Eggs are again linked to heart problems — though the study has problems

Though eggs are back on the menu, some are trying to rewrite the script.

Photo by REVOLT on Unsplash
  • A new study at Northwestern University found a link between egg consumption and cardiovascular disease and all-cause mortality.
  • The research relied on self-reporting at the beginning of observation, with no follow-up reporting.
  • Correlation is likely, not causation, as larger studies have found the opposite to be true.

Here we go again.

Few foods have taken a beating like eggs. From the world's "perfect food" to leading one down a certain path to a heart attack, eggs have somehow become as polarizing as politics.

In 2017, Harvard suggested that an egg a day shows no increase in your risk of a heart attack, stroke, or any other type of cardiovascular disease. This is not without caveats: three a week is probably the upper level for those suffering from diabetes; cutting down consumption if you've already experienced a heart attack (or if you smoke) is wise.

Based on similar research, the U.S. government removed limits related to egg consumption on its dietary guidelines. Dietary cholesterol seemed not to be the devil many assumed. Eggs were back on the plate. Faux egg concoctions dwindled. Yolk advocates reclaimed their trophy as more (but not all) restaurants dropped egg white omelettes from their menus.

Now a new study, conducted by researchers at Northwestern University's Department of Preventive Medicine — it was published this month in the medical journal JAMA — claims that high consumption of dietary cholesterol (or eggs) increases your risk of both cardiovascular diseases (CVD) and all-cause mortality.

Are eggs good for you?

Data collection for this paper covered 29,165 participants over 31 years — each participant was followed for an average of 17.5 years. A total of 5,400 CVDs were logged. Specifically: 2,088 coronary artery problems, 1,897 heart failures, 1,302 strokes, and 113 deaths from CVDs. The total number of deaths (all-cause mortality) during this period was 6,132.

The researchers were backtracking to discover participant diets; food logs were not kept. The study is based on self-reporting, which was conducted only at the beginning of the research. Thus, two serious problems: self-reporting without regular tracking can vary widely; their diets might have changed dramatically over the course of 17-plus years. If you claim you eat two eggs a day, then a year later drop eggs altogether, this was not taken into account.

The group's results were derived from tracking 300 mg increases in daily cholesterol intake. (One large egg has 186 mg, all of which are in the yolk.) For every 300 mg added, a 3.24 percent increase in the chance of suffering from CVD and 4.43 percent increase in dying from anything was observed.

To break this down to round numbers, associate professor Norrina Allen, who participated in the study, notes that consuming two eggs per day increases your likelihood of developing heart disease by 27 percent. She also says that the study, being observational, does not include other factors that could play a role in developing CVD, though the team did factor in age, sex, ethnicity, smoking and drinking habits, and exercise levels — again, all self-reported.

When Bruce Y. Lee was a member of the National Academies of Science, Medicine, and Engineering in 2017, he served on a committee that recommended a multi-factor approach to better understand the relationship between diet and health. As an analogy, he writes that during a rocket launch, engineers take into consideration more than one or two weather factors when determining whether or not to conduct the mission.

Turkish men show unsold eggs at Rami Dried Food and Vegetable Market in Istanbul. Photo credit: Ali Ozuler / AFP / Getty Images

This is a constant problem with health studies. For example, Gary Taubes noted that research decrying the macronutrient, fat, never considered the amount of carbohydrates participants were eating, which seriously skewed the results. Fans of ketogenic diets use the same argument to defend their dietary approach.

Lee says that a holistic mindset should be applied with all nutritional research, noting the eggs are excellent sources of "protein, vitamin D, choline, lutein, and zeaxanthin." Focusing exclusively on cholesterol levels while negating the benefits might steer people away from a food that could prove beneficial.

Lee also takes note of a study involving half-million Chinese adults, which showed moderate egg consumption is "significantly associated with lower risk of CVD, largely independent of other risk factors."

Which is all to say that moderation, as with everything, is key. Will an egg a day keep the doctor away? Perhaps. Should you be careful if you suffer from problems such as hypercholesterolemia (genetic high cholesterol)? Absolutely. But does this imply that everyone needs to avoid eggs? Highly doubtful.

Fourteen eggs a week might simply be overkill, especially since you can get the micronutrients elsewhere. Skipping them altogether doesn't appear to be the right move either. Until more isolated research, involving actual dietary tracking and not self-reporting, takes place, headlines about the dangers of eggs need to be taken with a grain — okay, a pinch — of salt.

--

Stay in touch with Derek on Twitter and Facebook.

A still from the film "We Became Fragments" by Luisa Conlon , Lacy Roberts and Hanna Miller, part of the Global Oneness Project library.

Photo: Luisa Conlon , Lacy Roberts and Hanna Miller / Global Oneness Project
Sponsored by Charles Koch Foundation
  • Stories are at the heart of learning, writes Cleary Vaughan-Lee, Executive Director for the Global Oneness Project. They have always challenged us to think beyond ourselves, expanding our experience and revealing deep truths.
  • Vaughan-Lee explains 6 ways that storytelling can foster empathy and deliver powerful learning experiences.
  • Global Oneness Project is a free library of stories—containing short documentaries, photo essays, and essays—that each contain a companion lesson plan and learning activities for students so they can expand their experience of the world.
Keep reading Show less

What the world will look like in the year 250,002,018

This is what the world will look like, 250 million years from now

On Pangaea Proxima, Lagos will be north of New York, and Cape Town close to Mexico City
Surprising Science

To us humans, the shape and location of oceans and continents seems fixed. But that's only because our lives are so short.

Keep reading Show less

Why we must teach students to solve big problems

The future of education and work will rely on teaching students deeper problem-solving skills.

Future of Learning
  • Asking kids 'What do you want to be when you grow up?' is a question that used to make sense, says Jaime Casap. But it not longer does; the nature of automation and artificial intelligence means future jobs are likely to shift and reform many times over.
  • Instead, educators should foster a culture of problem solving. Ask children: What problem do you want to solve? And what talents or passions do you have that can be the avenues by which you solve it?
  • "[T]he future of education starts on Monday and then Tuesday and then Wednesday and it's constant and consistent and it's always growing, always improving, and if we create that culture I think that would bring us a long way," Casap says.
Keep reading Show less

Allosaurus dabbled in cannibalism according to new fossil evidence

These Jurassic predators resorted to cannibalism when hit with hard times, according to a deliciously rare discovery.

Fig 3. Shed lateral tooth of Allosaurus sp. (MWC 5011) found at the Mygatt-Moore Quarry, white arrow indicates the distal denticles.

Stephanie K. Drumheller et.al
Surprising Science
  • Rare fossil evidence of dinosaur cannibalism among the Allosaurus has been discovered.
  • Scientists analyzed dinosaur bones found in the Mygatt-Moore Quarry in western Colorado, paying special attention to bite marks that were present on 2,368 of the bones.
  • It's likely that the predatory carnivore only ate their already-dead peers during times when resources were scarce.
Keep reading Show less
Scroll down to load more…