Throughout the month of February, affectionately known as American Heart Month, the News Blog is highlighting news and stories related to cardiovascular health from across Penn Medicine.
There may not be a more tortured tug-of-war in the food world as that of whether eggs are beneficial or harmful to our heart health. It seems like every time we turn around there’s a new take on whether or not we should eat them. And while new dietary guideline recommendations appear to put eggs and other cholesterol-laden food (like shrimp and beef) on the “ok” list, there does seem to be some additional clarification this time around.
In December 2014, the Dietary Guidelines Advisory Committee issued a report saying that “cholesterol is not considered a nutrient of concern for overconsumption.” Cholesterol, a fat-like compound that’s found in all of our body’s cells, is important in the formation of cell membranes, hormone production and other processes. But basically, the committee seems to be saying that the most recent data show cholesterol in food is not as significant a factor in blood cholesterol levels for healthy adults as previously thought.
So, what does this mean? Omelet for breakfast, burger for lunch, and shrimp scampi for dinner? Not quite. As with most things, moderation and knowledge are key.
“It makes sense that cholesterol in our food would be related to the cholesterol in our blood — it’s intuitive, but it’s not correct,” says Daniel Rader, MD, director of the Preventive Cardiovascular Medicine Program at Penn Medicine, who says these new recommendations are right in line with what research shows. Instead of foods that are high in cholesterol, he says the foods that are bigger contributors to elevated cholesterol in the blood and risk for developing heart disease are those containing saturated fats (red meat, dairy, fried foods) or trans fats (many processed foods).
“I think people are confused,” says Fran Burke, MS, RD, clinical dietician in the Preventive Cardiovascular Medicine Program. “Most patients I see avoid eggs because of the cholesterol content, but I tell them they can have up to seven egg yolks a week. The body has a very fine-tuned mechanism for cholesterol regulation.”
Every five years, the U.S. Department of Health and Human Services and the U.S. Department of Agriculture jointly review recommendations from this Dietary Guidelines Advisory Committee and then develop and publish the Dietary Guidelines for Americans policy document. The last set of these guidelines came out in 2010, and this newest set is expected later this year.
However, these new recommendations — along with similar guidelines jointly issued by the American Heart Association and the American College of Cardiology in 2013 — seem to contradict the last 40+ years of warnings to avoid eating high-cholesterol foods. The first dietary guidelines were issued by the American Heart Association in 1957 in an effort to raise public awareness about how to prevent heart disease, and included a focus on fat content in foods.
In later years, according to Rader, studies in which animals were fed very high cholesterol diets showed increased cholesterol in the blood and increased cardiovascular disease, so the guidelines evolved to include recommendations to reduce cholesterol intake. This made sense, given that high levels of LDL (or “bad”) cholesterol levels have been associated with a build-up of plaque that can narrow or block blood vessels, which can lead to heart attack and stroke.
Now that research shows that cholesterol in the diet has little to do with cholesterol in the blood, these new guidelines are expected to reflect that change. But how do advisory committees come up with their recommendations?
In short, says Rader, it’s a complex process because a group of experts are brought together, all of whom have various opinions and look at the same data in different ways. These individuals must be experts in their field, willing to donate their time, participate in multiple meetings (both in-person and via teleconference), and not have any major conflicts of interest. Then they’re asked to come up with a set of recommendations that physicians should relay to their patients — really focusing on the optimal scenario (ie, maintaining a healthy weight). It’s no small task.
And then, even with all the work that goes into creating the guideline recommendations, there are often misinterpretations. For example, diets low in saturated fat and trans fats are still recommended for people who have high LDL cholesterol or are at risk for heart disease. In fact, Rader says that “half of the variation in bad cholesterol is genetically determined, and the other half is environmental, mostly dietary fat.”
As we look towards the 250th birthday of the Perelman School of Medicine this May, it seems an appropriate time to reflect on the myriad advances in medical research, and particularly research around heart disease. The evolution of something as seemingly simple as what to eat or not eat is truly fascinating, especially considering that investigators like Rader continue to work on identifying new genes responsible for high LDL cholesterol and early heart disease, some of which might underlie individual differences in response to diet. There’s no doubt that this will remain an area of much research in future years.
Bottom line? Know your family history, be mindful of your cholesterol numbers, and eat a healthy diet — including eggs every now and then, if you so choose, but leave out the butter, cheese and bacon!