Egg nutrition: Get the facts

Over 75 billion eggs are produced in the U.S. each year. That’s a lot of omelets. Most people know that eggs contain protein, but what else? Here are some egg nutrition facts.

 

A single large egg laid by a hen contains 70 calories, as well as:

• 5 grams of fat (2 grams saturated)
• 6 grams of protein
• 0.5 grams of carbohydrate

More than 60 percent of calories in an egg come from dietary fat. About 35 percent come from protein. But when it comes to eggs, here’s the question many people debate: should I eat the yolk?

 

To eat the yolk or not?

Fat-phobic dieters usually chuck the yolks before they reach the frying pan, but what many egg-white-only eaters don’t realize is that about half the protein in an egg is found in the yolk.

 

There are other benefits of eating the yolk as well.

 

Choline, though not a highly-touted nutrient in diet articles, plays an essential role in fetal brain development. Pregnant women need to eat the yolks to help prevent birth defects. Two whole eggs contain 250 milligrams of choline, about half the recommended daily value.

 

Yolks also contain two other nutrients that pregnant women need, including B vitamins, crucial for fetal nervous system and spinal cord development. The other nutrient is iron. Though an egg has only 5 percent daily value of iron, the iron found in eggs is a healthy mix of both sources of iron—heme and non-heme.

 

Eating two eggs, then, supplies a pregnant or breast-feeding woman with 10 percent daily value of iron, lowering the chance of developing anemia, something to which pregnant and breast-feeding women are more susceptible.

 

What if I’m not pregnant or breast feeding?

You should still eat the whole egg. In addition to the B vitamins, almost the entire amount of the following vitamins and minerals are found in the yolk:

• calcium
• iron
• zinc
• selenium (nearly 25 percent of daily value)
• phosphorous (10 percent of daily value)
• Vitamins A, D, E, and K (the fat soluble vitamins)

The yolks also contain heart-healthy Omega-3 Essential Fatty Acids.

 

And yet another reason to eat the whole egg is that yolks contain the full spectrum of essential amino acids. Eating only the whites will require food combining to make sure you get the complementary essential amino acids.

 

But what about cholesterol? Don’t the yolks contain a lot of it?

To some doctors and nutritionists, yes, an egg yolk may indeed have a lot of cholesterol. One whole egg contains approximately 200 milligrams of cholesterol, or roughly 70 percent of suggested daily values.

 

Don’t panic if you just gulped down a three-egg omelet. Your body naturally produces cholesterol for a variety of purposes, including making sex hormones, Vitamin D, and bile acids to help digest fat.

 

If you eat foods containing cholesterol, your body doesn’t have to work as hard to produce it.

 

Conservative recommendations usually allow for one whole egg per day.

 

Yolks also contain the antioxidant lutein, which is thought to promote eye health.

 

Are eggs the best source of protein?

Eggs are considered by many the gold-standard of protein, especially for an all-natural source of food. One egg contains for an average person, over 10 percent of the daily value for protein.

 

More than 90 percent of a whole egg’s protein is absorbable by the body, which scores eggs way up high on the protein bioavailability scale.

 

Many bodybuilders place whey protein on a higher muscle-building pedestal than eggs, but whey protein isn’t a whole food like an egg.

 

Eggs cost roughly 25 cents each, making them one of the least expensive sources of complete protein, plus they’re easy to cook. Being a naturally-nutritiously dense food, it’s no wonder eggs have been eaten for thousands of years.

Best Sources of Protein

Whether it’s to repair and build muscle tissue after a workout, or to manage blood sugar levels or other dietary concerns, finding the best sources of protein can be tricky.

 

Many proteins are ranked according to how much our bodies can utilize and absorb the amino acids, which form the building blocks of protein in everything from not only our muscles, but also our skin, teeth, hair and nails.

 

Because every person has a unique biochemistry, and therefore different dietary needs, presenting a one-size-fits-all list of the best protein sources should be taken with a grain of salt.

 

Many bodybuilders’ protein standard is the Biological Value (BV) scale. Unlike dietary fats and carbohydrates, proteins contain nitrogen. The BV scale measures protein quality by calculating the nitrogen used for tissue formation divided by the nitrogen absorbed from food.

 

A whole egg ranks 100 on the scale. But don’t jump to conclusions assuming that you will digest 100 percent of the protein in an egg; it’s just a base number with which researchers compare other proteins.

 

Not all BV scales are the same. There are dozens of factors which could influence outcomes of how high a protein ranks.

 

According to a 2004 study published in the Journal of Sports Science and Medicine, researchers Jay R. Hoffman and Michael J. Falvo from the College of New Jersey rank the following sources of protein on their BV scale, with BV scores in parenthesis:

• Whey protein (104)
• Whole chicken egg (100)
• Milk (91)
• Beef (80)
• Casein (77; Casein is the second primary protein milk besides whey, it’s processed into curds and cheese.)
• Soy protein (74)
• Wheat gluten (64)

What are other high-ranking sources of protein on the BV scale?
According to Wikipedia’s entry on Biological Value, other sources of protein on the scale include:

• Rice (83)
• Fish (76)
• Tofu (74)

Should I be skeptical about the Biological Value scale?
Yes, for a variety of reasons. Whey protein products have the highest ranking on the BV scale — up to 150 on some scales — making it the best source of protein, but not necessarily for everybody. Just because a certain food ranks tops on the scale doesn’t mean that everybody can easily digest the protein. Millions lack the lactase enzymes needed to absorb one of the highest-ranked items on the BV scale: milk.

 

Another problem with the BV scale is that it doesn’t take into consideration how the foods, specifically animal proteins, are raised. Although beef ranks high on the scale, research is hard to come by in determining if, for example, grass-fed, pasture-raised beef has a different score than feed-lot, factory-farmed beef.

 

Why are vegetarian sources of protein on the bottom of the scale? 
It’s not because the bioavailability scale was funded by a pro-carnivore lobbying group. It’s because vegetarian sources of protein are almost always incomplete proteins. Not getting all nine essential amino acids from foods can potentially cause serious health and developmental problems.

 

There’s a good reason that you don’t see bodybuilders chugging wheat protein smoothies (which don’t exist) after a workout, or pea protein shakes (which do exist).

 

Vegetarians need to learn how to combine foods to ensure they are getting the complimentary proteins. Beans and rice is the most common example. Some others include:

• Macaroni and cheese (not a good idea if you already have a pasta belly)
• Spaghetti and broccoli (same caution as above; opt for quinoa spaghetti instead)
• Yogurt and granola (eat only full-fat, preferably plain-Greek yogurt so you won’t get a blood sugar crash)
• Toast and almond butter (try a gluten-free bread, which is better for reducing bloating)

Final caution about best sources of protein
Consider the source of your protein. Opt for grass-fed beef and cheese sources; wild-caught cold-water fish; blended, pre-digested whey; fertile organic eggs; and organic chicken. Vegans would do well to get lots of supplemental vitamin B12 and rice protein and/or hemp protein shakes. Unless you’re doing hardcore bodybuilding, you don’t need triple-digit-level grams of protein because excess protein can lead to unhealthy levels of ammonia in the urine.