The anthrocyanins in cranberries and blueberries are thought to inhibit bacteria from adhering to bladder walls, which would explain why these fruits seem to help ward off urinary tract infections. Lab analysis suggests the same protective compounds may also help suppress herpes outbreaks.
Anthocyanins are increasingly recognized for their anticancer effects. Scientists at Clemson University in South Carolina have used anthocyanins in raspberry, strawberry and muscadine grape extracts to cut the growth of cancer cell lines cultured from breast and cervical tumors by more than half. Blackberry and blueberry extracts weren’t as effective against cervical cancer cells, but they did suppress the growth of breast cancer cells.
In addition, a University of Maryland study found that anthocyanin-rich extracts reduced several markers for colon cancer in animal studies. Whether these antioxidants could survive the harsh conditions of human digestion and similarly benefit humans has yet to be confirmed. Encouragingly, German scientists have shown that 85 percent of the anthocyanins in blueberries make it as far as the colon. And in a University of Georgia study, blueberry anthocyanins applied to human colon cancer cells reduced proliferation and increased apoptosis (programmed cell death), leading researchers to conclude that “blueberry intake may reduce colon cancer risk.”
Several animal studies have suggested that anthocyanins may also help promote heart health. Researchers at the Indiana University School of Medicine found that anthocyanins from chokeberries, bilberries and elderberries improved the vascular elasticity of blood vessels, even when they were exposed to free radicals, making them supple enough to function normally. Another study from the University of Maine demonstrated similar benefits, this time from wild blueberries, to the aortic blood vessels close to the heart.