Asparagus nutrition facts

Asparagus is a tender shoot (spear) vegetable that emerges out from the underground rhizome network. They are quite popular as flavorful spring season delicacies. Their food use was well-known to ancient Greeks and Romans who admired their delicacy. One of the oldest recorded vegetables, it is thought to have originated in the coastal areas of the eastern Mediterranean and Asia Minor regions.

Botanically, asparagus is a herbaceous perennial plant belonging to the Asparagaceae family. It is closely related to the Liliaceae plants which also include onion, garlic, tulip, daffodil…etc. Scientific name: A. officinalis. This spear vegetable is grown extensively today as a major commercial crop in China, Europe, Peru, Australia, and the USA.

Asparagus spears.
(Photo courtesy: muffet)

Asparagus crowns planted in early spring. It grows into tall, branched stems, bearing fine fern-like green needles (phylloclades); giving the whole plant an overall feathery appearance. The fresh crop can also be established by direct seeding or through transplanting 10-12 week-old seedlings.

A fully-grown plant reaches about 5 feet in height. Young scaly edible spears emerge from the underground extensive matted root systems, which can be ready for harvesting by early spring.


Young shoots erupting. Courtesy: net_efekt)	A. officinalis- note for an erupting shoot.

Normally, 7 to 9-inch tall young shoots are harvested by either snapping or using a paring knife, cutting close to the ground level. There is no need to cut asparagus shoots far below the soil with a knife, which might injure other erupting buds on the crown. The stump that left in the ground after snapping dries up and disintegrates.

Warm weather would adversely result in premature opening up of spear tips that might reduce their overall flavor and quality. Asparagus is harvested once a year for over an 8 to 10-week period in a season.

White or blanched asparagus (spargel) spears are reaped by heaping up surrounding soil around the erupting shoots, depriving them of sunlight. This method, like in endive, makes the shoots turn pale through inhibition of photosynthesis. In some European markets, these blanched spears (spargel) are preferred over green ones because of their pleasant taste and delicate flavor.

Health Benefits of Asparagus

Asparagus is a very low-calorie vegetable. 100 g fresh spears carry just 20 calories.
Besides, its spears contain moderate levels of dietary fiber. 100 g of fresh spears provide 2.1 g of roughage. Dietary fiber helps control constipation conditions, decrease bad (LDL) cholesterol levels by binding to it in the intestines, and regulate blood sugar levels. Studies suggest that a high-fiber diet helps cut down colon-rectal cancer risks by preventing toxic compounds in the food from absorption.
Its shoots have long been used in many traditional medicines to treat conditions like dropsy and irritable bowel syndrome.
Fresh asparagus spears are a good source of antioxidants such as lutein, zeaxanthin, carotenes, and cryptoxanthins. Their total antioxidant strength, measured regarding oxygen radical absorbance capacity (ORAC value), is 2150 µmol TE/100g.
Together, these flavonoid compounds help remove harmful oxidant free radicals from the body and protect it from possible cancer, neurodegenerative diseases, and viral infections.
Fresh asparagus is rich sources of folates. 100 g of spears provide about 54 µg or 14% of RDA of folic acid. Folates are one of the essential co-factors for DNA synthesis inside the cell. Scientific studies have shown that adequate consumption of folates in the diet during the pre-conception period and early pregnancy helps prevent neural tube defects in the newborn baby.
Its shoots are also rich in the B-complex group of vitamins such as thiamin, riboflavin, niacin, vitamin B-6 (pyridoxine), and pantothenic acid. This group of vitamins is essential for optimum cellular enzymatic and metabolic functions.
Fresh asparagus also contains fair amounts of antioxidant vitamins such as vitamin C, vitamin A, and vitamin E. Regular consumption of foods rich in these vitamins helps develop resistance against infectious agents and scavenge harmful, pro-inflammatory free radicals from the body.
Its shoots are also an excellent source of vitamin K. 100 grams carry about 35% of DRI. Vitamin K has a potential role in bone health by promoting bone formation activity. Adequate vitamin K levels in the diet help limit neuronal damage in the brain. It thus has a role in the treatment of patients with Alzheimer's disease.
Asparagus is an excellent source of minerals, especially copper and iron. Also, it has small amounts of some other essential minerals and electrolytes such as calcium, potassium, manganese, and phosphorus.
Potassium is an important component of cell and body fluids that helps control heart rate and blood pressure by countering the effects of sodium. Manganese is used by the body as a co-factor for the antioxidant enzyme, superoxide dismutase.
Copper is required in the production of red blood cells. Iron is essential for cellular respiration and red blood cell formation.

See the table below for in depth analysis of nutrients:

Asparagus nutrition profile per 100 g (A. officinalis), raw, ORAC value 2150, (Source: USDA National Nutrient data base)

Principle	Nutrient Value	Percent of RDA
Energy	20 Kcal	1%
Carbohydrates	3.38 g	2.5%
Protein	2.20 g	4%
Total Fat	0.12 g	0.5%
Cholesterol	0 mg	0%
Dietary Fiber	2.1 g	5.5%
Vitamins
Folates	52 µg	13%
Niacin	0.978 mg	6%
Pantothenic acid	0.274 mg	5%
Pyridoxine	0.091 mg	7%
Riboflavin	0.141 mg	11%
Thiamin	0.143 mg	12%
Vitamin C	5.6 mg	9%
Vitamin-A	756 IU	25%
Vitamin E	1.13 mg	7.5%
Vitamin K	41.6 µg	35%
Electrolytes
Sodium	2 mg	<1%
Potassium	202 mg	4%
Minerals
Calcium	24 mg	2.5%
Copper	0.189 mg	21%
Iron	1.14 mg	14%
Magnesium	14 mg	1%
Manganese	0.158 mg	7%
Phosphorus	52 mg	7.5%
Selenium	2.3 µg	4%
Zinc	0.54 mg	5%
Phyto-nutrients
Carotene-ß	449 µg
Carotene-α	9 µg
Lutein-zeaxanthin	710 µg

Selection and storage

Asparagus spears are also known by many local names as Spragel,Spargelkraut, Asperges, Asperge Commune, Espárragos, etc.

Peeled asparagus stalks. (Photo courtesy: peter kaminski)

Although one may find asparagus all around the season in the supermarkets, they are at their best and most flavorful during the spring. In Europe, its shoots are sold in shops from December to June.

Asparagus should be used as soon as possible after harvesting. Otherwise, it soon loses sweetness since most of its sugar is converted into starch. Purchasing from the local farms or farmer markets would be an ideal way to enjoy them fresh.

In the markets select tender, firm, straight, smooth, uniform-sized, dark green/purple stalks with tightly closed tips. Avoid thick stalks with broad ridges in the stems, sunken or dull-colored, as they indicate old stock and hence, off-flavored.

Since its spears perish early, they should be harvested in the morning hours when the weather is cold. After picking, immerse them in ice-cold water to remove heat, drain the water, and place spears inside plastic bags. Store in the refrigerator set at 38 to 40 degrees F and 90% to 95% relative humidity. At higher temperatures, its spears tend to lose natural sugars and vitamin C. As a result, they lose their flavor as they become tougher and begin to decay.

Preparation and serving methods


The spears will snap where any woodiness begins. (Photo courtesy: The essential vegetarian cookbook).	Tie spears into a bundle. Cook for 2-3 minutes in boiling water with tips upward. Then just dip the tips briefly into the boiling water.

Asparagus shoots are one of the most sought-after vegetables enjoyed in the spring.

Fresh spears are preferred in cooking. To prepare, wash them in cool running water with a gentle scrub. Tender, pencil-thin spears can be cooked directly. Thick stalks, however, peeled before being used in the recipes.

In general, asparagus spears just need brief cooking. In some households, traditional pots are employed to cook them, wherein the stalks are immersed in boiling water while tips are just allowed to steam cook.

Here are some serving suggestions:

Bruschetta with asparagus, tomato, and cheese toppings.
Photo courtesy: rizkapb

Asparagus spears can be enjoyed raw, steamed, sautéed, stir-fried, or mixed with vegetables, beans, poultry, or seafood.
Steamed spears served with citrus hollandaise sauce, melted butter, parmesan, or pecorino cheese in beautiful French-style recipes.
Grilled spring onions and asparagus stalks smeared with macadamia nut oil is a mouth-watering appetizer.
Stir-fry its tender shoots with sesame seeds, and season with garlic, ginger, and pepper paste.
Many restaurants in Germany offer special spargel menus during the spring season.

Safety profile

In general, asparagus is well tolerated, and allergic reactions are relatively rare.

Ingestion of young shoots may give an offensive smell to the urine. It is due to the metabolism of asparagusic acid, which breaks down into various sulfur-containing degradation products such as methanethiol, sulfides, etc. The condition, however, is harmless. (Medical disclaimer).

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