Popular diets, like the Keto diet, could curve a tumour’s progression, but more research is needed to evaluate its impact on humans, a new study shows.
ADVERTISEMENTDiets that restrict overall calories, glucose intake or specific nutrients, like ketogenic, time-restricted, and intermittent fasting diets, have been found to inhibit the growth of cancerous tumours.
While there’s “no one-size-fits-all” diet that can influence cancer’s development, new research has highlighted how nutrition could play a part in cancer treatment plans.
The results were published in a new study by Semmelweis University in Hungary which reviewed a compilation of over 300 studies focused on how different diets affect the metabolism of cancerous cells.
“Cancers are very heterogeneous in their metabolic dependencies: there is no one-size-fits-all,” Dr Otilia Menyhárt, an assistant professor at Semmelweis University and the study’s first author, said in a statement.
“What they do have in common is an extremely high energy need to support their growth,” she added.
By adjusting the diet, it could be possible to enhance a patient’s response to treatment, for example, as well as impact a tumour’s progression, according to the study authors.
Colorectal, cervical, and certain types of breast tumours rely on glucose to fuel them.
Glutamine, an amino acid commonly found in the human body, is used by non-small cell lung cancer, pancreatic cancer, myeloma and brain tumours while fructose can enhance the growth of prostate cancer cells.
Exploiting the metabolic differences of the cells
“When we cut back on the body’s energy sources, deprive the body of glucose for a long enough period, the body goes into a fasting state,” Menyhárt said.
This forces your body to find an alternative fuel source. The body begins to produce ketones- molecules that serve as an alternative energy source - in the liver, a process that gave its name to the popular Keto diet.
Those who follow the high-fat, low-carb diet eat fish and seafood, meat and poultry, non-starchy vegetables, eggs, nuts and so on.
Healthy cells can effectively use ketones as an energy source. In contrast, cancer cells with metabolic inflexibility struggle to adapt to this shift, resulting in a limited capacity to derive energy from ketones.
When stressed, for example by chemotherapy or radiotherapy, fasting induces a transition in healthy cells from a growth phase to a state of maintenance and repair while cancerous cells don’t.
In addition, starved tumour cells generate elevated levels of reactive oxygen species, heightening their vulnerability to DNA damage caused by treatment.
This explains the enhanced efficacy of chemotherapy when preceded and followed by fasting, accompanied by a significant reduction in associated side effects.
However, this was only observed in certain diseases.
“[A] ketogenic diet in anticancer therapy can lead to increased survival and decreased tumour growth but in certain cancers, it accelerates disease progression,” Menyhárt said.
Low compliance at clinical trials - due to side effects or poor adherence - means there are no clinical recommendations for dietary needs during treatment at this stage.
ADVERTISEMENT“To change that, protocols that patients are able and willing to follow should be created and clinically tested,” she added.
