Is there a ‘breast cancer diet’?
The latest evidence on the foods that increase or reduce your risk
The subject of breast cancer and nutrition can be fraught and controversial. When I was diagnosed in 2021, I was inundated with advice from well-meaning friends, acquaintances and even strangers, keen to tell me that I absolutely must not have any dairy, avoid soya at all costs and, if possible, eat entirely raw food.
I disregarded most of the (often conflicting) advice. But I knew that what we eat does have an impact, so I made it my mission to learn as much as I can - from the experts. I attended workshops and seminars on breast cancer and nutrition, some of them run by the NHS, others by charities such as Future Dreams, and I took a deep dive with nutritional scientist Toral Shah’s integrative breast cancer course.
As a result, I feel pretty well-informed on what the evidence says, but I’m aware that research in this area is evolving all the time and am always keen to learn more.
So my ears pricked up when I heard that virtual cancer clinic Perci Health is collaborating with Field Doctor, who make dietician-led, chef-made frozen meals, to design meals specifically for breast cancer patients and survivors. They’ve been awarded a grant by government-funded Innovate UK, which means that funding is being spent on researching the best way to eat to support you through breast cancer treatment and reduce your risk of recurrence. This is big news for all of us, since 1 in 7 British women will receive a breast cancer diagnosis and, if eating a certain way can reduce your risk, that is worth knowing about.
Right now you might be thinking: OK so I have to buy a range of frozen meals for optimal nutrition? No, says Kelly McCabe, a former cancer dietician who is co-founder & CEO of Perci Health. “The meals will be great for when you're busy or tired, and you just want something in the freezer that you know is good for you,” she says. “But we also want to educate the people on how to prepare similar meals at home that follow the same guidelines, so it's more sustainable.”
There will also be a 12-week educational programme for anyone who buys the meals and, eventually, the plan is to work with the NHS to make it accessible to all.
The nutritional composition of the meals, and the aim of the course, will focus on the things that reduce your risk (ie. optimising nutrition for immunity) as well as supporting you post-treatment by improving energy, psychological wellbeing, bone health, menopausal symptoms and being a healthy weight.
The Field Doctor meals for breast cancer are still in development, but Kelly shares the steps that we can put into action to reduce our risk of breast cancer right now…
Optimise vitamin D to support your immunity, which helps your body identify and destroy cancer cells before they become a tumour. Food sources include oily fish and egg yolks, but the best source is the sun so get outside every day.
Focus on plant foods - not only veg, but also nuts, seeds, beans, lentils, chickpeas and grains. The nutrients and fibre in plants improve immunity, reduce inflammation and support your energy and even your mood.
Improve your gut health. Again, this is about eating more plant foods, but also including fermented foods such as sauerkraut, and reducing ultra-processed, high-sugar foods that are known to have a negative impact on your microbiome.
Soya products contain phytoestrogens, which set alarm bells ringing for anyone with oestrogen-sensitive breast cancer. “But the consensus from the scientific literature is that soya is safe,” says Kelly. “This is a challenging message to get across, since there’s this belief that phytoestrogens might have the same effect on an oestrogen-sensitive cancer as our own natural oestrogen. But there's never been any evidence to suggest that. In fact, the science shows it can be beneficial.”
Similarly, with dairy, there is a lot of misinformation out there, but Kelly says the evidence shows that breast cancer is not linked with dairy. In fact, fermented dairy such as kefir is now thought to be beneficial for reducing your risk. Also, bear in mind that cancer treatment can impact bone density. “We don't want people to exclude dairy and then end up with osteoporosis,” says Kelly.
While there is certainly a link between processed meat (ham, bacon, etc) and several types of cancer, there is no evidence that moderate amounts of unprocessed meat increase your risk. If you eat meat, you’re getting iron and protein for strength and energy, but focus on organic white meat where possible.
“There is so much evidence that drinking alcohol is correlated with breast cancer risk,” says Kelly. “Experts tend to skirt around it because drinking is sociable, and it can be off-putting to people. But we should be bolder in our recommendations.” Cut back if you can.
Nutrition doesn’t work in a vacuum, and exercise helps with everything from immunity and bone density to brain health and mood. It’s often said that being overweight is a risk factor for breast cancer recurrence, but Kelly says the evidence is more around body composition, ie. fat vs muscle. Exercise can keep that ratio more in favour of muscle than fat, whatever your shape, size or weight.
For the same reason, minimise ultra-processed high-sugar foods, since they’re not doing your body composition any favours. “This will also support appetite regulation,” explains Kelly, "because when we feel tired, we feel hungrier and often crave sugary foods, then we create this cycle of constantly needing to snack.”
As well as food and exercise, consider your stress management and sleep - both vital for immunity, fatigue, brain fog and anxiety - all of which require support after cancer treatment.
So, back to my question from the beginning: is there a diet that reduces your risk of breast cancer? “I think the answer is yes, but your definition of ‘diet’ has to be broad,” says Kelly. “You can't just look at what you eat. If the question was: is there a lifestyle that can reduce your risk of cancer? The answer is yes.”
The Field Doctor meals and educational programme won’t be available until next year, as they’re still in development, but Perci Health are recruiting for 150 women living with and beyond breast cancer to evaluate the meals and course later this year. Everything will be provided for free in exchange for feedback. If you’d like to take part, scroll down to the bottom for the details.
This week I’m…
Swerving Kung Fu Panda 4 and taking the kids to see adorable dialogue-free animation Robot Dreams instead.
Reading two brilliant new books by psychotherapists: What am I Missing? by Emma Reed Turrell, which is a joyful personality test, helping you identify the blind spot that’s holding you back (and how to overcome it). And Weathering by Ruth Allen, a beautiful meditation on what the natural world can teach us about resilience.