Wednesday, November 6, 2013

The Nutrition Debate #158: Demolishing the Saturated Fat Bogeyman

In a commissioned, peer-reviewed and foot-noted “Observations” column published October 22, 2013, in the prestigious BMJ (British Medical Journal), interventional cardiologist Aseem Malhotra presented this stunning conclusion: “It is time to bust the myth of the role of saturated fat in heart disease and wind back the harms of dietary advice that has contributed to obesity.” The ground shook and a tsunami rolled around the world. Ripples were even felt in the mainstream.

Dr. Malhotra reminds us that, “Saturated fat has been demonized ever since Ancel Keys’s landmark ‘seven countries’ study in 1970. This concluded that a correlation existed between the incidence of coronary heart disease and total cholesterol concentrations, which then correlated with the proportion of energy provided by saturated fat. But correlation is not causation; and Keys cherry-picked his data. Nevertheless, we were advised to cut fat intake to 30% of total energy and saturated fat to 10%.” That was and is a core recommendation incorporated into the “Dietary Guidelines for Americans” from its inception in 1980 to this day.

“The mantra that saturated fat must be removed to reduce the risk of cardiovascular disease has dominated dietary advice and guidelines for almost four decades,” Dr. Malhotra continues. “Yet scientific evidence shows that this advice has, paradoxically, increased our cardiovascular risks. Furthermore, the government’s obsession with levels of total cholesterol, which has led to the overmedication of millions of people with statins, has diverted our attention from the more egregious risk factor of atherogenic dyslipidaemia.” Translation: Low HDL and high triglycerides, plus small-dense LDL lipoprotein particles (“Pattern B” LDL) accompanied by systemic inflammation, all of which are potent cardiovascular disease risk factors.

To explain how that comes about, Dr. Malhotra continues, “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.” Translation: Reduced saturated fat intake = fewer large buoyant (type A) LDL particles; Increased carbohydrate intake = more small dense (type B) LDL particles. Conclusion: Saturated fat: good; Carbohydrates: bad.

Dr. Malhotra covers some familiar ground as well: “Scientists universally accept that trans fats – found in many fast foods, bakery products and margarines – increase the risk of cardiovascular disease through inflammatory processes.” And he nicely clarifies a point: “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.” But he comes back to saturated fat with this: “Indeed, recent prospective cohort studies have not supported any significant association between saturated fat intake and cardiovascular risk. Instead, saturated fat has been found to be protective.” See his citation here.

“In previous generations cardiovascular disease existed largely in isolation,” he says. “Now two thirds of people admitted to hospital with a diagnosis of acute myocardial infarction really have metabolic syndrome – but 75% of these patients have completely normal total cholesterol concentrations. Maybe this is because total cholesterol isn’t really the problem,” he quips (emphasis mine). Metabolic Syndrome is “the cluster of hypertension, dysglycaemia, raised triglycerides, low HDL cholesterol, and increased waist circumference.” Do these sound familiar? Does it apply to you? Does it worry you, yet?

Dr. Malhotra reminds us that, “The notoriety of fat is based on its higher energy content per gram in comparison with protein and carbohydrate,” but he cites Richard Feinman and Eugene Fine’s work on “metabolic advantage” to show that “different diet compositions showed that the body did not metabolize different macronutrients in the same way.” “The ‘calorie is not a calorie’ theory has been further substantiated,” he adds, “by a recent JAMA study 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.” This is beginning to sound like a broken record.

So, will this message resonate? Were there aftershocks? Sure, I was startled awake one morning with a ‘teaser’ on an early morning TV news program. Later, the Diet Doctor, Andreas Eenfeldt, featured it here. The BBC Health News featured it here, and they also had a morning show video segment. The had this piece by Melissa Healy. And early tremors were registered at here.  Maybe it will resonate this time, if enough people hear it, over and over…
Finally, Dr. Malhotra comes at it from a different angle: “When you take the fat out (of food), the food tastes worse.” “The food industry compensated by replacing saturated fat with added sugar. The scientific evidence is mounting that sugar is a possible independent risk factor for the metabolic syndrome.” He’s now come full circle. “Saturated Fat is not the major issue,” the title of the piece shouts. The sub-title, “Let’s bust the myth of its role in heart disease…” Bravo! This stake to the heart will help. But ‘SFAs = bad’ is an undead concept that will persist to eat away at our health, like a zombie apocalypse.