In the past 50 years eggs have gone from an indispensable part of the human diet to the leading cause of heart attack and back again as many times as there have been reporters with a deadline and nothing solid to report. Sometimes it’s the whole egg, sometimes just the yolk that gets thrown under the bus.
There have been some actual studies of egg consumption, but as likely as not what you’ll see is someone focusing on one nutrient in the egg — usually cholesterol or fat — and saying that’s the reason eggs are so bad for you. Most of these claims are getting the science completely wrong, but it would help to start out with understanding what’s actually in both parts of an egg.
(Skip to the bottom for the summary.)
|Nutrient||White||Yolk||% Total in White||% Total in Yolk|
|Vitamin A||0 IU||245 IU||0.0%||100.0%|
|B6||0.002 mg||0.059 mg||3.3%||96.7%|
|B12||0.03 mcg||0.331 mcg||8.3%||91.7%|
|Vitamin D||0 IU||18.3 IU||0.0%||100.0%|
|Vitamin E||0 mg||0.684 mg||0.0%||100.0%|
|Vitamin K||0 IU||0.119 IU||0.0%||100.0%|
|DHA and AA||0 mg||94 mg||0.0%||100.0%|
|Carotenoids||0 mcg||21 mcg||0.0%||100.0%|
|Zinc||0.01 mg||0.4 mg||0.2%||99.8%|
|Thiamin||0.01 mg||0.03 mg||3.2%||96.8%|
|Folate||1.3 mcg||24.8 mcg||5.0%||95.0%|
|Iron||0.03 mg||0.4 mg||6.2%||93.8%|
|Phosphorus||5 mg||66.3 mg||7.0%||93.0%|
|Calcium||2.3 mg||21.9 mg||9.5%||90.5%|
|Pantothenic acid.||0.63 mg||0.51 mg||11.0%||89.0%|
|Manganese||0.004 mg||0.009 mg||30.8%||69.2%|
|Copper||0.008 mg||0.013 mg||38.0%||62.0%|
|Selenium||6.6 mcg||9.5 mcg||41.0%||59.0%|
|Riboflavin||0.145 mg||0.09 mg||51.7%||48.3%|
|Potassium||53.8 mg||18.5 mg||74.4%||25.6%|
|Magnesium||3.6 mg||0.85 mg||80.8%||19.2%|
|Sodium||54.8 mg||8.2 mg||87.0%||13.0%|
|Niacin||0.035 mg||0.004 mg||89.7%||10.2%|
Virtually all the vitamins are in the yolk, as are the majority of nearly every other nutrient: iron, calcium, zinc. Yes, there is more protein in the white than the yolk, but only barely: 57% to 43%. And there are a few minerals — potassium, magnesium, sodium and niacin — that are mostly in the white.
In short, when you throw out the yolk, you are throwing out most of what makes eggs so great.