Lettuce

Health Benefits

The old record — wageo (萵苣). The Donguibogam, in its Tangaekpyeon volume on materia medica, lists lettuce under the name wageo (萵苣). Baekgeo (白苣) and saengchae (生菜) are also handed down as old names for it. The name and the fact of that entry are what can be confirmed; what an old medical text wrote differs from how it is judged today.

The lactones in the sap. Compositional analysis confirms that the white sap running from a cut stem or leaf carries sesquiterpene lactones such as lactucin and lactucopicrin. They account for the faint bitterness, which grows stronger as the plant bolts and sends up a flower stalk.

The scope of the sleep research. Studies that pair lettuce with sleep were run on extracts drawn from the leaves of particular cultivars such as Heukharang, a different set of conditions and quantities from lettuce eaten as food. Studies in people are scarce, so what can be stated today goes only as far as the composition.

Nutrition

• Lactucin (Found in the milky sap) — A sesquiterpene lactone behind the faint bitterness
• Folate (Present in the leaves) — One of the water-soluble B vitamins
• Anthocyanins and beta-carotene (Leaf pigments) — Anthocyanins color the red leaves; beta-carotene runs high in the deep green ones

Water content 95%+ Lettuce is around 95% water, high even among vegetables. A full bowl carries almost no calorie burden, and most of the crispness comes from that water.

Lactucin & lactucopicrin The white sap that flows when a lettuce stem is cut holds the sesquiterpene lactones lactucin and lactucopicrin. They account for the faint bitterness, and the old story that eating lettuce brings on drowsiness is handed down alongside that sap. The related research, though, has mostly used extracts drawn from the leaves, so it cannot be carried straight over to lettuce eaten fresh in a wrap.

Luteolin, kaempferol & quercetin Flavonoids such as luteolin, kaempferol and quercetin are found in lettuce leaves. Their capacity to neutralize reactive oxygen species is something laboratory assays address; it does not mean the same thing happens in the body when a person eats lettuce.

Vitamin K, A, folate & C Lettuce is comparatively high in vitamin K and beta-carotene, and carries folate and vitamin C as well. The deeper-colored leaves of romaine or green leaf lettuce hold more, supplying more micronutrients than the same weight of head lettuce.

Potassium & dietary fiber Potassium and dietary fiber are present. Nutrition research discusses potassium in connection with sodium excretion, and fiber with bowel movement. With so much water, the vegetable stays low in calories for its bulk.

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. Chili Pepper (Gochu) · Garlic

○ 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. Chili Pepper (Gochu) · Cucumber

○ 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)