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.

This chart graphically details the %DV that a serving of Romaine lettuce provides for each of the nutrients of which it is a good, very good, or excellent source according to our Food Rating System. Additional information about the amount of these nutrients provided by Romaine lettuce can be found in the Food Rating System Chart. A link that takes you to the In-Depth Nutritional Profile for Romaine lettuce, featuring information over 80 nutrients, can be found under the Food Rating System Chart.

• Health Benefits
• Description
• History
• How to Select and Store
• Tips for Preparing and Cooking
• How to Enjoy
• Nutritional Profile
• References

Health Benefits

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).

Salad Days Keep Your Heart Young

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.

Description

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:

• Romaine: Also known as Cos, this variety of head forming lettuce has deep green, long leaves with a crisp texture and deep taste.
• Crisphead: With green leaves on the outside and whitish ones on the inside, this variety of head lettuce has a crisp texture and a watery, mild taste. The best known variety of crisphead lettuce is iceberg.
• Butterhead: These types of lettuce feature tender large leaves that form a loosely arranged head that is easily separated from the stem, a sweet flavor and a soft texture. The best known varieties of Butterhead lettuce include Boston and Bibb.
• Leaf: Featuring broad, curly leaf varieties that are green and/or red, the leaf lettuces offer a delicate taste and a mildly crispy texture. Best known varieties of leaf lettuce include green leaf and red leaf.

While vegetables such as arugula, watercress and mizuna are not technically lettuce, these greens are often used interchangeably with lettuces in salads.

History

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.

How to Select and Store

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.

Tips for Preparing and Cooking

Tips for Preparing Romaine Lettuce

To clean lettuce, first remove the outer leaves and with one slice cut off the tips of the lettuce since they 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.

Wash greens such as arugula and watercress like you would spinach. Trim their roots and separate the leaves, placing them in a large bowl of tepid water and swishing them around with your hands. This will allow any sand to become dislodged. Remove the leaves from the water, empty the bowl, refill with clean water and repeat this process until no dirt remains in the water (usually two or three times will do the trick). Make sure your leaves are spun or patted dry before adding dressing so as not to dilute flavor.

How to Enjoy

A Few Quick Serving Ideas

• Give sandwiches extra crunch (and nutrients) by garnishing with lettuce leaves.
• When it comes to salads, the only limitation is your imagination. Be creative: use a variety of different lettuce types and add your favorite foods. Whether they're vegetables, fruits, seeds, nuts, whole grains, whole wheat croutons, soy products, meats or cheeses, most every food goes well with lettuce.
• For an interactive meal that is both unusual and fun, arrange nuts, diced vegetables, chicken and/or baked tofu and romaine lettuce leaves on a large plate. Everyone then has the chance to make their own lettuce pockets by placing their favorite fillings in a lettuce leaf and making a breadless sandwich wrap.

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.

Nutritional Profile

Romaine lettuce is an excellent source of vitamin A (in the form of carotenoids), vitamin K, folate and molybdenum. In addition, romaine lettuce is a very good source of dietary fiber, manganese, potassium, biotin, vitamin B1, copper, iron and vitamin C. It is also a good source of vitamin B2, omega-3 fatty acids, vitamin B6, phosphorus, chromium, magnesium, calcium and pantothenic acid.

Introduction to Food Rating System Chart

In order to better help you identify foods that feature a high concentration of nutrients for the calories they contain, we created a Food Rating System. This system allows us to highlight the foods that are especially rich in particular nutrients. The following chart shows the nutrients for which this food is either an excellent, very good, or good source (below the chart you will find a table that explains these qualifications). If a nutrient is not listed in the chart, it does not necessarily mean that the food doesn't contain it. It simply means that the nutrient is not provided in a sufficient amount or concentration to meet our rating criteria. (To view this food's in-depth nutritional profile that includes values for dozens of nutrients - not just the ones rated as excellent, very good, or good - please use the link below the chart.) To read this chart accurately, you'll need to glance up in the top left corner where you will find the name of the food and the serving size we used to calculate the food's nutrient composition. This serving size will tell you how much of the food you need to eat to obtain the amount of nutrients found in the chart. Now, returning to the chart itself, you can look next to the nutrient name in order to find the nutrient amount it offers, the percent Daily Value (DV%) that this amount represents, the nutrient density that we calculated for this food and nutrient, and the rating we established in our rating system. For most of our nutrient ratings, we adopted the government standards for food labeling that are found in the U.S. Food and Drug Administration's "Reference Values for Nutrition Labeling." Read more background information and details of our rating system.

In-Depth Nutritional Profile

In addition to the nutrients highlighted in our ratings chart, here is an in-depth nutritional profile for Romaine lettuce. This profile includes information on a full array of nutrients, including carbohydrates, sugar, soluble and insoluble fiber, sodium, vitamins, minerals, fatty acids, amino acids and more.

Romaine Lettuce, raw (Note: "--" indicates data unavailable)
2.00 cups (94.00 g)	GI: very low
BASIC MACRONUTRIENTS AND CALORIES
nutrient	amount	DRI/DV (%)
Protein	1.16 g	2
Carbohydrates	3.09 g	1
Fat - total	0.28 g	0
Dietary Fiber	1.97 g	7
Calories	15.98	1
MACRONUTRIENT AND CALORIE DETAIL
nutrient	amount	DRI/DV (%)
Carbohydrate:
Starch	0.00 g
Total Sugars	1.12 g
Monosaccharides	1.12 g
Fructose	0.75 g
Glucose	0.37 g
Galactose	0.00 g
Disaccharides	0.00 g
Lactose	0.00 g
Maltose	0.00 g
Sucrose	0.00 g
Soluble Fiber	-- g
Insoluble Fiber	-- g
Other Carbohydrates	0.00 g
Fat:
Monounsaturated Fat	0.01 g
Polyunsaturated Fat	0.15 g
Saturated Fat	0.04 g
Trans Fat	0.00 g
Calories from Fat	2.54
Calories from Saturated Fat	0.33
Calories from Trans Fat	0.00
Cholesterol	0.00 mg
Water	88.93 g
MICRONUTRIENTS
nutrient	amount	DRI/DV (%)
Vitamins
Water-Soluble Vitamins
B-Complex Vitamins
Vitamin B1	0.07 mg	6
Vitamin B2	0.06 mg	5
Vitamin B3	0.29 mg	2
Vitamin B3 (Niacin Equivalents)	0.45 mg
Vitamin B6	0.07 mg	4
Vitamin B12	0.00 mcg	0
Biotin	1.79 mcg	6
Choline	9.31 mg	2
Folate	127.84 mcg	32
Folate (DFE)	127.84 mcg
Folate (food)	127.84 mcg
Pantothenic Acid	0.13 mg	3
Vitamin C	3.76 mg	5
Fat-Soluble Vitamins
Vitamin A (Retinoids and Carotenoids)
Vitamin A International Units (IU)	8187.40 IU
Vitamin A mcg Retinol Activity Equivalents (RAE)	409.37 mcg (RAE)	45
Vitamin A mcg Retinol Equivalents (RE)	818.74 mcg (RE)
Retinol mcg Retinol Equivalents (RE)	0.00 mcg (RE)
Carotenoid mcg Retinol Equivalents (RE)	818.74 mcg (RE)
Alpha-Carotene	0.00 mcg
Beta-Carotene	4912.44 mcg
Beta-Carotene Equivalents	4912.44 mcg
Cryptoxanthin	0.00 mcg
Lutein and Zeaxanthin	2173.28 mcg
Lycopene	0.00 mcg
Vitamin D
Vitamin D International Units (IU)	0.00 IU	0
Vitamin D mcg	0.00 mcg
Vitamin E
Vitamin E mg Alpha-Tocopherol Equivalents (ATE)	0.12 mg (ATE)	1
Vitamin E International Units (IU)	0.18 IU
Vitamin E mg	0.12 mg
Vitamin K	96.35 mcg	107
Minerals
nutrient	amount	DRI/DV (%)
Boron	78.72 mcg
Calcium	31.02 mg	3
Chloride	53.58 mg
Chromium	1.25 mcg	4
Copper	0.05 mg	6
Fluoride	-- mg	--
Iodine	3.10 mcg	2
Iron	0.91 mg	5
Magnesium	13.16 mg	3
Manganese	0.15 mg	7
Molybdenum	5.64 mcg	13
Phosphorus	28.20 mg	4
Potassium	232.18 mg	5
Selenium	0.38 mcg	1
Sodium	7.52 mg	1
Zinc	0.22 mg	2
INDIVIDUAL FATTY ACIDS
nutrient	amount	DRI/DV (%)
Omega-3 Fatty Acids	0.11 g	5
Omega-6 Fatty Acids	0.04 g
Monounsaturated Fats
14:1 Myristoleic	0.00 g
15:1 Pentadecenoic	0.00 g
16:1 Palmitol	0.00 g
17:1 Heptadecenoic	0.00 g
18:1 Oleic	0.01 g
20:1 Eicosenoic	0.00 g
22:1 Erucic	0.00 g
24:1 Nervonic	0.00 g
Polyunsaturated Fatty Acids
18:2 Linoleic	0.04 g
18:2 Conjugated Linoleic (CLA)	-- g
18:3 Linolenic	0.11 g
18:4 Stearidonic	0.00 g
20:3 Eicosatrienoic	0.00 g
20:4 Arachidonic	0.00 g
20:5 Eicosapentaenoic (EPA)	0.00 g
22:5 Docosapentaenoic (DPA)	0.00 g
22:6 Docosahexaenoic (DHA)	0.00 g
Saturated Fatty Acids
4:0 Butyric	0.00 g
6:0 Caproic	0.00 g
8:0 Caprylic	0.00 g
10:0 Capric	0.00 g
12:0 Lauric	0.00 g
14:0 Myristic	0.00 g
15:0 Pentadecanoic	0.00 g
16:0 Palmitic	0.03 g
17:0 Margaric	0.00 g
18:0 Stearic	0.00 g
20:0 Arachidic	0.00 g
22:0 Behenate	0.00 g
24:0 Lignoceric	0.00 g
INDIVIDUAL AMINO ACIDS
nutrient	amount	DRI/DV (%)
Alanine	0.05 g
Arginine	0.05 g
Aspartic Acid	0.13 g
Cysteine	0.01 g
Glutamic Acid	0.17 g
Glycine	0.05 g
Histidine	0.02 g
Isoleucine	0.04 g
Leucine	0.07 g
Lysine	0.06 g
Methionine	0.01 g
Phenylalanine	0.06 g
Proline	0.04 g
Serine	0.05 g
Threonine	0.04 g
Tryptophan	0.01 g
Tyrosine	0.02 g
Valine	0.05 g
OTHER COMPONENTS
nutrient	amount	DRI/DV (%)
Ash	0.55 g
Organic Acids (Total)	0.00 g
Acetic Acid	0.00 g
Citric Acid	0.00 g
Lactic Acid	0.00 g
Malic Acid	0.00 g
Taurine	-- g
Sugar Alcohols (Total)	0.00 g
Glycerol	0.00 g
Inositol	0.00 g
Mannitol	0.00 g
Sorbitol	0.00 g
Xylitol	0.00 g
Artificial Sweeteners (Total)	-- mg
Aspartame	-- mg
Saccharin	-- mg
Alcohol	0.00 g
Caffeine	0.00 mg
Note: The nutrient profiles provided in this website are derived from The Food Processor, Version 10.12.0, ESHA Research, Salem, Oregon, USA. Among the 50,000+ food items in the master database and 163 nutritional components per item, specific nutrient values were frequently missing from any particular food item. We chose the designation "--" to represent those nutrients for which no value was included in this version of the database.

References

• Bazzano LA, He J, Odgen LG et al. Dietary intake of folate and risk of stroke in US men and women:NHANES I Epidemiologic Follow-up Study. Stroke 2002 May;33(5):1183-9. 2002.
• Ensminger AH, Ensminger, ME, Kondale JE, Robson JRK. Foods & Nutriton Encyclopedia. Pegus Press, Clovis, California. 1983.
• Ensminger AH, Esminger M. K. J. e. al. Food for Health: A Nutrition Encyclopedia. Clovis, California: Pegus Press; 1986. 1986. PMID:15210.
• Fortin, Francois, Editorial Director. The Visual Foods Encyclopedia. Macmillan, New York. 1996.
• Wood, Rebecca. The Whole Foods Encyclopedia. New York, NY: Prentice-Hall Press; 1988. 1988. PMID:15220.