Lettuce and tomatoes both help you reach your weekly veggie intake — 21 cups for men or 17.5 cups for women, according to the U.S. Department of Agriculture. They offer some nutritional differences — for instance, tomatoes contain the cancer-fighting compound lycopene, a nutrient not found in lettuce. However, lettuce and tomatoes also share a few common essential nutrients that help maintain your health.
Tomatoes and lettuce both provide you with fiber. Fiber aids in healthy digestion. A cup of chopped tomatoes provides 2.2 grams of fiber toward this goal. Romaine, butterhead and iceberg lettuce contain 2, 1.2 or 1.8 grams of fiber, respectively, per two-cup serving.
Incorporating tomatoes and lettuce into your diet also helps you reach your recommended daily intake of vitamin C, also called ascorbic acid. Tomatoes serve as a rich source of ascorbic acid. A cup of chopped tomatoes contains 25 milligrams of vitamin C — one-third of the 75 milligrams required daily for women and 28 percent of the 90 milligrams needed for men, according to the NYU Langone Medical Center. Lettuce contains smaller amounts of vitamin C, with a 2-cup serving of romaine, butterhead or iceberg lettuce each providing approximately 4 milligrams of ascorbic acid. Your body uses this vitamin C to nourish your immune system, aid in wound healing and promote healthy brain function.
Tomatoes and lettuce — particularly romaine lettuce — boost your intake of vitamin A. Your body uses vitamin A to aid in cell communication, and the vitamin A in your system helps to guide cell development. Vitamin A also helps your body for rhodopsin, a chemical important to vision. Men need 3,000 international units of vitamin A daily to maintain good health, according to the Office of Dietary Supplements, while women need 2,333 IU. A two-cup serving of either romaine or butterhead lettuce provides your entire daily intake of vitamin A, containing 8,188 IU or 3,644 IU of vitamin A, respectively. Tomatoes contain 1,499 IU of vitamin A per cup, and a two-cup serving of iceberg lettuce provides 722 IU of vitamin A.