In Defense of Egg Yolks
Would you like to make That Nice Boy I Married very sad? Then you're a horrible, evil person, and I hate you. No, wait, sorry. That's just a knee-jerk reaction to the very notion, because I adore him, and seeing him sad breaks my heart. I meant to say, "throw away an egg yolk." To make him really, really sad, throw away all your egg yolks.
If there is one perfect food, eggs are it, and the yolk is a major part of that wonderfulness. Let's take a look at the nutritional value of eggs, shall we?
One egg -- just your standard, grocery store chicken egg, not some super-great pasture-raised eggs like the ones from our very own back yard -- has the following:
4 grams fat -- 1 gram saturated, 1 gram unsaturated, 2 grams monounsaturated
187 mgs cholesterol
.39 gram carbohydrate
6 grams protein
2% of your sodium
2% of your potassium
2% of your calcium
1% of your iron (in the most available form)
3% of your zinc
8% of your vitamin A (again, in the most available form)
3% of your B6
7% of your B12
1% of your thiamin
13% of your riboflavin
5% of your folacin
6% of your vitamin E
6% of your vitamin D (uncommon in foods)
Just a teeny bit of vitamin K
166 mgs of the antioxidants lutein and zeaxanthin
That's a broad array of nutrients, no?
But what about that cholesterol? What about that fat? Maybe we'd better have an egg white omelet instead, huh? In that white you'll get:
2% of your sodium
1% of your potassium (notice the sudden imbalance between sodium and potassium)
A trace of carbohydrate
4 grams of protein
a trace of iron
0 vitamin A
0 vitamin C
1% of your B12
9% of your riboflavin
0 lutein and zeaxanthin
In other words, throw away the egg yolk and you throw away the vitamins.
You'll also throw away the choline, an essential nutrient usually grouped with the B vitamins. Choline is an essential nutrient that forms a vital part of your cell membranes, not to mention being part of the neurotransmitter acetylcholine, the main chemical means of sending messages between nerves and muscles. In the brain, acetylcholine is necessary for focus, and lack of acetylcholine is associated with Alzheimer's disease. Choline is a vital part of major compounds of brain tissue as well.
Choline also reduces inflammatory responses in the body. Since inflammation is suspected to be the main cause of heart disease, this means egg yolks are actually good for your heart. Choline is also good for your liver, reducing the risk of non-alcoholic fatty liver disease.
The choline in egg yolks is in the form of a substance called lecithin (LESS-i-thin). Lecithin has the interesting property of binding with water at one end of the molecule, and with fats at the other end. This makes it an emulsifier, and this is why egg yolk can be used to bind together vinegar and oil into mayonnaise. Ironically, lecithin has the property of lowering blood cholesterol.
The kicker is that dietary cholesterol has very little effect on blood cholesterol levels. (We won't even go into the question here of whether high total cholesterol is a cause of heart disease, though I will state that I doubt it.) Cholesterol is so important, your liver will make it if you don't eat it. Eat less, your liver will make more. Eat more, your liver will make less. So throwing away your egg yolks won't even lower your cholesterol.
How about Egg Beaters? Will they give you the nutrition of egg yolks without the fat and cholesterol? Egg Beaters are made with egg whites, some xanthan and guar, some onion powder and other flavorings. They have vitamins added to them, but they lack the fat needed for the absorption of the fat-soluble vitamins. They also lack the lutein and zeaxanthin of the real thing, and also are missing the very valuable lecithin, with its choline.
In short, the yolk is the most valuable part of the egg by far. I simply will not throw them away. When I make a recipe that calls only for egg white -- a meringue, for instance -- I put a small pan of water on the stove and bring it to a simmer before I start separating my eggs. I drop the yolks, one by one, into the hot water, and let them cook till set. I then mash them with mayonnaise, mustard, some minced scallion, and other seasonings, into something very like deviled egg filling. This makes a wonderful spread on toasted, buttered low carb bread.
If this sounds like too much trouble, you could just scramble an extra yolk or two into your next breakfast. Or you could make custard; extra yolks do great things for the texture.
Just don't, for the love of all that is nutritious, throw your yolks away. You wouldn't want to make That Nice Boy I Married cry, would you?