Lettuce, cos or romaine, raw
Whole food · Vegetables and Vegetable Products
Photo: Wikipedia
Cos or romaine lettuce is a crisp, elongated head with sturdy, pale green ribs and tender, darker green leaves. Its texture is a delightful contrast—crunchy at the base and soft at the tips—with a mildly sweet, refreshing flavor that's less bitter than many other lettuces. Nutritionally, it's a low-calorie powerhouse, offering a good source of vitamin A and vitamin K per serving.
💚 Why it's loved
People adore romaine for its satisfying crunch and refreshing, clean taste that serves as the perfect canvas for bold dressings and toppings. It's the undisputed king of the Caesar salad, a cultural staple that has cemented its place in kitchens worldwide.
⚠️ Watch-outs & how to enjoy it better
Romaine has been linked to foodborne illness outbreaks (like E. coli) due to its leafy structure, which can harbor bacteria. To counter this, always wash leaves thoroughly under running water, even if pre-washed, and consider using a salad spinner. Those on blood-thinning medication should maintain consistent vitamin K intake, as romaine is a rich source.
Key benefits
- Excellent source of vitamin A, crucial for vision and immune function
- Good source of vitamin K, essential for blood clotting and bone health
- Very low in calories and carbohydrates, ideal for weight management
- Provides dietary fiber for digestive health
- High water content helps with hydration
🍽️ Popular dishes
🌍 Where it's eaten
💡 Did you know?
The name 'romaine' is believed to derive from the French 'romaine,' meaning 'Roman,' as the lettuce was popular in Rome and introduced to France from there in the 16th century.
Full nutrition (scales with serving)
| Water | 94.7 g |
| Energy | 17.0 kcal |
| Energy | 70.0 kj |
| Nitrogen | 0.20 g |
| Protein | 1.2 g |
| Total lipid (fat) | 0.26 g |
| Ash | 0.55 g |
| Carbohydrate, by difference | 3.2 g |
| Carbohydrate, by summation | 3.0 g |
| Fiber, total dietary | 1.8 g |
| Fiber, soluble | 0.10 g |
| Fiber, insoluble | 1.7 g |
| Sugars, Total | 1.2 g |
| Sucrose | 0.00 g |
| Glucose | 0.39 g |
| Fructose | 0.80 g |
| Lactose | 0.00 g |
| Maltose | 0.00 g |
| Galactose | 0.00 g |
| Starch | 0.00 g |
| Calcium, Ca | 35.0 mg |
| Iron, Fe | 0.95 mg |
| Magnesium, Mg | 13.7 mg |
| Phosphorus, P | 30.0 mg |
| Potassium, K | 253 mg |
| Zinc, Zn | 0.25 mg |
| Copper, Cu | 0.05 mg |
| Manganese, Mn | 0.13 mg |
| Selenium, Se | 0.40 ug |
| Vitamin C, total ascorbic acid | 4.6 mg |
| Thiamin | 0.08 mg |
| Riboflavin | 0.07 mg |
| Niacin | 0.32 mg |
| Pantothenic acid | 0.14 mg |
| Vitamin B-6 | 0.08 mg |
| Folate, total | 50.0 ug |
| Vitamin A, RAE | 436 ug |
| Carotene, beta | 5230 ug |
| Carotene, alpha | 0.00 ug |
| Cryptoxanthin, beta | 0.00 ug |
| Lycopene | 0.00 ug |
| Lutein + zeaxanthin | 2310 ug |
| Phytoene | 0.00 ug |
| Phytofluene | 0.00 ug |
| Vitamin E (alpha-tocopherol) | 0.14 mg |
| Tocopherol, beta | 0.00 mg |
| Tocopherol, gamma | 0.32 mg |
| Tocopherol, delta | 0.01 mg |
| Tocotrienol, alpha | 0.03 mg |
| Tocotrienol, beta | 0.00 mg |
| Tocotrienol, gamma | 0.00 mg |
| Tocotrienol, delta | 0.00 mg |
| Vitamin K (phylloquinone) | 102 ug |
| Vitamin K (Dihydrophylloquinone) | 0.00 ug |
| 5-methyl tetrahydrofolate (5-MTHF) | 40.0 ug |
| Tryptophan | 0.01 g |
| Threonine | 0.04 g |
| Isoleucine | 0.04 g |
| Leucine | 0.08 g |
| Lysine | 0.06 g |
| Methionine | 0.01 g |
| Cystine | 0.01 g |
| Phenylalanine | 0.07 g |
| Tyrosine | 0.02 g |
| Valine | 0.06 g |
| Arginine | 0.05 g |
| Histidine | 0.02 g |
| Alanine | 0.06 g |
| Aspartic acid | 0.14 g |
| Glutamic acid | 0.18 g |
| Glycine | 0.05 g |
| Proline | 0.04 g |
| Serine | 0.05 g |
| 10-Formyl folic acid (10HCOFA) | 9.0 ug |
| 5-Formyltetrahydrofolic acid (5-HCOH4 | 5.0 ug |
FAQ
Is romaine lettuce nutritious?
Yes, it's very nutrient-dense for its calorie count. A single cup provides over 80% of your daily vitamin K and about 20% of your daily vitamin A, along with small amounts of folate and vitamin C.
What's the difference between romaine and iceberg lettuce?
Romaine has a taller, more open head with darker green leaves and a stronger, sweeter flavor. It's nutritionally superior, offering significantly more vitamins A, C, and K than iceberg, which is milder and crunchier but mostly water.
How do I keep romaine lettuce fresh longer?
Wrap the unwashed head in a dry paper towel and place it in a plastic bag or container in the crisper drawer. The paper towel absorbs excess moisture, which is the main cause of wilting and slime.