Dietary flavonoid for preventing colorectal neoplasms

Area of Science:

• Nutritional Science
• Oncology
• Gastroenterology

Background:

• Flavonoids, abundant in fruits and vegetables, are polyphenolic compounds with over 5,000 identified variants.
• Previous research suggests a potential role for flavonoids in cancer prevention.
• This study investigates the link between dietary flavonoids and colorectal neoplasm risk.

Purpose of the Study:

• To assess the impact of dietary flavonoid intake on the incidence of colorectal adenoma and colorectal cancer (CRC).

Main Methods:

• A systematic review of eligible studies was conducted using multiple databases (Cochrane Library, PubMed, EMBASE, CINAHL) up to July 2011.
• Included studies were prospective, controlled interventional, and observational studies assessing flavonoid association with CRC or adenoma risk.
• Data extraction and methodological quality assessment (Newcastle-Ottawa scale) were performed independently by at least two investigators.

Main Results:

• Eight studies involving 390,769 participants were analyzed, with varying study designs (cohort, case-control, RCT).
• Overall flavonoid intake did not show a reduced risk of colorectal neoplasms; evidence for Isoflavones, Flavonols, Flavones, and Flavanones was conflicting.
• Increased intake of Flavan-3-ols, epicatechin, procyanidin, and phytoestrogen suggested a reduced risk of CRC and colorectal adenomas, while anthocyanin showed no inverse association.

Conclusions:

• Insufficient and conflicting evidence exists regarding flavonoid intake and colorectal neoplasm prevention.
• Challenges in accurately determining flavonoid intake complicate definitive conclusions.
• Further research is necessary to clarify the association between specific flavonoids and colorectal neoplasm risk.