Omega-3 Polyunsaturated Fatty Acids: The Way Forward in Times of Mixed Evidence

Table 6

Current state of evidence for the effects of omega-3 PUFA in published human studies regarding colorectal cancer.

Type of study	Beneficial effect	Beneficial effect limited to subpopulation	Detrimental effect limited to subpopulations	No effect
Clinical trials	Antiproliferative effect [83–85, 87, 90]			No antiproliferative effect [86, 88, 93, 94]
	Proapoptotic effect [89, 90]			No proapoptotic effect [93, 94]
	Reduced polyp number and size in FAP [91]			No anti-inflammatory effect in colony biopsies [93, 94]
	Reduced angiogenesis [92]
	Reduced CRP levels in serum [93–95]
Observational studies		Inverse association between increased dietary intake and risk of CR adenomas (only in women) [96]	Positive associations between FO use and CRC in high risk groups [97]
		Inverse association between FO use and cancer risk (in men, not in women; in colon, not in rectum) [97]	Positive association between increased intake and distal CC [98]
		Inverse associations between FO use and CRC in low-moderate genetic risk groups, and positive associations among high risk groups [97]
		Inverse association between increased intake and RC (but not CC) [98]
		Inverse association between increased dietary intake and risk of CRC (only in specific genetic variants) [99]
Meta-analyses	Significant inverse association between fish consumption and RC [100]			Limited evidence of a role in CRC prevention [101, 102]

CC: colon cancer; CRC: colorectal cancer; CRP: C-Reactive Protein; FAP: familial adenomatous polyposis; FO: fish oil; RC: rectal cancer.