Lettuce

Health Benefits

Sleep and relaxation. A study found that leaf extract of Heukharang, a Korean lettuce variety, promoted sleep through the GABA(A) receptor in animal testing. This offers a molecular mechanism that helps explain lettuce's traditional reputation as a calming, sleep-supporting vegetable.

Tradition meets modern science. The belief that lettuce aids relaxation and sleep is not limited to Korea and China — its use as a medicinal plant traces back as far as the pharaohs of ancient Egypt. It is notable that this far-reaching tradition is now unified under modern pharmacology by lactucin's activity at the GABA receptor.

Human sleep-quality RCT (Heukharang lettuce extract). In a 2025 randomized, double-blind, placebo-controlled trial of 91 Korean adults, supplementation with Heukharang lettuce leaf extract significantly improved sleep quality. PSQI scores were lower than in the placebo group (6.48 vs. 7.41, p=0.0462), actigraphy-measured total sleep time increased by roughly 35 minutes (p=0.0023), and polysomnography showed improved sleep efficiency — establishing human clinical evidence.

Nutrition

• Lactucin (Found in the milky sap) — Mild sedative effect; supports sleep
• Folate (49 mcg/100g) — Important during pregnancy and for cell formation
• Anthocyanins and beta-carotene (Leaf pigments) — Antioxidant

Pairings

○ Pork belly and beef — Wrapping grilled pork belly (samgyeopsal) or beef in a lettuce leaf — ssam — is a cornerstone of Korean food culture. The fat and protein of the meat meet the fiber, water, and calming effect of the lettuce, turning a heavy meal into a balanced, lighter finish.

○ Garlic, chili, and doenjang — Ssamjang, the dipping paste that goes inside the wrap, is built on garlic, chili, and doenjang (fermented soybean paste). Its heat and fermented depth balance the soft lettuce leaf, delivering several flavors in a single bite — the heart of Korea's ssam tradition.

○ Kimchi, cucumber, and chili — Add a piece of kimchi, a fresh green chili, and a clove of garlic to a single lettuce leaf and you complete both nutrition and flavor. Fermented foods meet fresh vegetables, supplying probiotics, vitamin C, and sulfur compounds all at once.

○ Olive oil and balsamic — In a Western salad, lettuce dressed with olive oil and balsamic vinegar is the most basic pairing of all. The fat in the olive oil helps the body absorb lettuce's fat-soluble vitamins, while the acidity of the balsamic crisply offsets the softness of the leaves.

○ An evening meal — Finishing dinner with lettuce lets lactucin's calming effect help ease you toward sleep. Traditionally it has been used to lighten the heaviness of a late meal while gently preparing the body to fall asleep naturally.

△ Large amounts right before driving or operating machinery — Lactucin, a compound in lettuce, has a mild sedative effect, so it's best to avoid eating large amounts right before driving or operating machinery. A normal serving with a meal is rarely an issue, but sensitive individuals may feel drowsy.

△ Weak digestion or a cold constitution — Lettuce is considered a "cooling" food, so people with weak stomachs or chronically cold hands and feet should avoid eating it in large quantities. Pairing it with warming seasonings like garlic or gochujang (Korean red-pepper paste) to restore balance is part of the wisdom behind Korea's ssam (lettuce-wrap) tradition.

△ Anticoagulants — Lettuce is relatively high in vitamin K, so anyone taking anticoagulants like warfarin should keep their intake consistent. Suddenly eating much more or much less can throw off the medication's effectiveness.

Varieties

• Green leaf lettuce — The most common, everyday lettuce
• Red leaf lettuce — Red-tinged leaves rich in anthocyanins
• Romaine — Crisp texture; the classic Caesar salad green
• Butterhead — Soft, mild, slightly nutty leaves
• Heukharang — 124x the lactucin and a deep sleep aid (developed by the Jeonnam Agricultural Research and Extension Services)