A team of scientists has found that a fasting-mimicking diet combined with hormone therapy has the potential to help treat breast cancer, according to newly published animal studies and small clinical trials in humans.
In studies on mice and in two small breast cancer clinical trials, researchers at USC and the IFOM Cancer Institute in Milan — in collaboration with the University of Genova — found that the fasting-mimicking diet reduces blood insulin, insulin-like growth factor 1 (IGF1) and leptin. In mice, these effects appear to increase the power of the cancer hormone drugs tamoxifen and fulvestrant and delay any resistance to them. The results from 36 women treated with the hormone therapy and fasting-mimicking diet are promising, but researchers say it is still too early to determine whether the effects will be confirmed in large-scale clinical trials.
The research was published in the journal Nature.
“Our new study suggests that a fasting-mimicking diet together with endocrine therapy for breast cancer has the potential to not only shrink tumors but also reverse resistant tumors in mice,” said Valter Longo, the study’s co-senior author and the director of the Longevity Institute at the USC Leonard Davis School of Gerontology and professor of biological sciences at the USC Dornsife College of Letters, Arts and Sciences. “We have data that for the first time suggests that a fasting-mimicking diet works by changing at least three different factors: IGF1, leptin and insulin.”
The researchers say the two small clinical trials are feasibility studies that showed promising results, but they are in no way conclusive. They believe the results support further clinical studies of a fasting-mimicking diet used in combination with endocrine therapy in hormone-receptor-positive breast cancer.
The scientists also contributed to a recent clinical study of 129 breast cancer patients conducted with the University of Leiden. The results, published last month in Nature Communications, appeared to show increased efficacy of chemotherapy in patients receiving a combination of chemotherapy and a fasting-mimicking diet.
Two trials involving fasting show promise
In the two new small clinical trials — one of which was directed by the study’s co-corresponding author Alessio Nencioni — patients with hormone-receptor-positive breast cancer receiving estrogen therapy along with cycles of a fasting-mimicking diet seemed to experience metabolic changes similar to those observed in mice. These changes included a reduction in insulin, leptin and IGF1 levels, with the last two remaining low for extended periods. In mice, these long-lasting effects are associated with long-term anti-cancer activity, so further studies in humans are needed.
I like to call it the nontoxic wildcard for cancer treatment.
“Some patients followed monthly cycles of the fasting-mimicking diet for almost two years without any problems, suggesting that it is a…