your breasts. Did you know that a 36C breast weighs 500g? They can delay the inevitable dropping that comes with age and can help with back pain if you have particularly large breasts. It’s your choice to wear one or not, but don’t make that decision based on an influencer telling you they’re dangerous.
Dr Liz O’Riordan is a breast cancer surgeon with breast cancer. She is the author of the new book Under The Knife: Life Lessons from the Operating Theatre is out now. She is also the host of new podcast So Now I’ve Got Breast Cancer.