Lettuce is considered a hardy vegetable that thrives in cool weather. This vegetable is popular throughout the world and available in grocery stores year-round. There are many types and varieties of lettuce. The five most common types of lettuce are butterhead, crisphead, loose-leaf, romaine and stem. Common varieties include arugula, escarole, endive, field, radicchio and chicory. Crisphead lettuce, more commonly known as iceberg lettuce, used to dominate selections; however, other varieties have gained popularity. Lettuce contains many nutrients and is an important part of a healthful diet.
Nutritional Value and Serving Size
The nutritional value of lettuce varies widely among varieties. Lettuce is a good source of vitamins A and C, beta carotene, potassium, calcium, iron and copper. It also contains trace amounts of protein, fat, carbohydrates, folate and dietary fiber. Dietary fiber is found in the spine and ribs while vitamins and minerals are concentrated in the lettuce leaf. In general, the darker the variety, the greater the nutritional value of the lettuce. For example, the Your Personal Nutrition Guide website states that romaine lettuce contains up to six times more vitamin C and five times more beta-carotene than iceberg lettuce. On average, 1 cup of chopped lettuce is equal to one serving. Depending upon the type of lettuce, one leaf may be equivalent to one serving.
Calories
A leaf of lettuce contains between five and 10 calories, depending upon the type of lettuce and the size of the leaf. Because the calorie content of lettuce is very low compared with other foods, it is considered a free food. This means you can eat as much of it as you would like. Lettuce is an excellent high volume, low-calorie food to satisfy your appetite. You can use it to help fill your plate up in place of high-calorie foods. However, you do not typically eat lettuce by itself. It is more commonly consumed with a variety of vegetables or fruits, used as a filling on sandwiches or used to add color as a garnish. It is the foods that you add to lettuce that can cause the calorie content to rise.
Fiber
Dietary fiber is essential to good health. It clears the body of cholesterol, adds bulk to stools, eases bowel movements and helps you feel fuller longer. Although a piece of lettuce typically contains less than 1 g of fiber, it does add roughage to your diet and helps increase your daily fiber intake.
Antioxidants
Lettuce is rich in beta carotene, a yellow-orange antioxidant found in an array of fruits and vegetables. Its color is hidden due to the green pigment known as chlorophyll in lettuce. In the body, beta carotene is converted into vitamin A. Vitamin A is necessary for healthy skin, eyes and hair. In its beta carotene form, it boosts the immune system and prevents infection. Lettuce is a good source of another antioxidant: vitamin C. Vitamin C is responsible for healthy skin, bones, teeth, cartilage and blood vessels. It aids the body in iron absorption and wound healing. Depending upon the type of lettuce, a leaf contains about 70 percent of your daily vitamin A needs and 20 percent of your vitamin C needs with 229 to 4495 mcg of beta-carotene.
Minerals
Lettuce also contains a number of essential minerals. Although it is sodium-free, it contains calcium, potassium, iron and copper. One piece of lettuce is fairly small and therefore contains only trace amounts of each of these nutrients. However, eating lettuce will help you meet your daily mineral needs. Calcium is a major component of bones and teeth. It is also required for blood pressure regulation, enzyme formation and blood clotting. Potassium works closely with sodium to maintain your body’s fluid and electrolyte balance, normal blood pressure, heartbeat and nerve impulses. Iron enables red blood cells to carry oxygen throughout the body while copper synthesizes connective tissue and promotes optimal brain function.
References
- University of Illinois Extension: Watch Your Garden Grow – Lettuce
- Centers for Disease Control and Prevention: Vegetable of the Month – Lettuce
- Colorado State University Extension; Health Benefits and Safe Handling of Salad Greens; M. Bunning and P. Kendall; June 2007
- Your Personal Nutrition Guide: Lettuce Nutritional Facts
- National University Hospital; Vitamins and Minerals Chart; June 2006
Member Comments