Kale vs. Spinach: Which Leafy Green Has More Benefits?

There are plenty of nutrient-rich dark, leafy greens to choose from. Some people appreciate the peppery flavor of arugula, while others prefer the bitter notes of collard greens and Swiss chard. But when it comes to two of the most popular greens—kale and spinach—is one healthier than the other? Or is it just a matter of preference?

Here's what registered dietitians have to say about the similarities and differences between kale and spinach. 

"Both are dark, leafy greens, and superfoods in their own right," registered dietitian nutritionist Mascha Davis MPH, RDN, says. "They each contain a lot of phytonutrients, antioxidants, and prebiotic fiber." 

Incorporating extra dietary fiber into the diet is important, given that most people are not meeting their daily recommended requirements1. Many people go for fiber-rich foods when looking to improve digestion, but fiber's gut health benefits go far beyond the bathroom. 

"Fiber aids in the reduction of total and LDL cholesterol by binding to cholesterol in the gastrointestinal tract and moving it out of circulation," registered dietitian and nutritionist Maya Feller, M.S., R.D., CDN, previously told mbg. "These actions reduce the risk of developing cardiovascular disease, some cancers, and type 2 diabetes2."

Along with prebiotic fiber, kale and spinach are both sources of antioxidants, like beta-carotene, vitamins A and K, and lutein, Maggie Moon, M.S., R.D., says.

Both are made up of about 90% water, which means they're also naturally hydrating, Moon adds. 

"While they have a lot in common, they do have some key nutritional differences," Davis says.

To get a broad overview of how they differ, these are the nutritional values of 1 cup of kale3 and 1 cup of spinach4, according to the U.S. Department of Agriculture (USDA)5:

In terms of nutrition, spinach has more iron, twice the amount of magnesium, and more folate, Moon says. "Spinach is also much higher in choline, lutein, and vitamin K, though both are really good sources."

For anyone worried about fiber intake, kale may be the better option, as it provides about twice the amount compared to spinach. Kale also has three times as much calcium and vitamin C. "It's also higher in B vitamins involved in metabolism," Moon says. 

In terms of flavor, spinach tends to be more mild and tender, which makes it easier to enjoy raw or cooked, she explains. Kale, on the other hand, tends to be tougher, slightly more bitter, and can withstand longer cooking times. 

Because of those texture and flavor differences, kale may work better in a sauté or stew. Spinach can, too, but it won't require as much cooking time and tends to wilt far quicker. That said, spinach is a good option for green smoothies because of its milder flavor and delicate leaves. 

"Both are nutritional powerhouses, and one isn't necessarily better than the other," says Davis.

When deciding between spinach and kale, the option is really subjective. Both are nutrient-rich and versatile leafy greens with comparable levels of antioxidants and vitamins. "Both are brain-boosting beauties that I'd recommend any day of the week," Moon says. 

If choosing kale, here are some of integrative medicine doctor Taz Bhatia, M.D.'s favorite ways to use kale, from salad to stir fry. To reduce waste, be sure to use the stems.

For spinach, consider whipping up these spinach pancakes or finding a recipe from a knowledgeable food expert or chef.

At the end of the day, simply incorporating greens into your diet is what matters most.