Friday, November 1, 2013

BMJ: We Missed the Mark on Sat Fat

This is a great read, I highly recommend you read the whole piece.
"The aspect of dietary saturated fat that is believed to have the greatest influence on cardiovascular risk is elevated concentrations of low density lipoprotein (LDL) cholesterol. Yet the reduction in LDL cholesterol from reducing saturated fat intake seems to be specific to large, buoyant (type A) LDL particles, when in fact it is the small, dense (type B) particles (responsive to carbohydrate intake) that are implicated in cardiovascular disease.4
"Indeed, recent prospective cohort studies have not supported any significant association between saturated fat intake and cardiovascular risk.5 Instead, saturated fat has been found to be protective. The source of the saturated fat may be important. Dairy foods are exemplary providers of vitamins A and D. As well as a link between vitamin D deficiency and a significantly increased risk of cardiovascular mortality, calcium and phosphorus found commonly in dairy foods may have antihypertensive effects that may contribute to inverse associations with cardiovascular risk.6 7 8 One study showed that higher concentrations of plasmatrans-palmitoleic acid, a fatty acid mainly found in dairy foods, was associated with higher concentrations of high density lipoprotein, lower concentrations of triglycerides and C reactive protein, reduced insulin resistance, and a lower incidence of diabetes in adults.9 Red meat is another major source of saturated fat. Consumption of processed meats, but not red meat, has been associated with coronary heart disease and diabetes mellitus, which may be explained by nitrates and sodium as preservatives.10
"The notoriety of fat is based on its higher energy content per gram in comparison with protein and carbohydrate. However, work by the biochemist Richard Feinman and nuclear physicist Eugene Fine on thermodynamics and the metabolic advantage of different diet compositions showed that the body did not metabolise different macronutrients in the same way.11 Kekwick and Pawan carried out one of the earliest obesity experiments, published in the Lancet in 1956.12 They compared groups consuming diets of 90% fat, 90% protein, and 90% carbohydrate and showed that the greatest weight loss was in the fat consuming group. The authors concluded that the “composition of the diet appeared to outweigh in importance the intake of calories.”
"The “calorie is not a calorie” theory has been further substantiated by a recent JAMAstudy showing that a “low fat” diet resulted in the greatest decrease in energy expenditure, an unhealthy lipid pattern, and increased insulin resistance in comparison with a low carbohydrate and low glycaemic index diet.13 In the past 30 years in the United States the proportion of energy from consumed fat has fallen from 40% to 30% (although absolute fat consumption has remained the same), yet obesity has rocketed."
This one is a mind blower, as I have read the NNT was 100, whereas baby aspirin is 40.  It's much worse than that:
"A meta-analysis of predominantly industry sponsored data reported that in a low risk group of people aged 60-70 years taking statins the number needed to treat (NNT) to prevent one cardiovascular event in one year was 345.20 The strongest evidence base for statins is in secondary prevention, where all patients after a myocardial infarction are prescribed maximum dose treatment irrespective of total cholesterol, because of statins’ anti-inflammatory or pleiotropic (coronary plaque stabilising) effects. In this group the NNT is 83 for mortality over five years. This doesn’t mean that each patient benefits a little but rather that 82 will receive no prognostic benefit.21 The fact that no other cholesterol lowering drug has shown a benefit in terms of mortality supports the hypothesis that the benefits of statins are independent of their effects on cholesterol."

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