Eggs and cholesterol: Why a new study may be misleading

Eggs are a nutrient-rich healthful choice, when eaten in moderation.
Eggs
For the healthiest, lowest calorie way to prepare eggs, aim for poached, hard boiled, or scrambled with non-stick spray.Getty Images

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By Madelyn Fernstrom

Go ahead, enjoy your omelet.

A new study published Friday in JAMA has tossed some major confusion into the egg debate: Are eggs good for you, or are you putting yourself at risk for heart disease?

The researchers were looking for an association between daily cholesterol or eggs consumption with cardiovascular disease. So they combined findings from six different studies, involving 30,000 participants over 17 years, and analyzed the findings. Their conclusion? For each additional 300 milligrams a day of cholesterol in the diet, there was a significant increase of risk of cardiovascular disease and risk of early death from any cause.

You can relax. Eggs remain a nutrient-rich healthful choice, when eaten in moderation.

While this study sounds strong, there are a lot of gaps in information and assumptions that can be both misleading and confusing. And while the main focus is on statistical modeling, it’s most important to take a closer look at where the raw data, the information about what the participants ate, came from that was analyzed.

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The thousands of participants were a result of combining studies where the information was collected differently. The technique of combining studies, called meta-analyses, to provide larger numbers, often minimizes the fact that the data collection is highly variable, and often not comparable.

Because this is based on food consumption, it’s important to identify how this was done. For this study, it was based on food recall — what people remembered eating — over a period of weeks. Many people have a hard time recalling what they ate for breakfast on the same day, much less several weeks prior.

While many studies utilize food recall, interpretation of accuracy is problematic. It can be one factor, but not the only one to formulate a conclusion.

Cholesterol in the diet comes only from animal foods, including egg yolk, full-fat dairy products, shellfish, meats and poultry. One large egg contains about 186 milligrams of cholesterol.

But many other lifestyle factors can also contribute to cardiovascular risk. Some of the prominent ones like BMI, weight, smoking, other sources of cholesterol intake and saturated fat, and exercise patterns were acknowledged as important, but they were not adequately factored in, for the conclusions exclusively attributed to eggs.

So, what about bacon? Were the participants enjoying fried bacon with their eggs?

The current U.S. dietary guidelines, issued in 2015, dropped the absolute amount of daily cholesterol in the diet. While the previous recommendation had been to limit dietary cholesterol to 300 mg per day, the government panel of nutrition experts wrote, “Available evidence shows no appreciable relationship between consumption of dietary cholesterol and serum cholesterol.”

In the new study, researchers suggested that, in contrast to the current guidelines, the issue of cholesterol should be revisited.

But as stated in the current guidelines, eating patterns, not necessarily an isolated aspect of the diet, are a key relationship to health.

For the healthiest, lowest calorie way to prepare eggs, aim for poached, hard boiled, or scrambled with non-stick spray. If you choose fried eggs, stick with a small amount of vegetable oil, and skip the butter.

And you can lower the cholesterol intake of your egg dishes by combining one egg and one or two egg whites, to boost the volume.

For now, an egg a day — or seven eggs a week — as approved by the American Heart Association, can be part of a heart-healthy diet.