Soya and breast cancer

Does anyone know: what are the adverse effects of soya on oestrogen related breast cancer?

Also, is it better to use rice milk products?

Thanks, Judie x

The jury seems to be out on soya and breast cancer although some oncs and consultants are advising against it when diagnosed with oes+ BC. Some available info states that soya has a positive effect on BC while other info states the opposite. It seems that soya can be good for some people and bad for others with no indication why or who it will effect differently. Personally I avoid it and I’m not convinced of it’s protective qualities. I’ve been a vegetarian for over 20 years and eaten tons of soya as an alternative source of protein. I was diagnosed with grade 2 invasive BC last year so soya does n’t appear to have done me any good what so ever. My onc has advised me to avoid substances that mimic oestrogen, including significant sources in food.


Hi Judie,'re
I’ve been avoiding dairy products since BC diagnosis last year and use Soya milk, tried rice and oat milk too and found them all quite pallitable. You’ll find that Soya is in lots of different processed foods. When I initially asked oncologist about changing my diet to try to help recovery/avoidance of recurrence etc. he said not to change anything in particular - “just eat a balanced diet”. It seems that noone wants to or can give any scientifically proven advice and so it’s left up to yourself to make your own judgement. Unfortunatley the amount of information on the web is vast and contradictory but I think worth ploughing through if it gives you confidence in what your dietary choice is. You might want to have a look at sites like this
Try to avoid web sites by companies with a vested interest in products due to their bias.
One thought though - when reading posts in the local recurrence or new primary site - it would be interesting to know if any of these ladies changed their diets after initial diagnosis - might give an indication one way or another!


Thanks for your replies, very helpful x

Hi Judie,

I used to use soya products befroe being diagnosed with Er+ bc. I have read up and although the jury is still out, there is an awful lot of research which suggests a link between soya products and Er+ bc. Apparently soya contains a naturally produced Oestrogen.

I know we can’t avoid everything, the latest being grapefruit, but personally I’ve erred on the side of caution and have gone back to good old cows milk,


For a few weeks following diagnosis I stopped using dairy and used soy products now having read and researched a bit more - have dumped the soy and gone back to cows milk for my cereals and tea - have some natural yoghurt & cheese occasionally. I try to have a healthy balanced diet. I was (prior to diagnosis) and still am one of the most health conscious people (amongst family and friends) I know - yet I got the dreaded disease - so there are no guarantees - but having a healthy diet does protect against other serious illness anyway - so it is a good investment for the future. I also think that the fitter I am the better I will be able to mentally and physically handle a recurrece if it ever happened.

I was vegan for a time and ate lots of soya, then went veggie and ate a bit of dairy, now I have a mixture of soya and dairy. I asked my onc whether I should go one way or another. She said the jury is out on soya and dairy. Some women stop dairy and turn to soya as women in Japan whose diets are rich in soya have very low levels of breast cancer. The reason it is linked to diet is that when Japanese women have a western diet their breast cancer settles at Western levels. However, once you have breast cancer its not really known what is best. If I could I would give up both, I do believe our bodies arent made to drink milk which is designed for baby calves, and I also worry about the hormones they inject into dairy cows. As for soya, Im uncomfortable with the fact that it mimics oestrogen. However, I cant stand rice milk and other substitutes! My onc says that Im going through enough at the moment and I should just drink whatever I enjoy most, soya milk or dairy milk so thats what Im doing, soya in tea, and milk in coffee!

Hi Judie

This one get raised quite a lot. I’m fairly strict on myself and do not take dairy or soya. I do think that there could be something in the fact that cows produce oestrogen. I read an article recently which said our forebears had no taste for milk. I feel if the BC is oestrogen driven it’s best to avoid animal oestrogen. I’m very happy with Rice Milk and an occasional Oat Milk. However, I have just read a article which says that eating lots of fruit and vegetables does not save you from a recurrence. This is contrary to the hand-out I got from the recent BCC Living with Breast Cancer Course. The hand-out said that by eating lots of fruit and vegetables + exercise you could save yourself from recurrence by about 40%. I’m not sure how much control I have over what happens to me in the way of my BC. However, I do have control over how I feel about my eating habits and if it makes me feel good, I enjoy it and my body is happy, then do it.