Because lettuce is a low-calorie non-starchy vegetable, it's an excellent addition to any meal plan when you're trying to maintain a healthy weight. Lettuce helps fill you up without the extra calories of starchier veggies. Certain types of lettuce are slightly more nutrient-dense (contain higher amounts of vitamins and minerals) than others.
One cup of Romaine lettuce provides you with just 8 calories, 0.5 grams of protein, 1.5 grams of carb, and is fat-free. In each 1-cup portion, you'll be getting about 1 gram of fiber. Micronutrients (vitamins and minerals) found in Romaine lettuce include 0.5 grams of iron, 116 milligrams of potassium, 64 micrograms of folate, 205 micrograms of vitamin A, and 48 micrograms of vitamin K. There are trace amounts of other vitamins and minerals in Romaine lettuce, but these values aren't significant enough to meet daily nutritional needs.
Green Leaf Lettuce
One cup of shredded green leaf lettuce contains about 5 calories, 0.5 grams of protein, 1 gram of carbs, and 0.5 grams of dietary fiber. Micronutrients found in green leaf lettuce include 0.3 grams of iron, 70 milligrams of potassium, 14 micrograms of folate, 133 micrograms of vitamin A, and 46 micrograms of vitamin K.
Butterhead Lettuce (Includes Bibb and Boston Lettuce)
If you're choosing butterhead lettuce (or Boston or bibb lettuce types), you'll be getting just 7 calories in each 1-cup shredded portion. In the same portion size, you'll be consuming 0.75 grams of protein, 1.25 grams of carbs, and 0.6 grams of dietary fiber. Micronutrients found in 1 cup of shredded butterhead lettuce include 0.7 grams of iron, 131 grams of potassium, 40 micrograms of folate, 91 micrograms of vitamin A, and 56 micrograms of vitamin K.
Iceberg Lettuce (Includes Crisphead Lettuce)
Iceberg lettuce is perhaps the lowest in micronutrient content, but highest in calories -- but is by no means a high-calorie food. In each 1-cup shredded portion of iceberg lettuce you'll be getting 10 calories, 0.7 grams of protein, 2 grams of carbs, 0.9 grams of dietary fiber, 0.3 grams of iron, 102 milligrams of potassium, 21 micrograms of folate, 18 micrograms of vitamin A, and 17 micrograms of vitamin K.
Red Leaf Lettuce
When choosing red leaf lettuce, you'll be getting just 4 calories in each 1-cup portion. Red leaf lettuce also provides you with 0.4 grams of protein, 0.6 grams of carbs, and 0.3 grams of dietary fiber in each cup. Micronutrients found in this type of lettuce include 0.3 grams of iron, 52 milligrams of potassium, 10 micrograms of folate, 105 micrograms of vitamin A, and 39 micrograms of vitamin K.
Which Lettuce Is Most Nutritious?
When looking at different varieties of lettuce for use in recipes, it might be difficult to determine which is the most nutritious, as they are all so similar nutritionally. If you had to choose one, Romaine lettuce would probably be your best bet because it contains slightly more micronutrients than the others. Iceberg lettuce provides the fewest micronutrients and highest calorie content. However, these small differences in micronutrient content of different lettuce varieties are minute and likely won't make or break meeting (or not meeting) daily nutrient needs.
If you're seeking leafy green lettuce alternatives that are similar nutritionally to Romaine lettuce (or even slightly higher in micronutrients) but with the same calorie content, you have some options. Consider raw spinach, kale, Swiss chard, collard greens, mustard greens, and arugula as alternatives.