- Researchers studied the effects of a low protein diet on colon cancer growth.
- They found that a low protein diet reduces tumor growth and increases cancer cell death in mice.
- The researchers say that further study is needed to see if the results translate to humans.
Colon cancer occurs when cells in the colon or rectum grow out of control. The United States National Cancer Institute estimates that the condition accounted for
Studies show that nutrient-sensing molecules known as mTORC1
Although drugs that inhibit the signaling pathway for mTORC1 have been proven to be
“We observed that feeding human-derived colon cancer cells with low amino acids and treating them with chemotherapies synergizes to kill cancer cells,” , research investigator in Molecular and Integrative Physiology at the University of Michigan, first author of the study, told Medical News Today.
The researchers next investigated how these findings translated into live mice. To do so, they assessed the effects of a low protein diet on mouse models of colon cancer for two weeks, followed by a month of . Whereas mouse diets are typically 21% protein, they fed mice diets with just 4% protein.
From in-vitro tests, the researchers next found that a low protein diet—and specifically reduction of amino acids leucine and cystine—altered nutritional signals to mTORC1 via GATOR1 and GATOR2 protein complexes.
“[This study implies] that colon tumor cells may change the way amino acids are sensed to further activate mTORC1, leading to increased cell growth and proliferation of tumor cells. […] Hyperactive mTORC1 could be taken advantage of by restricting intake of amino acids- via dietary protein restriction- and thus triggering tumor cell and death.”
When asked what ‘feeds’ cancer cells, Dr. Solanki noted that cancer cells need large amounts of nutrients, including glucose, amino acids, and nucleotides, to proliferate. While some of these nutrients can be synthesized inside cells, others, like amino acids, must be taken from dietary sources.
“As body nutrients are influenced by diet, we found that feeding a low protein diet to animals created a demand versus supply crisis in colon cancer cells which resulted in massive cancer cell death,” he said.
“Feeding or starving cancer cells is clearly complicated, but this research shows that depriving certain amino acids influences the mTORC-1 pathways leading to cell death.”
— , surgical director at The Center for Inflammatory Bowel and Colorectal Diseases, Mercy Medical Center, Baltimore, who was not involved in the study, speaking to MNT
When asked about the study’s limitations, Dr. Nelson pointed out that the research was carried out in mice and cancer cell lines, and said it still remained “unclear how this might be applied clinically in humans as of yet.”
CAVEATS OF A LOW PROTEIN DIET FOR CANCER PATIENTS
“As cancer patients often undergo muscle wasting, putting patients on long-term low protein won’t be ideal. As cancer cells are rapidly dividing, they may require increased nutrients to recover after chemotherapy regimens. Thus, giving low protein diets at key windows, like a week before/after chemotherapy, may synergize in eradicating these tumor cells with high demand.”
— Dr. Sumeet Solanki
“Extrapolation of our findings in animal models to humans would be premature, although this is a small step in the right direction. We would strongly suggest consulting an oncologist and dietician for medical advice.”