Leeks are a versatile and healthy vegetable. They are gratinated, baked in omelets, served with pasta, in the form of a quiche or made into a delicious soup with potatoes. Leeks were once highly valued not only as a vegetable but also as a medicinal plant.
Leek: The mild variant of the onion
The leek (Allium porrum), like the onion and garlic, belongs to the daffodil family, but tastes much milder than its spicy relatives.
The western Mediterranean is the home of the Leeks, which was known more than 2000 years before our time. The Egyptian slaves are said to have eaten this vegetable during the construction of the pyramids, and Emperor Nero also swore at it because he believed that it enhances his voice. Probably in the Middle Ages, this vegetable found its way to us.
It has been cultivated as a vegetable and spice plant for at least 4000 years and was also previously a recognized medicinal plant, for example for respiratory infections, because the leek has an expectorant effect on the bronchi (9).
Allium porrum is a two-year-old herbaceous plant. The winter-proof onion vegetables grow up to 80 cm in height and form leaves instead of an onion. These can be up to five centimeters wide and 50 centimeters long. In its course, its shaft changes the color from yellowish to strong green. At its end, an egg-round capsule fruit is formed.
This versatile vegetable originally comes from southern Europe. From Italy, the leek made its way to central and northern Europe, where it was welcomed with joy.
This is still evident today in the fact that the leek is a national symbol and adorns the coat of arms of Wales (England) and is a main ingredient in the Scottish national dish “Cock-a-leeki”, which is a must at special occasions such as weddings.
Leeks are also impressive due to their nutritional value (e.g. vitamin C, fiber, beta-carotene) and their special ingredients, such as kaempferol and allicin – see below.
Season and Storage of Leeks
Leeks are available all year round. The summer leek is slimmer than the winter leek and tastes a little milder and more tender in comparison. Outdoor cultivation is the rule for this vegetable.
If you remove the outermost leaf and the dark green leaf ends, you can store the stems. It stays in the fridge for about five days. Leeks emit a rather intense smell, so it should be kept separately from other vegetables. It can also be frozen.
The right preparation
Leeks are a great vegetable side dish, but can also be used as the main ingredient in soups, quiches, stews and casseroles. They also go well in pasta sauces and are excellent in risotto.
Since leeks have an impressive seasoning power even in small quantities, they can also be used to enhance mashed potatoes, for example.
Leeks can be boiled, steamed, braised, blanched and briefly fried. But the gentler the cooking method, the healthier this varied stalk is.
The vegetable can also be eaten raw in small quantities (cut into fine rings) and gives its typical aromatic note to colorful salad creations, for example.
A favorite of mine is Kohlrabi schnitzel with leek puree.
When preparing them, remember that summer leeks taste much more delicate than winter leeks. Summer leeks are ideal for steaming whole like asparagus and serving with a herb sauce (e.g. salsa verde).
As already mentioned, the green leaves are unfortunately often considered waste, although they contain much more of the medicinal active ingredients (e.g. beta-carotene or polyphenols). The tart-tasting leek greens can be used up to 15 centimeters above the white stem.
You can season the leek very well with chervil, caraway, tarragon, lovage, parsley, thyme, nutmeg or even chili.
What should I consider when shopping?
You can buy leeks all year round in the supermarket or at weekly markets.
From November to February, the tender, milder summer leek (varieties such as Faraday and Volta) is available, and from March to spring, the stronger and spicier autumn or winter leek (varieties such as Fahrenheit and Galvani) is available. The “seasonal gap” is bridged with leeks grown under plastic film.
When buying, make sure that the leek has firm green leaves and a white stem. If the green leaves look limp or damaged, it is better to leave the stalk alone.
And if the white root hairs have already turned brown, the vegetable’s good days are also far behind it.
What is the best way to store leeks?
Leeks can be stored in the vegetable compartment of the refrigerator for five to seven days if wrapped in plastic wrap or a damp cloth. The wrap or cloth prevents evaporation and ensures that the leek leaves remain fresh and firm.
This storage method also prevents the leek from transferring its onion-like smell to aroma-sensitive foods such as butter or sliced fruit.
The vegetable sticks can also be frozen. However, since the texture and taste change for the worse when thawed, you should not let it thaw, but continue processing it while it is frozen.
It is best to clean it, cut it into thin strips or rings and blanch it before freezing. Leeks will keep for at least 3 months when frozen.
How to clean leeks properly
The hardest part about using leeks is the preparation. The only reason the stalk stays white and tender is because, like white asparagus , it is continually covered in soil as it grows. As a result, soil can get into each layer of leeks, and this should be removed before preparation.
So after you have removed the outermost, not so pretty layer and the top of the green leaves, you should clean the vegetable thoroughly under running water. This is particularly easy if you cut it lengthways and then rinse the individual layers.
Nutritional values, vitamins and minerals
Please note to not eat the leek raw in large quantities.
If you stew, steam or boil it, then naturally there will be a loss of nutrients. When steaming – one of the gentlest preparation methods – for example, 25 percent of the vitamin C is lost. With vitamin K, on the other hand, losses of only around 5 percent are to be expected.
Nutritional table: Leeks (per 100 grams)
| Minerals (mg) Sodium (Na) Potassium (K) Calcium (Ca) Magnesium (Mg) Phosphate (P) Iron (Fe) Zinc (Zn) | 5 280 65 15 50 0,8 0,3 |
| Vitamins Beta-Carotin (µg) Vitamin E (mg) Vitamin B1 (mg) Vitamin B2 (mg) Vitamin B6 (mg) Folic acid (µg) Vitamin C (mg) | 740 0,5 0,08 0,07 0,25 100 25 |
Fiber for the intestinal flora
Leeks are one of the few foods with high inulin content. Inulin is a soluble fiber with extremely beneficial effects on the intestinal flora, which is why inulin is often taken as a dietary supplement as part of a healthy intestinal flora buildup.
Regular consumption of leeks can therefore contribute greatly to intestinal health. It not only nourishes the beneficial intestinal bacteria, but also stimulates intestinal activity. People who tend to get flatulence after eating leeks can prevent this by seasoning them with caraway seeds .
Beta-carotene protects against free radicals
Leeks are a good source of beta-carotene and are therefore also characterized by their antioxidant properties. Beta-carotene captures free radicals and consequently protects the body’s cells – especially the eyes and skin – from damage.
Studies have shown that beta-carotene can prevent heart disease and protect against cancer. Unfortunately, many people cut off the green part of the leek and simply throw it away. It is best not to do this, because this is where there is 300 times more beta-carotene than in the white part.
Vitamin C for the immune system
Leeks contain a relatively high amount of vitamin C, which stimulates the immune system. If you include this healthy vegetable in your diet more often, you can protect yourself from annoying colds, for example . If you combine leeks with iron-rich foods such as millet, you can increase the positive effect on the immune system even further, as the body can use the plant-based iron better thanks to the vitamin C.
Manganese for Depression and Dementia
Manganese is an essential trace element and an important component of many enzymes. Eating a lot of leeks can also increase the absorption of vitamin B1, which is important for strong nerves.
In addition, studies have shown that an increased intake of manganese helps combat depression and dementia and can naturally reduce epileptic seizures.
The Healing Effects of Leeks
In contrast to its siblings garlic and onion, the leek is still a stepchild of medical research and is no longer classified as a medicinal plant. In traditional medicine, for example, the following areas of application of the leek were/are important:
- detoxification
- cardiovascular diseases
- stimulating kidney function and preventing kidney stones
- promoting digestion
- acceleration of bile flow
- bronchial diseases
Since leek contains the same or similar ingredients as its medically recognized relatives, including sulfur-containing essential oils and polyphenols (secondary plant substances), it should finally be given more importance in the field of phytotherapy.
Many experts agree that leeks can at least help prevent diseases that are related to oxidative stress and chronic inflammation (3), such as atherosclerosis, type 2 diabetes and cancer.
Kaempferol protects the heart and acts against cancer
Leeks are characterized by a particularly high polyphenol content and contain, for example, considerable amounts of the flavonoid kaempferol. Various studies have shown that kaempferol can protect the inner walls of blood vessels from damage and thus also contributes to heart health. This is attributed to the fact that kaempferol intercepts and neutralizes free radicals. (2)
In addition, there are already a number of studies that have shown that kaempferol can prevent cancer, kill existing tumor cells and prevent the growth of metastases. These research results were confirmed by a study conducted at West Virginia University.
In addition, kaempferol is said to have an antimicrobial and anti-inflammatory effect. The allicin described below also has an antimicrobial and anti-inflammatory effect, so that these substances can reinforce and support each other – and make the leek a very special food.
Allicin: A Natural Antibiotic
Leeks contain a sulfur-containing amino acid called alliin. It is located in the cell plasma. The cell stores an enzyme in small cell vesicles (vacuoles) – the so-called alliinase. If the leek (or garlic or onion) is chopped up, the vacuoles are destroyed. The alliinase then encounters the alliin and converts it into allicin in a matter of seconds.
Allicin is responsible for the typical sharp smell and taste of leeks, garlic and onions. Allicin also has a strong antibacterial and antifungal effect.
Researchers are firmly convinced that allicin is a natural antibiotic and could be a promising active ingredient in the future in view of the increasing antibiotic resistance (5)(7). Here you can find our text about the natural antibiotic.
Allicin also increases physical fitness, lowers cholesterol levels and blood pressure and is already considered a recognized remedy against arteriosclerosis.
Externally, appropriate preparations are used against fungal diseases and infections transmitted by parasites (e.g. ticks). Allicin is also considered particularly interesting in cancer research , as various studies have shown that it can render cancer cells harmless (6)(8).
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