10 things you never knew about eggs

• Americans eat a ton of eggs — 76.5 billion a year, to be exact.
• The shell and yolk colors depend on the hen's breed and diet.
• Eggs may help reverse bad moods and fight fatigue.

Why'd the chicken cross the road?

To get to the other side.

That one always cracks people up. These egg facts, however, are no yolk.

Superb sources of vital nutrients, this unassuming superfood has been a staple of the human diet since the dawn of time, and can be prepared an infinite number of ways.

Here are 10 things you probably didn't know about eggs.

The average American eats around 290 eggs per year.

That's a lot of eggs.      REUTERS/Vasily Fedosenko

Egg consumption in the US has increased 16% over 20 years, according to the United Egg Producers.

Iowa produces the most eggs out of any state in the US.

An egg-packing factory.      Mike Blake/Reuters

Iowa produces around 16.5 billion eggs per year.

The color of the shell depends on the breed of the hen that laid it.

Eggs come in different colors.      Chris Jackson / Getty

The hen's age, diet, and stressors all play a part in determining the pigmentation of the shell.

The color of the yolk depends on the hen's diet.

Yolk color has nothing to do with freshness.      Shutterstock

A dark yellow yolk means the hen ate vegetables, and a lighter yolk indicates a diet of wheat and barley.

The age of a hen affects the size of an egg.

Older hens lay bigger eggs.      Prof foto 101/Shutterstock

The older the hen, the bigger the egg.

Eggs come with a "sell by" date, not an expiration date.

Not an expiration date.      Shutterstock

You can keep them for three to five weeks after the date on the carton.

Two eggs will give you more than enough cholesterol for the day.

An egg and avocado on toast.      Zeleno/Getty Images

One egg contains about 186 milligrams of cholesterol, and the USDA recommends capping our intake at 300 milligrams.

With a blend of omega-3 fatty acids, zinc, B vitamins, and iodide, eggs can help reverse bad moods and fight fatigue.

So healthy.      Alexander Spatari/Getty Images

The choline found in eggs can also improve your memory.

If you're going to eat raw cookie dough, use pasteurized eggs, which are free from any risk of salmonella.

Who doesn't love raw cookie dough?      Sydney Kramer/INSIDER

In fact, flour could be more of a risk than raw eggs.

For the best hard boiled eggs, use eggs that are at least 10 days old.

Peeling a hard boiled egg.      Shutterstock

Fresh eggs will be more difficult to peel.

• Read more:
• 8 myths about eggs you should stop believing
• 8 egg dishes that Michelin-starred chefs can't live without
• I made scrambled eggs using English, French, and American methods and was shocked by how different they all tasted
• I made scrambled eggs using 8 celebrity chefs' recipes, and the best had a special ingredient