What eggs-actly does this mean? A study just published in JAMA seemed to give eggs a bit of a beating after they’ve been on a roll since 2015. After all, that year the Dietary Guidelines of America no longer included a recommended limit on the number of eggs that you should eat a week. But does this new study scramble this situation? Well, here’s a closer egg-amination, which may be a bit punny.
The study laid together data from six different cohorts in the U.S. that had a combined total of 29,615 people who were followed for an average of 17.5 years between between March 25, 1985, and August 31, 2016. During this eggs-tensive time period, these people had a total of 5400 cardiovascular events, which included 2088 coronary artery problems (like a heart attack), 1302 strokes, 1897 heart failure events, and 113 deaths from cardiovascular disease. There were also 6,132 deaths in general or in other words, eggs-its for all different reasons.
The research team then tried to determine if there was an association between the amount of cholesterol and eggs these people had consumed each day and whether they were more likely to have had cardiovascular events or die during that time period. In their statistical analysis, the team tried to account for factors such as people’s ages, sexes, races, ethnicity, education levels, smoking habits, alcohol intake, physical activity levels, body mass indices (BMIs), blood pressures, lipid levels, use of particular medications, and medical conditions.
The analysis found a correlation between the amount of cholesterol consumed each day and the likelihood of suffering a cardiovascular event and dying. Every 300 mg increase in cholesterol intake each day was associated with a 3.24% higher likelihood of having a cardiovascular event and a 4.43% higher likelihood of dying during that time period.
The analysis also found correlations with the number of eggs consumed each day. For each additional half an egg eaten per day, the likelihood of a cardiovascular event went up by 1.93% and the likelihood of death increased by 0.71%.
So, does this study re-hatch the idea that there should be a limit on the number of eggs that your should eat because a typical large egg will contain about 186 mg of cholesterol? What about the fact that eggs are eggs-ellent sources of protein, vitamin D, choline, lutein, and zeaxanthin without an egg-cessive amount of calories (just 78 an egg)? What about studies that have suggested more sunny-sides of eggs such as the one covering over a half a million people in China and published in the journal Heart? That study determined that those who ate a moderate amount of eggs (less than one a day) had a lower risk of cardiovascular disease than those who ate no eggs.
This video summarizes some of the thoughts from the American Heart Association:
While the JAMA and Heart studies may have been relatively well done population cohort studies, there are numerous cracks in such study approaches in general. These types of studies can never really show or determine cause-and-effect. Both took large pots of data and then tried to boil them down to simple correlations or associations. But life is a lot more complex than that. The relationship between a food item and cardiovascular disease involves complex systems, many of which were not really considered or represented in such analyses. For example, how about things such as the job stress or social situations that a person encounters? Both of these can affect a person’s diet and also his or her cardiovascular risk. What about other components of the person’s diet? Do people who eat more eggs tend to eat more or less of other things as well? Moreover, eggs can be prepared in many, many different ways, some healthier than others.
Depending too heavily on such large population cohort studies to develop nutritional recommendations would be the wrong ap-poach. Notice how viewpoints about eggs have seemed to run back and forth over the years. That’s because these large cohort studies only provide indirect evidence, no more than shells of what may really be occurring. Nevertheless, every time one of these studies comes out, headlines fry around saying either “eggs are bad” or “eggs are good.” The same has happened to other food and beverage items such as coffee.
This is why our committee convened by the National Academies of Science, Medicine, and Engineering to review the process by which the Dietary Guidelines of America are put together came out with the following recommendation: use more systems approaches and methods. There are a number of methods such as mapping and modeling that can help better account for and delineate the systems that govern the relationship between diet and various health outcomes such as cardiovascular diseases. Such methods can help bring together data and information from laboratory studies, animal studies, clinical trials, cohort studies, and other sources and determine how they fit together and try to reconstruct the systems involved. When trying to determine what will happen to the weather or a rocket launch, you don’t just focus on one or two factors and show how these correlate with what may happen. Instead, meteorologists and aerospace engineers build sophisticated computer models and try to simulate what may occur. The same needs to be done more in nutrition research. The next phase in nutrition research should be to dive deeper and better understand these complex systems such as the other aspects of your life and your diet that then may affect how many eggs you should eat. After all, your choice is not simply between eating only eggs versus eating no eggs at all.
So, for now, omletting any strong conclusions about eggs go. In general, moderation and balance are quiche for a healthy diet. You don’t want to eat an egg-cessive number of eggs but you also don’t have to completely eggs-lude eggs from your diet, unless of course you are vegetarian or vegan. Keep in mind that eggs can offer important nutrients but also have cholesterol. Your decision about how many eggs to eat should depend on a number of factors such as what your other sources of protein, vitamin D, and other nutrients may be and how much cholesterol you are consuming otherwise. There is still much to be learned about eggs and other food and beverage items and the complex system involved. Hopefully all of this will egg on changes in how nutrition research is conducted.