Review · Molecules (Basel, Switzerland) · 2025Conflicts declared

Kale's nutrients, health effects and food uses reviewed

What it found

Kale is rich in vitamins, minerals and plant compounds that may help against heart disease, type 2 diabetes and some cancers.

Studies in people, animals and cells point to benefits for cholesterol, blood sugar and gut bacteria.

What they found

Studies in people

Cholesterol in men

Men with high cholesterol who drank 150 mL of fresh kale juice daily for 12 weeks had a 10% drop in LDL cholesterol and a 27% rise in HDL cholesterol. Another study in men with slightly high blood pressure found similar changes after 300 mL of kale juice daily for 6 weeks.

Blood sugar in diabetes

In a 12-week trial, people with type 2 diabetes who ate bars with 78 g of freeze-dried kale daily had a drop in a long-term blood sugar marker compared with the control group. Other small studies found that kale taken with meals reduced peak blood sugar levels.

Animal and lab studies

Cancer and cell studies

In lab tests, kale extracts reduced the growth of prostate cancer cells and protected DNA from damage in mice. Compounds in kale like sulforaphane and indole-3-carbinol are thought to play a role in these effects.

Studies in people and animals

Gut bacteria

A 4-week trial in people found that eating kale improved bowel movements and changed some gut bacteria. In mice, a high-fat diet with 9% kale shifted the balance of gut bacteria and increased a type of bacteria called Bacteroides thetaiotaomicron.

Skin and cosmetics

A 10-month study found that a carotenoid-rich kale extract taken by mouth increased skin carotenoid levels and improved the ratio of collagen to elastin. In cell studies, kale extracts protected skin cells from oxidative stress.

Other findings

Nutrient richness

Kale is a very good source of vitamins A, C and K, minerals like calcium, potassium and iron, and dietary fiber. It has about 110 mg of vitamin C per 100 g of fresh weight. The calcium in kale is well absorbed by the body.

What the authors conclude

“Kale ( Brassica oleracea var. acephala ) emerges as a multifunctional plant species with exceptional nutritional, therapeutic, and functional food potential.”
Łukaszyk A, Kwiecień I, Kanik A, et al, 2025

Also in their conclusions

  • They conclude that kale is a multifunctional plant with exceptional nutritional, therapeutic and functional food potential.
  • They state that clinical and preclinical evidence supports kale's role in reducing risk factors for chronic diseases such as cardiovascular disorders, type 2 diabetes and hormone-related cancers.
  • They support the integration of kale into health-oriented dietary strategies and highlight its relevance in preventive medicine, food innovation and cosmeceutical development.

How it was done

The authors wanted to bring together up-to-date findings on kale's nutrients, health effects and uses in food, medicine and cosmetics. They also wanted to highlight advances in growing kale and boosting its active compounds.

They reviewed published research on kale, including its nutrients, plant compounds, and effects in people, animals and cells. The review covered studies on cholesterol, blood sugar, gut bacteria, cancer and skin, as well as how kale is grown and processed.

What it can’t tell you

  • Many of the studies in this review were done in animals or cells, so the results may not be the same in people.
  • Some of the human studies were small or looked at specific groups, so the findings may not apply to everyone.
  • The review cannot show that eating kale directly prevents or treats any disease.

The paper

Title
Nutritional, Therapeutic, and Functional Food Perspectives of Kale ( Brassica oleracea var. acephala ): An Integrative Review
Type
ReviewThe authors read earlier studies and describe what they found. It isn’t a new study.
Evidence
Studies in people · animals · lab
Summarised from
Full text
Cite
Łukaszyk A, Kwiecień I, Kanik A, et al (2025). Nutritional, Therapeutic, and Functional Food Perspectives of Kale ( Brassica oleracea var. acephala ): An Integrative Review. Molecules (Basel, Switzerland). doi:10.3390/molecules30214214Free full textPubMed 41226173DOI

Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error