Consumption of walnuts may help suppress growth and survival of breast cancer, a study claims. The study, published in the journal Nutrition Research, found that consumption of two ounces of walnuts a day for about two weeks significantly changed gene expression in confirmed breast cancers.
"Consumption of walnuts has slowed breast cancer growth and reduced the risk of mammary cancer in mice," said W Elaine Hardman, from Marshall University in the US.
"Building on this research, our team hypothesised that walnut consumption would alter gene expression in pathologically-confirmed breast cancers of women in a direction that would decrease breast cancer growth and survival," Hardman said in a statement.
In this first clinical trial, women with breast lumps large enough for research and pathology biopsies were recruited and randomised to walnut consuming or control groups. Immediately following biopsy collection, women in the walnut group began to consume two ounces of walnuts per day until follow-up surgery.
Pathological studies confirmed that lumps were breast cancer in all women who remained in the trial. At surgery, about two weeks after biopsy, additional specimens were taken from the breast cancers.
Changes in gene expression in the surgical specimen compared to baseline were determined in each individual woman in walnut-consuming and control groups. RNA sequencing expression profiling revealed that expression of 456 identified genes was significantly changed in the tumour due to walnut consumption.
The study showed activation of pathways that promote apoptosis or programmed cell death and cell adhesion and inhibition of pathways that promote cell proliferation and migration. "These results support the hypothesis that, in humans, walnut consumption could suppress growth and survival of breast cancers," Hardman said.
"Additional research through a larger-scale study would be needed to clinically confirm that walnut consumption actually does reduce the risk of breast cancer or breast cancer recurrence," said Hardman.