How Leeks Can Protect You from Both Cancer & Heart Disease

September 8, 2019

The leek is a sister plant to onion and garlic, and like those incredible nutrient-rich foods, leeks offer a whole host of health benefits.

The list of what leeks can do is a long one. From preventing inflammation — the root of most diseases — to protecting the body from cancer, heart disease and everything in between, there are plenty of reasons to make leeks a regular part of your diet.

So what are leeks, and how can you start taking advantage of the many benefits that they have to offer? Keep reading for everything you need to know about this power-packed veggie and how to add it to your diet.

What Are Leeks? (Leek Nutrition Facts)

What are leeks? Botanically speaking, leeks are part of the vegetable genus Allium, which is part of the Amaryllidacea family.

The edible section of the leek plant is a bundle of leaf sheaths, which is commonly confused with a stalk or stem. While onions and garlic form a tight bulb, leeks produce a long cylinder of leaf sheaths that are blanched by spreading soil around them.

The more of the plant that can be prevented from entering photosynthesis, the more nutritional punch it will have.

What do leeks taste like?

These crunchy, firm veggies have a mild taste that is very similar to onions. Other common leek substitutes include green onions and shallots, both of which boast similar flavor profiles.

Native to the Mediterranean and Central Asia, leeks have also been a staple of many European diets for centuries, and they are found in many leeks recipes around the globe.

Leeks are a great source of vitamins A, K and C, as well as folate and fiber.

100 grams of leeks contains the following nutrients:

61 calories
14.2 grams carbohydrates
1.5 grams protein
0.3 grams fat
1.8 grams fiber
47 micrograms vitamin K (59 percent DV)
1,667 international units vitamin A (33 percent DV)
0.5 milligrams manganese (24 percent DV)
12 milligrams vitamin C (20 percent DV)
64 micrograms folate (16 percent DV)
0.2 milligrams vitamin B6 (12 percent DV)
2.1 milligrams iron (12 percent DV)
28 milligrams magnesium (7 percent DV)
59 milligrams calcium (6 percent DV)
0.1 milligrams copper (6 percent DV)
180 milligrams potassium (5 percent DV)
0.9 milligrams vitamin E (5 percent DV)

Top Benefits

1. Protect Against Cancer

The most widely researched feature of leeks is their ability to protect against different kinds of cancer, thanks to the presence of several cancer-fighting compounds.

One such cancer-protective component is inulin, a dietary fiber that belongs to the fructan family. Inulin stores energy in plants, usually taking the place of other carbohydrates, such as starch.

In one study published in Genetics and Molecular Research, inulin was tested for its ability to protect DNA from damage that causes mutations. Mutations from damaged DNA are often considered to be the reason many cancers form.

Other research has focused on the major impact of leeks on cancers of the gastrointestinal tract. Consuming Allium vegetables is also correlated with a significant decrease in risk for prostate cancer.

Another factor in the leek’s cancer-fighting ability is diallyl trisulfide, a bioactive compound found in Allium vegetables. Also referred to as DATS, this valuable substance has been shown to stop the growth of new tumor cells and prevent the formation of blood vessels in existing tumor cells.

Leeks also contain allicin, an organosulfur compound that produces sulfenic acid as it digests. That may not sound thrilling, until you realize that sulfenic acid neutralizes the spread of cancer-causing free radicals in your body faster than any other nutrient.

Perhaps the most fascinating element in leeks, however, is kaempferol. This natural flavonol is an antioxidant, relieving oxidative stress in the body. According to one review of its properties:

Numerous preclinical studies have shown that kaempferol… [has] a wide range of pharmacological activities, including antioxidant, anti-inflammatory, antimicrobial, anticancer, cardioprotective, neuroprotective, antidiabetic, anti-osteoporotic, estrogenic/antiestrogenic, anxiolytic, analgesic and antiallergic activities.

2. Protect Heart Health

The flavonoids found in leeks are also associated with a lower risk of heart disease.

Flavonoids have a positive impact on blood pressure, vascular function and cholesterol levels. This protection is also partially due to the presence of kaempferol in leeks.

Leeks also contain a high concentration of the B vitamin folate. Folate plays a critical role in heart health.

It reduces levels of homocysteine in blood, which is a compound linked to risk of heart attack and stroke.

The third heart-protecting trait of leeks is their concentration of antioxidant polyphenols. Polyphenols shield blood vessels and cells from oxidative damage, which can help protect heart health and prevent disease.

3. Support Healthy Pregnancy

Leeks contain a good amount of folate in each serving, which has long been known to be a key component of a healthy pregnancy.

Folate aids in DNA absorption and cell division. It can also help prevent miscarriage, as well as neural tube defects, which are a type of birth defect that occurs when the spine and back do not properly close during fetal development.

Allium fruits and vegetables also lessen the risk for spontaneous preterm delivery, especially in the 28- to 31-week gestational period. This is important, because your baby needs plenty of time to develop in the womb in order to be delivered healthy and safe.

4. Regulate Cholesterol

The sulfur-containing compounds in leeks may also naturally reduce bad cholesterol levels, which is especially important if you’re at risk for heart disease.

Allicin, one of the compounds we discussed in the cancer-preventing qualities of leeks, inhibits a specific enzyme in the liver responsible for cholesterol production, HMG-CoA reductase.

The phytonutrients, sulfides and thiols in leeks may also help regulate cholesterol and fight inflammation in the body.

5. Boost Metabolism and Promote Weight Loss

With just 61 calories per serving, leeks bulk up a meal by helping you feel full without bumping up your daily calorie consumption.

Additionally, as high-fiber foods, they take longer to digest, meaning you won’t get hungry again very quickly after eating them.

Their fiber content also works as a metabolism booster, allowing you to burn more calories faster and maintain energy levels.

6. Improve Gut Health

The leek is rich in prebiotics, which are a type of fiber that feed the beneficial bacteria in the gut.

Prebiotics enhance nutrient absorption, eliminate noxious waste matter in your body, stimulate the movement of food through the intestines and secrete digestive fluids.

High-fiber foods, such as leeks, can also help reduce inflammation to protect against conditions like leaky gut syndrome.

7. Fight Infection

Leeks are well-known for their natural treatment of infections, because of their soothing action and antiseptic effect on different body systems.

They also contain a significant amount of vitamin A, which supports the development of healthy red and white blood cells that transport oxygen and fight off infection.

The Welsh onion, a sister vegetable to the leek, has been researched for its flu-fighting properties. It’s suspected that its ability to fight the influenza virus is due to the presence of fructans in the vegetable — the same fructans contained in leeks.

While a comparable study on leeks has not been published, it’s a safe assumption that this is probably part of why leeks exhibit the same anti-flu properties.

8. Other Benefits

The list of benefits continues with leeks. Research shows they can also:

Improve mood and cognitive function, including concentration and memory retention
Help your retinas see better in low light, thanks to the presence of vitamin A
Protect your eye tissue from oxidative damage that can cause cataracts and age-related macular degeneration, due to its content of antioxidants like lutein and zeaxanthin
Keep your bones healthy by regulating blood flow, activating the protein osteocalcin and providing a good amount of calcium and magnesium
Prevent anemia and treat anemic symptoms by providing both iron and vitamin C, which helps your body absorb the iron you consume

Healthy Recipes (Plus How to Choose, Store and Cook)

While you can find them year-round at most major grocery stores, leeks are most fresh during the winter and early spring.

When searching for the perfect organic leeks, look for uniformly sized, long, firm, white stalks with a healthy root bulb (no larger than 1.5 inches in diameter), and avoid leeks that may have yellowed.

Store them in your refrigerator, wrapped in a paper towel or plastic bag. They should stay fresh for anywhere from two days to a week.

There are two main methods for how to prepare leeks. Regardless of which method you choose, it’s important to first rinse the vegetables thoroughly, as leeks usually come with dirt or sand still on the outside.

The simplest method for how to cut a leek assumes that it will be chopped to use in soup:

First, cut the root from the leek.
Then, slice lengthwise.
After chopping the leeks, put them in a bowl of cold water and use your hands to agitate the water and remove any additional dirt.

To prepare leeks to use whole:

Use a sharp knife (starting at about a quarter inch below the lowest opening of the leek) to fan out the dark part of the leek.
Clean the long, fanned tops thoroughly under cold water.
Then cut off the dark tops (leaving about 2–3 inches of the fanned area) and either store or discard them. The dark section of a leek is generally used only to flavor soups and stews or to create stock.
Last, cut the root end of the leek off, staying as close as possible to the root to make sure the vegetable stays in one piece.

Generally, leeks are eaten boiled, fried or raw and added to a variety of leeks recipe options. However, the highest concentration of antioxidants and healthy goodness are maintained in steamed leeks rather than boiled leeks.

Here are a few delicious leek recipes that you can try out to get started:

Risks and Side Effects

While leeks are virtually anti-allergenic, they’re part of a small group of foods that contain oxalates, which are naturally occurring ions found in plants, animals and humans.

Generally, this is nothing to be concerned about — however, in people who have untreated gallbladder or kidney problems, a buildup of oxalates in body fluids could possibly cause complications in pre-existing conditions.

If you have untreated gallbladder or kidney issues, consult with your doctor before consuming high quantities of leeks.

Final Thoughts

What is a leek? The leek vegetable belongs to the Allium genus of plants, along with garlic, chives, onions and scallions.
The leek taste and texture are often described as mild and crunchy, which is similar to green onions, white onions and shallots.
Each serving is low in calories but rich in vitamins A, K and C, as well as folate and fiber.
What are leeks good for? Potential leek benefits include improved gut health, increased metabolism, lower cholesterol levels, protection against cancer and more.
There are several options for how to cook leeks in soup or other leek recipe ideas, which typically involve using whole, chopped or diced leeks.
Leeks can be a great addition to soups, stews, salads and side dishes. They can also be enjoyed boiled, steamed or raw to add a punch of nutrition to your daily diet.