Dietary lignan and proanthocyanidin consumption and colorectal adenoma recurrence in the Polyp Prevention Trial

Lignans and proanthocyanidins are plant polyphenols that have shown protective properties against colorectal neoplasms in some human studies. Using logistic regression, we estimated odds ratios (ORs) and 95% confidence intervals (CIs) to prospectively evaluate the association between lignan and proanthocyanidin intake, estimated from databases linked to a food frequency questionnaire, and adenoma recurrence in 1,859 participants of the Polyp Prevention Trial. Overall, individual or total lignans or proanthocyanidins were not associated with colorectal adenoma recurrence. However, in sex-specific analyses, total lignan intake was positively associated with any adenoma recurrence in women (highest vs. lowest lignan intake quartile OR 5 2.07, 95% CI: 1.22–3.52, p trend 5 0.004) but not in men (p interaction 5 0.04). To conclude, dietary lignan and proanthocyanidin consumption were not generally related to colorectal adenoma recurrence; however, high lignan intake may increase the risk of adenoma recurrence in women. Polyphenols have generated interest as components of fruits and vegetables that show cancer protective properties. 1,2 On the basis of their chemical structure, polyphenols are divided into subclasses, the most pertinent being tannins (proanthocyanidins, hydrolysable tannins), lignans, stilbenes, phenolic acids and flavonoids. 3 We previously showed that the flavonoid subgroups flavonols and isoflavonoids and the flavan-3-ol epigallocatechin-3-gallate (EGCG) decrease the risk of advanced adenoma recurrence in the Polyp Prevention Trial (PPT). 4,5