The cholesterol theory of cardiovascular disease states that dietary cholesterol and saturated fatty acids cause raised plasma levels of cholesterol, and that in turn this causes atherosclerosis which drives cardiovascular disease. However, this theory is provably false based on the nutritional literature. Current thinking suggests that it low quality diets containing processed and manufactured food, that result in the ingestion of toxic substances, as well as imbalances to normal dietary intakes of fats, that is the driver of cardiovascular disease and cancer. In particular trans fatty acids, a by-product of the conversion of polyunsaturated fatty acids to hydrogenated fatty acids, and an imbalance in the omega 6 to omega 3 fatty acid ratio, are implicated as drivers of Western disease. In addition, it is now thought that the seed for the development of Western disease is sewn many decades before any symptoms are detectable, and the dietary habits during childhood now play a larger role in adult health than was once believed.
Researchers have investigated the association between fatty acid intake and the risk of cardiovascular disease by measuring the fatty acid intake and carotid intima-media thickness (a measure of atherosclerosis) in children below 18 years and during a 27 year follow-up1. The results showed that childhood percentages of saturated fatty acids, monounsaturated fatty acids and omega 3 fatty acids of cholesterol esters were directly associated with adult carotid intima thickness (showing healthier arteries). In contrast, percentages of omega 6 fatty acid of cholesterol esters were inversely associated with carotid intima-media thickness. Similar associations were also found in adult women, but not in men. In another study, researchers investigated the association between dietary fat intake and the risk of non-Hodgkin lymphoma (a form of cancer)2. The results showed that diets high in trans fatty acids and processed meats were positively associated with the risk of non-Hodgkin lymphoma, whereas omega 3 fatty acids were inversely associated with risk.
These results support other studies in the nutritional literature that show a role for essential fatty acid imbalances and trans fatty acids in the development of cardiovascular disease and cancer. The ratio of omega 6 to omega 3 fatty acids is traditionally thought to be around 3 to 1, but the Western diet provides a ratio that is thought to be as high as 10-20 to 1. The high intake of omega 6 fatty acids overloads the essential fatty acid pathway which inhibits the production of the anti-inflammatory series 1 and series 3 eicosanoids, and at the same time increases production of arachidonic acid which increases production of the pro-inflammatory series 2 eicosanoids. The Western diet also contains high concentrations of trans fatty acids, and these are thought to interfere with normal metabolic regulation including the metabolism of the essential fatty acids, which increases inflammation. The increased inflammation caused by the Western diet is the driver of Western disease, as it significantly increases the risk of cardiovascular disease and cancer.
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