SAN DIEGO, Calif. — Intermittent fasting has emerged recently as a trendy weight loss avenue, but a study involving mice suggests it may hold serious cancer-fighting capabilities as well. Researchers from the University of California, San Diego say when a group of mice restricted their eating to an eight-hour time period, their risk for the development, growth, and metastasis of breast cancer declined.
Time-restricted feeding is a variety of intermittent fasting in alignment with circadian rhythms. Study authors conclude it can help improve both metabolic health and tumor circadian rhythms in mice suffering from obesity-caused postmenopausal breast cancer.
“Previous research has shown that obesity increases the risk of a variety of cancers by negatively affecting how the body reacts to insulin levels and changing circadian rhythms,” says senior author Nicholas Webster, PhD, professor at UC San Diego School of Medicine in a university release. “We were able to increase insulin sensitivity, reduce hyperinsulinemia, restore circadian rhythms and reduce tumor growth by simply modifying when and for how long mice had access to food.”
While these findings only involve mice, the potential avenues for human breast cancer prevention they open up are promising. The American Cancer Society estimates one in eight women will develop breast cancer in their lifetime.
Can fasting restore insulin levels linked to cancer?
To investigate if time-restricted eating influences tumor growth and or breast cancer metastasis to the lungs, researchers placed a group of obese female mice engineered to “mimic” postmenopausal hormone conditions on a strict intermittent fasting regimen.
Study authors separated the mice into three experimental groups. The first had 24-hour access to food, the second could only eat for eight hours at night (mice are typically most active in the evening), and the third had to follow an unrestricted low-fat diet.
Studies find that both obesity and menopause can throw circadian rhythms out of whack. This can eventually lead to insulin resistance. Elevated insulin resistance can predispose people toward other conditions including cancer.
Previous research discovered that artificially raising insulin levels in obese mice led to accelerated tumor growth. At the same time, lowering insulin levels helped stymie cancer growth. Based on these findings, and the results of their own experiment, researchers believe intermittent fasting effectively recreates the effects of low insulin levels.
Intermittent fasting is a cost-effective cancer defense
“Time-restricted eating has a positive effect on metabolic health and does not trigger the hunger and irritability that is associated with long-term fasting or calorie restriction,” says study first author Manasi Das, PhD. “Through its beneficial metabolic effects, time-restricted eating may also provide an inexpensive, easy to adopt, but effective strategy to prevent and inhibit breast cancer without requiring a change in diet or physical activity.”
“The increase in risk of breast cancer is particularly high in women who are overweight and have been through menopause. For this reason, doctors may advice women to adopt weight loss strategies to prevent tumor growth,” Das concludes. “Our data suggests that a person may benefit from simply timing their meals differently to prevent breast cancer rather than changing what they eat.”
The study is published in Nature Communications.