A couple of years ago, my daughter and I decided to raise chickens. I wrote about that here.
In time, the hens grew, and they started laying very regularly. I thought this would be a good way to provide ourselves with cheap and nutritious food, cut down our dependency on store bought groceries, and even supplement our income in the event of a financial crisis. My daughter loves birds, and the chicken chores are her major contribution to our household economy. The eggs are plentiful, but up until recently, they didn’t cut down our grocery bill by much.
Why? Because even though I love eating eggs, I developed an allergy. Well, it’s not a full blown allergy, but eggs don’t agree with me anymore. I would feast heartily, only to be repaid with a day long stomach ache. I had to stop eating them, because that just wasn’t worth it.
Bow, our chimpanzee, also doesn’t like eggs very much. And we still don’t know how to sell them. So my daughter is the only one who has been eating eggs– and we give the ones we don’t eat to the dogs, along with other scraps. In time, even my daughter got tired of eggs.
And then this morning, I discovered a way around my egg allergy. I had fried my daughter an egg sunny side up, and though she usually loves that, she didn’t feel like eating it. And there it was, just sitting there. I was hungry. “It won’t hurt if I just have a little of the yoke,” I reasoned with myself. So I took a taste, and then another and another until I’d finished the entire yolk. And you know what? I’m fine. Nothing bad happened.
That’s when it occurred to me to look up “egg nutrition” in the wikipedia. It turns out that most people who have a problem with eggs are really reacting to the proteins in the egg white. While some people are also allergic to the yoke, most are not. I don’t have a true allergy, anyway. I have a food sensitivity. Here’s what the wikipedia has to say about that: “In addition to true allergic reactions, some people experience a food intolerance to egg whites.”
So what is it about the egg whites? Here’s my theory: I think it’s because the egg white consists almost entirely of protein that I can’t tolerate it. It’s all a matter of percentages. It’s the percentage of protein in the part of the egg you are eating that matters. You see, about half the protein in the egg is in the yolk and about half is in the white. (To be exact, 57% of the protein in the egg is in white, and 43% in the yolk.) But nearly all the fat in the egg is in the yolk. And all almost none of the fat is in the white. So it’s not the absolute number of grams of protein that upsets my stomach. It’s the percentage of protein that I’m trying to digest at a time.
Here is some overall nutritional information about the egg that I copied from the wikipedia:
Table 1: Overall Egg Nutrition
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 647 kJ (155 kcal) |
| Carbohydrates | 1.12 g |
| Fat | 10.6 g |
| Protein | 12.6 g |
| – Tryptophan | 0.153 g |
| – Threonine | 0.604 g |
| – Isoleucine | 0.686 g |
| – Leucine | 1.075 g |
| – Lysine | 0.904 g |
| – Methionine | 0.392 g |
| – Cystine | 0.292 g |
| – Phenylalanine | 0.668 g |
| – Tyrosine | 0.513 g |
| – Valine | 0.767 g |
| – Arginine | 0.755 g |
| – Histidine | 0.298 g |
| – Alanine | 0.700 g |
| – Aspartic acid | 1.264 g |
| – Glutamic acid | 1.644 g |
| – Glycine | 0.423 g |
| – Proline | 0.501 g |
| – Serine | 0.936 g |
| Water | 75 g |
| Vitamin A equiv. | 140 μg (16%) |
| Thiamine (Vit. B1) | 0.066 mg (5%) |
| Riboflavin (Vit. B2) | 0.5 mg (33%) |
| Pantothenic acid (B5) | 1.4 mg (28%) |
| Folate (Vit. B9) | 44 μg (11%) |
| Calcium | 50 mg (5%) |
| Iron | 1.2 mg (10%) |
| Magnesium | 10 mg (3%) |
| Phosphorus | 172 mg (25%) |
| Potassium | 126 mg (3%) |
| Zinc | 1.0 mg (10%) |
| Choline | 225 mg |
| Cholesterol | 424 mg |
| For edible portion only. Refuse: 12% (Shell). One large egg is 50 grams. Percentages are relative to US recommendations for adults. Source: USDA Nutrient database |
|
But here is a comparison of the nutritional value of the yolk and the white taken from this article: http://www.cholesterol-and-health.com/Egg_Yolk.html
Table 2: Egg Yolks Versus Egg Whites
| Nutrient | White | Yolk | % Total in White | % Total in Yolk |
| Protein | 3.6 g | 2.7g | 57% | 43% |
| Fat | 0.05g | 4.5g | 1% | 99% |
| Calcium | 2.3 mg | 21.9 mg | 9.5% | 90.5% |
| Magnesium | 3.6 mg | 0.85 mg | 80.8% | 19.2% |
| Iron | 0.03 mg | 0.4 mg | 6.2% | 93.8% |
| Phosphorus | 5 mg | 66.3 mg | 7% | 93% |
| Potassium | 53.8 mg | 18.5 mg | 74.4% | 25.6% |
| Sodium | 54.8 mg | 8.2 mg | 87% | 13% |
| Zinc | 0.01 mg | 0.4 mg | 0.2% | 99.8% |
| Copper | 0.008 mg | 0.013 mg | 38% | 62% |
| Manganese | 0.004 mg | 0.009 mg | 30.8% | 69.2% |
| Selenium | 6.6 mcg | 9.5 mcg | 41% | 59% |
| Thiamin | 0.01 mg | 0.03 mg | 3.2% | 96.8% |
| Riboflavin | 0.145 mg | 0.09 mg | 61.7% | 48.3% |
| Niacin | 0.035 mg | 0.004 mg | 89.7% | 9.3% |
| Pantothenic acid. | 0.63 mg | 0.51 mg | 11% | 89% |
| B6 | 0.002 mg | 0.059 mg | 3.3% | 96.7% |
| Folate | 1.3 mcg | 24.8 mcg | 5% | 95% |
| B12 | 0.03 mcg | 0.331 mcg | 8.3% | 91.7% |
| Vitamin A | 0 IU | 245 IU | 0% | 100% |
| Vitamin E | 0 mg | 0.684 mg | 0% | 100% |
| Vitamin D | 0 IU | 18.3 IU | 0% | 100% |
| Vitamin K | 0 IU | 0.119 IU | 0% | 100% |
| DHA and AA | 0 | 94 mg | 0% | 100% |
| Carotenoids | 0 mcg | 21 mcg | 0% | 100% |
What this means is that the egg white consists of 91% protein, 6 percent carbs and 3% fat, while the egg yolk consists of 35% protein, 63% fat and 2% carbs. So it seems to me that I can take a food that is 35% protein, but I cannot tolerate one that consists of 91% protein, even if the number of grams of protein in each is about the same. In a whole egg, it’s a little over fifty percent protein, and even that is too high a percentage for me.
You’re probably thinking that it could be the specific proteins in egg white that I’m reacting to, and that percentages have nothing to do with it. After all, egg white consists of 54% ovalbumin, a protein that blocks digestive enzymes. Yolk proteins are different, and they serve other functions, such as “sequestering calcium, iron and other cations for the developing embryo”.
Still, I hold to my theory: I can take the entire egg’s supply of proteins just fine, as long as they are a small percentage of the nutrients in the food I am eating. I can’t digest a whole egg alone, but the same absolute number of grams of protein, consisting of the same specific proteins, do me no harm when I eat them as part of a tagini.
Don’t know what a tagini is?
Here’s a recipe: take one whole egg, beat it, soak a white piece of bread in it until the egg is absorbed. Fry in a pan till golden brown. It’s a simplified Israeli version of French toast. If I eat that, the protein in the egg doesn’t bother me. If I eat a whole egg, I get sick. I’m thinking it’s because the overall enormous serving of carbs in the white bread diminishes the percentage of proteins in the tagini meal to an acceptable low.
But if you want to eat something that is actually good for you, I recommend egg yolk. It contains most of the vitamins and minerals that an egg has to offer and 99% percent of its fat, which is the most important part!
© 2011 Aya Katz
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