This is a confusing one. Egg yolks are known primarily for their high cholesterol content. But the medical research community has learned that dietary cholesterol is a different measure than blood level of cholesterol, which is associated with increased risk of heart attack and stroke.
One recent study echoes the growing research, showing that egg consumption had no effect on the overall blood cholesterol levels of 115 healthy adults. What’s more, another recent study found some evidence that eating whole eggs increases HDL (High Density Lipoprotein)– the heart-protective, “good” cholesterol.
“There are much bigger problems in the American diet than cholesterol,” says Drew Ramsey, M.D. an assistant clinical professor of Psychiatry at Columbia University College of Physicians & Surgeons, who studies the connection between lifestyle behaviors like diet and psychological health. “There’s not data to suggest that it should be at the top of people’s worries about food choices. Everyone’s in agreement about that: The real problem with diabetes and obesity is eating too much processed food.”
And there are several nutrients specific to the egg yolk that help promote overall health. Egg yolks are one of the richest dietary sources of the B-complex vitamin choline, which is associated with better neurological function and reduced inflammation. There’s also evidence that dietary choline helps with fetal brain development when pregnant women eat it. Another side benefit of a diet rich in choline is, well, happiness.
Choline breaks down into bethanechol, which is used during the methylation cycle, which in turn helps produce ‘happiness’ hormones like serotonin, dopamine, norephinephrine, explains Ramsey.
Egg yolks also contain two carotenoids, lutein and zeaxanthin, which protect against vision loss. And, as we have reported earlier, they have a big dose of sulfur:
Eggs are also high in sulfur, an essential nutrient that helps with everything from vitamin B absorption to liver function. But sulfur is also necessary for the production of collagen and keratin, which help create and maintain shiny hair, strong nails and glowing skin.
The yolk’s health benefits should not overshadow egg whites, however, which are a low-calorie, low-fat source of perfect protein. In fact, eggs are considered the “gold standard” for protein quality because their amino acids are the most digestible to humans.
But even though egg yolks are certainly a health food, they haven’t been cleared for unlimited consumption: Mayo Clinic recommends consuming no more than four eggs per week, which is the amount they found to be healthy in adults.