Not all lettuce is created equal, but if you start your meal with a salad made of romaine lettuce you will be sure to add not only a variety of textures and flavors to your meal but an enormous amount of nutritional value. Most of the domestic U.S. harvest of romaine lettuce and other salad greens comes from California and is available throughout the year.
Lettuce is synonymous with salads as they are predominantly made from crispy green lettuce leaves. Most varieties of lettuce exude small amounts of a white, milky liquid when their leaves are broken. This "milk" gives lettuce its slightly bitter flavor and its scientific name, Lactuca sativa derived from the Latin word for milk.
Want to maximize the health benefits of your salads? Start with romaine lettuce for a salad guaranteed to be packed with nutrients. The vitamins, minerals, phytonutrients and fiber found in romaine lettuce are especially good for the prevention or alleviation of many common health complaints.
Due to its extremely low calorie content and high water volume, romaine lettuce—while often overlooked in the nutrition world—is actually a very nutritious food. Based on its nutrient richness, our food ranking system qualified it as an excellent source of vitamin A (notably through its concentration of the pro-vitamin A carotenoid, beta-carotene), vitamin K, folate, and molybdenum. Romaine lettuce also emerged from our ranking system as a very good source of dietary fiber, four minerals (manganese, potassium, copper, and iron), and three vitamins (biotin, vitamin B1, and vitamin C).
Romaine's vitamin C and beta-carotene content make it a heart-healthy green. 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 in the 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 adds another plus in its column of heart-healthy effects. In the colon, fiber binds to bile salts and removes them from the body. This forces the body to make more bile, which is helpful because it must break down cholesterol to do so. This is just one way in which fiber is able to lower high cholesterol levels.
Equally beneficial to heart health is Romaine's folic acid content. This B vitamin is needed by the body to convert a damaging chemical called homocysteine into other, benign substances. If not converted, homocysteine can directly damage blood vessels, thus greatly increasing the risk of heart attack and stroke. In addition, romaine lettuce is a very good source of potassium, which has been shown in numerous studies to be useful in lowering high blood pressure, another risk factor for heart disease. With its folic acid, vitamin C, beta-carotene, potassium, and fiber content, romaine lettuce can significantly contribute to a heart-healthy diet.
The words lettuce and salad are practically interchangeable since most salads are made predominantly with the green crispy leaves of lettuce. Most varieties of lettuce exude small amounts of a white, milky liquid when their leaves are broken. This "milk" gives lettuce its slightly bitter flavor and its scientific name, Lactuca sativa since Lactuca is derived from the Latin word for milk.
Lettuce can be classified into various categories with the most common being:
While vegetables such as arugula, watercress and mizuna are not technically lettuce, these greens are often used interchangeably with lettuces in salads.
Native to the eastern Mediterranean region and western Asia, lettuce has a long and distinguished history. With depictions appearing in ancient Egyptian tombs, the cultivation of lettuce is thought to date back to at least 4500 BC. The ancient Greeks and Romans held lettuce in high regard both as a food and for its therapeutic medicinal properties.
In China, where lettuce has been growing since the 5th century, lettuce represents good luck. It is served on birthdays, New Year's Day and other special occasions. Christopher Columbus introduced varieties of lettuce to North America during his second voyage in 1493. Lettuce was first planted in California, the lettuce capital of the United States, by the Spanish missionaries in the 17th century. Its popularity across the US did not become widespread until centuries later with the development of refrigeration and railway transportation.
Regardless of the type, all lettuces 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. Lettuces such as Romaine and Boston should have compact heads and stem ends that are not too brown.
At WHFoods, we encourage the purchase of certified organically grown foods, and lettuce is no exception. Repeated research studies on organic foods as a group show that your likelihood of exposure to contaminants such as pesticides and heavy metals can be greatly reduced through the purchased of certified organic foods, including lettuce. In many cases, you may be able to find a local organic grower who sells lettuce but has not applied for formal organic certification either through the U.S. Department of Agriculture (USDA) or through a state agency. (Examples of states offering state-certified organic foods include California, New York, Oregon, Vermont, and Washington.) However, if you are shopping in a large supermarket, your most reliable source of organically grown lettuce is very likely to be lettuce that displays the USDA organic logo.
Since different types of lettuce have different qualities, different methods should be used when storing. Romaine and leaf lettuce should be washed and dried before storing in the refrigerator to remove their excess moisture, while Boston lettuce need not be washed before storing. A salad spinner can be very helpful in the drying of lettuce (and other salad ingredients as well). These lettuces should be either stored in a plastic bag or wrapped in a damp cloth and stored in the refrigerator crisper.
To store arugula, watercress and other types of salad greens that are sold with their roots attached, wrap the roots in a damp paper towel and place the entire greens in a plastic bag.
Romaine lettuce will keep for five to seven days, Boston and leaf lettuce for two to three days, while fragile greens such as arugula and watercress ideally should be prepared the day of purchase. All types of lettuce should be stored away from ethylene-producing fruits, such as apples, bananas and pears, since they will cause the lettuce leaves to brown.
Here is some background on why we recommend refrigerating lettuce. Whenever food is stored, four basic factors affect its nutrient composition: exposure to air, exposure to light, exposure to heat, and length of time in storage. Vitamin C, vitamin B6, and carotenoids are good examples of nutrients highly susceptible to heat, and for this reason, their loss from food is very likely to be slowed down through refrigeration.
For some of our favorite recipes, click Recipes.
If you'd like even more recipes and ways to prepare lettuce the Nutrient-Rich Way, you may want to explore The World's Healthiest Foods book.
Romaine Lettuce, raw
GI: very low
|vitamin K||96.35 mcg||107||120.6||excellent|
|vitamin A||409.37 mcg RAE||45||51.2||excellent|
|fiber||1.97 g||8||8.9||very good|
|manganese||0.15 mg||8||8.4||very good|
|potassium||232.18 mg||7||7.5||very good|
|biotin||1.79 mcg||6||6.7||very good|
|vitamin B1||0.07 mg||6||6.6||very good|
|copper||0.05 mg||6||6.3||very good|
|iron||0.91 mg||5||5.7||very good|
|vitamin C||3.76 mg||5||5.6||very good|
|vitamin B2||0.06 mg||5||5.2||good|
|omega-3 fats||0.11 g||5||5.2||good|
|vitamin B6||0.07 mg||4||4.6||good|
|pantothenic acid||0.13 mg||3||2.9||good|
Density>=7.6 AND DRI/DV>=10%
Density>=3.4 AND DRI/DV>=5%
Density>=1.5 AND DRI/DV>=2.5%