Limiting protein: A strategy for cancer treatment and prevention

The search for a cure for cancer is proving to be a long-term effort, but experts are honing in on the mechanisms by which cancer cells grow and spread.  

Nutrition has often been examined as a possible path to controlling cancer. For example, it’s been determined that men who eat ultra-processed meats and drink sugary drinks are more likely to end up with colon cancer.

Now, researchers are uncovering another dietary strategy for controlling the spread of cancer cells that lead to colorectal cancer.

Low-protein diet puts tumor cells in crisis

A study from the University of Michigan Rogel Cancer Center suggests that a low protein diet could provide effective control of the system of signals that turns colon cancer on and off.

“In colon cancer, when you decrease the nutrients available in the tumors, the cells don’t know what to do. Without the nutrients to grow, they undergo a kind of crisis, which leads to massive cell death,” says senior author Dr. Yatrik M. Shah, Horace W. Davenport Collegiate Professor of Physiology at Michigan Medicine.

Specifically, a regulator known as mTORC1 controls how cells use nutritional signals to grow and multiply. When a cell has plenty of nutrients, mTorc1 is activated. When nutrients are low, it is deactivated.

It seems that a low protein diet deprives the cell of crucial amino acids and blocks the signaling that turns mTorc1 on, thus blocking the cell’s ability to use nutrients to feed cancer.

Previous efforts had focused on blocking cancer-causing signals directly, rather than blocking the nutrient pathway that feeds those cancer cells.

“We knew that nutrients were important in mTORC regulation but we didn’t know how they directly signal to mTORC. We discovered the nutrient signaling pathway is just as important to regulate mTORC as the oncogenic signaling pathway,” says first author Dr. Sumeet Solanki, a research investigator at the Rogel Cancer Center.

A low-protein diet could be risky for cancer patients

While cutting protein intake seems promising in terms of preventing colon cancer, there is one risk.

Persons with cancer often experience muscle weakness and weight loss and limiting protein would only make this worse.

“Putting cancer patients on a protein-deficient diet long-term is not ideal. But if you can find key windows — like at the start of chemotherapy or radiation — when patients could go on a low protein diet for a week or two, we could potentially increase the efficacy of those treatments,” says Dr. Shah.

In other words, when scientists figure out when in the cancer journey a low-protein diet would have the most beneficial effect, then it could be prescribed for specific short-term periods of time, minimizing the possible detrimental effects.

Dietary strategies for prevention

Research into low-protein diets continues. But in the meantime, your hands are certainly not tied when it comes to taking action to decrease your risk of colon cancer.

A good start is cutting red meat out of your diet. Other types of proteins such as fish and chicken haven’t been found to raise your cancer risk, but we’ve long known that red meat and colon cancer go hand-in-hand.

In a study, published in Cancer Discovery, scientists concluded that eating red meat leads to genetic mutations in colon tissue that results in a type of DNA damage known as alkylation.

Not only can the mutation cause damage, but patients with colon tumors showing high levels of alkylating damage had a 47 percent greater chance of dying from the disease.

Instead of red meat, add some spinach (shown to have anti-tumor properties), along with these seven other foods to a healthy plant-based diet that leans away from colon cancer.

Weight loss has also been found to confer some serious protection against colon cancer. In a trial that involved a whopping 154,942 people and spanned a period of eight years, people who lost weight benefitted from a 46 percent lower risk for colorectal adenoma — a polyp that could become cancerous.

Sources:

Dietary change starves cancer cells, overcoming treatment resistance — Science Daily

Dysregulated Amino Acid Sensing Drives Colorectal Cancer Growth and Metabolic Reprogramming Leading to Chemoresistance —Gastroenterology