Asparagus : Benefits & Nutritional values

Asparagus characteristics

  • Rich in dietary fiber;
  • Excellent source of vitamins B9 and K;
  • Promotes drainage and renal elimination;
  • Contributes to digestive well-being.

Nutritional and caloric values ​​of asparagus

NutrientsAsparagus, boiled, drained, 6 whole stems / 90 gCanned asparagus, drained, 6 whole stems / 108 g
Calories2021
Protein2.2 g2.3 g
Carbohydrates3.7 g2.7 g
Lipids0.2 g0.7 g
Dietary fiber1.8 g1.5 g
Glycemic load : No data available.
Antioxidant power : Very high for raw asparagus. High for cooked asparagus.

Focus on the micronutrients contained in asparagus 

Asparagus, whether green, white or purple, is a true concentrate of vitamins and minerals essential for the good health of the organism. Among these nutrients present in good quantity in the flesh of asparagus, we can quote: 

  • Vitamin B9 (folate) : asparagus is an excellent source of vitamin B9;
  • Vitamin K : Asparagus is an excellent source of vitamin K;
  • Copper : boiled asparagus is a good source of copper while canned asparagus is a source;
  • Iron : Canned asparagus is a good source of iron for men and a source for women. Boiled asparagus is a source of iron for humans;
  • Vitamin A : Boiled asparagus is a source of vitamin A (in the form of beta-carotene) while canned asparagus is a source for women;
  • Vitamin B1 (thiamine) : asparagus is a source of vitamin B1;
  • Vitamin B2 (riboflavin) : asparagus is a source of vitamin B2;
  • Vitamin B3 (niacin) : asparagus is a source of vitamin B3;
  • Vitamin B6 (pyridoxine) : asparagus is a source of vitamin B6;
  • Vitamin C : asparagus is a source of vitamin C;
  • Vitamin E : boiled asparagus is a source of vitamin E;
  • Manganese : asparagus is a source of manganese;
  • Phosphorus : asparagus is a source of phosphorus;
  • Selenium : boiled asparagus is a source of selenium;
  • Zinc : Canned asparagus is a source of zinc for women .

The benefits of asparagus

Very few studies have evaluated the specific benefits of asparagus on human health. However, several prospective and epidemiological studies have shown that a high consumption of vegetables and fruits decreases the risk of cardiovascular diseases, certain cancers and other chronic diseases. The presence of antioxidant compounds in vegetables and fruits may play a role in this protection.

Rich in phenolic compounds

Asparagus contains several phenolic compounds, the main ones being flavonoids (mainly rutin) and phenolic acids (including hydroxycinnamic acid). These compounds are said to have antioxidant properties, that is, they reduce the damage caused by free radicals in the body. These are very reactive molecules that are believed to be involved in the onset of cardiovascular diseases, certain cancers and other diseases linked to aging.

Green and purple asparagus are said to contain more phenolic compounds than white asparagus. Peeling asparagus would not seem to influence its phenolic content when fresh, but would reduce its phenolic content when peeled prior to storage.

Asparagus is believed to have higher quality antioxidants than several vegetables commonly eaten in Europe and the United States, such as yellow onion, red onion, garlic, broccoli and peppers. But its consumption is relatively low. From a health point of view, an increase in the consumption of asparagus would therefore be welcome.

Antioxidant carotenoids

Asparagus contains carotenoid pigments, mainly beta-carotene, lutein, zeaxanthin and capsanthin. As asparagus ripens, the concentrations of lutein and beta-carotene tend to decrease, while the amounts of zeaxanthin and capsanthin increase. Carotenoids are compounds with antioxidant properties and the consumption of foods rich in carotenoids would be linked to a lower risk of suffering from certain cancers and cardiovascular diseases.

An excellent source of folate (vitamin B9)

Asparagus is high in folate, making it the 5th most folate-rich food, after beef liver and certain types of legumes. Five cooked asparagus provides about 25% of the daily folate requirement for the general population, and 15% to 20% for pregnant or breastfeeding women. Canned asparagus contains almost as much folate as fresh asparagus.

Thiols content

Among fifteen vegetables, asparagus ranks 1st in terms of its content in two types of thiols, glutathione and acetylcysteine. These compounds are said to have different antioxidant properties. Among other things, glutathione could improve the elimination of oxidized cholesterol, which is very damaging to the arteries. Consuming foods rich in glutathione may also decrease the risk of upper digestive tract cancer. As these results are not related to the specific ingestion of asparagus, more studies will have to be carried out in order to know the effect of the consumption of thiols of this vegetable.

Saponins 

Asparagus contains saponin, mainly protodioscin. In addition to contributing to the antioxidant activity of asparagus, this saponin is also known for its toxic effects in vitro on certain human cancer cells. This effect has not been evaluated on the consumption of asparagus, but researchers have observed that the lower part (base) of this vegetable contains up to 100 times more protodioscin than the upper part (tip). As the base of asparagus is usually cut before consumption, the beneficial effects of this compound would most often be lost.

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Anti-cancer phytoestrogens? 

Asparagus contains small amounts of isoflavones and lignans, two types of phytoestrogens. These compounds, which are structurally similar to estrogen, may reduce the risk of certain cancers. It should be noted that the isoflavone content of asparagus is considerably lower than that of soy products (around 200 times less isoflavones than tofu and 90 times less than soy milk). In contrast, the amount of lignans present in asparagus is generally equal to or greater than that of soy products. In addition, cooking asparagus would not have a major impact on their phytoestrogen concentration. Asparagus could therefore help increase the dietary intake of phytoestrogens.

Fructooligosaccharides and prebiotic effect

Fructooligosaccharides (FOS) or oligofructoses are a type of carbohydrate naturally found in certain vegetables and fruits such as asparagus, onion, chicory, artichoke, garlic and bananas. Fructooligosaccharides are recognized for their health benefits, in particular for their prebiotic effect, their favorable effect on the absorption of minerals, as well as the reduction in the levels of cholesterol, triacylglycerols and blood phospholipids.

Sulphide compounds

A sulfur compound called dimer has been detected in a few vegetables, including asparagus. This molecule has recently demonstrated antioxidant properties and has been found in urine and human plasma. These results are promising and further research is needed to better understand the effect of this compound in humans.

A word from the nutritionist

Cooking would tend to increase the content of certain phenolic compounds in both fresh and stored asparagus. However, overcooking asparagus can reduce its flavonoid content. For example, boiling asparagus for 60 minutes can decrease its content by up to 45%. It is therefore important to cook them in very little water, in the oven, in the microwave, or in a daisy, and only the time necessary to soften them. In addition, the tip of green asparagus and white asparagus would be more concentrated in certain minerals than the base of asparagus (1.5 to 2.5 times more). This is good news, as the tip of the asparagus is particularly popular with consumers.

How to choose the right asparagus?

Asparagus is a plant native to the Mediterranean basin and consumed as a vegetable in France since the 15th century. If asparagus is very popular in France, its production has been halved over the past 25 years. To date, China is the world’s largest producer of asparagus, far ahead of Peru, Germany and the United States. 

ID card

  • Family: liliales;
  • Origin: Eurasia and the Mediterranean basin;
  • Season: spring;
  • Color: green, white or purple;
  • Flavor: bitter and sweet.

Choosing the right asparagus

Contrary to popular belief, fine asparagus is less tender than large, because it is proportionately richer in woody fiber. Choose asparagus with well closed and compact tips. You can find purple asparagus on the market. However, cooking causes them to lose their color.

Store the asparagus

The longer you keep asparagus before eating it, the more fibrous it will be, especially at room temperature. Their sugars quickly turn into starch and the formation of woody tissue is accelerated.

  • Refrigerator: first wrap the base of the bundle with damp paper towels and put everything in a plastic bag. Or, place them upright in a jar containing 2 inches of water. They will keep for 1 or 2 weeks;
  • Freezer: once blanched for 3 minutes in boiling water, asparagus will keep for about 8 months. Cook them without thawing them.

How to prepare asparagus

Whether we prefer it green or white, cooked or in a salad, asparagus offers a multitude of possibilities in the kitchen. On the plate, it brings as many colors as vitamins and is a great ally for the creation of healthy and delicious recipes. 

Should you peel the asparagus?

If they are fresh, green and purple asparagus do not need to be peeled. On the other hand, it is imperative to peel the white ones. To remove the rigid part, we hold the body of the asparagus in one hand and the foot in the other, and we fold. The break will be where the asparagus is no longer edible because it is too tough.

Milanese asparagus

There are saucepans on the market specially designed for asparagus: tall and narrow, they allow them to be cooked vertically, leaving the tips, which cook faster than the rest, out of the water.

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Some simple recipe ideas

  • Flemish style. Boiled, serve with half a hot hard-boiled egg, and melted butter. The yolk of the egg is crushed with a fork, seasoned and mounted in butter on the plate by the guest himself;
  • Boiled or steamed. It takes 3 to 5 minutes for the green ones and, depending on their diameter, 8 to 12 minutes for the white ones;
  • Floods. With a yogurt-based dip, present them nicely by serving greens, whites and violets;
  • Roasted. You can simply brush them with oil and spicy salt or marinate them in a sauce made with olive oil, balsamic vinegar, a little maple syrup and mustard seeds. Then grill them in the oven or on the barbecue (5 to 7 minutes, in either case).
  • With Mornay or Hollandaise sauce;
  • With grated Parmesan cheese. Brown in the oven and add a knob of butter before serving;
  • With a green sauce made from yogurt and herbs;
  • With a sauce prepared with butter, orange juice and zest, salt and pepper;
  • Chinese stir-fries. Cook the pieces cut into lengths of 1 to 2 cm for 3 to 5 minutes in hot oil, stirring constantly. Or, sauté them with shiitake mushrooms and peas. Add orange juice and cook until the vegetables are tender. Serve over lettuce with orange wedges and toasted pecans;
  • As an omelet, after blanching them for 5 minutes;
  • In the form of soup, cream or soup;
  • As a dip. Cook them first, then put them in a blender with sour cream, onion, garlic and salt;
  • As a garnish on canapes. Serve tender tips that can be beaten with cream or yogurt.

Dare asparagus in a sweet version

Asparagus can also be used as a base for making ice cream. Asparagus is also excellent candied in a sugar syrup and garnished with an orange or lemon mousse.

Contraindications and allergies to asparagus

As with all foods, there are a few contraindications to consuming asparagus. Among these contraindications, the most important is undoubtedly the taking of an anticoagulant treatment with which the vitamin K contained in quantity in asparagus could interfere. 

Vitamin K and anticoagulants

Asparagus contains high amounts of vitamin K. This vitamin, necessary among other things for blood clotting, can be made by the body in addition to being found in certain foods. People taking anticoagulant drugs (Coumadin®, Warfilone®, Sintrom®, etc.) should eat a diet whose vitamin K content is relatively stable from day to day. Asparagus is part of a list of foods that should be eaten at most once a day. The recommended serving is 250 ml (1 cup) each time. People on anticoagulation therapy are strongly advised to consult a dietitian-nutritionist or a doctor in order to know the dietary sources of vitamin K and to ensure a daily intake as stable as possible.

Asparagus and botulism

Food botulism is caused by eating food contaminated with botulinum toxin. Inadequate home canning of low-acid foods, such as asparagus, has been implicated in several reported cases of food botulism.

Symptoms of such poisoning appear within 6 to 36 hours of consuming the offending food. They consist of double or blurred vision, difficulty speaking and absorbing, dry mouth and fatigue. Food botulism is still rare, but since it can be fatal, special care should be taken to avoid it, especially when home canning.

 History and anecdotes

A little history

Asparagus is a plant whose claw produces buds each year that grow into fleshy stems called spears. It takes its name from the Latin asparagus which itself borrowed it from the Greek asparagos, which would come from Persian. The term “asparge” appeared in the French language in 1256. Until the 17th century, we also wrote “asparge”.

Asparagus is believed to originate from the eastern Mediterranean basin and Asia Minor. The Romans would have domesticated it 200 years before our era. The Greeks, for their part, would have preferred to pick it from the wild, convinced that it made a much better remedy. Indeed, it enjoyed a very great reputation as a medicinal plant. She was supposed to cure everything from bee stings and heart ailments to dropsy and toothache. It was also considered an aphrodisiac and for this reason we did not hesitate to drink the water in which it had cooked. Anyway, its diuretic properties are undeniable, as any consumer of asparagus can attest …

Asparagus is one of the “exotic” plants that the Italian Princess Catherine de Medici brought in her luggage when, in the 16th century, she crossed the Alps to marry the future King of France, Henry II. A century later, Louis XIV will grant his first gardener a title and a piece of land to thank him for having found a way to cultivate this precious vegetable all year round. At the same time, French gardeners developed the technique to obtain white shoots. The method involves buttering them (covering their base with soil as they grow) so as to deprive them of sunlight and thus prevent them from making chlorophyll. This technique will pass in Germany and in other countries of Europe,

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Universally appreciated, asparagus has been incorporated into all cuisines, both eastern and western. However, it is still relatively expensive, because unlike many other vegetables, it must be harvested by hand.

A vegetable that leaves fragrant traces 

The very peculiar smell that asparagus can impart to urine is attributable to the presence of 6 sulfur compounds which come from the degradation of certain amino acids contained in the plant24. But it seems that some people do not detect this particular smell.

A little gardening

Asparagus prefers sandy soils, but will settle for any soil as long as it is well-drained. She hates having wet feet, which is the main cause of claw rot. The pH of asparagus ranging from 6.5 to 7.5, we should avoid planting it where it is less than 6.

Asparagus can be propagated from seeds or from 1 year old claws. In the first case, sowing is done indoors 10 or 12 weeks before the last frosts. Young plants or claws will be placed in the ground when the soil temperature has reached 10 ° C. You have to think about installing them north or west of the vegetable garden, because the plant, which easily rises to 2 m, provides a lot of shade.

It was long thought that asparagus should be planted deep (30 cm and more), but researchers recently found that the deeper the claws, the less productive the plants. Ideally, 10 to 15 cm deep

Dig a furrow 10 to 15 cm deep, add a good layer of manure or compost, place the young plant or the claw in it and cover with soil. Leave a spacing of 45 cm in the row and 1.5 m between the rows. The spears will emerge a few weeks later. It will be necessary to refrain from harvesting them the 1st year, and it will be necessary to harvest them only during 3 weeks the second year, in order to allow the plant to make reserves of nutrients. Its longevity (15 years at the very least) and its productivity depend on compliance with this rule. For the same reasons, starting in the 3rd year, spears should only be harvested for 6 to 8 weeks each spring, and the foliage will not be pruned until late fall or early spring.

Irrigation of asparagus plants

The first 2 years, it is necessary to water well if the weather is dry. Then, water once or twice during the harvest period and a few times during the summer, when the foliage is forming. Finally, a few good waterings in the fall will increase production the following year and protect the plants against damage that could cause frost during the winter.

Harvest and care

The shoots are preferably harvested in the morning, when they are 15 to 25 cm long and their tip is still well closed. You can either cut them a few centimeters below ground level with a knife, or break them by hand. As long as the harvest period lasts, collect all spears, regardless of their quality. This avoids the hasty formation of foliage and delays the arrival of the beetle, an insect that feeds on it and weakens the plant. Harvesting is normally stopped when the diameter of three-quarters of the spears is no more than 1 cm or less. At this point, harvest all the spears one last time, add a good layer of compost and mulch abundantly to thwart the emergence of weeds. Each spring, add a layer of compost or decomposed manure, and in the fall, a 10 to 12 cm mulch, which you will remove the following spring. A mature plant will produce 15 to 20 spears per year. To meet the fresh asparagus needs of a family of 4, it is estimated that 12 to 18 plants are needed.

Diseases and insects

In the family vegetable garden, diseases and harmful insects are rare. The majority of problems can be prevented by making sure to respect the recommended spacing between plants and rows, to drain the soil well, to have good air circulation between the plants and to water and fatten the plants well. In case of rust attack, treat with sulfur. To avoid Fusarium wilt, for which there is no treatment, care must be taken to ensure that the original seeds or plants are not contaminated. To do this, do business with a reputable seed grower or nurseryman. The new “Jersey” varieties, which only give male plants, are said to be more resistant than the traditional varieties.