Cutting out meat may stop breast cancer spreading

Surviving on an extreme diet of fruit and vegetables could be the key to preventing breast cancer from spreading, new research suggests.

Feeding affected mice a diet low in the amino acid asparagine significantly reduces their tumours’ abilities to spread, a study found today.

Asparagine is found in high amounts in meat, dairy and seafood, as well as asparagus, potatoes, whole grains, legumes, and nuts and seeds.  

It is unclear how the amino acid promotes tumour growth, however, it is thought to somehow aid cancerous cells in leaving the breast, surviving in the bloodstream and colonising other areas of the body.

Lead author Professor Greg Hannon from the Cancer Research UK Cambridge Institute, said: ‘Our work has pinpointed one of the key mechanisms that promotes the ability of breast cancer cells to spread. 

‘When the availability of asparagine was reduced, tumour cells had reduced capacity for metastases in other parts of the body.’

The researchers believe combining a low-asparagine diet with chemotherapy could significantly improve breast cancer patients’ survival prospects.

Cutting out foods rich in the amino acid asparagine may help stop breast cancers spreading. Fruit and vegetables are known to be low in it

WHAT FOODS CONTAIN ASPARAGINE AND HOW DO THESE AFFECT BREAST CANCER? 

Feeding mice with breast cancer a diet low in the amino acid asparagine significantly reduces their tumours’ abilities to spread, a study found.

Asparagine occurs in high amounts in:

  • Meat
  • Poultry
  • Seafood
  • Dairy
  • Asparagus
  • Potatoes
  • Nuts and seeds
  • Legumes

Previous studies have also linked asparagine to reduced survival in leukemia sufferers. 

It is unclear how the amino acid promotes tumour growth, however, it is thought to somehow aid cancerous cells in leaving their original site, surviving in the bloodstream and colonising other organs.

‘This adds vital information to how we can stop cancer spreading’

Professor Hannon said: ‘Our work has pinpointed one of the key mechanisms that promotes the ability of breast cancer cells to spread. 

‘When the availability of asparagine was reduced, tumour cells had reduced capacity for metastases in other parts of the body.

‘This finding adds vital information to our understanding of how we can stop cancer spreading – the main reason patients die from their disease.’ 

Although Charles Swanton, Cancer Research UK’s chief clinician, agrees the findings are ‘interesting’, he adds further research is required to determine whether the results apply in real-life settings out of the lab.  

Martin Ledwick, Cancer Research UK’s head nurse, also stresses it is important for cancer patients to speak to their doctors before making any dietary changes. 

Baroness Delyth Morgan, chief executive of Breast Cancer Now, added: ‘If shown to be an effective approach, it’s possible that dietary advice to avoid foods containing asparagine, or drugs that break down this nutrient, could be added to standard treatment to help prevent metastasis.

‘We encourage all patients to follow a healthy and varied diet – rich in fruit, vegetables and pulses, and limited in processed meat and high fat or sugar foods – to help give them the best chance of survival.’

Asparagine is found in high amounts in dairy, meat and seafood, as well as nuts and seeds

Asparagine is found in high amounts in dairy, meat and seafood, as well as nuts and seeds

How the research was carried out  

The researchers gave mice with breast cancer an enzyme that prevents the production of the amino acid asparagine.

The rodents were given the enzyme, known as L-asparaginase, five times a week for 19 days. 

They were also put on a low-asparagine diet. 

The findings were published in the journal Nature.  



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