Asparagus Nutrition Facts

3 Health Benefits That May Surprise You

Asparagus spears are both delicious and nutritious, so they're a perfect vegetable to add to almost any diet. You can find asparagus in green, white, or even purple varietals. In the United States, the green variety is most common, while white asparagus is prevalent throughout Europe.

Asparagus (scientific name Asparagus officinalis) is a perennial flowering plant that has been used as a food and medicine since as far back as 3,000 B.C.

Many early cultures imbued it with aphrodisiac properties, while the 15th-century Indian sex manual Ananga Ranga asserted that asparagus was effective in relieving fatigue. Today, asparagus is recognized as an excellent source of vitamins, minerals, and fiber, with few calories or sodium.

The great news is that you can enjoy asparagus all year long as it has become a common staple in most produce markets. Still, the peak season is around April and May, so be sure to take advantage of the best and most tender spears during the spring.

Asparagus Nutrition Facts
Serving Size 1/2 cup cooked, drained without salt (90 g)
Per Serving% Daily Value*
Calories 20 
Calories from Fat 2 
Total Fat 0.2g0%
Saturated Fat 0g0%
Polyunsaturated Fat 0.1g 
Monounsaturated Fat 0g 
Cholesterol 0mg0%
Sodium 13mg1%
Potassium 201.6mg6%
Carbohydrates 3.7g1%
Dietary Fiber 1.8g7%
Sugars 1.2g 
Protein 2.2g 
Vitamin A 18% · Vitamin C 12%
Calcium 2% · Iron 5%

*Based on a 2,000 calorie diet

Nutrition Facts

Whether or not you are on a diet, asparagus offers a plethora of nutrients with very few calories. It is especially rich in essential vitamins and minerals. 

Carbs in Asparagus

Asparagus is an excellent addition to any low-carb or ketogenic diet, boasting a scant 3.7 grams of net carbs per half-cup serving.

Only a small portion of the content is from simple carbs (namely sugar), so it has little impact on your blood sugar and a glycemic index (GI) of less than 15.

Asparagus also offer a healthy dose of dietary fiber, the indigestible carbs that help regulate digestion, blood sugar, and fat absorption in the body. Most of the fiber in asparagus is insoluble, meaning that it draws water from the intestines to soften stools and ease them from the digestive tract.

Fats in Asparagus

Asparagus is virtually fat-free, with only scant amounts of "healthy" polyunsaturated fat. These are essential fatty acids that the body needs for brain function and cell growth.

Clearly, you can undermine those benefits by slathering asparagus in butter, margarine, or hollandaise sauce. As an alternative, drizzle the spears with a teaspoon of extra virgin olive oil, and you'll only add only 0.65 grams of saturated fat, 0.5 grams of polyunsaturated fat, and 0.3 grams of monounsaturated fat.

Protein in Asparagus 

Asparagus doesn't offer a lot in the way of protein but enough to help meet some of your daily nutritional needs. On average, adults should eat around 0.8 grams of protein per kilogram of body weight (or 0.36 grams per pound) per day.

This amounts to 56 grams per day for the average sedentary man and 46 grams per day for the average sedentary woman.

At 2.2 grams per serving, asparagus sets you well on your way. Wrap the stalks in a couple of slices of deli ham (2 ounces) and you'll bolster your protein content by another 5 grams.

Micronutrients in Asparagus

According to the reference daily intake (RDI) issued by the Food and Nutrition Board of the Institute of Medicine, asparagus accounts for a significant portion of your daily nutritional needs, Based on a 2,000-calorie diet, the RDI breaks down as follows:

Asparagus also offers ample supplies of riboflavin (vitamin B2)thiamine (vitamin B1), and iron.

Health Benefits

While the nutrients in asparagus promote good health and metabolism, certain agents in asparagus are believed to offer significant health benefits. These include the reduction of high blood pressure, the promotion of a healthy pregnancy, and the avoidance of certain diseases.

High Blood Pressure

As a rich source of potassium, asparagus can lower the help lower your blood pressure by relaxing the walls of your arteries (thereby improving circulation) and increasing the excretion of sodium from the kidneys.

Vitamin A and C are also powerful antioxidants that help eliminate free radicals circulating in the blood. Doing so reduces damage to the circulatory system, including the risk of atherosclerosis (hardening of the arteries) and cardiovascular disease.

For its part, purple asparagus contains anthocyanins, antioxidant compounds that provide the vegetable its vibrant color and exert robust cardio-protective properties.

Asparagus also exerts mild diuretic properties that inherently lowers blood pressure by promoting the excretion of excess fluids from the body. 

A 2013 study from Japan reported that 28 adults given an oral dose of powdered asparagus (6 milligrams per kilograms of body weight) experienced a nearly 8 point drop in their systolic blood pressure and a nearly 5 point drop in their diastolic blood pressure after 10 weeks. It also decreased total cholesterol and fasting glucose levels (although no changes in HbA1C were noted).

Pregnancy

Most obstetricians will recommend that a pregnant woman take a daily 400-microgram folate supplement to promote a healthy pregnancy. A half-cup serving of asparagus meets 134 micrograms of those needs. 

Low folate levels are associated with an increased risk of neural tube defects, such as spina bifida. As such, a diet rich in asparagus may be considered protective against these potentially devastating defects that affect around 3,000 pregnancies in the United States every year. 

In addition, asparagus is the single richest source of an amino acid known as asparagine, which is required for the normal development and function of the brain.

Disease Prevention

Asparagus is also a key source of inulin, a type of fiber that supports healthy gut bacteria. It does so in part by inhibiting powerful bacterial endotoxins known as polysaccharides

According to a 2014 study from Italy, inulin reduces the concentration of polysaccharides in the blood by around 600 hundred percent by blocking their absorption through the mucous membrane of the colon. 

With roughly 2 to 3 grams of inulin per serving, asparagus could potentially aid in the control of certain diseases attributed to excessive polysaccharides. These include ulcerative colitis, Crohn's disease, Helicobacter pylori (H. pylori) infection, and, to a lesser degree, cystic fibrosis, atherosclerosis, and certain autoimmune diseases like rheumatoid arthritis.

Common Questions

Is green asparagus better than white?

In comparison, both white and green asparagus contain roughly the same amount of calories, carbohydrates, and fiber per serving. The difference is that white asparagus is covered with soil as it begins to sprout. Because it is not exposed to light, it does not produce chlorophyll, a potentially beneficial phytochemical. White asparagus contains marginally less vitamin C as well.

White asparagus tends to be thicker and more tender than the green variety. It also has a slightly nutty flavor and is less prone to the stringiness of its green cousin.

Why does asparagus make your urine smell?

There's nothing unusual about having smelly urine after eating asparagus. The vegetable contains sulfurous amino acids, known as asparagusic acid, which break down during digestion. This produces pungent chemical compounds that are excreted soon after eating asparagus and up to a day later. While somewhat off-putting, the sulfurous chemicals are in no way harmful.

Recipes and Preparation

When selecting fresh asparagus, choose stalks that have a tightly closed bud. The stalks should be rich in color, stand firm, and appear plump and straight. Avoid asparagus that is limp, mushy, blemished, or dull in color. Asparagus can also be purchased frozen and canned. 

Fresh asparagus can dry out quickly, so it's important to store it properly to maintain freshness. To extend its shelf life and prevent food waste:

  1. Keep your asparagus bundle in a rubber band
  2. Trim an inch off the bottoms of the stalks.
  3. Wrap the ends in a moist paper towel.
  4. Stand them in a small container of water (about 1 inch) and store them in the refrigerator.

The stalks should not be washed until just before cooking. Asparagus can be steamed, boiled, stir-fried, grilled, or sliced thinly and eaten raw in salads. Thicker, late-season stalks may be needed to be peeled before cooking.

Cook asparagus long enough so that it still retains its bright green color. Once it begins to turn a pea soup green, it will likely be overcooked and limp. Overcooked asparagus loses some of its nutrients and health benefits.

If you are an asparagus lover, there are several recipes you should definitely try:

Allergies and Interactions

Asparagus is rarely implicated in allergy. With that being said, a compound known as trithiane-5-carboxylic acid is found in higher concentrations in young asparagus stalks. People who pick or eat these slender, early-season stalks may experience contact dermatitis, mainly on the hands or fingers, or contact urticaria, causing swollen and itchy lips.

Allergy symptoms tend to be mild or last for only a few minutes. Call your doctor if the symptoms persist or worsen.

Because asparagus has a mild diuretic effect, you may need to avoid eating it while taking the drug lithium. Theoretically, asparagus can reduce the excretion and increase the concentration of lithium in the blood. Doing so may amplify the side effects of the drug.

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