Lettuce Nutrition & Calories – Complete Data of All Nutrients

Calories

Lettuce is considered a low-calorie food, containing only 15 calories per 100-gram serving. Per one standard serving (36 grams), lettuce provides only 5.4 calories.

What Do 15 Calories or 100 Grams of Lettuce Look Like?

Our team conducted measurements to visually represent the weight and calorie content of 100 grams of lettuce. 

The image below illustrates that approximately 20 lettuce leaves are 100 grams, equivalent to 15-17 calories. This implies that each lettuce leaf weighs approximately 5 grams and contains only 0.75-1 calories. 

For practical serving sizes, one cup of lettuce weighs about 36 grams, providing a calorie content of 5.4 calories accordingly. It's important to note that these values may vary based on the specific type and density of the lettuce.

Carbohydrates

Per 100-gram serving, lettuce contains 2.87 grams of carbs. About half of these carbs are net carbs – 1.57g. The rest are fiber (1.3g) and other sugars (glucose, fructose).

Protein

Lettuce contains small amounts of protein and various essential amino acids, including isoleucine and threonine. Per 100-gram serving of lettuce, you receive about 1.36 grams of protein. 

Fats

Lettuce also contains very small amounts of fat. A 100-gram serving contains only 0.15 grams of fat, which are primarily polyunsaturated fatty acids.

Lettuce contains no cholesterol. 

Vitamins

Lettuce is especially rich in Vitamin A and Vitamin K. 

Per 100-gram serving, lettuce contains 7405IU of Vitamin A. The recommended daily amount for Vitamin A is around 2000-3000 IU; hence, a 100-gram serving of lettuce fully covers your daily needs.

Lettuce also contains 126.3µg of Vitamin K per 100-gram serving. The daily need for Vitamin K is about 75-120µg; hence, a 100-gram serving of lettuce fully covers the daily need for Vitamin K as well. 

Lettuce also contains small amounts of Vitamin C, Vitamin B9 (folate), and Vitamin B6.

It completely lacks Vitamin D and Vitamin B12. 

Minerals

The predominant minerals found in lettuce are iron and manganese. Per 100-gram serving, lettuce provides 0.25mg of manganese and 0.86mg of iron. It also provides small amounts of other minerals, including 194mg of potassium, 36mg of calcium, and 29mg of phosphorus. 

Oxalates

Even though leafy green vegetables are high in oxalates, the amount of oxalates in lettuce is about 16mg per 100g, which is considered low.

While oxalates are generally considered safe for most people, they can pose a concern for individuals prone to kidney stones or those with certain medical conditions.

Nitrates    

Lettuce contains high amounts of nitrates, known for their beneficial and potentially harmful effects on health. The scientific literature on the topic of nitrates and lettuce is conflicting. For instance, an observational study by Bondonno et al. looked at the link between nitrate-rich vegetable consumption and cardiovascular outcomes, revealing that vegetable nitrate had cardioprotective outcomes (11). However, the study was observational, and no causation was established. Other nutrients in the vegetables may have contributed to the improved outcomes. 

On the other hand, Brkic et al. examined the nitrate levels in green leafy vegetables across various locations and seasons in Croatia (12). They found that the nitrate levels in lettuce varied across seasons and locations. The authors discovered that the mean value of nitrates in lettuce sampled in spring was 703.7mg/kg, while in autumn, the mean value was higher – 1264.8mg/kg. Although these levels were found to be quite high, they still did not exceed the daily acceptable intake of nitrate. 

In the Canary Islands, the average nitrate levels for lettuce were 573.7mg/kg, while in Slovenia, it was 962mg/kg (13, 14). However, some of the samples in Slovenia exceeded the European Union recommendations.  

The European Food Safety Authority (EFSA) has released a comprehensive report addressing the risks and benefits of nitrate-rich vegetable consumption (9). The mean nitrate concentration in the report for lettuce samples was 1324mg/kg. However, the production season, method, and region all influenced the nitrate content. Moreover, they referenced studies that discuss how washing off the vegetable reduces the nitrate content by up to 15%, whereas removing the stem reduces the nitrate content by up to 40%.

Their reports suggest that the advantages of consuming these vegetables are undoubtedly important, while the potential negative effects on health are unlikely to have a substantial impact. Another finding highlighted in the report is that the outer leaves of lettuce contain higher concentrations of nitrates than the inner leaves.

Phenolic Compounds

Phenolic compounds in lettuce include phenolic acids and flavonoids (1). The most common phenolic acids identified in lettuce include caffeic acid and chlorogenic acid, which are known to possess antidiabetic, anti-inflammatory, and antibacterial properties. 

Quercetin, isorhamnetin, kaempferol, and anthocyanins are the main flavonoids in lettuce, possessing several medicinal benefits, including anticancer, antioxidant, anti-inflammatory, and antiviral properties.

Carotenoids

Carotenoids found in lettuce include carotenes and xanthophylls (1). Research has also found a link between carotenoids and protective cardiovascular, anti-cancer, and anti-obesity effects. Per 100 grams, lettuce contains 4440μg of β-carotene. 

Chlorophyll

The chlorophyll A and chlorophyll B found in lettuce have been associated with antioxidant and anticancer properties (1).

Wild vs. Commercial Lettuce Varieties

In a recent study examining the differences between wild, commercial, and traditional lettuce varieties, Medina-Lozano et al. revealed that wild and traditional varieties contain 21% and 8% more Vitamin C than commercial varieties (10). However, commercial varieties contained the highest amounts of anthocyanins.    

General Nutritional Differences

Green leaf and red leaf lettuce varieties have similar nutritional profiles and provide similar amounts of minerals and vitamins with only very few distinctions. For example, green leaf lettuce provides slightly more Vitamin C. Per 100-gram serving, green leaf lettuce contains 9.2mg of Vitamin C, while red leaf lettuce contains only 3.7mg.

Refer to our green leaf lettuce vs. red leaf lettuce page for the complete nutritional comparison.

Lettuce Varieties by Shape

In addition to differences in the amounts of phytochemicals observed based on the color, the shape of the lettuce has also been found to be correlated to the amounts of phytochemicals, especially to the amounts of carotenoids and chlorophylls (1). Shi et al. explain that crisphead lettuce, which contains a closed head shape, produces fewer carotenoids due to reduced exposure to sunlight than other types of lettuce. Additionally, the authors cite various articles where the openness or closeness of the lettuce head, depending on the exposure to sunlight, also influences the production of chlorophyll and other metabolites.

In terms of other nutritional differences, when comparing iceberg lettuce to butterhead and romaine varieties, it is evident that it contains fewer vitamins and minerals. Specifically, iceberg lettuce provides about 7 and 17 times less Vitamin A than butterhead and romaine lettuce, respectively. Moreover, iceberg lettuce provides only 0.41mg of iron per 100-gram serving, compared to 1.24mg in butterhead lettuce and 0.97mg in romaine lettuce. The amount of folate in iceberg lettuce is also around 3 and 5 times lower than in butterhead and romaine lettuce types, respectively. Romaine and butterhead varieties also provide around 4 times more Vitamin K than iceberg lettuce. 

Consequently, when comparing romaine lettuce to butterhead lettuce, we can see that romaine lettuce provides more folate and Vitamin A than butterhead lettuce. Refer to our butterhead lettuce vs. iceberg lettuce and romaine lettuce vs. iceberg lettuce articles for more information.