Table of ContentsView AllTable of ContentsBenefitsNutritionWho Should Avoid Kale?Best Ways to Eat Kale
Table of ContentsView All
View All
Table of Contents
Benefits
Nutrition
Who Should Avoid Kale?
Best Ways to Eat Kale
Kale is a hearty leafy green, cruciferous vegetable. It belongs to theBrassicaceae(mustard)family, which also includes bok choy, cabbage, cauliflower, watercress, radishes, broccoli, arugula, and Brussels sprouts.
Kale is packed with vitamins, minerals, and plant-based compounds. Due to its impressive nutrition profile, it is often referred toas a superfood.
This article discusses kale’s nutrition content, health benefits, and why some people may need to limit their intake.
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Kale Benefits
Kale is a nutrient-dense leafy green vegetable that provides a variety of fiber, vitamins, minerals, and beneficial plant-based compounds, including glucosinolates, antioxidants like beta carotene (beta-carotene), lutein, zeaxanthin and more.
Purple varieties have anthocyanins, which are linked to improved heart health.The numerous amounts of phytochemicals in it make kale a nutrient-dense vegetable that is also low-calorie andnon-starchy.
Diets rich in a variety of plant-based foods are associated with reduced risk of certain diseases,as well an increase in longevity.In addition, using a food-as-medicine approach and eating a diet rich in vegetables like kale, may help prevent and treatinsulin resistance(when cells can’t take up glucose from the blood, requiring the pancreas to make more insulin), inflammation, and more.
Diabetes
A meta-analysis published in theJournal of Diabetes Investigationfound a link between a lower risk of type 2 diabetes and higher intakes of fruits (especially berries), leafy green vegetables, yellow vegetables, and cruciferous vegetables.
Researchers believe this is due to a variety of factors, including high fiber content (which reduces insulin resistance and promotes satiety), as well as antioxidant compounds (including vitamin C), folate, and potassium.
Heart Disease
Consuming kale can support heart health because of the nutrients it contains. Kale contains, glucosinolates, a class of plant-based compounds that has anti-inflammatory properties.
Many studies have shown a reduced risk of cardiovascular disease with increased intake of leafy green vegetables and cruciferous vegetables.
Cancer
The American Institute for Cancer Research recommends eating kale regularly due to its high amounts of antioxidants, including carotenoids and vitamin C.Various studies have shown that eating cruciferous vegetables daily is associated with a lower risk of cancer, particularly colorectal cancer.
Glucosinolates, plant-based compounds found in kale that are activated after cutting, chewing, and digesting kale, have been investigated for their role in preventing and treating cancer. Glucosinolates are broken down into isothiocyanates (such as sulforaphane) and indoles.
In laboratory and animal studies, these compounds have been shown to decrease inflammation that can damage cells, which increases cancer risk, and inhibit enzymes that activate carcinogens. They may also stimulate enzymes that deactivate carcinogens.
Yet, human research is limited and analyzing it is difficult because the amount of glucosinolates present depends on a variety of factors, including, growth conditions, plant stage, plant tissue analyzed, storage conditions, and preparation and cooking methods.
Some studies have shown a positive impact of specific glucosinolates, like sulforaphane, and their ability to lessen the side effects of cancer therapies.However, more human studies are needed.
Bone Health
Kale’s impact on bone health resides in its levels of vitamin K and plant-based calcium. Vitamin K is essential for blood clotting, but also important for bone strength, and has a positive impact on bone metabolism (building, remodeling, and breaking down bone).Calcium is essential for building bone, and it makes up much of the structure of bone and teeth.
Digestion
Adequate amounts of fiber and water can help to prevent and treat constipation and keep bowels regular. Kale contains fiber, which adds bulk to stools.
Kale also containsprebiotics, key contributors to a diverse microbiome (a healthy combination of gut microbes). Microbial diversity in the gut is linked to a reduced risk of various diseases, including diabetes, Alzheimer’s disease, and more.
Skin and Hair Health
Rich in water-soluble vitamin C and beta-carotene (precursor to vitamin A), kale contains nutrients that support skin and hair.Vitamin C plays an important role in supporting immunity, repairing cells, and slowing the aging process.
Vitamin C is also important for collagen synthesis.Collagen is found in connective tissues and provides the structural frameworkfor the body, including hair and skin. It also aids in skin elasticity.
Eye Health
Specific nutrients are promoted for eye health. For example, nutrients such asvitamins Cand E, carotenoids (lutein, zeaxanthin, beta-carotene),zinc, and omega-3 fatty acids are important in vision due to their anti-inflammatory and antioxidant functions.
Kale contains a variety of these nutrients. Studies have shown that diets highest in lutein and zeaxanthin are associated with a long-term reduced risk ofage-related macular degeneration.
What to Eat When You Have Macular Degeneration
Kale Nutrition
Kale is low in calories and rich in vitamins and minerals. By volume, raw kale as opposed to cooked kale will have fewer calories and nutrients but is still a nutritious food source.
A 1-cup serving of raw kale provides the following nutrients:
A 1-cup serving of cooked kale (without added fat) provides the following nutrients:
People who takeblood-thinning medications (anticoagulants)need to eat consistent amounts of vitamin K so that their medication works as it’s supposed to. This is because vitamin K plays a role in blood clotting.
Raw kale also containsgoitrogens, a type of antinutrient that can prevent iodine from entering the thyroid gland. This is mostly a concern for people with iodine deficiency; cooking or fermenting kale destroys the enzyme responsible for its goitrogenic activity.
What’s the Best Way to Eat Kale?
Eating kale either raw or cooked is nutritious. However, when you cook kale, you are likely to eat more volume, which increases the nutrient intake. Some research suggests that steaming kale maximizes glucosinolates.
Consume kale with some heart-healthy fat likeextra-virgin olive oilor avocado oil to assist in fat-soluble vitamin absorption.
Chop and toss kale with extra virgin olive oil for salads, add it to soups and smoothies, blend it into dips, or steam it and pair it alongside your favorite whole grain, legume, fish, or lean protein source. Kale is versatile and can be added to a variety of dishes.
Summary
Kale is an extremely nutrient-dense, leafy green vegetable packed with a variety of vitamins, minerals, and plant-based compounds. Eating kale and other vegetables regularly is advantageous and supports a healthy eating plan.
22 SourcesVerywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ortega-Hernández E, Antunes-Ricardo M, Jacobo-Velázquez DA.Improving the health-benefits of kales (Brassica oleraceaL. var.acephalaDC) through the application of controlled abiotic stresses: a review.Plants (Basel). 2021;10(12):2629. doi:10.3390/plants10122629Kimble R, Keane KM, Lodge JK, Howatson G.Dietary intake of anthocyanins and risk of cardiovascular disease: a systematic review and meta-analysis of prospective cohort studies.Crit Rev Food Sci Nutr. 2019;59(18):3032-3043. doi:10.1080/10408398.2018.1509835U.S. Department of Agriculture.MyPlate: vegetables.Bellavia A, Larsson SC, Bottai M, Wolk A, Orsini N.Fruit and vegetable consumption and all-cause mortality: a dose-response analysis.Am J Clin Nutr.2013;(2):454-9. doi: 10.3945/ajcn.112.056119.Wang PY, Fang JC, Gao ZH, Zhang C, Xie SY.Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: a meta-analysis.J Diabetes Investig.2016;7(1):56-69. doi:10.1111/jdi.12376Blekkenhorst LC, Sim M, Bondonno CP, et al.Cardiovascular health benefits of specific vegetable types: a narrative review.Nutrients.2018;10(5):595. doi:10.3390/nu10050595Ma Y, He FJ, Sun Q, et al.24-hour urinary sodium and potassium excretion and cardiovascular risk.N Engl J Med.2022;386:252-263. doi:10.1056/NEJMoa2109794American Institute for Cancer Research.Kale: rich in antioxidants.Ağagündüz D, Şahin TÖ, Yılmaz B, Ekenci KD, Duyar Özer Ş, Capasso R.Cruciferous vegetables and their bioactive metabolites: from prevention to novel therapies of colorectal cancer.Evid Based Complement Alternat Med.2022:1534083. doi:10.1155/2022/1534083.Connolly EL, Sim M, Travica N, et al.Glucosinolates from cruciferous vegetables and their potential role in chronic disease: investigating the preclinical and clinical evidence.Front Pharmacol.2021;12:767975. doi:10.3389/fphar.2021.767975Akbari S, Rasouli-Ghahroudi AA.Vitamin K and bone metabolism: a review of the latest evidence in preclinical studies.Biomed Res Int.2018:4629383. doi:10.1155/2018/4629383.Office of Dietary Supplements.Calcium.Satheesh N, Fanta SW.Kale: review on nutritional composition, bio-active compounds, anti-nutritional factors, health beneficial properties and value-added products.Cogent Food Agric.2020;6(1):1811048. doi:10.1080/23311932.2020.1811048Varesi A, Pierella E, Romeo M, Piccini GB, Alfano C, Bjørklund G, Oppong A, Ricevuti G, Esposito C, Chirumbolo S, Pascale A.The potential role of gut microbiota in Alzheimer’s disease: from diagnosis to treatment.Nutrients.2022;14(3):668. doi: 10.3390/nu14030668.VanBuren CA, Everts HB.Vitamin A in skin and hair: an update.Nutrients.2022;14(14):2952. doi:10.3390/nu14142952Office of Dietary Supplements.Vitamin C: fact sheet for health professionals.National Eye Institute.AREDS/AREDS2 frequently asked questions.Rasmussen HM, Johnson EJ.Nutrients for the aging eye.Clin Interv Aging. 2013;8:741‐748. doi:10.2147/CIA.S45399Wu J, Cho E, Willett WC, Sastry SM, Schaumberg DA.Intakes of lutein, zeaxanthin, and other carotenoids and age-related macular degeneration during 2 decades of prospective follow-up.JAMA Ophthalmol. 2015;133(12):1415‐1424. doi:10.1001/jamaophthalmol.2015.3590U.S. Department of Agriculture. FoodData Central.Kale, raw.U.S. Department of Agriculture. FoodData Central.Kale, fresh, cooked (no fat added).Ali L.Hail to kale.Today’s Dietitian.2022;24(4):42.
22 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.Ortega-Hernández E, Antunes-Ricardo M, Jacobo-Velázquez DA.Improving the health-benefits of kales (Brassica oleraceaL. var.acephalaDC) through the application of controlled abiotic stresses: a review.Plants (Basel). 2021;10(12):2629. doi:10.3390/plants10122629Kimble R, Keane KM, Lodge JK, Howatson G.Dietary intake of anthocyanins and risk of cardiovascular disease: a systematic review and meta-analysis of prospective cohort studies.Crit Rev Food Sci Nutr. 2019;59(18):3032-3043. doi:10.1080/10408398.2018.1509835U.S. Department of Agriculture.MyPlate: vegetables.Bellavia A, Larsson SC, Bottai M, Wolk A, Orsini N.Fruit and vegetable consumption and all-cause mortality: a dose-response analysis.Am J Clin Nutr.2013;(2):454-9. doi: 10.3945/ajcn.112.056119.Wang PY, Fang JC, Gao ZH, Zhang C, Xie SY.Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: a meta-analysis.J Diabetes Investig.2016;7(1):56-69. doi:10.1111/jdi.12376Blekkenhorst LC, Sim M, Bondonno CP, et al.Cardiovascular health benefits of specific vegetable types: a narrative review.Nutrients.2018;10(5):595. doi:10.3390/nu10050595Ma Y, He FJ, Sun Q, et al.24-hour urinary sodium and potassium excretion and cardiovascular risk.N Engl J Med.2022;386:252-263. doi:10.1056/NEJMoa2109794American Institute for Cancer Research.Kale: rich in antioxidants.Ağagündüz D, Şahin TÖ, Yılmaz B, Ekenci KD, Duyar Özer Ş, Capasso R.Cruciferous vegetables and their bioactive metabolites: from prevention to novel therapies of colorectal cancer.Evid Based Complement Alternat Med.2022:1534083. doi:10.1155/2022/1534083.Connolly EL, Sim M, Travica N, et al.Glucosinolates from cruciferous vegetables and their potential role in chronic disease: investigating the preclinical and clinical evidence.Front Pharmacol.2021;12:767975. doi:10.3389/fphar.2021.767975Akbari S, Rasouli-Ghahroudi AA.Vitamin K and bone metabolism: a review of the latest evidence in preclinical studies.Biomed Res Int.2018:4629383. doi:10.1155/2018/4629383.Office of Dietary Supplements.Calcium.Satheesh N, Fanta SW.Kale: review on nutritional composition, bio-active compounds, anti-nutritional factors, health beneficial properties and value-added products.Cogent Food Agric.2020;6(1):1811048. doi:10.1080/23311932.2020.1811048Varesi A, Pierella E, Romeo M, Piccini GB, Alfano C, Bjørklund G, Oppong A, Ricevuti G, Esposito C, Chirumbolo S, Pascale A.The potential role of gut microbiota in Alzheimer’s disease: from diagnosis to treatment.Nutrients.2022;14(3):668. doi: 10.3390/nu14030668.VanBuren CA, Everts HB.Vitamin A in skin and hair: an update.Nutrients.2022;14(14):2952. doi:10.3390/nu14142952Office of Dietary Supplements.Vitamin C: fact sheet for health professionals.National Eye Institute.AREDS/AREDS2 frequently asked questions.Rasmussen HM, Johnson EJ.Nutrients for the aging eye.Clin Interv Aging. 2013;8:741‐748. doi:10.2147/CIA.S45399Wu J, Cho E, Willett WC, Sastry SM, Schaumberg DA.Intakes of lutein, zeaxanthin, and other carotenoids and age-related macular degeneration during 2 decades of prospective follow-up.JAMA Ophthalmol. 2015;133(12):1415‐1424. doi:10.1001/jamaophthalmol.2015.3590U.S. Department of Agriculture. FoodData Central.Kale, raw.U.S. Department of Agriculture. FoodData Central.Kale, fresh, cooked (no fat added).Ali L.Hail to kale.Today’s Dietitian.2022;24(4):42.
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read oureditorial processto learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
Ortega-Hernández E, Antunes-Ricardo M, Jacobo-Velázquez DA.Improving the health-benefits of kales (Brassica oleraceaL. var.acephalaDC) through the application of controlled abiotic stresses: a review.Plants (Basel). 2021;10(12):2629. doi:10.3390/plants10122629Kimble R, Keane KM, Lodge JK, Howatson G.Dietary intake of anthocyanins and risk of cardiovascular disease: a systematic review and meta-analysis of prospective cohort studies.Crit Rev Food Sci Nutr. 2019;59(18):3032-3043. doi:10.1080/10408398.2018.1509835U.S. Department of Agriculture.MyPlate: vegetables.Bellavia A, Larsson SC, Bottai M, Wolk A, Orsini N.Fruit and vegetable consumption and all-cause mortality: a dose-response analysis.Am J Clin Nutr.2013;(2):454-9. doi: 10.3945/ajcn.112.056119.Wang PY, Fang JC, Gao ZH, Zhang C, Xie SY.Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: a meta-analysis.J Diabetes Investig.2016;7(1):56-69. doi:10.1111/jdi.12376Blekkenhorst LC, Sim M, Bondonno CP, et al.Cardiovascular health benefits of specific vegetable types: a narrative review.Nutrients.2018;10(5):595. doi:10.3390/nu10050595Ma Y, He FJ, Sun Q, et al.24-hour urinary sodium and potassium excretion and cardiovascular risk.N Engl J Med.2022;386:252-263. doi:10.1056/NEJMoa2109794American Institute for Cancer Research.Kale: rich in antioxidants.Ağagündüz D, Şahin TÖ, Yılmaz B, Ekenci KD, Duyar Özer Ş, Capasso R.Cruciferous vegetables and their bioactive metabolites: from prevention to novel therapies of colorectal cancer.Evid Based Complement Alternat Med.2022:1534083. doi:10.1155/2022/1534083.Connolly EL, Sim M, Travica N, et al.Glucosinolates from cruciferous vegetables and their potential role in chronic disease: investigating the preclinical and clinical evidence.Front Pharmacol.2021;12:767975. doi:10.3389/fphar.2021.767975Akbari S, Rasouli-Ghahroudi AA.Vitamin K and bone metabolism: a review of the latest evidence in preclinical studies.Biomed Res Int.2018:4629383. doi:10.1155/2018/4629383.Office of Dietary Supplements.Calcium.Satheesh N, Fanta SW.Kale: review on nutritional composition, bio-active compounds, anti-nutritional factors, health beneficial properties and value-added products.Cogent Food Agric.2020;6(1):1811048. doi:10.1080/23311932.2020.1811048Varesi A, Pierella E, Romeo M, Piccini GB, Alfano C, Bjørklund G, Oppong A, Ricevuti G, Esposito C, Chirumbolo S, Pascale A.The potential role of gut microbiota in Alzheimer’s disease: from diagnosis to treatment.Nutrients.2022;14(3):668. doi: 10.3390/nu14030668.VanBuren CA, Everts HB.Vitamin A in skin and hair: an update.Nutrients.2022;14(14):2952. doi:10.3390/nu14142952Office of Dietary Supplements.Vitamin C: fact sheet for health professionals.National Eye Institute.AREDS/AREDS2 frequently asked questions.Rasmussen HM, Johnson EJ.Nutrients for the aging eye.Clin Interv Aging. 2013;8:741‐748. doi:10.2147/CIA.S45399Wu J, Cho E, Willett WC, Sastry SM, Schaumberg DA.Intakes of lutein, zeaxanthin, and other carotenoids and age-related macular degeneration during 2 decades of prospective follow-up.JAMA Ophthalmol. 2015;133(12):1415‐1424. doi:10.1001/jamaophthalmol.2015.3590U.S. Department of Agriculture. FoodData Central.Kale, raw.U.S. Department of Agriculture. FoodData Central.Kale, fresh, cooked (no fat added).Ali L.Hail to kale.Today’s Dietitian.2022;24(4):42.
Ortega-Hernández E, Antunes-Ricardo M, Jacobo-Velázquez DA.Improving the health-benefits of kales (Brassica oleraceaL. var.acephalaDC) through the application of controlled abiotic stresses: a review.Plants (Basel). 2021;10(12):2629. doi:10.3390/plants10122629
Kimble R, Keane KM, Lodge JK, Howatson G.Dietary intake of anthocyanins and risk of cardiovascular disease: a systematic review and meta-analysis of prospective cohort studies.Crit Rev Food Sci Nutr. 2019;59(18):3032-3043. doi:10.1080/10408398.2018.1509835
U.S. Department of Agriculture.MyPlate: vegetables.
Bellavia A, Larsson SC, Bottai M, Wolk A, Orsini N.Fruit and vegetable consumption and all-cause mortality: a dose-response analysis.Am J Clin Nutr.2013;(2):454-9. doi: 10.3945/ajcn.112.056119.
Wang PY, Fang JC, Gao ZH, Zhang C, Xie SY.Higher intake of fruits, vegetables or their fiber reduces the risk of type 2 diabetes: a meta-analysis.J Diabetes Investig.2016;7(1):56-69. doi:10.1111/jdi.12376
Blekkenhorst LC, Sim M, Bondonno CP, et al.Cardiovascular health benefits of specific vegetable types: a narrative review.Nutrients.2018;10(5):595. doi:10.3390/nu10050595
Ma Y, He FJ, Sun Q, et al.24-hour urinary sodium and potassium excretion and cardiovascular risk.N Engl J Med.2022;386:252-263. doi:10.1056/NEJMoa2109794
American Institute for Cancer Research.Kale: rich in antioxidants.
Ağagündüz D, Şahin TÖ, Yılmaz B, Ekenci KD, Duyar Özer Ş, Capasso R.Cruciferous vegetables and their bioactive metabolites: from prevention to novel therapies of colorectal cancer.Evid Based Complement Alternat Med.2022:1534083. doi:10.1155/2022/1534083.
Connolly EL, Sim M, Travica N, et al.Glucosinolates from cruciferous vegetables and their potential role in chronic disease: investigating the preclinical and clinical evidence.Front Pharmacol.2021;12:767975. doi:10.3389/fphar.2021.767975
Akbari S, Rasouli-Ghahroudi AA.Vitamin K and bone metabolism: a review of the latest evidence in preclinical studies.Biomed Res Int.2018:4629383. doi:10.1155/2018/4629383.
Office of Dietary Supplements.Calcium.
Satheesh N, Fanta SW.Kale: review on nutritional composition, bio-active compounds, anti-nutritional factors, health beneficial properties and value-added products.Cogent Food Agric.2020;6(1):1811048. doi:10.1080/23311932.2020.1811048
Varesi A, Pierella E, Romeo M, Piccini GB, Alfano C, Bjørklund G, Oppong A, Ricevuti G, Esposito C, Chirumbolo S, Pascale A.The potential role of gut microbiota in Alzheimer’s disease: from diagnosis to treatment.Nutrients.2022;14(3):668. doi: 10.3390/nu14030668.
VanBuren CA, Everts HB.Vitamin A in skin and hair: an update.Nutrients.2022;14(14):2952. doi:10.3390/nu14142952
Office of Dietary Supplements.Vitamin C: fact sheet for health professionals.
National Eye Institute.AREDS/AREDS2 frequently asked questions.
Rasmussen HM, Johnson EJ.Nutrients for the aging eye.Clin Interv Aging. 2013;8:741‐748. doi:10.2147/CIA.S45399
Wu J, Cho E, Willett WC, Sastry SM, Schaumberg DA.Intakes of lutein, zeaxanthin, and other carotenoids and age-related macular degeneration during 2 decades of prospective follow-up.JAMA Ophthalmol. 2015;133(12):1415‐1424. doi:10.1001/jamaophthalmol.2015.3590
U.S. Department of Agriculture. FoodData Central.Kale, raw.
U.S. Department of Agriculture. FoodData Central.Kale, fresh, cooked (no fat added).
Ali L.Hail to kale.Today’s Dietitian.2022;24(4):42.
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