Can avoiding meat and eggs help fight cancer?

Certain nutrients and chemicals in food navigate the same molecular pathways that certain cancer therapies use to slow tumor growth, researchers report.

Researchers can manipulate one such shared pathway, which common chemotherapy drugs and radiation use to treat colon cancer and sarcoma, with a dietary restriction to similarly slow tumor growth, according to a new study.

The hope that food might somehow serve as a weapon in the cancer fight has long been a tantalizing notion among scientists and patients alike, but evidence supporting its benefits remains flimsy. Now, researchers are looking to change that.

Fighting cancer with food?

“We know that diet has a huge impact on other diseases, including diabetes and hypertension, and in some cases can be even more effective in containing the disease than drugs,” says senior author Jason Locasale, an associate professor in the pharmacology and cancer biology department at Duke University.

“We don’t have an analogous situation in cancer, but it’s looking like it might be moving in that direction,” he says.

“Cancer is in many ways more difficult, because it’s different diseases with multiple forms, and often defined at a molecular level, so we’re just beginning to understand how diet and nutrition are influencing that.”

The researchers focused on an essential amino acid known as methionine, which the body needs for proper cell function and must be acquired from diet, primarily from the consumption of meat and eggs.

Methionine’s function is increasingly being analyzed for its role in human health, with studies showing that the reduction of the amino acid has anti-aging and anti-obesity effects. It’s function in cancer has been unclear, but it absorbs into the body’s cellular mechanisms using the same pathways that several chemotherapy drugs and radiation use to slow tumor growth.

In their study, the research team first used colon cancer tumors from patients that were grafted into mice, along with mouse models of sarcoma tissues. The researchers then fed the mice a methionine-restricted diet, resulting in a reduction of tumor growth. An analysis of the metabolic process confirmed that the amino acid acted through the same cellular process that drugs and radiation employ.

Methionine’s double-edged sword

“This study suggests that dietary restriction of methionine induces rapid and specific metabolic profiles in mice and humans that can be induced in a clinical setting,” Locasale says.

“By disrupting metabolic pathway with the dietary restriction of methionine, it might be possible to enhance the effects of chemotherapies and that target these aspects of cancer metabolism.”

Locasale says the study findings are early and he cautions against misinterpreting the evidence to cause cancer patients to restrict methionine. In some cancers, he says, restricting the amino acid could cause tumor growth, given the unique ways malignancies arise and spread in different organs.

“This study may help to further establish principles of how dietary interventions may be used to influence cancer outcomes in broader contexts,” Locasale says.

The findings appear in the journal Nature.

Support for the study came from the National Institutes of Health, the Canadian Institutes of Health Research, and the Clinical Research Center at Penn State University.

Source: Duke University