Recent headlines claiming that egg yolks cause heart disease were misleading
'Egg yolks harm your health as much as smoking' warned a whole rash of recent newspaper and tv headlines. The stories were based on a new study that, according to its authors, found that egg yolks are as damaging as smoking in terms of causing atherosclerosis, hardening of the arteries. Reading the reports, the science seemed solid enough. However, the original paper was not made readily available to journalists (it was in a pay-to-view journal) and so they used the information they were given, which presented the facts in such a way as to lead to headline-grabbing conclusions.
The study involved more than a thousand patients, all of whom were attending clinics for people with risk factors for heart disease. The participants had their plaque levels checked (the build-up on their arteries) and were asked to fill out a questionnaire about their lifestyle, medication, smoking habits and the number of egg yolks they consumed per week. The researchers, from the Stroke Prevention and Atherosclerosis Research Centre, Robarts Research Institute, Canada, then analysed the data in an attempt to assess whether eating egg yolks had an effect on plaque build-up. They found that egg yolk consumption was associated with a raised risk of plaque build-up similar to that seen with smokers.
The problems with this study are many. As senior dietician Victoria Taylor from the British Heart Foundation says, “It was a single study and it found an association. But there are limitations and for that reason we shouldn’t draw conclusions from it. The researchers didn’t question participants about their diet overall, or how they prepared the eggs [fried, boiled or poached, for example, which would have an effect on fat intake], or whether the individuals exercised regularly or were overweight. So we wouldn’t change our advice based on this study. Eggs as part of a healthy balanced diet are fine. What’s important is to have a healthy varied diet and eggs can form a part of that. Just be sure to cook them without adding any fat – scrambled, boiled or poached, for example.”
The fact is that the findings from this study can only justify a rather wish-washy statement: people who already have a higher likelihood of heart disease (based on risk factors) may or may not increase their risk of plaque build-up if they eat egg yolks. The researchers cannot pinpoint egg yolks as the cause of the plaque build-up because they don’t know whether those who ate more egg yolks also ate a high-fat diet and those who ate fewer egg yolks tended to eat a low-fat diet. To finger egg yolks as the cause is fallacious.
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