A protein found in asparagus and other everyday foods has been linked to the spread of breast cancer, scientists have discovered.
Restricting the amino acid asparagine decreased the spread of the disease in mice.
Amino acids are essential building blocks that cells use to make proteins.
The body already produces some asparagine but it is also found in our diet in foods such as asparagus, soy, dairy, poultry, beef and seafood.
Researchers at the Cancer Research UK Cambridge Institute found that blocking the production of asparagine with a drug called L-asparaginase, and putting the mice on a low-asparagine diet greatly reduced the breast cancer's ability to spread.
In future, the scientists believe that alongside conventional treatments like chemotherapy, breast cancer patients could be given a diet in hospital that restricts asparagine to help stop the disease spreading.
"When the availability of asparagine was reduced, we saw little impact on the primary tumour in the breast, but tumour cells had reduced capacity for metastases (spread) in other parts of the body," the study's lead author, Professor Greg Hannon, said.
"This finding adds vital information to our understanding of how we can stop cancer spreading - the main reason patients die from their disease.
"In the future, restricting this amino acid through a controlled diet plan or by other means could be an additional part of treatment for some patients with breast and other cancers."