Top doctor warns cooking ingredient millions use is linked to aggressive breast cancer

Popular cooking oils used by millions could raise the risk of an aggressive form of breast cancer, one of Britain's leading cancer experts has warned.

Doctors believe linoleic acid, a common fat contained in seed oils such as soybean, sunflower and corn, reacts with heat helping cancer cells to grow and multiply.

Home cooks should therefore 'moderate' their seed oil consumption, 'especially high-risk individuals,' advised oncologist Professor Justin Stebbing.

'Many oils such as olive oil contain less linoleic acid,' he added.

In a new report, Professor Stebbing, who has led groundbreaking research into cancer treatments, described a recent study highlighting the cancer risk of seed oils as 'significant'.

The research, published by Weill Cornell Medicine in New York, found that linoleic acid can overstimulate the 'control centre' in cells helping to fuel breast cancer cell growth.

The scientists discovered this by feeding mice with triple negative breast cancer — the deadliest form of the disease — a high linoleic-acid oil diet, and comparing future tumour growth to a placebo group.

They found those in the oil group developed larger tumours than the animals that did not consume linoleic acid.

There was a link to humans too, with elevated linoleic acid levels detected in blood samples from triple-negative breast cancer patients, the scientists said.

Dr John Blenis, the study’s senior author and a cancer researcher at Weill Cornell Medicine, said: ‘We now know that linoleic acid feeds cancer cell growth in a very specific way.

‘This discovery sheds light on how to define which patients might benefit from specific nutritional recommendations.'

One in seven women in the UK are diagnosed with breast cancer in their lifetime — around 56,000 a year — making it the most common cancer in the UK.

The figure stands at roughly 300,000 annually in the US. Around 85 per cent of women diagnosed with breast cancer survive more than five years.

However, triple negative breast cancer — which accounts for around 15 per cent of all breast cancers in the UK and US — is far more challenging.

Typically, it grows and spreads faster than other breast cancer types and has fewer treatment options.

It is also more difficult to treat because it doesn’t interact with hormones such as oestrogen — for which there are targeted therapies.

On average around 77 per cent of women with triple negative breast cancer will survive their cancer for five years or more after they are diagnosed, but depending on the stage this can fall as low as 12 per cent.

This is compared to around 90 per cent of women with other forms of breast cancer who will survive for at least five years.

Professor Stebbing noted that 'the findings, while significant, require careful interpretation to avoid unnecessary alarm'.

He added: 'The findings do not warrant blanket avoidance of seed oils but suggest moderation and selectivity, especially for high-risk individuals.

'Do also consider eating more fruits and vegetables as part of a healthy, balanced diet.

'While linoleic acid’s role in triple-negative breast cancer is a critical discovery, it’s one piece of a vast puzzle.

'A balanced, wholefood diet remains an important cornerstone of cancer prevention, and a strategy everyone can adopt.'

Prof Stebbing's report, published in The Conversation, follows other recent research that has also suggested seed oils may accelerate cancer tumour growth.

In December, US scientists found that men with early-stage prostate cancer who ate less foods with vegetable oil over the course of a year had slower growing cancer compared to men who ate a normal western diet.

Another study published days earlier suggested that the fats found in seed oils may promote inflammation, which can damage tissue, making it more easy for colon cancer tumours to grow.

Around 23 per cent of breast cancer cases in the UK are thought to be preventable, with around 8 per cent of cases caused by obesity and 8 per cent by drinking too much alcohol.

But getting older is the major risk factor for any type of cancer, largely caused by cell DNA damage accumulating over time.

Despite the importance of fast access to diagnosis and treatment in improving outcomes, cancer performance figures show the NHS is still failing or only just managing to meet targets.

Just 67 per cent of newly-diagnosed cancer patients referred for urgent treatment were seen within 62 days — the target is 85 per cent.