Honey is composed primarily of the sugars levulose, dextrose, and maltose, with a small fraction of sucrose. However, honey also incorporates micronutrients with anticancer activities, including acacetin, apigenin, chrysin, galangin, kaempferol, luteolin, naringenin, pinobanksin, pinocembrin, and quercetin.
The micronutrient content of honey is derived from pollen and can vary greatly depending on the varieties of flowers visited by bees. Generally speaking, the darkest honeys, such as buckwheat honey, are a better source of phenolic compounds than lighter-colored honeys. These compounds contribute significantly to the antioxidant and chemopreventive properties of honey, but are not solely responsible. Now a new study has reported that Manuka honey greatly inhibited the growth of established tumors in a mouse model of ER+/PR+ breast cancer.

Manuka honey

Manuka honey is produced by bees that pollinate the manuka bush native to New Zealand. In recent years, the honey has also been produced outside New Zealand. Manuka honey has previously been reported to inhibit proliferation of ER+/PR+ breast cancer cells in a dose-dependent manner. Manuka honey has also been shown to inhibit triple negative (ER-/PR-/HER2-) breast cancer growth through the actions of some of the flavonoids present in the honey (chrysin, galangin, luteolin, and quercetin).

Latest research finds Manuka honey inhibits tumor growth

The study referenced above was designed to investigate the potential antitumor activity of manuka honey. The authors first examined the effects of varying concentrations of manuka honey powder in breast cancer cells. Manuka honey was found to result in significant dose-dependent reduction in proliferation of ER+/PR+ (MCF-7) cells. Manuka honey also stimulated apoptosis (programmed cell death) of ER+/PR+ cells. In fact, the antitumor impact of manuka honey in ER+/PR+ cells was comparable to that of tamoxifen. A weaker antitumor effect was observed in triple negative (MDA-MB-231) cells. The authors also demonstrated that manuka honey did not harm normal breast cells (non-malignant human mammary epithelial cells).
The authors then tested manuka honey in an animal model of ER+/PR+ breast cancer. MCF-7 tumor cells were implanted in the flanks of ovariectomized mice supplemented with estradiol. Once the resulting tumors reached a size of 50–75 cm3, the mice received either manuka honey or dextrose (control) by oral gavage. Manuka honey was found to inhibit tumor growth by 84%, resulting in an evident reduction in tumor volume. The authors conclude that further research is warranted into the use of natural compounds such as manuka honey to investigate their antitumor effects and the underlying mechanisms of action.
Please see our article on ER+/PR+ breast cancer diet and the honey page for more information.