Ruth Patterson, PhD, on Time-Restricted Eating in Humans & Breast Cancer Prevention

Posted on July 8th 2016 (over 3 years)

Ruth Patterson, PhD, is a professor at the University of California San Diego (UCSD) in the Department of Family and Preventive Medicine. She also serves as the leader of the Cancer Prevention Program at USCD Health's Moores Cancer Center in La Jolla, California, where she is the Associate Director of Population Sciences. In addition, Dr. Patterson oversees the Transdisciplinary Center on Energetics and Cancer at UCSD, whose objective is to find answers to questions regarding links between insulin resistance, inflammation, and breast cancer carcinogenesis.

Dr. Patterson's research interests are focused on the hypothesis that prolonged nightly fasting can reduce the risk of chronic diseases, including some cancers, by improving overall metabolic health.

Breast cancer is the second leading cause of cancer deaths among women living in the U.S., claiming the lives of more than 40,000 women each year. Several factors may be at play in the development of breast cancer, but strong epidemiological and mechanistic data point to the roles of obesity, inflammation, and lifestyle factors in mediating risk.

Estrogen and insulin create fertile soil for cancer growth

Data from the Women's Health Initiative indicate that the risk of developing breast cancer among women who are overweight or obese is nearly 60 percent higher than it is among women who are at a healthy weight. In addition, heavier women tend to have a worse prognosis than healthy weight women, presenting with large, poorly differentiated tumors and lymph node involvement. Furthermore, deaths from breast cancer are more than 2-fold higher among the heaviest women.

Some of this increased risk may be due to the fact that women who are obese typically have higher circulating levels of estrogen and insulin. These hormones act as growth factors to create a kind of "fertile soil" that promotes the proliferative processes associated with cancer, allowing it to grow and spread.

Obesity fans the flames of cancer

Obesity also helps drive the inflammatory process. Inflammation involves the activation and release of immune cells, cell-signaling proteins, and pro-inflammatory factors and has been implicated in the pathophysiology of many diseases, including cancer. Fatty tissue is a metabolically active organ that produces many pro-inflammatory cytokines and mediators that work in a synergistic fashion with other pro-inflammatory molecules to create a pro-tumorigenic microenvironment.

Derangements in circadian rhythms promote metabolic dysregulation

Strong evidence also points to metabolic dysregulation in the pathophysiology of breast cancer. This dysregulation arises from perturbations in the body's circadian rhythms, the body's innate 24-hour cycles of biological, hormonal, and behavioral patterns. Circadian rhythms modulate a wide array of physiological processes, including the body’s production of hormones that regulate sleep, hunger, metabolism, and others, ultimately influencing body weight, performance, and susceptibility to disease.

Our modern lifestyle, with extended hours of light exposure and late-night eating, is counter to these deeply ingrained natural rhythms. For example, the body's sensitivity to the effects of insulin varies throughout the day, peaking in early morning and plummeting at night. Skipping breakfast, "grazing" throughout the day, or eating large quantities of food late at night can interfere with the body's ability to properly metabolize the energy provided and promote metabolic dysregulation.

Lifestyle modifications restore the body's natural rhythm

However, small lifestyle modifications, such as time-restricted eating, can reestablish proper metabolic regulation. Time-restricted eating is a form of fasting that limits the daytime hours during which a person can eat to an 8- to 12-hour window, leaving 12 to 16 hours of fasting. When practiced in the earlier part of the day – eating before 7 or 8 p.m. – time-restricted eating aligns the eating and fasting cycles more closely to the body’s metabolic rhythms.

Learn more about time-restricted eating in this topic article from FMF.

In this episode, Dr. Ruth Patterson describes how an intervention involving more than 2,500 breast cancer survivors who practiced time-restricted eating – fasting 13 hours overnight – reduced their risk of breast cancer recurrence by nearly 40 percent, regardless of what they ate or drank. The participants' metabolic and inflammatory biomarkers showed dramatic improvements, as well. This acceptable, sustainable eating pattern meshed with familial and cultural foodways and manifested in enhanced feelings of self-efficacy that gave rise to other healthy lifestyle behaviors.

Implications for public health

These findings have tremendous public health implications. Many of the factors that drive cancer also drive other chronic diseases, including diabetes and cardiovascular disease. Implementing similar interventions on a wider scale could shift the entire chronic disease risk curve downward, reducing the amount of money spent on healthcare each year and improving the lives of millions of people.

"We think that less than 5 percent overall of breast cancers are the result of genetic factors. And more like 65 percent to 75 percent are the result of lifestyle factors, including obesity, diet, physical activity, and smoking." - Dr. Ruth Patterson Click To Tweet

Learn more about Dr. Ruth Patterson

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