First eggs are bad. Then they’re OK. Now they’re bad again. Nutrition Diva puts the latest study on eggs and cholesterol in perspective (and provides solid, scientifically-based advice without the hype).
What the Latest Cholesterol Study Found
But is this association between cholesterol and heart disease even real? This latest study was a meta-analysis of six observational studies. In each of these studies, they asked a big group of people about their diet. Then they followed them for decades to see what sort of health problems they developed. Then they crunched the data to look for associations between their diet and their health.
But this is not the first time researchers have crunched this type of data. One big question is why this latest study found a link between cholesterol and heart disease when so many previous analyses did not? The authors argue that they did a better job adjusting for variables such as smoking, drinking, exercise habits, and other aspects of diet.
Keep in mind that these dietary surveys were done between 1985 and 2005. This was still during a time when people were counselled to limit eggs and cholesterol. So those who were eating a lot of eggs may not have been particularly concerned about nutrition. And that may have spilled over into other aspects of their lifestyle. Indeed, that those who ate the most eggs were more likely to be smokers, more likely to have diabetes, and had lower diet quality over all.
But there’s something else about this study that strikes me as even more problematic. The researchers only asked the subjects about their typical dietary patterns once, at the beginning of each study. They continued to gather data about their health for anywhere from 10 to 30 years. But they assumed that people continued to eat the same way the whole time.
The researchers only asked the subjects about their typical dietary patterns once...continued to gather data for 10-30 years...and assumed that people continued to eat the same way the whole time.
Do You Eat the Same Now as You Did 10 Years Ago?
Let me just ask you: Has your diet changed at all over the last 10 years? Mine sure has. We are likely to modify our diets as we go through life in response to evolving research, or a change in our own health, or any number of other influences, including our family, friends, and popular culture.
Let’s say one of these subjects started out as a healthy 49-year-old who reported eating a dozen eggs a week. Two years later at a routine physical, his doctor finds that he has elevated cholesterol. It’s the 90s, so he’s given the standard advice. He starts avoiding eggs and eating a low fat diet, one that’s a lot higher in carbohydrates. Twelve years later, when he’s 63, he has a heart attack. By this point, he’s been eating nothing but egg whites for 12 years. But in this analysis, he’d still be counted as someone who eats a dozen eggs a week and developed heart disease.
Another participant might have been a health-conscious 50-year-old who follows nutrition news avidly. At the time the study begins in 1988, she reports eating 2-3 eggs a week, in line with current recommendations. But over the years, she sees more and more research questioning the relationship between cholesterol and heart disease. Meanwhile, she’s reading a lot about the benefits of higher protein diets. As a result, she starts eating more eggs. At 65, she’s eating 8-10 eggs a week and is heart-disease free. But in this analysis, she’d be counted as someone who eats very few eggs and doesn’t have heart disease.
I actually think it’s pretty unlikely that people’s egg consumption remained constant over the course of these decades and that makes it hard for me to put much confidence in these associations.
How Many Eggs Are Safe?
In my opinion, when it comes to your risk of heart disease, the amount of cholesterol in your diet plays only a minor role compared to the your overall diet quality and lifestyle. It comes down to the three questions I always ask: How much are are you eating? What are you eating itwith? What would you be eating if you weren’t eating that instead?
If you’re replacing your breakfast pastry with a couple of eggs, or your afternoon candy bar with a hard-boiled egg, or your hamburger with a vegetable frittata, I think those eggs are doing a lot more good than harm.
Obviously, it’s possible to overdo just about anything. I’m not suggesting that it’s a good idea to be eating half a dozen eggs every day. But I don’t think you need to limit yourself to 3 eggs a week either. Personally, I feel perfectly comfortable consuming a dozen eggs a week and this study doesn’t change that.