What are the healthiest types of lettuce?

popeye spinach
Popeye owes his pipes to spinach. What would he reach for if spinach weren't around?
Hulton Archive/Getty Images

We all know why Popeye the Sailor was strong to the finish, and it wasn't weight training. It was because of spinach, one of the healthiest members of the dark green vegetable subgroup. Here's something you may not have known: Although spinach looks like lettuce and often finds itself near lettuce in our salad bowls, it's not lettuce. It belongs to the Amaranthaceae family, which also includes beets, quinoa and tumbleweeds. Lettuce, on the other hand, belongs to the Compositae, or daisy, family, the largest group of vascular plants.

According to some history books, lettuce first appeared near the Mediterranean basin more than 4,000 years ago. Ancient humans may have treated this leafy, low-growing plant as a nuisance and plucked it from their gardens like any weed. Gradually, however, they discovered the value of lettuce (and salads) as a food source and began cultivating the plant. Christopher Columbus carried lettuce on his voyages and introduced it to the New World, where it became a popular crop.


Over the years, farmers have developed many varieties of lettuce with many forms, textures and colors. Most fall into one of four categories -- crisphead, romaine (or cos), butterhead and loose-leaf. Crisphead lettuces include the iceberg strains, favorites in the United States. Romaine lettuce is another popular variety, especially as the key ingredient of Caesar salads. The two most common butterheads are Boston lettuce and bibb lettuce, both of which produce loose heads with small, tender leaves. Loose-leaf lettuces, on the other hand, don't grow to form true heads, but have leaves joined at the stem. This group includes green-leaf, red-leaf and oak-leaf lettuce.

But which one of these salad starters would be considered the healthiest? One clue can be found in the color of the leaves. The more they look like Popeye's dark-green spinach, the more vitamins and minerals they're likely to contain. Does that make romaine and butterhead lettuces healthier than crisphead kinds? On the next page, we'll use hard nutritional data to see if we can answer the question more precisely.



The Green Giants of Lettuce

lettuce table

Food scientists use sophisticated equipment to determine levels of vitamins, fat, sugar, protein and other nutrients in food. Luckily, you don't have to live next door to one of these experts to compare one lettuce to another. The United States Department of Agriculture (USDA) maintains a database -- the USDA National Nutrient Database for Standard Reference -- that makes it possible to find all of the key nutrients in various foods. The table shows the results for the four main types of lettuce:

As the USDA database and our abbreviated table make clear, not all lettuces are created equal. Iceberg lettuce, which is by far the most popular lettuce in the United States, delivers the least nutritional bang for the buck. Although it has more fiber than some lettuces, it's a bit of a dud when it comes to vitamin and mineral content. And it's high in sugar, which is a major source of calories.


Romaine lettuce is a better choice. Romaine has less sugar and more fiber. But it really excels in the vitamin and mineral departments. It's an excellent source of vitamin C and a good source of folate and vitamin A. It also provides 10 times more beta carotene than iceberg lettuce and almost as much as spinach. All of this combines to make romaine one of the healthiest of all the lettuces.

Green-leaf lettuce is a solid runner-up. It's low in fat and sugar and high in protein. It also delivers decent amounts of calcium, phosphorous, potassium, manganese and vitamins C, A and K. Red-leaf and butterhead lettuces aren't slouches either, as they surpass iceberg varieties in almost every nutrient category and have the highest amount of iron of all lettuces.

So if you really want to stay strong to the finish, stick with romaine and the other dark green leafy lettuces while cutting back on the crispheads. And don't forget to spice things up with the more exotic members of the family, such as arugula, curly endive, escarole and radicchio.


Lots More Information

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More Great Links

  • Ferrare, Cristina. "'Lettuce' Eat Healthy!" Oprah.com. Jan. 20, 2010. (May 1, 2010)http://www.oprah.com/food/Why-Eating-Lettuce-Is-Good-for-You-Cristina-Ferrares-Cooking-Blog
  • Fink, Leslie. "Salad 101." WeightWatchers. (May 1, 2010)http://www.weightwatchers.com/util/art/index_art.aspx?tabnum=1&art_id=9361&sc=3022
  • Jibrin, Janis. "9 Myths About Your Salad." WebMD. (May 1, 2010)http://www.webmd.com/food-recipes/features/9-myths-about-your-salad
  • Magee, Elaine. "11 Simple Steps to a Healthier Diet." WebMD. April 27, 2009. (May 1, 2010)http://www.webmd.com/diet/features/11-simple-steps-to-a-healthier-diet
  • Scarbrough, Mark and Bruce Weinstein. "The Skinny on Salad Greens." WeightWatchers. (May 1, 2010)http://www.weightwatchers.com/util/art/index_art.aspx?tabnum=1&art_id=69961&sc=3021
  • The USDA National Nutrient Database for Standard Reference. (May 1, 2010)http://www.nal.usda.gov/fnic/foodcomp/search/index.html