Restricting calorie intake to an eight-hour window coinciding with physical activity reduced breast cancer risk in female mouse models.
Researchers from University of California San Diego School of Medicine, Moores Cancer Center and Veterans Affairs San Diego Healthcare System (VASDSH) found that the restricted feeding times, which are kind of circadian rhythm-linked intermittent fasting, enhanced metabolic health and tumour circadian rhythms in female mice with obesity-driven postmenopausal breast cancer. Breast cancer is the second most common cancer in US women, after skin 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,” explained senior author Nicholas Webster, PhD. professor at UC San Diego School of Medicine and senior research career scientist at VASDSH. “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.”
Female mouse models mimicking postmenopausal hormone conditions were used to investigate if time-restricted feeding of obese mice affected the tumour growth and development, and reduced metastasis to the lungs. The mice were split into three groups, one with constant access to food, one with access for eight hours at night when they have the greatest activity, and the last was fed an unrestricted low-fat diet.
Obesity and menopause disrupt the circadian rhythm, with increased risk of insulin resistance and thereby chronic diseases such as cancer. A number of cancers are known to be associated with insulin resistance, such as breast cancer and pancreatic cancer. High insulin levels in obese mice drive tumour growth. Artificially increasing insulin levels has been shown to accelerate tumour growth whilst lowering them is similar to the effect of limiting eating.
Manasi Das, PhD, postdoctoral fellow in the Webster lab and first author, said: “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. 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.”
Webster believes that time-restricting eating warrants further investigations as it may present a way to reduce breast cancer risk, or that of cancer in general.
“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 advise women to adopt weight loss strategies to prevent tumor growth,” said Das. “Our data suggests that a person may benefit from simply timing their meals differently to prevent breast cancer rather than changing what they eat.”
Source: Medical Xpress
Journal information: Manasi Das et al. Time-restricted feeding normalizes hyperinsulinemia to inhibit breast cancer in obese postmenopausal mouse models, Nature Communications (2021). DOI: 10.1038/s41467-020-20743-7
