Salmon is one the the cold-water fatty fish loaded with omega-3 fatty acids
I’ve been sitting on this research report a few years, waiting until I had time to dig into it. That time never came. The full report is free online (thanks, British Medical Journal!). I scanned the full paper to learn that nearly all the studies in this meta-analysis used fish oil supplements, not the cold-water fatty fish the I recommend my patients eat twice a week.
Here’s the abstract:
Objective: To review systematically the evidence for an effect of long chain and shorter chain omega 3 fatty acids on total mortality, cardiovascular events, and cancer.
Data sources: Electronic databases searched to February 2002; authors contacted and bibliographies of randomised controlled trials (RCTs) checked to locate studies.
Review methods Review of RCTs of omega 3 intake for 3 6 months in adults (with or without risk factors for cardiovascular disease) with data on a relevant outcome. Cohort studies that estimated omega 3 intake and related this to clinical outcome during at least 6 months were also included. Application of inclusion criteria, data extraction, and quality assessments were performed independently in duplicate.
Results: Of 15 159 titles and abstracts assessed, 48 RCTs (36 913 participants) and 41 cohort studies were analysed. The trial results were inconsistent. The pooled estimate showed no strong evidence of reduced risk of total mortality (relative risk 0.87, 95% confidence interval 0.73 to 1.03) or combined cardiovascular events (0.95, 0.82 to 1.12) in participants taking additional omega 3 fats. The few studies at low risk of bias were more consistent, but they showed no effect of omega 3 on total mortality (0.98, 0.70 to 1.36) or cardiovascular events (1.09, 0.87 to 1.37). When data from the subgroup of studies of long chain omega 3 fats were analysed separately, total mortality (0.86, 0.70 to 1.04; 138 events) and cardiovascular events (0.93, 0.79 to 1.11) were not clearly reduced. Neither RCTs nor cohort studies suggested increased risk of cancer with a higher intake of omega 3 (trials: 1.07, 0.88 to 1.30; cohort studies: 1.02, 0.87 to 1.19), but clinically important harm could not be excluded.
Conclusion: Long chain and shorter chain omega 3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer.
Reference: Hooper, Lee et al. Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ 2006;332:752-760 (1 April), doi:10.1136/bmj.38755.366331.2F (published 24 March 2006).
Diabetic Mediterranean Diet 
“Ethnic food combinations for Greenland, Japanese, Mediterranean, and American populations give proportions of n-6 in tissue HUFA near 30%, 50% 60% and 80%, respectively. These surrogate clinical outcomes are associated with cardiovascular mortalities of 20, 50, 90, and 200 per 100,000, respectively.”
http://ods.od.nih.gov/docs/omega3_dcv_abstracts.html
I think I’ll stick with my low n6 high n3 intake!
Well, here we go with Wall Street Book Review today June 5, 2014 on a book by Nina Teicholz titled The Big Fat Surprise. The lead states The Worst Diet in US History..
Regarding this low fat diets and crusade about saturated fats was preventing heart disease! ” What was left, as Ms Teicholz adumbrates, was a monstrous thought: What if the crusade against cholesterol had fed the spread of obesity by encouraging a population to retreat from the very foods that would have satiated its hunger more efficiently than the hallowed grains and fruits and vegetables of the great dietary pyramid? What if the low fat mantra had driven a population into feeling constantly hungry?
What if you were better off eating meat, eggs, and dairy rather than a diet bloated in carbs and vegetable oils?”
And my question is – why the explosion in type 2 disease since the 1960’s and no success treating it cheaply, easily, and simply. Most type 2 diabetics -30 years myself, finally got their mess under control by following a low carb diet , booting and controlling the grains and their products tightly,, with some dietary fats as well as using the Mediterranean diet approach?
Jim, I’m not sure anyone has a definite answer to your question. I don’t think it’s just higher body weights.