Spinach vs. Lettuce — Health Impact and Nutrition Comparison

Calories

Spinach and lettuce are both very low-calorie foods; however, lettuce has fewer calories. 

A 100-gram serving of spinach contains 23 calories, while the same serving size of lettuce provides only 15 calories.

Protein and Fats

Spinach is richer in both protein and fats when compared to lettuce.

Both spinach and lettuce provide low levels of all essential amino acids.

As can be seen from the fat type comparison chart below, while the fat content found in leafy greens is very low, most of this fat consists of favorable polyunsaturated fatty acids, containing minimal amounts of saturated fats. 

Spinach and lettuce naturally contain no cholesterol, as they are plant-based products.

Fat Type Comparison

Fat type breakdown side-by-side comparison

Lettuce

1

Saturated Fat: Sat. Fat 0.02 g

Monounsaturated Fat: Mono. Fat 0.006 g

Polyunsaturated fat: Poly. Fat 0.082 g

Spinach raw

2

Saturated Fat: Sat. Fat 0.063 g

Monounsaturated Fat: Mono. Fat 0.01 g

Polyunsaturated fat: Poly. Fat 0.165 g

Contains less Sat. FatSaturated Fat

-68.3%

Contains more Mono. FatMonounsaturated Fat	+66.7%
Contains more Poly. FatPolyunsaturated fat	+101.2%

Carbohydrates

Spinach has a higher level of carbohydrates than lettuce. Consequently, spinach contains almost two times more dietary fiber.

The small amounts of sugars found in lettuce consist of glucose and fructose. In addition to these two, spinach also contains low levels of sucrose and galactose.

Cardiovascular Health

Section reviewed by cardiologist Astghik Grigoryan

Most studies have suggested that the intake of leafy greens, spinach and lettuce, particularly, has strong cardiovascular health benefits, potentially reducing the risk of fatal and nonfatal myocardial infarction, stroke, and overall cardiovascular mortality (6).

The high content of nitrates found in spinach may also contribute to beneficial hemodynamic effects, improving vascular health by decreasing arterial blood pressure and arterial stiffness (7).

In animal studies, lettuce has been researched to improve blood serum lipid levels, decrease liver cholesterol, and depress the apparent absorption of dietary cholesterol, which may have an important role in atherosclerosis prevention (8).

In summary, both spinach and lettuce offer cardiovascular benefits as part of a healthy diet. However, spinach stands out for its higher nutrient density, particularly in potassium, antioxidants, and dietary nitrates, which contribute to its greater potential in supporting heart health and reducing the risk of CVD. Incorporating a variety of leafy greens, including spinach and lettuce, into your diet can contribute to overall cardiovascular wellness.

Diabetes

We have already stated that spinach and lettuce are low in sugars and have low glycemic index values. In addition, these leafy greens have certain properties that may contribute to the prevention of diabetes.

Nitrates found in spinach have been researched to ameliorate insulin resistance by improving nitrate status and blood lipid levels, relieving inflammation, and enhancing protective endothelial function (9).

Spinach leaves also demonstrate hypoglycemic qualities by decreasing blood glucose levels after a meal (10).

Red lettuce, high in polyphenols and antioxidants, has been researched to have anti-diabetic qualities, potentially reducing hyperglycemia and improving insulin sensitivity (11).

Cancer

There is probable evidence that foods high in dietary fiber, such as spinach, decrease the risk of breast cancer (12). Studies have also shown that raw salad vegetables may protect against breast cancer (13).

There is probable evidence that non-starchy vegetables reduce the risk of aerodigestive cancers, such as mouth, pharynx, larynx, esophageal, lung, stomach, and colorectal cancers (12).

Mental Health

Research has shown that mental well-being responds in a dose-depends fashion to increases in both the quantity and the frequency of the vegetables consumed (14).

Spinach and Medication

Green leafy vegetables and spinach, in particular, contain high levels of vitamin K. Several blood thinners, such as warfarin, function by inhibiting the role of vitamin K in the creation of blood clots. Due to this, some have recommended being careful when consuming high levels of spinach while on these medications.

However, available evidence does not support the advice to modify dietary habits when starting therapy with vitamin K antagonists (15).