No yolks about it, eggs are healthy

May 31, 2015

One day you hear they’re good for you and other days you hear they’re bad. The healthiness (or unhealthiness) of eggs have been debated for decades. Does the protein outweigh the cholesterol? What makes an egg good or bad and should we continue incorporating eggs into our diets?

This week on “Take Care,” Dr. Luc Djousse discusses the nutritional value of eggs. Djousse is director of research in the Division of Aging at Brigham and Women’s Hospital and is assistant professor of medicine at Harvard Medical School.

Little evidence is available to show that consuming two to four eggs per week has a negative effect on  your health, according to this week's guest. For people that consume more, Djousse says, data suggests there is a slight increased risk for diabetes, but there is no concrete evidence.

“Like any food item, consume everything in moderation,” Djousse says.  “The fact that one food item is great or healthier than the other doesn’t mean that you’re going to eat a lot of it because every food item contains energy, calories.”

Part of the concern surrounding eggs may comes from a lack of knowledge of what eggs are made of.

Eggs consist of two components: egg whites and yolks. Egg whites are 90 percent water and 10 percent protein, but they also contain minerals and vitamins. Egg yolks contain 2.7 to 3 grams of protein, but they also contain cholesterol.

“An average egg would contain these days between 160 to 200 milligrams of cholesterol,” Djousse says.

Cholesterol is a fat molecule that the liver can manufacture. According to Djousse, humans don’t need to consume food in order to have cholesterol.

“It’s a building block for cells in all animals and humans,” Djousse says.

For food products to be deemed good or bad depends on the small packages that carry cholesterol.

“Cholesterol cannot be dissolved in blood,” Djousse says. “It has to be carried in small packages by something called lipoprotein.”

Studies have shown that if you increase your dietary cholesterol (from eating eggs, for example), you may slow down the pace with which the liver manufactures its own cholesterol. This means, according to Djousse, there is no link between dietary cholesterol and blood cholesterol (the cholesterol you worry about at the doctor's office).

“So you cannot really say cholesterol in eggs is good and bad, it depends on the transport medium, what’s carrying that cholesterol,” Djousse says.

The way a body reacts to eggs, or cholesterol, depends on the individual.

“It’s not one size fits all,” Djousse says. “If you give eggs or any food for that matter to people they would react differently. Partly it’s because of the genetic makeup.”

Djousse says that your genes and environment has an effect as well, which would affect how the body reacts to consumed food.