A new experiment in mice suggests that a diet with below-normal calories could help the effectiveness of drug cancer treatment.
The team, led by Jean-Ehrland Ricci of the French Institute for Health and Medical Research in France, put mice who had developed lymphoma into two separate groups: those who ate a diet with caloric intake 25% lower than normal, and those who ate a regular diet.
After following these diets for 1 week, the mice were then divided into four groups for the next 10 days:
- Normal-diet mice who received an experimental cancer treatment
- Normal-diet mice who did not receive the drug
- Reduced-calorie diet mice given treatment
- Reduced-calorie diet mice not given cancer treatment.
The experimental treatment is dubbed ABT-737 - a targeted therapy designed to promote cancer cell death.
After these 10 days of the study, both the treatment and the calorie restriction ceased, at which point the mice resumed eating however much they wished.
Mice with lymphoma who were fed a low-calorie diet while on drug treatment survived longer.
Results showed that neither drug treatment alone nor cutting calories alone increased the survival rates of the mice.
But the mice who received the treatment and who were on a reduced-calorie diet survived longer than any of the others.
The group that received the treatment while on a reduced-calorie diet survived 41 days, whereas the regular-diet group of mice given the drug survived 33 days.
Metabolic effect in cancer
The researchers note that our bodies metabolize food to produce energy and help build proteins, but when fewer calories are consumed, it reduces the amount of nutrients available for the body's cells and slows the metabolic process.
They hypothesize that reducing caloric intake could potentially help inhibit the "over-expression of the protein Mcl-1, an alteration associated with several cancers."
Jean-Ehrland Ricci says:
"By understanding the link between metabolism and the body's natural cancer suppressors and activators, we can perhaps improve the efficacy of therapy and improve survival for patients suffering from specific types of cancer."
After the experiment, the researchers noticed that the mice in the restricted-calorie plus treatment group had fewer lymphoma cells, which suggests that the combination of the two "sensitized the lymphoma cells to treatment."
Ricci says that their results are encouraging:
"This is just the beginning of our journey to bring these research findings to the clinical setting.
We next want to examine what component of a reduced-calorie diet - fats, sugars, or another food compound - influenced the lymphoma cells' improved sensitivity to treatment."