The importance of the ratio of omega-6/omega-3 essential fatty acids.
Level 5 - mechanism / opinion, no new human data
Narrative review synthesizing selective prior literature without systematic review methodology
PubMed 12442909 · doi:10.1016/s0753-3322(02)00253-6
What was done
Narrative review synthesizing evidence on the evolutionary dietary ratio of omega-6 to omega-3 essential fatty acids (EFAs) compared with modern Western diets, and reviewing studies on how varying ratios affect cardiovascular disease, colorectal and breast cancer, rheumatoid arthritis, and asthma.
What was found
The author notes human evolutionary diets had an estimated omega-6/omega-3 ratio of ~1:1 versus 15/1–16.7/1 in Western diets. Reported study associations include: - Secondary cardiovascular disease prevention: a 4/1 ratio was associated with a 70% decrease in total mortality. - Colorectal cancer: a 2.5/1 ratio reduced rectal cell proliferation, whereas 4/1 with the same omega-3 dose had no effect. - Breast cancer: a lower ratio was associated with decreased risk (no numeric values reported). - Rheumatoid arthritis: a ratio of 2–3/1 suppressed inflammation. - Asthma: a ratio of 5/1 was beneficial, while 10/1 had adverse consequences.
Why it matters
Highlights the potential therapeutic importance of lowering the dietary omega-6/omega-3 ratio and suggests that optimal targets vary across specific chronic diseases.
Limits
This is a narrative review without systematic search or meta-analytic methodology. The abstract omits sample sizes, study designs, absolute nutrient doses, control groups, and confidence intervals for the cited findings.
Cited by
- supports The dietary ratio of omega-6 to omega-3 fatty acids in most Americans is approximately 20:1.