Leeks (Allium fistulosumL.) belong to the allium family of vegetables, which also includes onions, shallots, scallions, chives, and garlic. They have a mild, slightly sweet taste and are commonly used in dishes like soups and pasta.
Leeks are a rich source of antioxidant plant compounds and nutrients that may benefit health in several ways, such as protecting against certain diseases and promoting gut health.
Here's everything you need to know about leeks, including their potential health benefits, nutrition, and more.
Leeks are concentrated in cellular-protective and anti-inflammatory compounds, such as flavonoids and organosulfur compounds. For example, leeks are high in quercetin, a flavonoid compound that may help protect cells from oxidative damage, which may help lower the risk of chronic diseases, like heart disease.
Numerous studies have found that people with higher intakes of flavonoids, including quercetin, have lower rates of heart disease and heart-related health complications, such as heart attacks. Researchers suggest that the antioxidant and anti-inflammatory activity of quercetin and other flavonoids contributes significantly to their beneficial impact on heart health.
Quercetin may also help protect against neurodegenerative diseases by suppressing inflammation in the brain, stimulating the regeneration of nerve cells, and interfering with the formation of neurotoxic substances associated with the development of Alzheimer's disease.
2. May Protect Against Certain Cancers
A diet rich in allium vegetables, like leeks, may help protect against some cancers, such as breast cancer. The organosulfur compounds, flavonoids, and antioxidant nutrients concentrated in leeks have powerful anticancer effects, and studies show that people who consume more allium vegetables have lower rates of certain cancers.
For example, a 2022 review of 17 studies found that women with the highest intake of total allium vegetables, including garlic, onions, leeks, and chives, had a 30% lower risk of breast cancer compared to women with the lowest intake.
Research findings also suggest that allium vegetables may be protective against stomach cancer, prostate cancer, and many other common types of cancer. Findings from a 2022 review of 25 studies suggested thatconsumption of allium vegetables could decrease the risk of non-digestive tract cancers, such as prostate cancer, by as much as 14%.
The flavonoid antioxidants, organosulfur compounds, and vitamin C found in leeks may protect against cancer by inhibiting cancer cell growth, reducing inflammation, and protecting cells from oxidative damage.
Leeks are an excellent source of prebiotics. Prebiotics are undigestible compounds found in certain foods that are broken down by gut bacteria in the large intestine.When bacteria break down or ferment prebiotics, it releases byproducts called short-chain fatty acids (SCFAs). SCFAs act as an energy source for the cells that line the colon and benefit gut health in several ways.
For example, SCFAs suppress inflammation in the intestines, regulate intestinal pH, and support the growth of beneficial bacteria. What's more, SCFAs have anticancer effects and may help protect against cancers of the digestive system, like colorectal cancer.
Additionally, leeks contain anti-inflammatory substances, like organosulfur compounds and flavonoids, which may help promote a healthy gut environment and protect against bowel-related diseases, such as inflammatory bowel disease, by reducing intestinal inflammation.
4. May Benefit Cognitive Function
Eating more vegetables, in general, is an effective way to boost brain health, but certain vegetables, like leeks, may be especially effective for protecting and improving cognitive function.
Leeks contain carotenoid pigments, which have been shown to benefit brain health. Leeks are especially rich in the carotenoids lutein and zeaxanthin. These pigments are found in high concentration in the retina, a layer of tissue located at the back of the eyeball. Macular pigment (MP), or the retinal accumulation ofluteinand zeaxanthin, is linked to cognitive function, with higher MP associated with better cognitive performance and memory.
A number of studies in both children and adults have shown that lower MP is related to poorer performance on cognitive tests, poorer memory, and slower reaction times, while higher MP is associated with better cognitive function.
Additionally, people with Alzheimer's disease have been found to have significantly lower MP compared to people without Alzheimer's.
Diets rich in leeks have also been associated with smaller improvements in cognitive performance, including attention and memory, and research suggests that consuming lutein-rich foods may help prevent cognitive decline. Leeks are amongst the richest sources of lutein and zeaxanthin you can eat, making them an important food for brain health.
Leeks provide several nutrients, such as vitamins A, C, and B6.
Here's the nutrition breakdown for a one-cup serving of cooked leek:
- Calories: 31
- Fat: 0 grams (g)
- Carbohydrates: 7.62 g
- Fiber: 1 g
- Protein: 0.81 g
- Vitamin A: 41 micrograms (mcg) or 5% of the Daily Value (DV)
- B6: 0.113 milligrams (mg) or 7% of the DV
- Copper: 0.062 mg or 7% of the DV
- Folate: 24 mcg or 6% of the DV
- Vitamin C: 4.2 mg or 5% of the DV
- Vitamin K: 25.4 mcg or 21% of the DV
- Manganese: 0.247 mg or 11% of the DV
Leeks are very low in calories, but do contain a decent amount of essential vitamins and minerals, including vitamins like vitamins A, B6, C, and K, and minerals like copper and manganese.
They're especially rich in vitamin K, a nutrient that's required for blood clotting and plays important roles in bone and heart health.
Additionally, leeks are also a good source of manganese, a mineral that's also required for blood clotting as well as energy metabolism, and the functioning of the immune and nervous systems.
Risks of Eating Leeks
Leeks are safe for most people to eat, but should be avoided by those who are allergic to leeks. Leeks contain a compound called diallyl disulfide, which can cause skin reactions, including an itchy, red rash called contact dermatitis, in some people.
Also, leeks are high in compounds called FODMAPs, which is an acronym that stands for Fermentable Oligo-, Di-, Mono-saccharides, And Polyols. FODMAPs are types of carbohydrates concentrated in certain foods, like garlic and leeks, that are poorly absorbed by the digestive system.
People who are sensitive to FODMAPs may experience digestive symptoms, such as bloating, diarrhea, and gas after consuming high-FODMAP foods. People with certain digestive conditions, like Irritable bowel syndrome (IBS), are more likely to be intolerant to FODMAPs.
People who are intolerant to FODMAPs may need to cut high-FODMAP foods, like leeks, out of their diet to avoid gastrointestinal side effects.
Leeks can be added to a variety of savory dishes and can be used in the same way as onions and shallots.
They have a mild, sweet, onion-like flavor and are delicious in baked goods, soups, egg dishes, and more.
Here are a few ways to add leeks to your diet:
- Add caramelized leeks to savory baked goods, sandwiches, eggs, and potato salad.
- Use leeks in stews, soups, and broths for a kick of flavor.
- Incorporate sautéed leeks into egg dishes like omelets and frittatas.
- Thinly slice or dice raw leeks and use them in salads or as a garnish.
- Try adding leeks to guacamole and tuna, chicken, and bean salads.
- Use leeks in place of onions in stir-fry dishes.
- Add leeks to pasta, rice, and quinoa recipes.
- Use the tough part of leeks to add flavor to sauces and broths.
Leeks should be thoroughly washed before cooking because dirt and other debris can get caught in their many layers.
Though the entire leek is edible, most people use the more tender white and lighter-green parts of the plant and discard the tougher, dark green top part. However, this dark green section can be saved and used to infuse flavor into broths, sauces, and other recipes and can be stored in your freezer until you're ready to use it.
A Quick Review
Leeks are allium vegetables that are concentrated in health-promoting plant compounds, such as flavonoids and organosulfur compounds.
Eating leeks may benefit health in several ways, from increasing the antioxidant density of your diet to protecting against cognitive decline and some health conditions, like breast cancer.
Leeks have a sweet, onion-like taste that pairs well with many savory foods, but keep in mind that they're high in FODMAPs and may cause unpleasant gastrointestinal side effects in sensitive people.
