A number of studies using Omega 6 oils for health benefits have shown negative or nil outcomes, and with the analysis of arterial placque indicating that it was primarily composed of oxidised omega 6 oils.
This study is a review of data from an old study which was conducted to determine benefits of Omega 6 oils in reducing heart disease risk has shown that the intervention group had a higher all cause mortality and cardiovascular (CVD) mortality as well.
The primary problems with many of the older studies is they were looking primarily at reducing risk for CVD by using cholesterol levels as a risk marker. It has now been shown that the basis for the Saturated fat = high cholesterol = high CVD risk hypothesis was completely flawed and possibly fraudulent, but has taken 40 years to subdue it as it was adopted and promoted by government health agencies.
There is a summary below and at the bottom links to the entire paper and an interview with the head reseacher, the gentleman is very much reserved in his findings unlike the recent flawed study posted here regarding red meat and carnitine causing CVD who was fully blowing his own trumpet, this being the first sign of study flaws.
It is a good paper, well worth reading.
Use of dietary linoleic acid for secondary prevention of coronary heart disease and death: evaluation of recovered data from the Sydney Diet Heart Study and updated meta-analysis.
Ramsden CE, Zamora D, Leelarthaepin B, Majchrzak-Hong SF, Faurot KR, Suchindran CM, Ringel A, Davis JM, Hibbeln JR.
Laboratory of Membrane Biophysics and Biochemistry, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Bethesda, MD 20892, USA. Chris.Ramsden@nih.gov
To evaluate the effectiveness of replacing dietary saturated fat with omega 6 linoleic acid, for the secondary prevention of coronary heart disease and death.
Evaluation of recovered data from the Sydney Diet Heart Study, a single blinded, parallel group, randomized controlled trial conducted in 1966-73; and an updated meta-analysis including these previously missing data.
Ambulatory, coronary care clinic in Sydney, Australia.
458 men aged 30-59 years with a recent coronary event.
Replacement of dietary saturated fats (from animal fats, common margarines, and shortenings) with omega 6 linoleic acid (from safflower oil and safflower oil polyunsaturated margarine). Controls received no specific dietary instruction or study foods. All non-dietary aspects were designed to be equivalent in both groups.
All cause mortality (primary outcome), cardiovascular mortality, and mortality from coronary heart disease (secondary outcomes). We used an intention to treat, survival analysis approach to compare mortality outcomes by group.
The intervention group (n=221) had higher rates of death than controls (n=237) (all cause 17.6% v 11.8%, hazard ratio 1.62 (95% confidence interval 1.00 to 2.64), P=0.05; cardiovascular disease 17.2% v 11.0%, 1.70 (1.03 to 2.80), P=0.04; coronary heart disease 16.3% v 10.1%, 1.74 (1.04 to 2.92), P=0.04). Inclusion of these recovered data in an updated meta-analysis of linoleic acid intervention trials showed non-significant trends toward increased risks of death from coronary heart disease (hazard ratio 1.33 (0.99 to 1.79); P=0.06) and cardiovascular disease (1.27 (0.98 to 1.65); P=0.07).
Advice to substitute polyunsaturated fats for saturated fats is a key component of worldwide dietary guidelines for coronary heart disease risk reduction. However, clinical benefits of the most abundant polyunsaturated fatty acid, omega 6 linoleic acid, have not been established. In this cohort, substituting dietary linoleic acid in place of saturated fats increased the rates of death from all causes, coronary heart disease, and cardiovascular disease. An updated meta-analysis of linoleic acid intervention trials showed no evidence of cardiovascular benefit. These findings could have important implications for worldwide dietary advice to substitute omega 6 linoleic acid, or polyunsaturated fats in general, for saturated fats.
http://www.bmj.com/content/346/bmj.e870 ... d=23386268
http://www.meandmydiabetes.com/2013/03/ ... e-hibbeln/