An amino acid found in asparagus could be responsible for the spread of breast cancer, according to a new study. So should you stop eating it? 

Scientists discovered that restricting an amino acid called asparagine stopped cancer cells from invading other parts of the body in mice. 

Amino acids are the building blocks that cells use to make proteins. The body can make asparagine, however, it’s also found in high concentrations in foods like asparagus, seafood, soy, dairy and poultry products.

Despite the startling findings, researchers and breast cancer experts agree that people with cancer and the general public should not stop eating asparagus or other products rich in asparagine. 

Baroness Delyth Morgan, chief executive at Breast Cancer Now, said in a statement: “On current evidence, we don’t recommend patients totally exclude any specific food group from their diet without speaking to their doctors.”

How does cancer spread?
The place where cancer starts in the body is called primary cancer or primary site, according to Cancer Research UK. Cells from the primary site may break away and spread to other parts of the body through the bloodstream or lymphatic system. There they can start to grow into new tumours. This is known as metastases or secondary cancer.

Most breast cancer patients do not die from their primary tumour, but from the spread of cancer to the lungs, brain, bones or other organs. Currently, around 11,500 women die from breast cancer each year in the UK. Finding ways to stop this from happening is therefore fundamental to increasing survival. 

How did researchers stop it from spreading?
Researchers at the Cancer Research UK Cambridge Institute did two things: they put the put the mice on a low-asparagine diet and were able to block the body’s production of asparagine with a drug called L-asparaginase. 

Both of these changes greatly reduced breast cancer’s ability to spread.

Interesting, the drug L-asparaginase is already used to treat acute lymphoblastic leukaemia, which is dependent on asparagine. Professor Charles Swanton, Cancer Research UK’s chief clinician, said in response to the study: “It’s possible that in future, this drug could be repurposed to help treat breast cancer patients. The next step in the research would be to understand how this translates from the lab to patients and which patients are most likely to benefit from any potential treatment.”