Curly kale extract and skin aging in women
What it found
In 29 women, taking a curly kale extract daily for 10 months raised skin carotenoid levels and improved a measure of collagen I to elastin in the skin.
The authors say this suggests the extract could help prevent skin aging.
What they found
Studies in people
Skin carotenoids
In the women taking the kale extract, skin carotenoid levels rose significantly in the first 5 months and then fell, but were still higher than at the start after 10 months. The placebo group showed no significant change.
Collagen I/elastin index
After 5 months, the collagen I/elastin index (SAAID) rose significantly in both groups. After 10 months, only the kale extract group still had a significant rise, and their values were higher than the placebo group, significantly so on the cheek.
Link between measures
The two carotenoid measurements were strongly linked, and the two SAAID measurements were moderately linked. Carotenoid and SAAID values showed a slight to moderate positive link.
What the authors conclude
“Thus, the results show that a natural extract containing a mixture of carotenoids at physiological concentrations could prevent skin aging and improve the extracellular matrix.”
Also in their conclusions
- They conclude that a natural extract with a mix of carotenoids at body-typical amounts could prevent skin aging and improve the supporting structure of the skin.
- They advise that a healthy lifestyle with a diet rich in carotenoids is the best way to prevent early skin aging.
How it was done
The authors wanted to see whether carotenoids taken by mouth could increase collagen I or stop its loss, which normally happens with age and oxidative stress and leads to skin aging.
29 healthy women aged 40 to 56 took either a curly kale extract (1650 µg of carotenoids a day, as three capsules) or a placebo for 10 months. Skin carotenoids and the collagen I/elastin index were measured before, at 5 months and at 10 months.
What it can’t tell you
- This was a randomised trial, so it can show cause and effect for the measures taken. But it cannot prove that the kale extract prevents wrinkles or other visible signs of aging, because those were not measured.
- The study was small (29 women) and only in women aged 40 to 56 with skin type II, so the results may not apply to other groups.
Who paid
- Conflicts
- Hennig Vollert is owner of the company Bioactive Food. All authors declare no conflict of interest.
- Authors work at
- Charité-Universitätsmedizin Berlin, Germany
The paper
- Title
- Influences of Orally Taken Carotenoid-Rich Curly Kale Extract on Collagen I/Elastin Index of the Skin
- Type
- Randomised controlled trial
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Meinke MC, Nowbary CK, Schanzer S, Vollert H, Lademann J, Darvin ME (2017). Influences of Orally Taken Carotenoid-Rich Curly Kale Extract on Collagen I/Elastin Index of the Skin. Nutrients. doi:10.3390/nu9070775Free full textPubMed 28753935DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error