Leeks, known scientifically as Allium porrum, are related to garlic, onions, shallots, and scallions. Leeks look like large scallions, having a very small bulb and a long white cylindrical stalk of superimposed layers that flows into green, tightly wrapped, flat leaves. Cultivated leeks are usually about 12 inches in length and one to two inches in diameter and feature a fragrant flavor that is reminiscent of shallots but sweeter and more subtle. Wild leeks, known as ramps, are much smaller in size, but have a stronger, more intense flavor. They are available for a short period of time each year and are often widely sought out at farmers markets when they are in season.
With a more delicate and sweeter flavor than onions, leeks add a subtle touch to recipes without overpowering the other flavors that are present. Although leeks are available throughout the year they are in season from the fall through the early part of spring when they are at their best.
The flavonoids in leeks are most concentrated in their lower leaf and bulb portion. The flavonol kaempferol is one of leeks' premiere flavonoids, and it's also most concentrated in the lower leaf and bulb. Leeks rank ahead of white onions in terms of their kaempferol content, but they still provide slightly less kaempferol than red onions. Kaempferol has repeatedly been shown to help protect our blood vessel linings from damage, including damage by overly reactive oxygen molecules. Interestingly, one of the mechanisms involved in this blood vessel protection may involve increased production of nitric oxide (NO), a naturally occurring gas that helps to dilate and relax the blood vessels, as well as decreased production of that asymmetric dimethylarginine (ADMA), a substance that blocks production of NO.
Often overlooked in leeks is their important concentration of the B vitamin folate. Folate is present in leeks in one of its bioactive forms (5-methyltetrahydrofolate, or 5MTHF) and it is present throughout the plant (including the full leaf portion, not only the lower leaf and bulb). While it's true that we still get about 50% more 5MTHF from the bulb than the leaves, this distribution of folate throughout the plant makes leeks a cardioprotective food from top to bottom.
Unfortunately, leeks have received less research attention than their fellow allium vegetables (especially garlic and onions), and for this reason, there is less documentation of their likely health benefits. Given their substantial polyphenol content, including their notable amounts of kaempferol, we would expect to see overlap with garlic and onions in terms of support for many health problems related to oxidative stress and chronic low-level inflammation. These health problems would include atherosclerosis, type 2 diabetes, obesity, rheumatoid arthritis, and allergic airway inflammation.
Leeks enjoy a long and rich history, one that can trace its heritage back through antiquity. Thought to be native to Central Asia, they have been cultivated in this region and in Europe for thousands of years.
Leeks were prized by the ancient Greeks and Romans and were especially revered for their beneficial effect upon the throat. The Greek philosopher Aristotle credited the clear voice of the partridge to a diet of leeks, while the Roman emperor Nero supposedly ate leeks everyday to make his voice stronger.
The Romans are thought to have introduced leeks to the United Kingdom, where they were able to flourish because they could withstand cold weather. Leeks have attained an esteemed status in Wales, where they serve as this country's national emblem. According to one legend, King Cadwaladr of Gwynedd ordered his soldiers to identify themselves by wearing the vegetable on their helmets in an ancient battle against the Saxons that took place in a leek field. This story may have been made up by the English poet Michael Drayton, but it is known that the leek has been a symbol of Wales for a long time; Shakespeare, for example, refers to the custom of wearing a leek as an “ancient tradition” in Henry V. In the play, Henry tells Fluellen that he is wearing a leek “for I am Welsh, you know, good countryman.”
Leek has a mild onion-like taste. In its raw state, the vegetable is crunchy and firm. The edible portions of the leek are the white base of the leaves (above the roots and stem base), the light green parts, and to a lesser extent the dark green parts of the leaves. One of the most popular uses is for adding flavor to stock. The dark green portion is usually discarded because it has a tough texture, but they can be sauteed or added to stock. A few leaves are sometimes tied with twine and other herbs to form a bouquet garni. Leeks are an ingredient of cock-a-leekie soup, leek and potato soup and vichyssoise, as well as plain leek soup.
A nice collection of leek recipes - try Risotto with Beet Greens and Leeks!
BACK TO THE BAG