The Keto diet -- consisting of high-fat, low-carb foods -- known to help lose up to 10 per cent of your body weight, can also be used to fight cancer, suggests a study.
The popular weight loss diet is known to trick the body into burning its own fat and help in weight loss.
Similarly, the diet may also help fight a variety of cancers by starving tumours of the glucose they need to grow, said researchers in the study published in the journal Cell Metabolism.
Pancreatic and Colorectal Cancer
In the study conducted in mice with pancreatic and colorectal cancer, keto was found to accumulate toxic lipid byproducts and kill cancer cells by a process called ferroptosis.
While this slows tumour growth it also causes early-onset cachexia -- a lethal wasting disease called cachexia.
Patients and mice with cachexia experience loss of appetite, extreme weight loss, fatigue, and immune suppression. The disease has no effective treatment and contributes to about 2 million deaths per year.
"Cachexia results from a wound that doesn't heal," said Professor Tobias Janowitz from Cold Spring Harbor Laboratory (CSHL) in New York, US.
"It's very common in patients with progressive cancer. They become so weak they can no longer handle anti-cancer treatment. Everyday tasks become Herculean labours," he added.
In the study, the researchers thought of working to separate keto's cancer-fighting benefits from its lethal side effect.
They found pairing keto with common drugs called corticosteroids prevented cachexia in mice with cancer.
Their tumours shrank and the mice lived longer.
"Healthy mice also lose weight on keto, but their metabolism adapts and they plateau," Janowitz said.
"Mice with cancer can't adapt, because they can't make enough of a hormone called corticosterone that helps regulate keto's effects. They won't stop losing weight."
When researchers replaced the depleted hormone with a corticosteroid, keto still shrank tumours but didn't kickstart cachexia.
"Cancer is a whole-body disease. It reprogrammes normal biological processes to help it grow," said CSHL Postdoc Miriam Ferrer.
"Because of this reprogramming, mice can't use the nutrients from a keto diet, and waste away. But with the steroid, they did much better. They lived longer than with any other treatment we tried," she added.
The team is now working to fine-tune corticosteroid timing and dosage to widen the window for effective cancer therapies in combination with keto.
"We want to push back against cancer even harder, so it grows slower still," Janowitz said.
"If we can broaden this effect, make the treatment more efficient, we can ultimately benefit patients and improve cancer therapeutics."