MARIKA SBOROS: Opinions inflamed over the cause of heart disease
Some reject the focus on cholesterol and see lipoproteins as crucial factors, while others say new theories won’t change treatments
It wasn’t long ago that cardiologists told patients cholesterol caused heart attacks and strokes.
They spoke of cholesterol as “good” or “bad”. They added “ugly” cholesterol to the list of fatty bloodstream baddies that could fatally harm hearts and brains. They advised patients to eat low-fat foods and avoid saturated fat and red meat like the proverbial plague. Most cardiologists also wholeheartedly endorsed statins, the pharmaceutical industry’s blockbuster cholesterol-lowering drugs.
Among some in the medical profession, those conversations have recently changed — radically.
Many cardiologists locally and internationally now say they have a whole new theory of the cause of cardiovascular disease (CVD). It is that CVD is not a cholesterol disease; it’s a disease of lipoproteins — biochemical particles, vehicles, if you like — that transport blood lipids (fatty molecules, such as cholesterol and triglycerides) to all the body’s cells.
According to the theory, the cause of CVD is high levels of apolipoprotein-Bs (Apo-Bs), cholesterol-rich substances embedded in lipoprotein membranes.
Cardiologists hail the theory as a major advance. For proof, they say it underpins new guidelines from the annual European Society of Cardiology and European Atherosclerotic Society meeting in Paris in September.
The guidelines include new recommendations for CVD management and prevention in patients with diabetes or prediabetes. That’s especially relevant for SA’s “diabesity” epidemic — as doctors now call the twin, related occurrences of type 2 diabetes and obesity. Diabetes raises CVD risk.
Guideline task force co-chairs Dr Francesco Cosentino, of the Karolinska University Hospital in Stockholm, Sweden, and Dr Peter Grant, of the University of Leeds in the UK, have called the recommendations the result of “an unprecedented increase in the evidence base available for practising health-care professionals to refer to”.
Certainly, the guidelines are influential and in SA all cardiologists and lipidologists are bound by them. The Heart and Stroke Foundation of SA says it subscribes to the guidelines.
But just what changes can CVD patients expect?
Very little and, if anything, more drugs, say some cardiologists and other doctors who view the guidelines through a different lens.
Inflammation explains why otherwise healthy, fit young men collapse and die from a heart attack while running a marathon.Dr Riaz Motara
They say the guidelines miss the right target and are another case of “the more things change, the more they stay the same”.
The guidelines don’t let cholesterol off the hook, they say. They continue cardiologists’ embrace of statin drugs and the lower-is-better approach for Apo-B lipoproteins and low-density lipoprotein (LDL, formerly “bad”) cholesterol.
These critics are not saying statins and other cholesterol-lowering drugs don’t have their place. It’s just the knee-jerk, often first resort use that they find troubling — and the rancorous debate on their risk-vs-benefit profile.
And while some local cardiologists quietly use a low-carbohydrate approach for diabesity and CVD, they still promote low-fat foods and demonise saturated fat.
Johannesburg cardiologist Dr Riaz Motara says the biggest problem with the lipoprotein theory and guidelines is that they are “right for the wrong reasons”.
“They don’t address the cause of high levels of Apo-B lipoproteins; they continue the drug-based approach that treats symptoms, not causes, of disease.”
Motara has his own evidence-based theory on CVD cause. It is inflammation, based on groundbreaking research by Harvard professor of medicine Dr Paul Ridker. Ridker is acknowledged as a world authority on the role of inflammation in disease processes.
Motara joins Ridker in calling inflammation “the missing link” in heart disease and other chronic conditions, diabesity included.
“Inflammation explains why otherwise healthy, fit young men collapse and die from a heart attack while running a marathon,” Motara says.
It's why about 50% of people who die after a heart attack have “normal” cholesterol levels.
Of course, critics could say that also doesn’t answer the question of what causes inflammation. Ridker, Motara and others have a ready answer: Inflammation causes are multifactorial and include the “usual suspects”. A bad diet is just one.
Motara is no fan of low-fat diets but neither does he unquestioningly favour “high-fat diets”.
“It’s the quality of fats that counts,” he says.
Most people eat foods too high in inflammatory omega-6 fats from industrially farmed, grain-fed animals, refined, processed grains and vegetable oils.
Foods from pasture-fed animals and plant-based, mostly green foods and grown organically are high in omega-3 oils that are anti-inflammatory, he says. “But you can eat the healthiest diet and still die from heart attack or stroke,” says Motara.
That’s because a range of lifestyle factors creates the groundwork for inflammation to develop. Among these: smoking; too little physical activity (and not just any physical activity; Motara says yoga is hugely beneficial to fight inflammation); too little sleep; a lack of social connection; and that ubiquitous villain of modern, 21st century living and working: excessive stress.
You can eat the healthiest diet and still die from heart attack or stroke.Dr Riaz Motara
Stress drives up cortisol levels and, in turn, inflammatory pathways that lead to disease, says Motara.
Scottish GP and CVD specialist Dr Malcolm Kendrick is author of the best-selling The Great Cholesterol Con, The Truth About What Really Causes Heart Disease and How to Avoid It.
He has a different take on the causes of CVD. He says ongoing damage to arterial walls and inflammation is a marker. “To blame inflammation for CVD is to get the causal chain the wrong way round,” Kendrick says.
There are literally hundreds, possibly even thousands, of things that can damage arterial walls, says Kendrick. Therefore, there are no simple answers to causes or remedies.
Diet is “indirectly damaging”, says Kendrick. If you are insulin resistant, for example, and eat carbohydrates, your blood sugar rises and this damages arterial walls. “That’s how diabetes causes CVD,” he says.
He agrees that stress plays a role. It increases blood pressure, blood sugar and stress hormones.
But at heart, Kendrick’s remedies for reducing arterial damage don’t differ much from Motara’s on reducing inflammation.
“CVD treatment and prevention is not rocket science,” Kendrick says.
UK consultant cardiologist Dr Aseem Malhotra has the last word on the guidelines and LDL-cholesterol.
LDL-cholesterol is “clearly not a useful biomarker for over 99% of the population”, says Malhotra, who is also visiting professor of evidence-based medicine at the Bahiana School of Medicine and Public Health in Brazil.
Lowering LDL-cholesterol with “dubious drugs” that show marginal benefits at best from industry-sponsored trials and come with side effects is simply “bad medicine”, he says
If doctors, patients and the public want to know why the guidelines are drug-biased, Malhotra says the answer is in plain sight: “The institutional and financial ties of scientists producing [the guidelines] to drug companies manufacturing these drugs.”
Clearly, divisions among cardiologists worldwide run deep but experts say there is also consensus between supporters and diehard critics of the guidelines. It is that CVD is not caused by a deficiency of statins or any other cholesterol-lowering drugs. In the vast majority of cases CVD, like diabesity, is a lifestyle-related disease.
Therefore, it makes solid sense for lifestyle changes to be the first resort ahead of drug therapy in treatment protocols, wherever possible and appropriate. And for the emphasis on prevention to be paramount, because it is, after all, so much better than any cure.