May 20, 2024

Key Takeaways

  • Kale is a nutrient-dense superfood that contains vitamins K, C, A, fiber, and antioxidants.
  • Raw kale can be hard to digest. Kale’s fibrous cell walls may prevent your body from absorbing nutrients, but cooking kale can reduce its antioxidant content.
  • Nutrition experts say steaming kale is a good way to make it easier to digest while preserving most of the nutrients.

Kale earned its superfood status over a decade ago, and it’s still considered one of the healthiest vegetables since it’s full of fiber, vitamins, and antioxidants. But should you cook it or eat it raw to maximize your nutritional intake?

Raw kale is extremely nutrient-dense. One cup of kale has 94% of the recommended daily amount of vitamin K, which is important for blood clotting and bone formation.

However, some of these nutrients are wrapped inside fibrous cell walls, which means your gut has to work harder to absorb them, according to Heather Anita Garcia, MS, RD, a registered dietitian based in Los Angeles.

“When eaten raw, some of the nutrients stay hidden behind the unbroken cell walls and pass through our gut without being absorbed,” Garcia told Verywell in an email.

You could give raw kale a quick massage to help break down the fibrous walls, she said. Massaging kale can also reduce its bitter flavor.

Does Cooking Kale Reduce Its Nutritional Content?

Cooking kale might make the vegetable more palatable and easier to digest. The downside is that cooking can reduce the antioxidant and mineral content in kale, but some cooking methods are worse than others.

“If you were to boil kale, you’re going to have heat, and heat will denature the antioxidants, so vitamin C will get destroyed. Basically, it will leach into the water,” Sherry Gray, MPH, RD, a registered dietitian and extension educator at the University of Connecticut, told Verywell.

Steaming is a better option than boiling because you don’t lose as many nutrients with this cooking method, according to Gray.

“You’re not giving it heat treatment for very long, so it’s closest to raw that you can get and you still are cooking it to some degree,” she said.

Some social media users say that steaming kale can help reduce oxalate content. Sometimes called “anti-nutrients,” oxalates are naturally occurring molecules in vegetables that can prevent calcium absorption and cause kidney stones in some people. However, oxalates in kale are considerably lower than in other leafy greens, such as spinach and chard.

“For most people without preexisting kidney issues, the oxalate levels found in kale aren’t alarming at all. In fact, diets high in ultra-processed foods pose a much greater risk for kidney stones,” John Wesley McWhorter, DrPH, MS, RDN, director of lifestyle medicine at Suvida Healthcare, told Verywell in an email.

While steaming kale might reduce its oxalate content, the difference between raw and cooked kale mostly comes down to flavor preference, McWhorter added.

Which Is Better: Raw or Cooked Kale?

Nutrition science hasn’t determined the best way to prepare kale, but if you prefer raw kale, you might be getting some protection against certain types of cancer. According to a 2021 study published in the journal Cancer Epidemiology, raw cruciferous vegetables were found to have a stronger association with reduced risk of pancreatic cancer than cooked vegetables.

That doesn’t mean cooked kale isn’t worth eating. Fruit and vegetable consumption is associated with a lower risk of diabetes, heart disease, and certain cancers.

Cooked kale might be a more appetizing option for some people, but Garcia recommends using the cooking water as a nutrient-rich vegetable broth to get the nutrients that leached into the water.

Eating kale in any form adds vegetable intake to your diet. The Dietary Guidelines for Americans recommend that adults eat two to three cups of vegetables each day, but only 10% of U.S. adults currently meet this guideline.

With this in mind, nutrition experts say that most people should focus on adding more vegetables, like kale, to their diet instead of worrying if raw or cooked kale is better.

“Though most cooking methods result in loss of antioxidants, vitamins, and minerals, kale is still worth eating in whichever form you prefer. The benefits outweigh the nutrient loss,” Garcia said.

What This Means For You

Kale is a nutrient-dense vegetable that offers benefits whether it’s eaten raw or cooked. However, oxalates in kale could interfere with calcium absorption and cause kidney stones in some people.

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Harvard T. H. Chan School of Public Health. Kale.

  2. National Institutes of Health Office of Dietary Supplements. Vitamin K: fact sheet for health professionals.

  3. Harvard T. H. Chan School of Public Health. Vitamin K.

  4. Armesto J, Gómez-Limia L, Carballo J, Martínez S. Effects of different cooking methods on the antioxidant capacity and flavonoid, organic acid and mineral contents of Galega Kale (Brassica oleracea var. acephala cv. Galega). Int J Food Sci Nutr. 2019;70(2):136-149. doi:10.1080/09637486.2018.1482530

  5. Harvard T. H. Chan School of Public Health. Are anti-nutrients harmful?.

  6. Salgado N, Silva MA, Figueira ME, Costa HS, Albuquerque TG. Oxalate in foods: extraction conditions, analytical methods, occurrence, and health implications. Foods. 2023;12(17):3201. doi:10.3390/foods12173201

  7. Morrison MEW, Hobika EG, Joseph JM, et al. Cruciferous vegetable consumption and pancreatic cancer: a case-control study. Cancer Epidemiol. 2021;72:101924. doi:10.1016/j.canep.2021.101924

  8. National Cancer Institute. Fruit and vegetable consumption.

  9. Lee SH, Moore LV, Park S, Harris DM, Blanck HM. Adults meeting fruit and vegetable intake recommendations – United States, 2019. MMWR Morb Mortal Wkly Rep. 2022;71(1):1-9. doi:10.15585/mmwr.mm7101a1

Stephanie Brown

By Stephanie Brown

Brown is a nutrition writer who received her Didactic Program in Dietetics certification from the University of Tennessee at Knoxville. Previously, she worked as a nutrition educator and culinary instructor in New York City.

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