A new study, published in the medical journal Nature, may have cracked the code to how diet may prevent the spread of a deadly type of cancer. Researchers discovered that limiting a specific type of protein in the diet had a dramatic effect on preventing the spread cancer in mice studies.

The Study

The multicenter study, conducted at more than a dozen institutions, including Cedars-Sinai Medical Center in Los Angeles, found that a single protein building block (called an amino acid) “asparagine,” may be implicated in spreading an insidious type of breast cancer that is often fatal. When asparagine was withheld from the diet of laboratory mice with breast cancer, researchers discovered that the cancer’s ability to spread to distant areas in the body was considerably reduced. Dietary restriction was one method, among others, that scientists used to limit the amount of asparagine in the body.

Asparagine is commonly found in many foods, including:

  • Dairy
  • Whey
  • Beef
  • Poultry and eggs
  • Fish
  • Asparagus
  • Potatoes
  • Nuts and legumes
  • Seeds
  • Soy
  • Whole grains

Foods that are considered low in asparagine are most fruits and vegetables.
According to Simon Knott, PhD, associate director of the Center for Bioinformatics and Functional Genomics at Cedars-Sinai and one of two first authors of the study, “Our study adds to a growing body of evidence that suggests diet can influence the course of the disease.”

In the study, scientists looked at the cells from a deadly type of breast cancer called “triple-negative breast cancer.” These cells are known to grow and spread faster than most other types of cancer cells. This type of cancer is known to be resistant to common treatment modalities, making triple-negative cancer much more deadly than other types of slower growing cancer, which respond better to treatment.

How Triple-Negative Cancer Grows

Past research on triple-negative breast cancer discovered that most of the tumor cells stay in the primary cancer site—the breast; but a group of the cancerous cells leave the primary site and travel via the bloodstream. Subsequently, these bad cells end up colonizing, which is how cancer cells metastasize (spread) at a secondary cancer site. In the case of triple-negative breast cancer, these bad cells travel to the brain, lungs and liver.

The Study Findings

In the study, scientists recognized that the enzyme used to make asparagine in the body, was strongly associated with the spread of triple-negative cancer cells. When dietary restriction of asparagine was implemented, or a chemotherapy drug called L-asparaginase was administered, researchers found that the metastasis of the cancer cells was dramatically limited. When the lab mice were given foods high in asparagine, the cancer cells began to spread more rapidly.

Director of the Cancer Research UK Cambridge Institute in Cambridge, England, Gregory J. Hannon, PhD, stated, “The study results are extremely suggestive that changes in diet might impact both how an individual respond to primary therapy and their chances of lethal disease spreading later in life.”

Early-phase human studies are now being considered to find out if a low asparagine diet would impact cancer patients.

“This study may have implications not only for breast cancer, but for many metastatic cancers,” said Ravi Thadhani, MD, MPH, vice dean, Research and Graduate Research Education, at Cedars-Sinai.

Experts say that studying the effects of a low asparagine diet (and chemotherapy using L-asparaginase) may lead to breakthroughs in effective treatment for other types of cancer as well.


Science Daily (2018, February).