Like many foods, eggs are a nutritional part of a balanced diet when you eat them in moderation. With that said, eggs have their good points and their bad points. If you enjoy hard-boiled eggs, you should understand how their nutritional value changes depending on whether or not you eat the yolk.
Calories and Protein
Eggs are not exactly low-calorie foods, but take away the yolk and they lose most of their calorie count. According to the University of Michigan Health System website, one large, omega-3 enriched egg -- which is an egg that comes from chickens that are fed a diet of natural grains fortified with sources of omega-3 fatty acids -- has 71 calories, while a hard-boiled egg without the yolk contains a mere 17 calories. The white of the hard-boiled egg also contains an impressive 3.6 g of protein. Protein is essential for good health, regulating all of your body’s activities including muscle contractions, nutrient transportation and electrolyte balance.
Fat, Cholesterol and Carbohydrates
Fat content accounts for much of the calorie reduction when you remove the yolk from a hard-boiled egg. Egg yolks are high in fat and cholesterol. According to the University of Michigan Health System, the entire cholesterol content of an egg is in the yolk -- a whopping 210 milligrams. The yolk also contains 1.6 grams of unhealthy saturated fat while the egg white contains no saturated fat. Removing the yolk also lowers the carb count. With the yolk, the hard-boiled egg contains .85 gram of carbohydrates. Without the yolk, the carbohydrate count drops to .24 grams.
Choline, Folate, Iron and Calcium
The whites of hard-boiled eggs contain small amounts of several important nutrients. Calcium concentrations within the white of the egg average 2 milligrams, while the iron content is approximately .03 micrograms, and the folate content is 1.0 micrograms. These counts are considerably less than what they would be with the yolk. The same goes for choline. Choline is a member of the B-complex group of vitamins and noted for its ability to reduce heart disease and birth defect risks. According to the University of Michigan Health System .42 milligrams of choline are found in the white of the omega-3 enriched egg, compared to the 215.1 milligrams in the entire egg.
What You’re Missing
If you remove the yolk from your hard-boiled egg to avoid fat and cholesterol, you may be overlooking a few beneficial vitamins. An egg yolk contains 245 international units of vitamin A, 18.26 IU of vitamin D, .44 milligrams of vitamin E and .1 micrograms of vitamin K, none of which are found in the egg white. The Pennington Biomedical Research Center also explains that yolks contain lutein and zeaxanthin, two powerful carotenoids that can help guard against certain chronic diseases and cancers, and also keep your eyes healthy.