Food Health Lifestyle

The Benefits of Lettuce: Why You Shouldn’t Underestimate This Simple Leafy Green

12 min read

Most of us don’t think of lettuce as a super-nutritious food. Sure, it makes up the bulk of “ordinary” salads, and iceberg accompanies fast food meals — but in terms of raw nutritional value, we tend to think of it as a sideshow. But should we reconsider our tepid view of lettuce? Might it turn out to be a nutritional powerhouse after all? And are there ways to enjoy it that don’t just involve salad dressing?

Have you ever noticed in TV and movies how eating a healthy salad is often a visual metaphor for a character’s lack of joy or vitality? The “Cobb Salad Lunch Scene” in Julie and Julia, for example, shows a table of professional women in their early 30s dining in Manhattan, each ordering a Cobb salad. Their conversation is cold, condescending, and clinical, as they’re all too busy climbing their career ladders to appreciate life’s pleasures. The not-so-subtle message, which drives Julie’s redemption arc in the film, is that eating rich food with lots of butter (note: not salad) is part of the path to fulfillment.

So if salads are visual shorthand for a diminished life, then there’s one ingredient that does the heavy lifting for that metaphor: lettuce. It’s often seen as “rabbit food” (which, technically, I suppose it is; most herbivores would be thrilled to gain access to my spring garden). And the rabbity-est lettuce of all, iceberg, is doubly damned as not only being tasteless but also devoid of nutrition.

Lettuce: An Underestimated Leafy Green

In the real world, of course, many people love their salads; a good one can be a tasty, crunchy way of getting lots of veggies, especially leafy greens. Even people eating the modern industrialized diet so often depicted in films get their share of lettuce. It’s one of the few vegetables that’s routinely eaten raw, providing much-needed fiber and water, as well as various micronutrients. In fact, iceberg lettuce was the first fresh produce item, other than root vegetables, that Americans were able to buy year-round in grocery stores.

For decades, iceberg dominated the lettuce market. But these days, other varieties like butterhead, romaine, and leaf types compete for “plate share.” And many chefs turn down their noses at the pale, crunchy iceberg. Still, more iceberg is grown in California than all other varieties combined. It’s cheaper to grow than the others and is an indispensable ingredient in many fast food meals. In fact, as of 2015, McDonald’s was the world’s largest buyer of iceberg lettuce.

Economically, lettuce is one of the world’s most significant leafy vegetable crops. And as production spreads to more communities, consumers are now able to enjoy many varieties other than iceberg lettuce.

Wherever you stand in the great lettuce debate, it’s time to give this leafy green its due. Overlooked and undervalued for too long, lettuce actually has a lot to offer us in terms of nutrition and health benefits.

In this article, we’ll look at what science says about why lettuce is good for you, explore how best to store it, and share a few recipes (salad and non-salad alike) for you to try.

Types of Lettuce

Different types of lettuce planted in a field

Lettuce or Lactuca sativa is part of the Asteraceae family of plants, along with daisies and sunflowers. Originally, lettuce was cultivated by ancient Egyptians, who valued the seeds for the oil they contained. Over time, they developed varieties that provided nutritious and tasty leaves as well.

The Romans also loved their lettuce; the name lactuca comes from the word lac, meaning milk, and refers to the milky sap that flowed from the base of the plant into its leaves.

There are four main types of lettuce grown commercially today: cos/romaine, loose-leaf, crisphead, and butterhead. Of these four types, you can further differentiate by color, with green leaf and red/purple leaf varieties in each of the four main categories.

The most common lettuce variety, as we’ve seen, is iceberg, which was first developed and sold by Burpee Seed Co. in 1894. Other popular kinds of lettuce include romaine, butter, Bibb, Boston, red leaf, and Little Gem.

There are also a number of leafy salad greens, including endive, frisée, and radicchio, that are commonly referred to as lettuces but are actually members of the chicory family of vegetables.

Lettuce Nutrition Facts

Since there’s no single kind of lettuce, there’s no definitive nutritional profile for the plant. The nutrient composition varies among the different types. That said, there are some generalizations that do apply.

Like many other plants, the darker the color, the more nutrition and antioxidants the lettuce contains. These nutrients typically include vitamins A, C, and K1, as well as select B vitamins (like folate). Lettuce leaves also often contain polyphenols, carotenoids, and flavonols. Green lettuce types contain more chlorophyll, while red varieties provide more anthocyanins.

By weight, the main nutrient in lettuce is water. Nutritionally, that’s not a bad thing, as many people are chronically dehydrated. But lettuce is also a fiber powerhouse, which adds bulk to stools and helps with constipation. That’s also a good thing, as something like 95% of the American population is fiber-deficient, according to the organizers of the Food & Fiber Summit in Washington, DC. (Can you imagine the bathroom lines at that event?)

So given that fast food is a key culprit in that lack of fiber, lettuce may be the one reliable source of roughage that many people regularly access. Fiber and water together comprise a natural combination that’s really good for your digestive health, keeping things moving.

Iceberg Lettuce vs Romaine

Iceberg vs romaine lettuce combined on a white background and PotaeRin (Combined)

Iceberg and romaine are the top two types of lettuce. But how do they compare nutritionally? Many people think that iceberg lettuce is devoid of nutrients. So are they right?

Here’s a comparison of select nutrients found in iceberg and romaine lettuce.

Nutrient per 100g of lettuce Iceberg Romaine
Vitamin A (UI) 502 8711
Vitamin C (mg) 2.8 24.0
Vitamin K (mcg) 24.1 103
Niacin (mg) 0.1 0.3
Folate (mcg) 29 136
Calcium (mg) 18 33
Magnesium (mg) 7 14
Phosphorus (mg) 20 30
Potassium (mg) 141 247
Phytosterols (mg) 10 0
Water (g) 95.6 94.6

Romaine wins the head-to-head (or more accurately, “leaf-to-head”) comparison in almost every category, by a wide margin. Iceberg does deliver some phytosterols, which are important for heart health, while romaine is deficient in that one category.

The takeaway: if you’re a romaine fan, that’s awesome. Romaine clearly delivers lots of important nutrients and is definitely more nutritious than iceberg lettuce.

But if you’re not a fan (maybe you’ve listened to too much “Bad Romaine” by Lady Gaga — oh wait, that was “Bad Romance”), and milder iceberg is more your style, it’s still a solid addition and a source of some important nutrients.

Health Benefits of Lettuce

Lettuce health benefits listed on a notepad beside a bed of lettuce on a plate (Modified)

Lettuce may have a bunch of nutrients, but does eating it translate to better health? Let’s take a look at the research that’s been done in five key areas: metabolic health, sleep, cancer, dementia, and eye health.

Lettuce and Blood Sugar

Think of all those fast food meals that people consume, maybe with a few pieces of lettuce between the burger and the bun, or alongside a tiny side salad. Can the greens do anything to mitigate the harm of all the refined carbs and saturated fat?

A 2021 study sought to answer that question, pairing meals of white bread, hamburger, cheese, butter, and mayonnaise with either 100 grams of romaine lettuce, watercress, or the same amount of fiber in a placebo of microcrystalline cellulose. These meals were fed to healthy young men in their 20s, who had 15 minutes to clean their plates.

Their blood was drawn immediately before the meal, and then consecutively for four hours after eating. The researchers discovered two important things. First, study participants by and large preferred lettuce to watercress. And second, lettuce (and not watercress) significantly lowered blood glucose and insulin response compared to the placebo.

While the fiber may have played a role in lessening any glucose spike, it’s probably not the whole story, as cellulose is also a rich source of fiber. Researchers speculated that some of the phytonutrients in lettuce, such as the carotenoid lactucaxanthin, may help fight diabetes by suppressing key digestive enzymes in the intestines and pancreas.

Can Lettuce Help You Sleep?

Indeed, lettuce can help put you to sleep — and not because it’s boring! Lettuce seed oil has a long history as a folk remedy for insomnia. And extracts of lettuce seeds and leaves may be safer alternatives to pharmaceutical sleeping pills.

The milky latex that some lettuce plants produce also induces sedation in laboratory mice. (Our view on the use of animals in medical research is here.) And a 2017 study found that romaine seed extract can not only help people get to and stay asleep but may also contain phytonutrients that protect the body from oxidative damage that can accompany poor sleep.

Lettuce and Cancer

Red leaf lettuce contains polyphenols, minerals, and antioxidants known to fight the progression of cancer. In 2018, researchers out of China put six such red leaf cultivars to the test and identified one — which they poetically named “B-2” — that had the highest levels of anthocyanin, flavone, and phenolic acid. B-2 showed antitumor effects against a number of cancers, including lung, liver, and colorectal cancer cells.

In that same year, researchers in Korea found a way to extract pure carotenoid compounds from lettuce, which turned out to be a big deal because before that it was very costly and difficult to get these compounds. One of the compounds, named 9-Z-neoxanthin (I wonder if that means something scientific, or if perhaps the researchers were fans of the way Frank Zappa and Elon Musk named their children), was found to reduce the viability of cervical and lung cancer cells.

Lettuce’s Impact on Alzheimer’s and Dementia

When researchers look for connections between lifestyle habits and cognitive decline, one of the most consistent associations is leafy green consumption. Two large prospective studies published in the mid-2000s clearly showed that the more leafy greens consumed, the slower the rate of cognitive decline in older people. Aside from known nutritional powerhouses like spinach, kale, and collards, another top performer was — you guessed it — lettuce.

A 2018 study out of the Rush University Memory and Aging Project used food frequency questionnaires and ongoing cognitive assessments of close to 1,000 volunteers to identify nutrients protective against age-related dementia. These included phylloquinone (vitamin K1’s not-so-secret scientific identity), folate, and other compounds found in lettuce, leading the researchers to recommend that people eat a serving of leafy greens, including lettuce, daily to slow cognitive decline.

Lettuce and Eye Health

Green leaf lettuce can also help keep your peepers sharp. Two of the common phytocompounds found in green-hued lettuce, lutein and zeaxanthin, are among the top nutrients for eye health. And while lettuce isn’t the richest source of these compounds (for that you’d have to go a bit off the beaten culinary track and consume raw paprika, sweet potato leaves, and dandelion greens), it can make a significant contribution to the public’s intake because it’s one of the most commonly eaten foods that contain lutein and zeaxanthin. And when you combine those phytonutrients with the vitamin A found in lettuce, you have a potent vision-protecting food.

Lettuce on its Own is Nutritious, But it’s not Usually Eaten That Way

Garden Cobb salad with iceberg lettuce ham bacon and hardboiled eggs

To recap: Lettuce is a leafy green, and leafy greens are some of the healthiest foods on the planet. But there’s a caveat: The health impact of lettuce depends on what you eat along with the lettuce. If it’s a half-leaf of iceberg between American “cheese” and a white bun on top of a burger slathered in mayo, then the benefit of the lettuce will be marginal at best.

But even in salad, lettuce’s impact depends on what you pair it with. Most of the calories in conventional salads come from the dressing. Let’s do the math: Because it’s almost all water, lettuce delivers about 80 calories per pound. Which means, if you consume an entire pound of lettuce (10 cups!) along with a dressing that contains a mere two tablespoons of oil, at least 75% of your calories will still be coming from the dressing rather than the salad itself.

And if you add chicken breast, cheese, and bacon to your salad, you’re further diluting the nutritional prominence of the lettuce. That’s why most conventional salads, slathered in commercial salad dressing, provide a net nutritional impact of questionable value.

That’s not to say that salad can’t be an awesome way to enjoy lettuce. Here’s some info on how to craft a healthy salad. And here are some of FRN’s favorite oil-free salad dressing recipes to go along with that salad.

Lettuce also offers another benefit, even compared to other leafy greens. Due to the crispiness of lettuce (which is a sensory quality that allows us to further enjoy our food and know that it’s fresh), it’s one of the primary foods that people eat raw. And including both raw and cooked foods in your diet is important for health.

Read our article about how to get more vegetables into your diet for more ideas.

What to Look for When Buying and Storing Lettuce

Father and daughter in supermarket produce section picking vegetables

Iceberg has dominated the lettuce market for so long not so much because of its taste or nutritional value, but rather because of its ability to withstand long truck rides. Leaf lettuce has a much shorter shelf life, and is at its freshest and most nutritious when harvested from your own garden.

If you don’t grow your own, look for lettuce sold at farmers markets, CSAs, and roadside stands. If you get your lettuce from the supermarket, then make sure to serve and eat it shortly after purchase, as it may have been harvested up to a week prior, and may already be on borrowed time.

Lettuce stores best fully intact (as in full heads and stalks rather than chopped). How long it lasts depends largely on the temperature of your refrigerator. A relatively warm fridge interior of 40°F (4.5°C) will give you up to two weeks of viable leaves (if they were just picked when you got them), while a colder 33°F (1°C) can buy you up to three weeks. It also depends on the variety; iceberg lasts longer, while softer greens tend to rot quickly. If you get your lettuce chopped and prepackaged, try to use it within three to five days.

To keep lettuce fresh for as long as possible, keep it in the refrigerator crisper drawer so it doesn’t dry out. Bonus points for lettuce longevity if you wrap it in paper towels and store it in a reusable produce bag or container.

Worried your lettuce has gone bad? Luckily, it’s pretty easy to tell: the leaves get slimy, start turning brown, and smell rotten. This tends to afflict outer leaves first, so you may be able to peel them off and still have some good lettuce on the inside. When in doubt, compost and start fresh.

One way to preserve food for longer is to freeze it. Technically, frozen lettuce should keep for up to six months. But I seriously don’t recommend this strategy if you plan to eat your lettuce raw, without cooking. Since lettuce is mostly water, freezing it bursts the cell walls and makes it lose one of its best qualities — crispiness.

Lettuce Recipes

These tasty plant-based recipes are a far cry from the “rabbit food” you might have heard about. In fact, with a little know-how, lettuce can become a true culinary chameleon. Try out lettuce as a base for a cold soup or smoothie. Throw it into a hearty and flavorful pasta salad. Turn the leaves into wraps, tortillas, or even sandwich bread (we recommend a slightly hearty lettuce green like romaine for that). With three refreshing, light, and creative ways to enjoy your lettuce greens, these recipes may make you a lettuce connoisseur in no time!

1. Farmers Market Smoothie

Farmers Market Smoothie displayed around fruits and vegetables

Turn your daily greens blend up a notch with this superpowered Farmers Market Smoothie. Cucumber, celery, squash, romaine lettuce, pineapple, and mint transform into a beautiful, bright green smoothie that’s a delight for your senses. Romaine lettuce may seem like an eccentric ingredient to add, but it’s an excellent way to harness the nutrient power of lettuce and add a touch more crisp freshness to this creamy seasonal smoothie!

2. Teriyaki Mushroom Lettuce Cups

Teriyaki Mushroom Lettuce Cups on a plate near other Mediterranean side dishes

Butter lettuce has tender leaves with a very mild, buttery (duh!) flavor, making it an excellent complementary leafy green for these scrumptious Teriyaki Mushroom Lettuce Cups. Made with meaty shiitake mushrooms (that become caramelized with Homemade Teriyaki Sauce), nutty quinoa, and a heap of fresh and bright flavor from the ginger, garlic, green onions, and cilantro, these lettuce cups are a punch of bold plant-based flavor, texture, and nutrition. What’s more, this is a fun and tasty way to dress up your everyday bowl of leafy greens!

3. Udon Noodle Salad Bowl

Udon Noodle Bowl in a ceramic dish

Udon Noodle Salad Bowl is a colorful burst of nutrient-rich veggies, including stunning red leaf lettuce shreds (if it happens to be the lettuce you choose). Similar to butter lettuce, red leaf lettuce is mild with soft tender leaves and adds a nice texture alongside the crunchy veggies in this salad. The biggest difference between red lettuce and butter lettuce is the addition of anthocyanins, which give the red lettuce leaves their vibrant red color and a bit more of an antioxidant boost! This bowl comes together quickly and offers satisfying flavors and textures for a salad that is anything but boring!

Let Us Eat More Lettuce!

Lettuce is an often undervalued veggie since it’s not often eaten on its own. And many people have negative associations with it, thinking of sad and boring salads or nutritionally vapid iceberg lettuce.

But there are many varieties of lettuce, and all of them, especially the darker-colored varieties, are rich sources of water, antioxidants, and nutrition. Many lettuce varieties have shown important health benefits and may positively impact blood sugar, improve sleep quality, fight cancer, slow the progression of Alzheimer’s, and support eye health.

Getting your lettuce as fresh as possible and storing it appropriately will ensure you reap its full benefits. And don’t be afraid to both embrace salads and also use lettuce in exciting new ways as well!

Tell us in the comments:

  • What type of lettuce is most familiar to you?

  • Have you discovered new varieties of lettuce that you now enjoy?

  • What’s your favorite salad that includes leafy greens?

Featured Image: Gabarrella

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