their risk of liver cancer—or slow its growth—by simply eating less protein.
The research, published in the journal Science Advances, showed that low-protein diets helped slow liver tumor growth and improved survival in mice. It also revealed how damaged livers may accidentally help fuel cancer.
Liver cancer is one of the most deadly cancers in the U.S., with only about 22% of patients surviving five years after diagnosis. In 2025 alone, over 42,000 people were diagnosed and more than 30,000 died from the disease.
Even more people are at risk due to liver problems. About one in four adults in the U.S. has fatty liver disease, a condition that—along with hepatitis infections and heavy alcohol use—can damage the liver and increase the risk of cirrhosis and liver cancer.
The study’s senior author, Dr. Wei-Xing Zong from the Rutgers Ernest Mario School of Pharmacy, explained why protein matters. When we eat protein, the body creates nitrogen, which can turn into a chemical called ammonia.
Normally, a healthy liver safely converts ammonia into urea, which is removed from the body through urine. But in people with liver damage, this system doesn’t work well, and ammonia builds up in the body.
Doctors have long known that liver cancer patients often have problems handling ammonia. But until now, no one knew if the ammonia buildup was a result of the cancer or a cause of it.
To find out, Zong’s team conducted a mouse study. First, they gave mice liver tumors without affecting the liver’s ability to process ammonia. Then, in some of the mice, they used genetic tools to shut down the enzymes that normally remove ammonia. This caused ammonia levels to rise in those mice.
The results were clear. Mice that couldn’t clear ammonia developed more tumors and died sooner than mice with normal enzyme function. The team discovered that the excess ammonia was being used by cancer cells to make building blocks—amino acids and nucleotides—that help the tumors grow faster.
With this information in hand, the researchers tried a simple solution: cutting protein in the diet. Mice that were fed less protein had slower-growing tumors and lived longer than those on a normal diet.
This discovery may have big implications for people with liver damage, including those with fatty liver disease, hepatitis, or liver cancer.
People with healthy livers don’t need to worry about eating too much protein because their livers can handle it. But for people with impaired liver function, eating less protein might help lower ammonia levels and slow down cancer growth.
Still, Dr. Zong stressed that anyone thinking about changing their diet should talk to their doctor. Standard cancer care usually includes more protein to help patients keep their muscles strong. But in people with high ammonia levels, the benefits of cutting back on protein may outweigh the risks.
In conclusion, the study shows that something as simple as eating less protein could make a big difference in liver cancer progression—especially for those already dealing with liver damage. It opens the door to new dietary approaches that could support cancer treatment and improve survival.
If you care about liver health, please read studies that refined fiber is link to liver cancer, and the best and worst foods for liver health.
For more health information, please see recent studies about how to boost your liver naturally, and simple ways to detox your liver.
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