Romaine lettuce is a nutrient-dense leafy green rich in vitamins K, C, and folate, with minimal calories and a high water content that supports hydration and satiety.
HeartMetabolismInflammationBrainGutBoneEye
Nutrition per ~85 g · ¾ cup chopped
Form
14kcal
Protein1.0 g
Carbs2.8 g
Fat0.3 g
Fiber1.8 g
1.0 g net carbs after fiber.
Vitamins
Vitamin A7404 iu148%
Vitamin K87.1 mcg73%
Vitamin A371 mcg41%
Folate116 mcg29%
Thiamin61.2 mcg5%
Riboflavin57.0 mcg4%
Vitamin C3.4 mg4%
Vitamin B662.9 mcg4%
Pantothenic Acid0.12 mg2%
Niacin0.27 mg2%
Vitamin E0.11 mg1%
Minerals & other
Manganese0.13 mg6%
Iron0.82 mg5%
Copper40.8 mcg5%
Potassium210 mg4%
Magnesium11.9 mg3%
Calcium28.1 mg2%
Phosphorus25.5 mg2%
Zinc0.20 mg2%
Choline8.4 mg2%
Selenium0.34 mcg1%
Sodium6.8 mg0%
Sugars1.0 g—
Monounsaturated Fat0.010 g—
Polyunsaturated Fat0.14 g—
Saturated Fat0.033 g—
Bioactives estimated
Lutein & Zeaxanthin~5.1 mg
Carotenoids~5.1 mg
Quercetin~13 mg
Inulin / Prebiotic fibre~2.5 g
Polyphenols~128 mg
Representative amounts for this food, not measured for this item. Real content varies widely by variety, ripeness and storage.
What drives the score weighted inputs
Nutrient density34.1/35Vitamins and minerals relative to calories — the single biggest driver.
Protein quality10.9/15How much protein it delivers, by absolute grams and per calorie.
Bioactives12.3/15Polyphenols, flavonoids and other beneficial plant compounds.
Fiber10.0/10Dietary fiber for gut health, satiety and steadier blood sugar.
Healthy fats5.0/10Fat quality — unsaturated against saturated, and trans-fat free.
Glycemic impact10.0/10Low sugar with a high fiber-to-carb ratio scores best.
These are the scored components, not a sum: the published score also reflects normalisation across the catalog, so the parts above will not add to 95.
MethylationAntioxidantATP / MitoBoneThyroidCollagenNeurotransmitterDetoxGlucoseHematopoiesisLipidsGut MicrobiomeMembranesClottingHPA AxisGlycolysisβ-OxidationKetogenesisNAD⁺mTORAMPKUrea CycleDopamineSerotoninSteroidogenesisVitamin D ActivationInsulin Signaling
Overview
Romaine lettuce (Lactuca sativa var. longifolia) originated in the Mediterranean region and has been cultivated for centuries. As a cruciferous relative with dense nutrient concentration, romaine provides exceptional micronutrient density with only 15 calories per 100g. It is particularly rich in vitamin K (essential for bone mineralization and cardiovascular health), folate (crucial for methylation cycles and cognitive function), and vitamin C (a potent antioxidant). Romaine contains polyphenols including quercetin and caffeic acid, which exhibit anti-inflammatory properties documented in aging research. The high fiber-to-calorie ratio supports healthy gut microbiota composition and metabolic function. Its bioavailable lutein and zeaxanthin support macular and cognitive health. For longevity-focused individuals, romaine's nutrient density with minimal caloric burden makes it ideal for caloric restriction and intermittent fasting protocols. The crisp texture and mild flavor make it a versatile base for nutrient-stacking meals.
Health benefits 5
Supports bone health and cardiovascular function through vitamin K-dependent proteinsstrong
Vitamin K activates osteocalcin and matrix Gla-protein, essential for bone mineralization and prevention of arterial calcification
Reduces oxidative stress and supports anti-inflammatory statusmoderate
Polyphenols (quercetin, caffeic acid) and vitamin C scavenge free radicals and inhibit NF-κB inflammatory pathways
Supports cognitive and eye health through lutein and zeaxanthin accumulationmoderate
Carotenoids cross the blood-brain barrier and deposit in neural tissue and macula, protecting against age-related degeneration
Promotes healthy methylation and one-carbon metabolism via folatestrong
Folate serves as a methyl donor for DNA methylation, homocysteine regulation, and neurotransmitter synthesis
Supports healthy gut microbiota diversity through insoluble fiber and polyphenol substratesmoderate
Fiber and polyphenols serve as prebiotics, selectively feeding beneficial Bacteroidetes and Faecalibacterium species
Pairs with
Pair with extra virgin olive oil because fat-soluble vitamins (K, lutein, zeaxanthin) require lipid vehicles for intestinal absorption and transport
Combine with cruciferous vegetables (broccoli, Brussels sprouts) because synergistic polyphenols enhance total antioxidant capacity and glucosinolate bioavailability
Add fermented foods (sauerkraut, kimchi, tempeh) because probiotics enhance folate and vitamin K2 synthesis in the gut microbiota
Pair with citrus or tomato because vitamin C enhances non-heme iron absorption from romaine and other plant sources
In the kitchen
Store unwashed romaine in a breathable container with paper towels to maintain crispness for 7-10 days; wash only before consumption to minimize polyphenol oxidation
Consume romaine raw in salads rather than cooked to preserve heat-sensitive vitamin C and optimize polyphenol bioavailability
Select darker outer leaves over pale inner leaves; outer leaves contain 5-10x higher polyphenol and lutein concentrations
Incorporate 1-2 cups daily as a low-calorie, high-nutrient-density base for nutrient stacking; pairs well with protein and healthy fats for satiety and meal completion
When to eat it anytime
Romaine's minimal caloric and carbohydrate burden makes it suitable for any time of day or fasting state; midday and evening consumption supports satiety without disrupting metabolic clarity
Fasting-compatible
May be consumed during fasting windows if uncooked and unadorned (zero calories). Optimal when paired with meals containing fat and protein for maximal micronutrient absorption and glycemic stability.