Of all the nutrition questions that you get asked as a dietitian, by far and away the most common one is, do eggs increase blood cholesterol levels? And after another research paper was released last week arguing that eating too many eggs can be as bad for heart health as smoking, the humble egg has again found itself in the nutrition firing line. But before you start throwing away your egg yolks and swapping to processed breakfast cereals to ensure that your breakfast is ‘healthy’, there are a few other factors that need to be considered.
A high saturated fat intake is known to increase blood cholesterol, and high blood cholesterol is one of the biggest risk factors for heart disease, Australia’s biggest killer. Based on this, it has been hypothesised for many years that eggs, with their relatively high saturated fat and cholesterol content should be controlled in the diets of those who have heart disease risk factors. Indeed a recent study published in the prestigious cardiac journal Atherosclerosis found that the damage to arteries of over 1200 study participants who were at risk of heart disease who consume more than 3 eggs each week was worse than that of smokers. Unfortunately, other crucial dietary and lifestyle factors were not considered when this conclusion was reached, including factoring in the physical activity levels of study participants or controlling for their daily caloric intake or regular dietary intake patterns.
Yes, eggs do contain cholesterol and saturated fat but so too do numerous other foods including fatty cuts of red meat, full cream milk and most importantly processed and fast foods including biscuits, cakes, burgers, fries, pizza and donuts. Any diet which contains a significant amount of saturated fat (>20-30g per day) is likely to be impacting negatively on heart health, particularly for those individuals who are prone to high cholesterol. What is far less frequently mentioned when it comes to heart disease risk factors that being overweight is perhaps the greatest risk factor of all. People become overweight not only from a diet high in saturated fat, but from eating too many calories, high fat or not.
For this reason, when working with patients to reduce blood cholesterol levels, any intervention should primarily focus on weight loss, as opposed to only working on reducing a person’s intake of saturated fat. Not only are inflammatory processes reduced with weight loss, but so too is blood pressure and ‘bad’ cholesterol levels in the bloodstream, even with just a 3-5kg loss.
Now when it comes to eggs here are my thoughts – there is good evidence to show that eating up to 2 eggs a day as part of a high protein breakfast is a breakfast that is more conducive to weight loss than a high carbohydrate break or cereal rich breakfast. 2 eggs contain almost 20g of high biological value protein, of which there is a significant amount of leucine, the amino acid known to help regulate insulin levels and as a result fat metabolism in the body. For this reason, enjoying 1 or 2 eggs each day as part of a calorie controlled breakfast is a viable weight loss option.
Sure, eggs may contain some cholesterol and fat but no more than the potato chips, cakes, biscuits and fast food that too many of us eat far more frequently than we should, particular for those among us with high cholesterol. So, if you do have high cholesterol and/or a family history of heart disease and want to be vigilant, perhaps reducing to no more than 1 egg a day is a prudent decision, but ditching the other high fat saturated fat foods in your diet should be your real focus. Most importantly, losing a few kg via a diet packed full of fresh fruit, vegetables, wholegrains in conjunction with regular exercise; rather bland advice I know but far more powerful than eliminating eggs from your diet completely.