What Is in an Egg Yolk?

Egg yolk is rich in vitamins and essential nutrients, including calcium, phosphorus, zinc and vitamins B1, B12, A, E, D, and K. It makes up about 60% of the daily recommended value of choline. 

Yolk is a rich source of fat-soluble carotenoids, such as lutein and zeaxanthin, which protect the eyes from damage and reduce the risk of cataracts.

Egg yolk has a high-fat content of about 4.5-6 grams per egg, which contributes about 10% of the daily recommended value. Egg is a good source of omega-3 fatty acids and unsaturated fats which cannot be made by the body and must be obtained from the diet. 

Although egg yolk has several benefits, it is also high in dietary cholesterol; about 213 mg per yolk.

1. Promotes gut health: Egg yolk contains a protein called phosvitin, which helps reduce compounds in the body that cause inflammation and promotes the health of the gastrointestinal tract.
2. Boosts immune system: Sulfated glycopeptides present in the membrane of the egg yolk stimulate the production of macrophages, which are cells in the immune system that protect the body against disease and infection.
3. Maintains heart health: Egg yolk is packed with tryptophan, tyrosine, and amino acids, which help prevent the risk of developing heart diseases and high blood pressure.
4. Improves skin texture: Egg yolk helps supply the body with ceramides and peptides, which help keep the skin healthy and reduce the appearance of wrinkles.
5. Reduced the risk of vision problems: Carotenoids, mainly lutein and zeaxanthin may protect against cataracts and macular degeneration, which often develop in people over 55 years of age. Carotenoids are colorful pigments that are responsible for the yellow color of the egg yolk. They act as antioxidants, protecting the eye from damage caused by the free radicals.

Egg yolks are inherently high in cholesterol, but they do not affect blood cholesterol levels in the same way that other cholesterol-high foods such as trans fats and saturated fats do.

Although some studies have shown a link between eating eggs and heart disease, it has been found that there may be other causes for such findings. People who eat eggs with meat, such as bacon, sausage, and beef, are more prone to heart disease than people who just eat eggs. It is also important to consider how the eggs are cooked. Eggs that have been fried in oil or butter have been linked to an increased risk of heart disease.

Cholesterol is only found in the yolks. Those who must avoid cholesterol for medical reasons can eat solely egg whites, which are still high in protein but do not contain cholesterol.

Despite various health benefits, consuming more egg yolks than recommended can increase the risk of developing cardiovascular disease, insulin resistance, and diabetes mellitus.

Dietary cholesterol should be kept below 300 mg per day. A large egg yolk contains roughly 186 mg of cholesterol.

Most healthy adults can consume up to 7 whole eggs per week without raising their risk of heart disease. However, those with health issues, such as diabetes or heart disease, may need to limit their egg intake. It’s important to get diet advice from a doctor or nutritionist in such cases.