Yolk and albumen are the two parts of an egg. While yolk is the inner yellowish part of an egg, albumen is the external white part. Various proteins, minerals, and vitamins that are present in the egg white or the albumen make it nutritious. Albumen is made up of 99% water, and constitutes nearly two-third of the entire egg's weight. The yolk of an egg also consists of proteins and minerals, however, it is found to have higher cholesterol levels.
Hard-boiled eggs and raw eggs surprisingly have different nutritional values. Eggs lose some of their nutrients when cooked. Raw eggs contain more vitamin D, omega-3 fatty acids, zinc, biotin, choline, DHA (docosahexaenoic acid), lutein, and zeaxanthin. However, raw eggs are more likely to be contaminated by bacteria like Salmonella enteritidis.
|1 Large (50 g) Egg, Raw, Whole, Fresh|
|Total fat||4.76 g|
|Total Dietary Fiber||0.0 g|
|Total Sugars||0.18 g|
|Vitamin A, RAE||80 µg|
|Vitamin A, IU||270 IU|
|Vitamin B6||0.085 mg|
|Vitamin B12||0.44 mg|
|Vitamin C||0.0 mg|
|Vitamin D (D2+D3)||1.0 µg|
|Vitamin D||41.0 IU|
|Vitamin E||0.52 mg|
|Vitamin K||0.2 µg|
|Total Saturated Fatty Acids||1.563 g|
|Total Monounsaturated Fatty Acids||1.829 g|
|Total Polyunsaturated Fatty Acids||0.956 g|
|Total Trans Fatty Acids||0.019 g|
The energy value of a food is calculated from the knowledge of the macro-nutrient composition of the food. This energy value is expressed as calories or kilojoules. A large egg has an energy value of 72 kilo-calories. Consuming one egg per day, contributes to 3-4% of the average energy requirements for an adult.
Eggs are one of the best sources of proteins. The biological value of proteins in eggs is very high, owing to the number of amino acids present in them. It has been found that one egg consists of about 6 grams of protein and at least 9 amino acids. Proteins constitute nearly 13% of the weight of an egg. Proteins are found in both, the albumen and yolk, however, they are more prominent in the albumen part. Proteins increase the eggs nutritional value significantly. People who want to gain weight and build strong muscles always include eggs in their diet.
With the sole exception of vitamin C, eggs contain almost all vitamins. In particular, eggs are a rich source of vitamin B, especially B12 and B2 (called riboflavin). Vitamin A, vitamin D, and some amounts of vitamins E and K make eggs nutritious. Vitamin A plays an important role in eye health. All vitamins and minerals ensure proper functioning of bodily systems.
Minerals in Eggs
For a healthy body, many important minerals are required. Eggs, in particular, are a rich source of iodine and phosphorus. Iodine as we all know, is very useful for regulating the function of the thyroid gland. Along with calcium and magnesium, phosphorus also helps strengthen the bones. Zinc, magnesium, and potassium play an important role in various metabolic activities. They are essential for proper functioning of heart and circulatory system, strong bones, production of new cells and enzymes, fast healing of wounds, etc.
Fat and Cholesterol in Eggs
Nearly 12% of the content of an egg is fat. Fat is found mostly in the yolk, and very less percentage of the fat is contained in the albumen. A large chicken egg contains 186 mg of cholesterol, while a large duck egg (70 g) contains 619 mg of cholesterol. Cholesterol content in eggs is considered to be a debating point in today's time. Cholesterol is mainly contained in the yolk part, therefore, dietitians nowadays suggest inclusion of three white eggs in the diet, instead of two eggs with the yolk. The eggs nutritional value is considered to be lessened by the cholesterol levels, however, when we look at various other benefits, this issue is not a big factor.
Some of the important nutritional benefits of eggs are as follows.
- Eating eggs on a regular basis strengthens the immune system.
- Eggs are good for eyes and they prevent macular degeneration.
- Including egg in our diets lowers the risk of developing cataracts.
- It is believed that eggs help reduce the risk of breast cancer.
- Eggs foster healthy growth of hair and nails, because they contain high amounts of sulfur, protein, vitamins, and minerals.
- Eggs contain the naturally occurring vitamin D, and are beneficial for skin.
- Eggs contain a nutrient called choline, that is useful in the regulation of the nervous system, brain, and cardiovascular system.
Disclaimer: This Buzzle article is for informative purposes only, and should not be replaced for the advice of a physician/nutritionist.