Romaine lettuce (Lactuca sativa longifolia) is an annual plant of the Asteraceae family. The Asteraceae family contains the herbs arnica, burdock, boneset, calendula, chamomile, chicory, cronewort (mugwort), coltsfoot, dandelion, echinacea, elecampane, feverfew, gravel root, grindelia, liferoot, milk thistle, tansy, yarrow, valerian, wormwood, and wild lettuce. It also contains the foods sunflower seeds, lettuces, true artichokes, sun chokes (also known as Jerusalem artichokes), escarole, and endive. And it contains the decorative flowers asters, chrysanthemums, dahlias, bachelor’s buttons, daisies, cosmos, coneflowers, goldenrods, sunflowers, and zinnias.

Romaine (also known as Cos lettuce) forms an erect, compact rosette of elongated leaves, approaching the character of a head. A white latex oozes from its leaf base and the thicker ribs of older, larger leaves and is reflected in the first part of its Latin name, Lactuca, which means milk.  It is relatively tolerant to heat and was developed in a moderately warm climate.

A Romaine-like lettuce appeared in Egyptian tomb paintings that date back to 4500 B.C. Romaine eventually made its way to the Middle East and to the Mediterranean. Romaine was in common use on the Greek island of Kos, from which it gets its British name. In ancient Rome, Romaine lettuce was eaten both cooked and raw, and was a common part of the Roman diet. The Romans called it Cappadocian lettuce, and believed in its healthful and medicinal properties. According to Pliny, the emperor Augustus Caesar erected a statue to honor its healing abilities after being cured of a serious illness. Lettuce juice was used as a medicine by many ancient herbalists.

The name Romaine dates from the time when the Popes moved from Rome to Avignon in the 14th century, bringing this type of lettuce with them and having it grown in the palace gardens. Light-green, dark-green, and red-spotted forms of Romaine were described in 1623. The type was common in Italy in the Middle Ages and is said to have been taken to France from Italy in 1537 by Rabelais. Toward the end of the 16th century it was still rarely grown in France and Germany.

For much of the 20th century, Romaine wasn’t known at all to many Americans. That’s because of the overwhelming success of iceberg lettuce, which can withstand days if not weeks of shipping. As late as the mid-1970s, iceberg lettuce accounted for more than 95% of all of the lettuce grown in this country. Then along came the reborn Caesar salad. Invented in a Tijuana restaurant in the 1920s, for decades the Caesar salad was known as a California specialty. In the late 1970s the Ceasar salad was “discovered” by the fast food industry, and there followed a couple of decades of popularity.

The top Romaine lettuce producing countries are China, United States, Spain, Italy and India.  In the United States, California produces about 75% of the Romaine lettuce. The second top producing state is Arizona which accounts for another 19%.

Because of its extremely low calorie content and high water volume, Romaine lettuce is a very nutritious food. It is an excellent source of vitamin A, vitamin K, vitamin C, and folate. In addition, Romaine lettuce is a very good source of fiber, molybdenum, manganese, potassium, and iron. It is also a good source of thiamine, omega-3 essential fatty acids, riboflavin, vitamin B6,  magnesium, calcium, phosphorus, and copper. It contains substantial protein, niacin, zinc, pantothenic acid, vitamin E, and selenium.

Romaine is especially good for your heart. The vitamin C and beta-carotene work together to prevent the oxidation of cholesterol. When cholesterol becomes oxidized, it becomes sticky and starts to build up on your artery walls, forming plaques. If these plaques become too large, they can block off blood flow or break, causing a clot that triggers a heart attack or stroke. The fiber in Romaine lettuce binds to bile salts in your colon and removes them from your body. This forces your body to make more bile, which is helpful because it must break down cholesterol from your blood to do so, lowering your blood cholesterol levels. Your body uses folate to convert a damaging chemical called homocysteine into other, benign substances. Homocysteine can directly damage blood vessels, greatly increasing your risk of heart attack and stroke. In addition, Romaine lettuce is a very good source of potassium, which can lower high blood pressure, another risk factor for heart disease.

Nutrients in 2 cups (94 grams) of Romaine Lettuce

Romaine lettuce should feature crisp looking, unwilted leaves that are free of dark or slimy spots. In addition, the leaves” edges should be free of brown or yellow discoloration. Romaine should have compact heads and stem ends that are not too brown. According to the Environmental Working Group, lettuce is among the 12 foods on which pesticide residues have been most frequently found; therefore, it’s best to choose organic Romaine.

Romaine lettuce should be washed and dried before storing in the refrigerator to remove excess moisture. A salad spinner can be very helpful in the drying of lettuce (and other salad ingredients as well). Romaine can be wrapped in a damp cloth and stored in the refrigerator crisper. Romaine lettuce will keep for five to seven days. All types of lettuce should be stored away from ethylene-producing fruits, such as apples, bananas, and pears, because ethylene will cause the lettuce leaves to brown.

To clean Romaine lettuce, first remove the outer leaves and with one slice cut off the tips of the stems, which tend to be bitter. Chop the remaining lettuce to the desired size and discard the bottom root portion. Rinse and pat dry or use a salad spinner if you have one available to remove the excess water.

You can give sandwiches extra crunch (and nutrients) by garnishing with Romaine lettuce leaves. Be creative with salads: use a variety of different lettuce types and add your favorite foods. Whether they’re vegetables, fruits, seeds, nuts, whole grains, whole wheat croutons, or tofu, almost every food goes well with lettuce.