The Latin name for the leek is Allium porrum. The word Allium shows its relation to the onion family. Even so, onions are considered to be more harsh, or even low-brow. Leeks have a more upscale appeal. The flavor is thought to be more subtle and sweet than the average onion.
Although scientists are by no means certain, it is believed that leeks, like many herbs, are native to the Mediterranean area and possibly Asia Minor. Even though leeks have only recently become popular in the United States, they have been grown and used for cooking for more than 3,000 years in Asia and Europe.
Even the Bible mentions leeks. In Numbers (11:5) we read, "Remember how in Egypt we had fish tor the asking, cucumbers, and watermelons, leeks and onions and garlic." This was from a lament by the Israelites as they wandered in the desert searching for the Promised Land. Later leeks would be traditionally consumed on Rosh Hashanah. It was meant to symbolize the desire for the people to have their enemies "cut off". This came from the idea that the Hebrew word for leek is karti, which is similar to the verb, to cut off, or yikartu.
It is widely reported that the Emperor, Nero (37-68 AD), ate leeks in quantity, cooked in oil. He believed it would improve his singing voice. He was so well known for eating leeks that he acquired the nickname, Porophagus (leek eater).
Leeks may have been introduced to Wales via Phoenician traders. The subsequent popularity of leeks in that country is exhibited by the fact that in 620 AD (or perhaps 640), King Cadwallader and his men wore leeks in their hats to differentiate themselves from their enemies, the Saxons. The onion-like vegetable was associated with Saint David and it was said that any maiden who slept with a leek under her pillow on his feast day (March 1st) would see her future husband in her dreams. The leek has become a national symbol of Wales.
Leeks were first brought to the United States, Canada, and Australia by the early settlers of those respective nations. The French call the leek, poireau, which also means "simpleton". In Europe, leeks are thought of as a kind of "poor man's asparagus". Agatha Christie named one of her most famous characters, the French detective, Poirot, after the leek. Today leeks are not as popular as they were in ancient times, largely because other similar vegetables such as onions are more convenient to use. - In Depth Info
Though leeks contain proportionately less thio-sulfinites than that in garlic, they still possess significant amounts of these anti-oxidants such as diallyl disulfide, diallyl trisulfide and allyl propyl disulfide. These compounds convert to allicin by enzymatic reaction when the stalk disturbed (crushing, cutting etc). Allicin also decreases blood vessel stiffness by release of nitric oxide (NO); thereby bring reduction in the total blood pressure. It also blocks platelet clot formation and has fibrinolytic action in the blood vessels which, helps decrease overall risk of coronary artery disease (CAD), peripheral vascular diseases (PVD), and stroke. - Nutrition & You
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. (Folate is a key B complex vitamin for supporting our cardiovascular system, because it helps keep our levels of homocysteine in proper balance. Excessively high levels of homocysteine are a risk factor for many cardiovascular diseases.) - Worlds Healthiest Foods
Leeks are a rich source of vitamin A. One hundred grams contain approximately 33 percent of your daily recommended total. Vitamin A is also known as the anti-infective vitamin, according to the Linus Pauling Institute. It functions by maintaining the integrity and health of the mucosal linings of your nose, throat, urinary tract and digestive tract. Vitamin A also plays a key role in the development and activation of white blood cells. - Live Strong
Leeks are one of the best sources of dietary fiber, a distinct type of carbohydrate that passes through the human digestive system and energizes the body's many functions, including digestion and metabolism. Because leeks are a bit hard to chew (as are most fibrous vegetables), they help people eat slower and more properly digest food. This also aids in preventing overeating and allowing the body to feel more full. - E How
Leeks are great source of minerals and vitamins that are essential for optimum health. Their leafy stems indeed contain several vital vitamins such as pyridoxine, folic acid, niacin, riboflavin, and thiamin in healthy proportions. 100 g fresh stalks provide 64 µg of folates. Folic acid is essential for DNA synthesis and cell division. Their adequate levels in the diet during pregnancy can help prevent neural tube defects in the newborn babies. - Nutrition & You