It’s time to “bust the myth of the role of saturated fat in heart disease,” writes a British cardiologist in a no-holds-barred commentary published Tuesday in the journal BMJ.
The medical community also needs to let go of its misguided “obsession” with using statin drugs to lower people’s total cholesterol, he adds.
“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,” writes Dr. Aseem Malhotra, who works at Croydon University Hospital in London. “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.”
The complexity of a cholesterol profile
Some background: Atherogenic dyslipidaemia (or dyslipidemia in U.S. spelling) is the medical term for a particular blood-cholesterol profile. Its most distinguishing feature is high levels of small low-density lipoprotein (LDL) cholesterol. (The condition also features low levels of high-density lipoprotein, or HDL, and high levels of triglycerides.)
The important factor here is that the LDL particles are small. It’s those small particles that have been implicated in cardiovascular disease. LDL also comes in a big, fluffy version, but scientists believe those particles are mostly benign.
As Malhotra points out in his commentary, when people reduce their saturated fat intake, it’s their large LDL levels that fall. The levels of small LDL remain essentially the same.
And that’s because small LDL levels appear to be influenced by the consumption of sugar and other carbohydrates, not saturated fat.
In other words, cutting back on saturated fat may lower LDL levels, but not the ones that protect against stroke, heart attack and other cardiovascular diseases.
“Indeed,” writes Malhotra, “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.”
As an example, he cites recent research that suggests saturated fat in dairy foods may protect against hypertension, insulin resistance and the development of obesity and type 2 diabetes — factors associated with an increased risk of heart disease.
A more important culprit
During all those decades when we were so focused on avoiding saturated fat, says Malhotra, we took our eyes off what may be a much more important dietary culprit in the development of cardiovascular risk factors: carbohydrates, particularly added sugar.
“The scientific evidence is mounting,” writes Malhotra, “that sugar is a possible independent risk factor for metabolic syndrome (the cluster of hypertension, dysglycaemia, raised triglycerides, low HDL cholesterol, and increased waist circumference).”
“In previous generations,” he adds, “cardiovascular disease existed largely in isolation. Now two thirds of people admitted to hospital with a diagnosis of acute myocardial infarction [a heart attack] 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?”
Dueling studies
The idea that high total cholesterol is a risk factor for heart disease got started in the early 1970s, when the Framingham Heart Study found a correlation (not a cause-and-effect) between heart disease and the consumption of saturated fat. Since then, however, other studies have found an association between low total cholesterol and heart disease.
So prescribing millions of healthy adults statins as a preventive measure to lower their risk of heart disease doesn’t make scientific sense, says Malhotra, particularly given the drugs’ considerable side effects, which include muscle pain, stomach upset, sleep and memory problems and erectile dysfunction.
Malhotra is not alone, of course, with this assessment of the overuse of statins. As I’ve noted here before, more than a dozen studies have shown that when used for primary prevention — in other words, by otherwise healthy people with no personal history or symptoms of heart disease — statins do very little, if anything, to prevent a heart attack or stroke.
The research has turned up different findings, however, when statins are prescribed to people who have had a previous heart attack or stroke. Studies suggest that the drugs can reduce those patients’ risk of dying within the next five years by as much as a third.
But that reduced risk may not have anything to do with the lowering of total cholesterol levels, says Mahlotra.
“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,” he writes.
A more powerful alternative
Malhotra points out that adopting a Mediterranean diet (which permits saturated fat, but certainly doesn’t go overboard with it) “is almost three times as powerful in reducing mortality as taking a statin.”
Drugs “can assuage the symptoms but can’t alter the pathophysiology,” he concludes. “Doctors need to embrace prevention as well as treatment. The greatest improvements in morbidity and mortality have been due not to personal responsibility but rather to public health. 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.”
Your can read Malhotra’s commentary on the BMJ website.
