The high cholesterol in egg yolks has given them a bit of a bad rap. According to the U.S. Department of Agriculture, a single egg yolk has 184 mg of cholesterol and 4.51 g of fat. Despite these values, egg yolks have a place in a healthy diet, if a person exercises moderation, because they are a good source of vitamins and other nutrients.
A and D
A yolk from a large egg has 245 IU of vitamin A and 27 IU of vitamin D, according to the U.S. Department of Agriculture. The recommended daily allowance for vitamin A for adult males and females is 3,000 and 2,333 IU, respectively. The Linus Pauling Institute says that the recommended daily allowance for vitamin D is 200 IU for adult males and females between 19 and 50 IU.
Vitamin A is so critical for vision that the Linus Pauling Institute reports that deficiency of vitamin A in children is the leading, preventable cause of blindness in the developing world. Deteriorating night vision is an early symptom of vitamin A deficiency. Vitamin D is essential for a healthy nervous system and immune system. Since it is involved in calcium metabolism, vitamin D also is critical for healthy bones.
A single egg yolk has 25 micrograms of folate and 166 mg of choline, according to the U.S. Department of Agriculture.
The Linus Pauling Institute says that folate--also called folic acid or vitamin B-9--is used to synthesize and repair DNA. It is so essential to cell division that a class of drugs called antifolates are used to fight cancer by preventing the use of folate in the body. Choline is generally lumped with B vitamins because it is water soluble. Choline provides structural integrity to the cell membrane and is involved in the synthesis of the neurotransmitter acetylcholine.
The recommended daily allowance of folate for adults of both genders is 400 micrograms of folate per day. Adult men and women need 550 mg and 425 mg of choline, respectively.
A single yolk from a large egg has 9.5 micrograms of selenium, 19 mg of potassium, 66 mg of phosphorus and 22 mg of calcium, according to the U.S. Department of Agriculture. It has 1 mg or less of iron, magnesium, zinc and copper.
The National Kidney Foundation says that people with advanced kidney disease often have to restrict their intake of potassium and phosphorus. Since egg yolks have relatively small amounts of these minerals, kidney patients with advanced disease and others who need to restrict their potassium and phosphorus can eat them because yolks have relatively small amounts of potassium and phosphorus.