Assessing the Highest Level of Evidence from Randomized Controlled Trials in Omega-3 Research

Abstract

Over the years, there has been heightened interest in the health benefits of n-3 polyunsaturated fatty acids (PUFA) in reducing chronic diseases such as, cardiovascular disease (CVD), cancer, type 2 diabetes, and acute macular degeneration (AMD). Due to inconsistent findings in the evidence, a review to critically examine the plethora of evidence from randomized controlled trials (RCTs) in n-3 PUFA research was undertaken. The aim of this review is to study the highest level of evidence and to identify gaps in n-3 PUFA research. RCTs were originally designed for pharmaceutical research and later adopted for nutrition and food-related research. RCTs with active diseases assume that n-3 PUFA will have “drug” like effects, and this high expectation may have led to the inconsistent evidence in the literature. The inconsistency in the literature may be related to varying doses of n-3 PUFA, sources of n-3 PUFA (food vs. supplement; plant vs. marine), type of n-3 PUFA (mixture vs. purified), trial duration, population characteristics, sample size, and genetic variation. For future research, there is a need to distinguish between primary and secondary prevention, and to focus RCTs on primary prevention of chronic diseases by n-3 PUFA which is lacking in the literature.

Colorectal ALOX15 as a host factor determinant of EPA and DHA effects on colorectal carcinogenesis

“…Studies investigating the link between fish oil, EPA, DHA, and cancers, including colorectal carcinogenesis (CRC), have largely focused on the effects of EPA and DHA supplementation. However, the effects of EPA and DHA supplementation on cancer risk have been inconsistent (4,5). For example, while fish oil was reported to suppress CRC in various preclinical rodent studies (6)(7)(8), it was also reported to promote CRC, especially with DHAenriched formulations (9,10).…”