For decades, there has been lively — sometimes intense — debate about the health merits and risks linked to eating eggs. This debate has closely mirrored the debate about dietary cholesterol — a waxy substance that’s found in many animal products, but in particularly large quantities in eggs and certain seafood items like shrimp (prawns). In some people, intake of dietary cholesterol is closely tied to blood levels of cholesterol — and blood cholesterol levels are tied to certain forms of cardiovascular disease. But recent research suggests that in most people, there isn’t a strong link between dietary cholesterol and blood cholesterol levels.
But blood cholesterol isn’t the only way that what you eat can affect your risk for cardiovascular disease. So looking at actual health outcomes related to eating eggs or cholesterol — rather than how they affect your results on a blood test — is a much better way to find out whether they contribute to the risk of disease and death. And according to a new study, eating eggs carries some substantial health risks.
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Higher risks of cardiovascular disease and death
The study, published in the journal PLOS Medicine, included 521,120 participants recruited in six U.S. states (plus two additional cities) between 1995 and 1996, and followed until the end of 2011. A detailed food questionnaire was given to assess each person’s intake of whole eggs, egg whites and substitutes, and cholesterol from any source. Researchers were mostly interested in how these eating patterns were related to death from various causes, especially cardiovascular disease.
During the follow-up period, which was about 16 years on average, 129,328 study participants died. Out of these deaths, 38,747 were from cardiovascular disease. The researchers found that intake of whole eggs and cholesterol was tied to a higher risk of death from all causes, cardiovascular disease and cancer. Specifically, each additional half of an egg that participants consumed was tied to a 7% higher risk of these outcomes. While this may not sound like a big difference, it means that someone who eats two eggs each day has a 31% higher risk of death — as well as death from cardiovascular disease or cancer — than someone who doesn’t eat eggs.
What’s more, dietary cholesterol appeared to be the likely main culprit in the higher risk of death linked to egg consumption. For each additional 300 milligrams of cholesterol that participants consumed, there was a 19% higher risk of death from all causes, a 16% higher risk of death from cardiovascular disease, and a 24% higher risk of death from cancer. By combining these numbers with the data on egg consumption, the researchers estimated that cholesterol intake was responsible for 63% of the overall death risk associated with eating eggs, along with 62% of the risk of death from cardiovascular disease and 50% of the risk of death from cancer linked to egg intake.
What’s more, people who consumed egg whites or egg substitutes were less likely than those who didn’t consume them to die from all causes, or from a stroke, cancer, respiratory disease or Alzheimer’s disease.
Should you avoid eggs?
This study makes a compelling — but not airtight — case that to avoid cardiovascular disease and cancer and to lower your overall risk of death, it’s best to avoid whole eggs or reduce your consumption of them. But there are some important limitations to the study, despite its enormous size and long duration.
One factor to consider is that this was an observational study, meaning that it simply looked at what people were already choosing to do. It’s possible that people who chose to eat whole eggs were also likely to engage in certain unhealthy behaviors, and that people who chose to eat egg whites or substitutes were also likely to engage in unrelated healthy behaviors. Researchers tried to adjust for these behaviors when possible — including other foods that people were likely to consume along with eggs or egg whites or substitutes — but it’s not possible to measure and adjust for every single behavior that might contribute to someone’s risk of disease or death.
Another potential limitation of the study is its reliance on self-reported food intake. It’s possible that certain groups of people are likely to misrepresent — either intentionally or unintentionally — what they eat, potentially affecting the results. For example, if healthier people with greater knowledge of what they “should” be eating were embarrassed about how many eggs they ate and under-reported their egg intake, this could account for some or all of the higher risks linked to eggs that the study found.
Ultimately, of course, it’s up to you to decide what to eat, based on consultation with your healthcare team and dietary guidelines from medical or governmental organizations. But this study might give you a reason to think again about the place that eggs have in your diet.