Can you eat the green part of leeks?

In this article, we will answer the question “Can you eat the green part of leeks?” and discuss what are the benefits of eating the green parts of leek. Leek is one of the most important field vegetable crops in Flanders, accounting for 16% of the total agricultural production value (1).

Can you eat the green part of leeks?

Yes, you can eat the green part of leeks. Because of its toughness, most people avoid it. The leaves are considered by-products of leek. However, studies show that they are superior to bulbs on their antioxidant capacity (1).

What are the benefits of eating the green part of leeks?

The green parts of leeks contain antioxidants. These are phenolic compounds and vitamin C, which have the potential to neutralize free radicals in the body. Free radicals are highly reactive substances, which may cause damage to DNA, proteins and lipids and have been associated with diseases such as cancer and coronary heart disease.

A study reported that, for some leek cultivars, a higher amount of phenolic content was measured in the green leaves in comparison with the phenolic content measured in the white shaft. In addition, in most of the cases (different cultivars analyzed) the ascorbate levels in the green leaves were significantly higher than those measured in the white shaft (1). 

The onion, garlic, shallot, scallion, and chive are all members of the same family as leeks. The edible section of the plant is the white and light green part, which is commonly referred to as the stalk or stem, despite the plant’s appearance. Despite its bitterness, the dark green section may be eaten, although it is frequently discarded.

All plants contain fleshy basal leaves that can be tubular or slightly flattened. Bulbs form from enlarged silvery light weight. Allium vegetables and herbs bear a wide array of sulfur compounds with characteristic taste, smell, and tear-inducing pungency and show strong antioxidant properties (4).

Leek is a nutritious vegetable, being low in calories and high in vitamin B6, vitamin C, folic acid, and iron. Leek is also a good source of vitamin K, which helps maintain healthy blood and bones, and vitamin A, which helps maintain healthy eyesight and a healthy immune system (5). 

What is the disadvantage of eating the green part of leeks?

The disadvantage of eating the green part of a leek is to eat a more bitter food. Due to the higher concentration of polyphenols in the sprouting garlic, it tastes more bitter and more adstringent (4).

Generally, higher concentrations of phenolic compounds are found in sprouts and seedlings than in the mature plant, consistent with the notion that plant phenolics provide a degree of protection against predation (6).

In addition, studies report that leeks may contain anti-nutrients, namely oxalates and nitrates. Soluble oxalate in the diet can bind calcium from other sources in the diet and from the body, thus decreasing the calcium absorption and leading to the formation of kidney stones (7).  

Small doses of oxalate in the body may cause headaches, pain and twitching in muscles, and cramps. Larger doses can cause a weak and irregular heartbeat, a drop in blood pressure, and signs of heart failure.

The accumulation of nitrates can cause significant harmful consequences. Nitrates are converted to nitrites within the digestive system, and are then taken up into the bloodstream, where they react with hemoglobin. 

This process converts ferrous iron to ferric iron, resulting in the formation of methaemoglobin. However, this complex cannot transport oxygen effectively.

How can you use the green parts of leeks?

You may use the green parts of leeks by adding them in soups or stews or making stocks.You may also try dehydrating them.

For a long period, the dehydrated leeks may be stored and used in soups. To dry leek, wash well and cut in ¼-inch slices. Dry at 145°F until crisp (2).

What is the best way to cook the green part of leeks?

The best way to cook the green part of leeks in order to retain the highest antioxidant properties is microwave cooking.

Cooking facilitates the extraction of carotenoids, and changes the texture of the vegetables. In the case of green parts of leeks, cooking may facilitate its consumption, as it softens the cell walls. However, some studies have shown that a loss of vitamins in vegetables during cooking varies with the cooking treatment.

In a study, the effect of different methods of cooking in the reduction of the antioxidant properties of vegetables  were compared, namely boiling, pressure cooking, baking, frying and microwaving. 

By all these methods, the antioxidant activity of leek was reduced by 30 to 50%, except by microwave cooking, where the antioxidant activity was preserved (8).

Other FAQs about Leeks that you may be interested in.

What can I substitute for leeks?

Conclusion

In this article, we answered the question “Can you eat the green part of leeks?” and we discussed how can you cook leeks to best preserve its properties.

Reference

  1. Bernaert, Nathalie, et al. Antioxidant capacity, total phenolic and ascorbate content as a function of the genetic diversity of leek (Allium ampeloprasum var. porrum). Food chem, 2012, 134, 669-677.
  2. Danto, R. Using, Storing and Preserving Leeks. 2013. Michigan State University. 
  3. Czech, Anna, Marek Szmigielski, and Iwona Sembratowicz. Nutritional value and antioxidant capacity of organic and conventional vegetables of the genus Allium. Scient Rep, 2022, 12, 18713.
  4. Upadhyay, Ravi Kant. Nutritional and therapeutic potential of Allium vegetables. J Nutr Ther, 2017, 6, 18-37.
  5. Mary Dixon and Guodong Liu. Leek Cultivation Guide for Florida. University of Florida.
  6. Drewnowski, Adam, and Carmen Gomez-Carneros. Bitter taste, phytonutrients, and the consumer: a review. 1–3. Am J Clin Nutr, 2000, 72, 1424-35.
  7. Sinha, Kavita, and Vikrant Khare. Review on: Antinutritional factors in vegetable crops. The Pharma Innov J, 2017, 6, 353-358.  
  8. Jiménez‐Monreal, A. M., et al. Influence of cooking methods on antioxidant activity of vegetables. J food sci, 2009, 74, H97-H103.