Nutrition

Biography

Biography: Gary Stoner

Abstract

We examined the ability of freeze-dried berries to prevent G.I. tract cancers in animals and humans. Most studies used black raspberries (BRBs), due to their high antioxidant potential and high content of anthocyanins and fiber. In rodent studies, the consumption of BRB powder, at 2.5, 5 and 10% of a synthetic diet, resulted in a 40-70% inhibition of carcinogen-induced cancer in the rat esophagus and colon, and the spontaneous development of intestinal tumors in mice. Mechanistically, BRBs inhibit proliferation, inflammation and angiogenesis and stimulate apoptosis and differentiation, and protectively modulate genes in multiple signaling pathways. The most active inhibitory constituents in BRBs are the anthocyanins. A Phase I trial showed that BRBs are well tolerated in humans at oral doses that elicit chemopreventive effects in rodents. The oral administration of BRB powder (45g/day) to 20 Barrett’s esophagus patients for 6 months led to reductions in oxidative stress, but minimal effects on the lesion. Oral administration of strawberry powder (60g/day) to 37 Chinese patients with esophageal dysplasia led to histologic regression of ~80% of mildly dysplastic lesions and reduced levels of iNOS, COX-2, and phospho-NF-κB-p65 proteins. Treatment of 20 colorectal cancer patients with BRB powder for an average of 3 weeks led to reduced cell proliferation and demethylation of suppressor genes in the Wnt signaling pathway. Treatment of patients with familial adenomatous polyposis with rectal BRB suppositories caused a 36% regression of rectal polyps. These trials indicate that berries have significant promise for chemoprevention of esophageal and colon cancer in humans.