Another study on eggs and heart disease risk has been published. Well, sort of. It’s a meta-analysis of 16 previously published studies. As soon as I see that an article was based on a meta-analysis I can’t help but question the conclusions it reaches. There are a number of issues to consider when looking at meta-analyses and I feel like there’s a huge opportunity for bias and misinterpretation of results. It’s far too easy to be selective about inclusion of research and implications of results. Oftentimes the original studies are flawed and those flaws are carried through into the meta-analysis but they’re not as apparent when you’re not looking at the entire study. That being said, let’s look at the present meta-analysis.
It appears that the authors don’t have any conflicts of interest (always the first thing to check when looking at research: where did the funding come from?). A quick Google search of each of the authors didn’t reveal any obvious affiliations that could have impacted their research. It doesn’t appear that they had any ulterior motives.
The study actually found no relationship between egg consumption and cardiovascular disease in the general population. Did you catch that behind the headlines suggesting that egg yolks are bad for you?: healthy individuals who eat eggs once a day are no more likely to die from a heart attack or stroke than healthy individuals who don’t eat eggs at all. However, the part that’s getting the most attention is the finding that egg consumption may be associated with an increased incidence of type 2 diabetes and those egg-eaters who have diabetes are at greater risk of dying from cardiovascular disease. Before you start freaking out and getting on the egg-white omelette bandwagon please note the presence of the words incidence and associated. These words tell us that people who regularly eat eggs may be at greater risk of developing type 2 diabetes than those who don’t. It also tells us that people who have diabetes and eat eggs may be at greater risk of dying from cardiovascular disease (CVD). This is assuming that all of the studies they looked at were sound and that all relevant studies were included (big assumptions). However, it doesn’t tell us that eating eggs was the reason for the increased risks. There could have been some other commonality among the egg-eaters that raised their risk for type 2 diabetes and there may have been something other than egg-consumption that increased their risk of dying from CVD.
Now, if you have diabetes, not knowing for certain if eggs may increase your risk of dying from CVD you may want to minimize your consumption of them. Better safe than sorry. And, while most of us can safely consume up to an egg a day, I think it’s important to bear in mind that variety is an important component to a healthy diet.