Not everyone is convinced cholesterol really is all that bad for your heart. “The cholesterol campaign is the greatest medical scandal in modern time,” says , a Danish independent researcher. He has published dozens of peer-reviewed papers about cholesterol’s biological role, and claims there is no link between blood-cholesterol levels and levels of atherosclerosis, the furring of the arteries that precipitates heart attacks.
It’s certainly true that half of all heart attacks and strokes occur among apparently healthy people with normal or low levels of “bad” low-density lipoprotein cholesterol, so it’s clearly not the sole factor. Drugs beside statins that lower LDL-C levels such as fibrates, ezetimibe and bile acid sequestrants also have little if any effect on heart-related deaths. Statins happen to both lower LDL-C levels and reduce deaths from heart attacks among those with diagnosed heart conditions, but that might just be coincidence, says of Cochrane, a non-profit organisation that reviews available medical data. “The association may or may not be causal,” he says.
Those who deny a link are talking complete nonsense, counters Rory Collins, head of the in Oxford, UK. “The few people who have raised the question are a bit like those individuals who think homoeopathy works or think Earth is flat,” he says. at the London School of Hygiene and Tropical Medicine agrees. “I’m all for proper debate, providing the people I’m debating with are not denying science,” he says. “But cholesterol demonstrably causes heart attacks.”
Advertisement
Lehman thinks that’s probably the case too – it’s just that we don’t yet have hard causal evidence. “This point is important because it allows drugs to be marketed on the basis of surrogate markers, like cholesterol-lowering, without long-term hard evidence of their benefits and harms,” he says.
False assurance
at the University of California, San Francisco, doesn’t deny a link either, but warns against over-emphasising cholesterol. “Measuring blood cholesterol diverts focus from things that are much more powerful in terms of reducing cardiovascular risk,” she says – things like not smoking, eating a healthy diet and exercising regularly. She points to evidence that people on cholesterol-lowering statins frequently , and . “It’s human nature,” she says. “They have a false assurance that they have now reduced their risk and they don’t need to be paying attention to their diet and exercise.”
Not a problem, says Collins: lifestyle factors don’t matter, as long as you bring your cholesterol levels down. “This is the beauty of the statin data,” he says. He argues that statins reduce the risk of coronary heart disease in direct proportion to the reduction in LDL-cholesterol. “That is true across a very wide range of individuals, from higher risk to lower risk,” he says. “What’s more, it is irrespective of why they are at risk.” It seems that where you stand on cholesterol is inextricably bound up with where you stand on the statin debate (see Cholesterol wars: Does a pill a day keep heart attacks away?).
Cholesterol: The good and bad news
Most of the cholesterol in your body is made in the liver. However, most people can bring their blood cholesterol down to levels considered safe through diet alone – just not necessarily by reducing cholesterol intake directly.
A review published in 2015 said that although dietary cholesterol does increase blood cholesterol, it is . Consumption of saturated fat seems to have a greater effect on blood cholesterol levels – although it’s far from clear that this leads directly to increased risk of heart disease either (see “Heart attack on a plate“).
Another complication is the existence of “good” and “bad” cholesterol. Actually, it’s not the cholesterol that’s good or bad: it’s the lipoprotein molecules that carry cholesterol to and from cells. Low-density lipoprotein cholesterol (LDL-C) is bad because of its reputation for sticking to artery walls, making them less flexible and impeding blood flow. Meanwhile, high-density lipoprotein cholesterol (HDL-C) is “good” because it helps slough LDL-C from artery walls. But while some say , others are not so sure: a number of studies show LDL-C – so perhaps it’s not so bad after all.
This article appeared in print under the headline “Cholesterol wars”
