Asparagus is a perennial flowering plant brought from Europe to North America hundreds of years ago. However, its history dates back to ancient Egypt, where images of it can be found on the walls of tombs. It originally grew wild along riverbanks or the seashore, preferring a soil too salty for other plants.
The world's top producers of asparagus are China, Peru and Germany. Most of the asparagus grown in the U.S. comes from three states: California, Washington and Michigan. Asparagus can take up to three years to produce a crop. It's harvested in the spring, and one plant will continue to produce for about 15 years. Under perfect growing conditions, asparagus can grow up to 10 inches in 24 hours.
Green is the most common color of asparagus, but white and purple have gained popularity. The white variety is picked before the spear breaks through the soil, so it's never exposed to the sun. Since it's only available for a few weeks, white asparagus is more expensive than green. Purple asparagus is pretty when raw but loses its color during cooking. The main difference between the colors is taste and texture. The nutritional value is virtually the same.
Asparagus can be part of a well-balanced diet. Low in fat and calories, one-half cup or five spears cooked contain only 20 calories. The primary nutrients in asparagus are vitamin K and folate. People on blood thinners may need to watch their vitamin K intake and should talk to their health care team to find out if it's OK to include asparagus in their diets.
After eating asparagus, some people notice their urine has a funky smell. That's due to asparagusic acid, which digestion breaks down into sulfur-containing compounds that give urine the distinctive asparagus odor and color. Only some people can smell this odor, and scientists are still trying to figure out why. But the temporary odor is no reason to pass on this healthful, versatile spring vegetable.
This article originally appeared on the Mayo Clinic Health System blog.