Health Benefits of Lettuce

Lettuce is a leafy vegetable, famous for giving salads their base. There are multiple types of lettuce, and they all share the scientific name Lactuca sativa.

The health benefits of lettuce come primarily from its vitamin content. Health benefits vary depending on the type of lettuce a person eats. All lettuces fall into one of four varieties:

  • Head lettuce (capitata)
  • Leaf lettuce (crispa)
  • Romaine lettuce (longifolia)
  • Celtuce lettuce (augustana)

Head lettuce gets its name from its round shape. This variety includes iceberg and butterhead lettuces, both of which are commonly sold in grocery stores. 

Leaf lettuces don't form a head, and are instead connected to a stem. Some of these lettuces are darker in color or have reddish leaves.

Romaine lettuce is another lettuce type commonly sold in grocery stores. It's also known as the main ingredient in Caesar salad.

Celtuce lettuce, also called asparagus lettuce or stem lettuce, has a distinctive, large stem. This lettuce variety is common in China, but less common in the Western world.

Health Benefits

The health benefits of lettuce vary across varieties of lettuce, based on their nutritional contents. Iceberg lettuce is generally the lettuce type with the lowest amount of nutrients.

Bone Strength

Lettuce is a source of vitamin K, which helps strengthen bones. Consuming adequate amounts of vitamin K can also reduce your risk of bone fracture.

Hydration

Water makes up over 95% of raw lettuce. As a result, eating lettuce hydrates the body. Although drinking liquids is necessary, water in foods can also significantly contribute to hydration.

Improved Vision

Lettuce is a source of vitamin A, which plays a role in eye health. Vitamin A can reduce a person's risk of cataracts. Vitamin A also helps prevent macular degeneration.

Improved Sleep

Extracts of multiple lettuce types have also been shown to promote sleep. Until further research is conducted, it's unknown if lettuce in its natural form can produce a similar effect.

Nutrition

The nutritional content of lettuce varies across varieties. Almost all lettuces contain a significant amount of vitamin A, along with small amounts of vitamin C and iron.

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Nutrients per Serving

A cup of chopped iceberg lettuce contains: 

Iceberg lettuce contains 7% of the daily value of vitamin A. It also contains small amounts of vitamin C and iron. It contains fewer vitamins and minerals than other lettuce varieties.

A cup of chopped butterhead lettuce contains: 

Butterhead lettuce contains 36% of the daily value of vitamin A. It also contains small amounts of vitamin C, iron, and calcium.

A cup of chopped red leaf lettuce contains: 

Red leaf lettuce contains 42% of the daily value of vitamin A. It also contains small amounts of vitamin C and iron.

A cup of chopped romaine lettuce contains: 

Romaine lettuce contains 82% of the daily value of vitamin A. It also contains small amounts of vitamin C, iron, and calcium.

Things to Watch Out For

Generally, lettuce is safe for most people to eat. It isn't a common allergen. Because it's low in calories, there's not a big problem with eating too much lettuce.

In recent years, however, there have been many instances of lettuce getting contaminated by E. coli. Sometimes lettuce, especially romaine, is recalled. These outbreaks are likely due to runoff from nearby animal farms that contaminates lettuce.

How to Prepare Lettuce

Although lettuce is known for its use in salads, it can be eaten in a variety of ways. To enjoy the health benefits of lettuce, try it in:

  • Wraps
  • Sandwiches
  • Egg rolls and spring rolls
  • Rice dishes
  • Tacos
  • Smoothies

Depending on the lettuce type, you can also use it as a substitute for bread with some sandwiches or burgers.

WebMD Medical Reference Reviewed by Brunilda Nazario, MD on September 16, 2020

Sources

SOURCES:

Britannica: "Lettuce"

Berkeley Wellness: "Types of Lettuce"

Journal of Food Composition and Analysis: "Nutritional Value, Bioactive Compounds and Health Benefits of Lettuce (Lactuca Sativa L.)".

The Open Orthopaedics Journal: "Essential Nutrients for Bone Health and a Review of their Availability in the Average North American Diet"

U.S. Department of Agriculture: "Lettuce, raw"

Nutrients: "Contribution of Water from Food and Fluids to Total Water Intake: Analysis of a French and UK Population Surveys"

Nutrition: "Association of Vitamin A and β-carotene with Risk for Age-Related Cataract: A Meta-Analysis"

Journal of the American Medical Association: "Dietary Intake of Antioxidants and Risk of Age-Related Macular Degeneration"

Food Science and Biotechnology: "Sleep-inducing effect of lettuce (Lactuca sativa) varieties on pentobarbital-induced sleep" 

Iranian Journal of Pharmaceutical Research: "Potentiating Effects of Lactuca sativa on Pentobarbital-Induced Sleep"

ESHA Research, Inc., Salem, Oregon

U.S. Food & Drug Administration: "Factors Potentially Contributing to the Contamination of Romaine Lettuce Implicated in the Three Outbreaks of E. coli O157:H7 During the Fall of 2019"

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