Flaxseed Bioactive Compounds and Colorectal Cancer Prevention.

Key Findings

The sequential progression from healthy to metastatic epithelium, known as the polyp-cancer progression sequence, is a widely accepted model of colorectal cancer (CRC). Recent findings have led to an increased interest in the consumption of flaxseed (FS), due to its high content of fiber, omega-3 (n3) fatty acids, flavonoids, and phytoestrogens amongst other bioactive compounds, and the role it may play in reducing CRC risk. This paper provides a comprehensive overview of the effect of FS and its bioactive components in CRC development, including evidence from clinical, pre-clinical, and mechanistic studies with an emphasis on the influence of FS consumption as a means of CRC prevention. Consumption of FS demonstrates chemopreventive properties, with regard to colon carcinogenesis in preclinical models, as evidenced by reduction of ACFs and colon tumor incidence, multiplicity, and size. Increased stool bulking, decreased transit time, and production of SCFAs due to dietary fiber intake are all associated with CRC prevention. Increased ALA and subsequent improvement of the n6 to n3 ratio are also beneficial to gut health by reducing inflammatory and oxidative stress markers as well as decreasing cell proliferation and inducing apoptosis. Following transformation to enterolignans, lignans induce cell cycle arrest, reduce cell proliferation, and increase apoptosis. Other bioactive components of FS are associated with cell cycle disruption and decreased colonic tumor incidence. Future clinical and preclinical studies of longer duration should examine the synergistic effect of the various bioactive components of FS (lignans, fiber, and ALA) in reducing the
onset of CRC.

ABSTRACT

Flaxseed and its bioactive components have been associated with a decreased risk of colorectal cancer incidence and progression. This review aims to summarize recent research regarding the role of flaxseed and each of its major dietary bioactive components in reducing colorectal cancer. In both human and animal model experiments, flaxseed consumption had beneficial effects on colon physiology associated with reduction in colorectal cancer risk or occurrence. Considered separately, each of flaxseed’s major bioactive components, including fiber, alpha-linolenic acid, lignans, and other phytochemicals, is also associated with decreased risk of colonic neoplasms and regulation of cell growth through several potential mechanisms. Collectively, experimental data suggests that consumption of flaxseed and/or its bioactive components may reduce colorectal cancer risk by a variety of mechanisms. Future studies should focus on the mechanisms by which whole flaxseed can prevent colorectal cancer.