Vegetables · Leafy Greens

Romaine Lettuce: Benefits, Nutrition, Uses & Side Effects

A physician's evidence-based guide to romaine lettuce: the nutrition that makes it one of the best everyday greens, the human studies on bones, blood pressure, brain health and sleep, and how to buy and prepare it for the most benefit.

By Dr. Josh Axe, DC, DNM, CNS·17-min read

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Evidence-based28 sources citedUpdated October 1, 2026

Published Oct 1, 2026Last updated Oct 1, 2026Editorial policyMedical review policyFact-checking policy

Romaine lettuce (Lactuca sativa var. longifolia), the tall, crisp-ribbed lettuce behind the classic Caesar salad.

The Dr. Axe Score™

6.8/10

Overall Dr. Axe Score · Romaine Lettuce

Romaine is far more nutritious than its reputation.

Scientific Evidence

6.0/10

Solid human data on lettuce and leafy greens; little on romaine alone.

Antioxidant & Anti-Inflammatory

6.4/10

Lutein, beta-carotene and polyphenols; less than darker greens.

Clinical Effectiveness

7.0/10

An easy daily habit linked to bone, heart, brain and weight benefits.

Nutrient Density

8.2/10

Scores 82 on my nutrient density chart, level with broccoli.

Why this score?

Why Romaine Lettuce scores 6.8 / 10

Two cups deliver about 80% of the daily value for vitamin K and 32% for folate, for about 16 calories.
Cup for cup, it has about 2.8 times the vitamin K, 11 times the vitamin A and 3 times the folate of iceberg lettuce.
In 72,327 women, eating lettuce daily was linked to a 45% lower risk of hip fracture.
In a controlled trial, a serving of high-nitrate lettuce lowered systolic blood pressure by 4.9 points within hours.
How the score works: Scientific Evidence rates the amount and quality of human, animal and lab research; Antioxidant & Anti-Inflammatory Power and Nutrient Density reflect measured composition; Clinical Effectiveness is our judgment of real-world usefulness, informed by human studies, traditional use and Dr. Axe's clinical experience. These are editorial ratings, not validated clinical measurements.
Weighting: Evidence 30% · Antioxidant & Anti-Inflammatory 25% · Clinical Effectiveness 25% · Nutrient Density 20% (6.0×0.30 + 6.4×0.25 + 7.0×0.25 + 8.2×0.20 = 6.79, shown as 6.8).

Per 100 calories it delivers more than a full day's vitamin A, vitamin K and folate, it's roughly three times as nutritious as iceberg, and human studies of lettuce and leafy greens link it to stronger bones, lower blood pressure and a sharper aging brain. Its antioxidant load is modest next to darker greens, which is part of what holds the score where it is.

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Romaine lettuce at a glance

Romaine lettuce is a crisp, nutrient-dense leafy green that delivers real vitamin K, vitamin A and folate for almost no calories, roughly three times the nutrition of iceberg. Human studies link eating lettuce and leafy greens to stronger bones, healthier blood pressure, slower brain aging and fuller meals, and lettuce seed has improved sleep in two placebo-controlled trials. Buy whole heads, wash and cut them yourself, and eat them with olive oil or avocado.

Best uses: everyday salad base, sandwich and taco topper, lettuce wraps, grilled wedges
Typical amount: 2 cups raw as a side salad, or more as a main-meal base
How it works: fat-soluble vitamin K and carotenoids, folate, and nitrate for healthy blood flow
Buy whole heads over bagged, wash well, and keep vitamin K intake steady if you take warfarin

Romaine lettuce is one of the most underrated foods in the produce aisle, and one of the easiest ways to eat more leafy greens every day.

Most people treat lettuce as filler, the crunchy layer under the real meal. Romaine deserves better. On my nutrient density chart it scores 82, level with broccoli,1 and per 100 calories it clears the full daily value for vitamin A, vitamin K and folate.2 Leafy greens are also one of the foods I rank highest for healthy blood pressure, for their nitrate, magnesium and potassium.3

The human studies on lettuce and leafy greens are encouraging, from a 45% lower hip fracture risk in women who ate lettuce daily to a measurable drop in blood pressure after a single serving. Below I'll walk through that research with the real numbers and show you how to buy, store and prepare romaine for the most benefit.

Want to know if you're low in folate or other key nutrients? Open the free 25 Bloodwork Markers protocol (free with your Dr. Axe account, email or Google; you'll also get the protocol's short email series and the Dr. Axe newsletter; unsubscribe anytime).

Kale, arugula and romaine: vitamin K, carotenoids and protective phytonutrients.Dr. Josh Axe

What is romaine lettuce?

Quick answer

Romaine lettuce (Lactuca sativa var. longifolia), also called cos lettuce, is a tall, upright head lettuce with crisp ribs and darker green outer leaves than iceberg. It's the lettuce in a classic Caesar salad, sold both as whole heads and as pre-cut bagged greens.

Lettuce is one of the oldest cultivated foods. Ancient Egyptians grew a tall, upright lettuce much like modern romaine about 4,700 years ago and depicted it in tomb art,4 and the word "salad" comes from the Latin salata, salted greens, after the Roman habit of dipping raw lettuce in salt.5 The name "romaine" points to its history around Rome, and "cos" to the Greek island of Kos.

Cut a romaine stem and it releases a milky latex. That sap carries lactucin and lactucopicrin, the bitter compounds behind lettuce's long folk reputation as a sleep aid.6 One practical distinction runs through this whole article: a whole head that you wash and cut yourself is fresher, keeps more of its antioxidants and carries less processing risk than pre-cut bagged romaine, even though the nutrition label looks the same.

Romaine lettuce nutrition facts

Quick answer

One cup (47 grams) of shredded raw romaine has 8 calories and delivers 40% of the daily value for vitamin K, 23% for vitamin A and 16% for folate, plus about 1,090 micrograms of lutein and zeaxanthin. A 2-cup salad doubles every number.

Romaine lettuce, raw (USDA FoodData Central, FDC 169247)
Nutrient	Per 1 cup (47 g)	Per 2 cups (94 g)	% Daily Value (2 cups)
Calories	8	16	n/a
Vitamin K	48 mcg	96 mcg	80%
Vitamin A	205 mcg RAE	410 mcg RAE	46%
Folate	64 mcg DFE	128 mcg DFE	32%
Lutein + zeaxanthin	1,087 mcg	2,173 mcg	n/a
Fiber	1.0 g	2.0 g	7%
Potassium	116 mg	232 mg	5%
Iron	0.46 mg	0.9 mg	5%
Water	94.6%	94.6%	n/a

That's the story of romaine in one table: real vitamin K, vitamin A and folate at almost no calorie cost. Because vitamin K and the carotenoids are fat-soluble, a dressing made with real olive oil, or a handful of avocado, does more than add flavor. It's what lets your body absorb them.

What is romaine lettuce good for?

Quick answer

Romaine is best for adding vitamin K, vitamin A and folate to your diet at almost no calorie cost. Human studies of lettuce and leafy greens link it to stronger bones, fuller meals, healthier blood pressure, slower brain aging and better antioxidant status, and lettuce seed has improved sleep in human trials.

Where the research stands

Romaine's nutrition is measured directly. Its health research comes mostly from human studies of lettuce or leafy greens as a group: a large cohort linking daily lettuce to fewer hip fractures, a cohort linking leafy greens to slower brain aging, and small controlled trials on blood pressure, fullness and antioxidant levels. Very few studies have tested romaine by itself, and its sleep research splits into human trials of lettuce seed and animal studies of romaine extract. What romaine does have is excellent nutrition per calorie and a food pattern with consistent human support, which is why it earns a daily place on the plate.

Romaine lettuce benefits, graded by evidence strength (Updated September 2026)
Benefit	Evidence	What was studied	What the research shows	Good to know
Stronger bones (vitamin K)	Moderate	72,327 women, lettuce intake	Daily lettuce linked to 45% lower hip fracture risk	Lettuce was the top vitamin K source
Fuller meals, easier weight control	Moderate	42 women, salad first course	Ate 7–12% fewer calories at the meal	Keep the dressing light
Brain health	Moderate	960 older adults, leafy greens	Slower decline, like being 11 years younger	About 1.3 servings a day
Healthy blood pressure	Emerging	19 adults, high-nitrate lettuce	Systolic pressure 4.9 points lower within hours	Nitrate varies with growing
Eyes & antioxidant status	Emerging	Fresh lettuce; salads with and without fat	Blood antioxidants rose; carotenoids absorbed only with fat	Fresh beats stored and bagged
Folate status	Moderate	USDA data; 17,000+ adults	32% DV per 2 cups; salad eaters had higher blood folate	Three times iceberg's folate
Better sleep	Emerging	Lettuce seed in people; romaine extract in rodents	Better sleep scores with seed; longer sleep in rodents	Leaf "lettuce water" untested in people

How romaine lettuce works in your body

Romaine works in three main ways: its fat-soluble vitamin K and carotenoids support bones, clotting and eyes when eaten with fat, its folate powers methylation and red blood cell production, and its nitrate converts to nitric oxide, which relaxes blood vessels.

Vitamin K and carotenoids go to work with fat. Vitamin K activates proteins that build bone and control clotting.7 Lutein and zeaxanthin collect in the macula of the eye, where they filter high-energy light.8 All of them are fat-soluble: in a study where each of 7 people tried each dressing, they absorbed almost no carotenoids from a salad of spinach, romaine, tomatoes and carrots with fat-free dressing, and absorption rose substantially with a full-fat dressing.9
Folate powers methylation. Folate helps build DNA, make red blood cells and keep homocysteine, an amino acid linked to heart and brain health, in check.10 In a national survey of more than 17,000 adults, people who ate more salad and raw vegetables had higher blood levels of folate, vitamins C and E and carotenoids.11
Nitrate relaxes blood vessels. The nitrate in leafy greens converts to nitric oxide, which widens blood vessels. When young adults ate high-nitrate lettuce, their blood and saliva nitrate climbed and their blood pressure fell within three to six hours.12

Notice the through-line. Romaine isn't dramatic, but it delivers steady amounts of nutrients your body uses every day, and a little healthy fat on the plate is what unlocks most of them.

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Health benefits of romaine lettuce, ranked by evidence

Ranked by the strength of the research, romaine's six best-supported benefits are for bone strength, fuller meals, brain health, blood pressure, eye health and antioxidants, and folate status, in that order. Each one is labeled as a human, animal or lab finding.

Bone support

Moderate evidenceHuman studyCohort · 72,327 women

Two cups of romaine deliver about 96 micrograms of vitamin K, 80% of the daily value.2 In the Nurses' Health Study, which followed 72,327 women for 10 years, lettuce was the single largest source of vitamin K in their diets, and women who ate lettuce once a day or more had a 45% lower risk of hip fracture than women who ate it once a week or less.13 This was an observational study of lettuce in general, and it's one of the most impressive findings for any everyday vegetable. See my vitamin K foods guide for more.

Study takeaway: in 72,327 women, eating lettuce daily was linked to a 45% lower risk of hip fracture.

Fuller meals

Moderate evidenceHuman studyRandomized crossover · 42 women

Romaine is 94.6% water, which makes it a perfect first course. In a Penn State study, 42 women ate lunch in the lab once a week for seven weeks, sometimes starting with a salad and sometimes not. Starting with a large, lightly dressed salad cut total calories at the meal by 12%, and a smaller one by 7%. Salads loaded with rich dressing and cheese did the opposite, raising calories by up to 17%.14 The salads used a mix of vegetables, so the credit goes to a lettuce-based salad rather than romaine alone.

Study takeaway: a large, lightly dressed salad before a meal cut total calories eaten by 12%.

Brain health

Moderate evidenceHuman studyCohort · 960 older adults

In the Rush Memory and Aging Project, 960 adults aged 58 to 99 were followed for an average of 4.7 years. Those who ate the most leafy greens, about 1.3 servings a day, had cognitive decline slower by the equivalent of being 11 years younger. Vitamin K, lutein, folate and nitrate were each linked to slower decline on their own.15 The study measured leafy greens as a group, including lettuce, so romaine's share can't be separated out. The MIND diet is built around this kind of daily greens habit.

Study takeaway: about one serving of leafy greens a day was linked to brain aging slower by the equivalent of 11 years.

Blood pressure support

Emerging evidenceHuman studyControlled crossover · 19 adults

In a trial where neither the people nor the researchers knew who got what, researchers grew lettuce two ways so one batch was high in nitrate and the other low. When 19 healthy young adults ate 50 grams of the high-nitrate lettuce, systolic blood pressure fell 4.9 points between three and six hours later compared with the low-nitrate lettuce, tracking the rise in nitrate in their blood and saliva.12 It was one small, short trial, and nitrate levels in store-bought lettuce vary with how it's grown. It fits with why leafy greens top my list of foods for healthy blood pressure.3

Study takeaway: a single serving of high-nitrate lettuce lowered systolic blood pressure by 4.9 points within hours.

Eye health and antioxidants

Emerging evidenceHuman studies · 11 adults · 7 adults

Romaine has about 11 times the vitamin A and several times the lutein and zeaxanthin of iceberg, cup for cup,2 16 and those carotenoids are established contributors to protecting the macula.8 In a small study, 11 adults who ate 250 grams of fresh lettuce saw significant rises in blood antioxidant capacity, quercetin, beta-carotene and vitamin C within hours. The same lettuce stored three days in modified-atmosphere packaging, the method used for bagged salads, produced no change at all.17 Add the finding that carotenoids are barely absorbed without fat,9 and the practical lesson is clear: eat it fresh, and eat it with fat.

Study takeaway: fresh lettuce raised blood antioxidants within hours, and the same lettuce after packaged storage did not.

Folate

Moderate evidenceComposition · human survey · USDA · 17,000+ adults

Two cups of romaine carry about 128 micrograms of folate, 32% of the daily value and three times what iceberg provides.2 16 In the national NHANES survey of 17,688 adults, people who ate salad and raw vegetables had higher blood levels of folate, vitamins C and E and carotenoids, and each serving of salad was linked to a 165% higher likelihood of women meeting their vitamin C needs.11 That survey measured salad in general rather than romaine, but it's direct human evidence that folate from salad greens shows up in the blood.

Study takeaway: salad eaters had higher blood folate, a sign the folate in greens is well absorbed.

Four markers that show your folate and nutrient status

Romaine is one of the easiest ways to add folate, but many people still run low, or can't use folate well. These markers show whether folate and its partner B12 are doing their job, and whether inflammation is part of your picture. Ranges are functional medicine optimal ranges, the window where the body heals and functions optimally. These markers can't tell you which foods are responsible or diagnose a condition on their own.

Homocysteine: Rises when folate and B12 run low. Optimal is under 7 µmol/L.
Folate (serum): Your folate intake and stores. Optimal is above 15 ng/mL.
Vitamin B12: Works hand in hand with folate. Optimal is 500–900 pg/mL.
hs-CRP: Low-grade inflammation anywhere in the body. Optimal is under 1.0 mg/L.

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Does romaine lettuce help you sleep?

Quick answer

Lettuce has been used as a sleep aid since ancient times, and the research is more interesting than most people realize. Lettuce seed improved sleep in two placebo-controlled human trials, and romaine leaf extract lengthened sleep in rodents through the same GABA receptors that calming compounds act on.

Folk medicine has used lettuce as an aid to sleep and an appetite stimulant for thousands of years,18 and traditional Persian medicine still recommends lettuce seed for sleeplessness, including during pregnancy.19 The research now backs that up in three layers.

Lettuce seed in pregnancy (human). In a placebo-controlled trial in Iran, 100 pregnant women with insomnia took 1,000 mg of lettuce seed or a placebo daily for two weeks. Sleep quality improved significantly more with lettuce seed, and the researchers described it as a safe natural remedy.19 It was one small, two-week trial, so it isn't a reason to start lettuce seed during pregnancy without guidance from whoever is caring for your pregnancy.
Lettuce seed oil (human). In a placebo-controlled pilot of 60 adults with insomnia, 1,000 mg of lettuce seed oil daily for one week significantly improved sleep and anxiety scores, with no side effects.18
Romaine leaf extract (animal). Green romaine extract is rich in lactucin and lactucopicrin. In mice and rats it lengthened sleep, increased deep non-REM sleep and increased sleep time in caffeine-induced insomnia, working through the GABA-A benzodiazepine receptor.6 Mixed with skullcap root, romaine extract increased total sleep time by 51% in another rodent study.20

What hasn't been tested is the social-media version, a few romaine leaves steeped in hot water before bed. The human trials used concentrated seed or seed oil, and the leaf studies used extracts in animals, so no one has measured whether a mug of lettuce water delivers enough to matter. It's gentle and unlikely to hurt, and romaine does carry these calming compounds.6

Other ways romaine lettuce supports your health

Romaine is also hydrating, low in carbs, low in oxalates and a source of fiber, which makes it easy to eat in large amounts on almost any eating plan.

Hydration. At 94.6% water, a big romaine salad counts toward your fluid intake.2
Fiber. Two cups carry about 2 grams of fiber, more than the same amount of iceberg.2 16
Low oxalate. Unlike spinach and Swiss chard, lettuce isn't a high-oxalate green, so it's an easy choice for people limiting oxalates.
Keto and low-carb friendly. About 1.5 grams of carbohydrate per cup fits easily into a keto or low-carb plan.2

The key active compounds in romaine lettuce

Romaine's key compounds are vitamin K1 for bones and clotting, the carotenoids lutein, zeaxanthin and beta-carotene for eyes and immunity, and the bitter lactucin and lactucopicrin in its milky sap, the compounds behind lettuce's calming reputation.

1Fresh whole head

Washed & cut at home

2Add healthy fat

Olive oil · avocado

3Nutrients absorbed

Vitamin K · carotenoids

Freshness keeps romaine's antioxidants intact, and fat unlocks its vitamin K and carotenoids. With fat-free dressing, salad carotenoids were barely absorbed.9

Vitamin K1

Phylloquinone

80% of the daily value in 2 cups. Activates bone-building and clotting proteins.7

Carotenoids

Lutein, zeaxanthin, beta-carotene

Protect the eyes and supply vitamin A; absorbed with fat.8 9

Lactucin

& lactucopicrin

Bitter compounds in the milky sap that bind calming GABA receptors in animal studies.6

Romaine vs. iceberg vs. spinach

Romaine beats iceberg on nearly every nutrient. Against raw spinach, cup for cup, romaine has more vitamin A, folate and fiber, while spinach wins on vitamin K and lutein.

Romaine, iceberg and spinach, per cup raw (USDA FoodData Central)
	Romaine (47 g)	Iceberg (72 g)	Spinach (30 g)
Vitamin K	48 mcg (40% DV)	17 mcg (14% DV)	145 mcg (121% DV)
Vitamin A	205 mcg RAE	18 mcg RAE	141 mcg RAE
Folate	64 mcg DFE	21 mcg DFE	58 mcg DFE
Lutein + zeaxanthin	1,087 mcg	199 mcg	3,659 mcg
Fiber	1.0 g	0.9 g	0.7 g
Best use	Everyday raw salad base	Crunch and hydration	Vitamin K and lutein; great cooked

The takeaway: romaine clearly beats iceberg on the same USDA data,2 16 and it holds its own against spinach as a raw salad base.21 Use romaine as your everyday base and rotate in spinach, kale or arugula when you want more vitamin K and lutein.

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How much romaine lettuce should you eat?

Quick answer

There's no set dose. Two cups a day as a side salad or sandwich base is a great habit, and eating more is easy at about 8 calories a cup. The studies linking lettuce and leafy greens to bone and brain benefits involved about one serving a day.

Romaine is a food you build a plate around. The women with the lowest hip fracture risk ate lettuce once a day or more,13 and the slowest brain aging came with about 1.3 servings of leafy greens a day.15 If you take warfarin, read the blood-thinner note under side effects first.

Side salad

2 cups with an olive oil dressing, before or with a meal.

Wraps

Large outer leaves in place of tortillas or bread.

Grilled

Halve a head, brush with olive oil, grill 2–3 minutes.

Smoothie

A few leaves add volume and vitamin K with little flavor.

Easy ways to eat more romaine

Romaine shines raw as a salad base, as a crunchy wrap, and lightly grilled. Pair it with olive oil, avocado, lemon and garlic to absorb its vitamins and brighten its mild flavor.

Make a classic Caesar with real olive oil, lemon and garlic

Swap it for iceberg on tacos, burgers and wraps

Grill halved hearts for a smoky wedge salad

Fill whole leaves with chicken salad or grass-fed beef

Blend a few leaves into a green smoothie

Top with avocado, salmon and a squeeze of lemon

How to pick, store and grow romaine

Choose a firm, crisp whole head with deep green outer leaves, buy organic when you can, store it unwashed in the fridge wrapped in a damp towel, and wash it just before eating. It keeps about a week, and it's one of the easiest greens to grow.

Buying. Look for crisp ribs, leaves that snap rather than bend, and no browning, yellowing or sliminess at the base. Whole heads keep more of their antioxidants than packaged, pre-cut lettuce.17 I recommend organic for lettuce, because you eat the outer leaf directly and non-organic lettuce can carry high chemical residues.23

Storing. Refrigerate right away, unwashed, loosely wrapped in a damp paper towel inside a produce bag, and use within about a week. Wash leaves just before eating.

Growing. Romaine is a cool-weather crop and a great beginner green. Sow seeds about half an inch deep in early spring or fall, in loose soil with sun to partial shade. Seeds sprout in about 10 days, and you can harvest outer leaves within about a month while the head keeps growing.

Myths vs. facts

Myth

Romaine is basically water with no real nutrition.

Fact

Two cups deliver 80% of your daily vitamin K and 32% of your folate for 16 calories.

Myth

All lettuce is the same.

Fact

Cup for cup, romaine has about 11 times the vitamin A and 3 times the folate of iceberg.

Myth

A fat-free dressing makes a salad healthier.

Fact

Without fat, your body absorbs almost none of a salad's carotenoids. Use real olive oil.

Romaine lettuce side effects & who should be careful

Quick answer

Romaine itself is one of the gentlest foods you can eat. The practical cautions are food safety, since romaine has been linked to several E. coli outbreaks; vitamin K, if you take warfarin; and digestion, for people who find raw salads hard to handle.

Is romaine lettuce safe to eat?

Yes, with a few simple habits. Romaine has been linked to several multistate E. coli outbreaks since 2011. In 2011, 58 people in 10 states became ill in an outbreak traced to a single farm supplying a grocery chain's salad bars.24 The largest, in spring 2018, sickened 210 people in 36 states and was traced to canal water in the Yuma, Arizona growing region,25 28 and a 2019 outbreak linked to the Salinas Valley sickened 167 people.26 Most outbreaks start with contaminated water or handling before the lettuce reaches the store, which is why buying whole heads, washing them well and checking for active recalls, especially before buying bagged romaine, makes sense.

Does romaine interact with blood thinners?

Its vitamin K can affect how warfarin works.22 That doesn't mean avoiding romaine; it means keeping your intake of romaine and other leafy greens consistent from week to week.

Good to know before you start

Choose whole heads over pre-cut bags when you can, and wash leaves well under running water
Check for active recalls before buying leafy greens, especially bagged romaine
Pregnant women, young children, older adults and anyone with a weakened immune system should be extra careful during a recall; thorough cooking kills the bacteria
With a sensitive gut, raw salads can be harder to tolerate; lightly cooked vegetables and slow, thorough chewing help27
Buy organic when you can, since you eat the outer leaf directly23

The bottom line

Should you eat romaine lettuce?

Yes. Romaine is one of the easiest ways to eat more leafy greens every day, and it delivers real vitamin K, vitamin A and folate for almost no calories, about three times the nutrition of iceberg. Human studies link lettuce and leafy greens to stronger bones, healthier blood pressure, fuller meals and slower brain aging, and lettuce seed has improved sleep in two human trials. The daily habit that research points to is one I'd recommend to almost anyone.

Buy organic whole heads when you can, wash and cut them yourself, and eat about two cups a day with olive oil, avocado or another healthy fat so you absorb what's in them. Rotate in spinach, kale and arugula for more vitamin K and lutein, and build the rest of your plate around clean protein and colorful vegetables. Simple habits like a daily salad are how real health gets built.

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Romaine lettuce: frequently asked questions

Is romaine lettuce good for you?

Yes. Romaine delivers real vitamin K, vitamin A and folate for about 8 calories a cup, roughly three times the nutrition of iceberg, and human studies link lettuce and leafy greens to stronger bones, healthier blood pressure and slower brain aging.

Is romaine better than iceberg lettuce?

Yes. Cup for cup, romaine has about 2.8 times the vitamin K, 11 times the vitamin A and 3 times the folate of iceberg, on USDA data.

How many calories are in romaine lettuce?

About 8 calories per cup (47 grams) of shredded raw romaine, and about 16 in a 2-cup side salad.

Does lettuce help you sleep?

Lettuce seed improved sleep quality in two placebo-controlled human trials, including one in 100 pregnant women with insomnia, and romaine extract lengthened sleep in mice.

Is romaine lettuce good for bones?

It's a strong source of vitamin K, which activates bone-building proteins. In the Nurses' Health Study, women who ate lettuce once a day or more had a 45% lower risk of hip fracture than those who ate it once a week or less.

Does romaine lettuce lower blood pressure?

Its nitrate may help. In a trial where neither the people nor the researchers knew who got what, a serving of high-nitrate lettuce lowered systolic blood pressure by 4.9 points within hours compared with low-nitrate lettuce.

Should I eat romaine with oil?

Yes. Vitamin K and carotenoids are fat-soluble, and people absorbed almost none of a salad's carotenoids with fat-free dressing. Olive oil or avocado helps you absorb them.

Is whole-head romaine better than bagged?

Whole heads are fresher and carry less processing risk. In one study, fresh lettuce raised blood antioxidant levels, while the same lettuce stored three days in modified-atmosphere packaging did not.

Is romaine lettuce safe to eat?

Yes, with simple habits. Romaine has been linked to several E. coli outbreaks, so buy whole heads when you can, wash leaves well, and check for active recalls, especially before buying bagged romaine.

Does romaine lettuce interact with blood thinners?

Its vitamin K can affect how warfarin works. That doesn't mean avoiding it; keep your intake of romaine and other leafy greens consistent from week to week.

Should I buy organic romaine?

When you can, yes. You eat the outer leaf directly, and non-organic lettuce can carry high chemical residues.

Freshness & update log

What changed in this update (September 30, 2026) — Added a chart of the salad-and-fullness study and restored the three-step diagram of how to get the most from romaine; stated the research limits once per finding and the warfarin note once; added study designs and sizes; corrected which animals the romaine sleep study used and the note on cooking during a recall; added a CDC source for the 2018 outbreak; and moved the bottom line above the FAQ.

What changed in this update (September 23, 2026) — Brought up to the current DrAxe.com article standard: labeled the Dr. Axe Score as an editorial assessment and showed its calculation; added an at-a-glance summary and jump menu; simplified headings and kept quick answers for the key questions; replaced the illustration with the DrAxe.com photo; clarified what the bloodwork markers can and can't show; removed unconfirmed review claims; and synchronized dates with the structured data.

What changed in this update (September 2026) — Rewritten around what romaine does and how to use it; added human studies on lettuce and hip fracture (72,327 women), salad and fullness, lettuce nitrate and blood pressure, fresh versus packaged lettuce and blood antioxidants, fat and carotenoid absorption, and two human trials of lettuce seed for sleep; corrected the salad-survey folate finding; condensed food safety into one practical section; scored with the food methodology (Evidence 30% · Antioxidant & Anti-Inflammatory 25% · Clinical Effectiveness 25% · Nutrient Density 20%); verified USDA nutrient values and every PubMed citation against NCBI records.

References

Dr. Josh Axe, DC, DNM, CNS

Doctor of Natural Medicine · Founder, DrAxe.com

Dr. Axe is a certified doctor of natural medicine, clinical nutritionist, and multiple New York Times bestselling author. He has spent 20+ years in clinical practice helping people heal at the root cause and founded one of the most-visited natural-health platforms in the world.

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