Women over 40 can make their skin younger-looking and softer by drinking five cups of green tea a day. Dermatologists at the University of Witten-Herdecke in Germany drew this conclusion from a study in which 60 women aged 40-65 participated. According to the researchers, green tea protects the skin against the ultraviolet radiation in sunlight too.
Not so long ago green tea was so hip that we – unworldly and nerdy as we are – didn’t dare write about it. Meanwhile interest in green tea has waned – and we plucked up enough courage to read the study that Ulrike Heinrich published in 2011 in the Journal of Nutrition.
Heinrich gave 30 women 1 litre – say five cups – of a product from the Coca-Cola Company lab, every day for 12 weeks. Coca-Cola sponsored the study. The composition of the product is shown below. If you compare it with analyses of green tea like you’d make at home, you’ll notice almost no difference.
A control group of 30 women were given a placebo.
Before, halfway through, and at the end of the 12 weeks, the researchers exposed a small piece of each woman’s skin to UV light, and measured how much the skin burned [a-value]. As you can see below, green tea supplementation gave the skin some protection against UV radiation. All the women were of skin type 2: European, fair-skinned, burned easily but did tan a little.
The skin of the women in the control group did not change; that of the women in the experimental group did. Their skin became softer and less flaky. The photo below shows the change in skin texture of a random subject in the experimental group. The white patches are flakes of skin.
Green tea improved the circulation in the skin and the oxygen supply to the skin cells.
“Improvements of skin structure may be related to flavanol mediated increases in cutaneous blood flow”, the researchers write. “Microcirculation is important for nutrient and oxygen supply of the skin and an improved delivery likely affects skin condition and appearance.”
“The present study demonstrated that dietary constituents protected skin and improved overall skin quality”, the researchers summarise. “Regular consumption of a beverage rich in tea flavanols contributed photoprotection against harmful UV radiation and helped maintain skin structure and function.”
Green tea polyphenols provide photoprotection, increase microcirculation, and modulate skin properties of women.
Dietary constituents including polyphenols and carotenoids contribute to endogenous photoprotection and modulate skin characteristics related to structure and function of the tissue. Animal and in-vitro studies indicate that green tea polyphenols affect skin properties. In a 12-wk, double-blind, placebo-controlled study, 60 female volunteers were randomized to an intervention or control group. Participants consumed either a beverage with green tea polyphenols providing 1402 mg total catechins/d or a control beverage. Skin photoprotection, structure, and function were measured at baseline (wk 0), wk 6, and wk 12. Following exposure of the skin areas to 1.25 minimal erythemal dose of radiation from a solar simulator, UV-induced erythema decreased significantly in the intervention group by 16 and 25% after 6 and 12 wk, respectively. Skin structural characteristics that were positively affected included elasticity, roughness, scaling, density, and water homeostasis. Intake of the green tea polyphenol beverage for 12 wk increased blood flow and oxygen delivery to the skin. Likewise, in a separate, randomized, double-blind, single-dose (0.5, 1.0, and 2.0 g) study of green tea polyphenols, blood flow was maximized at 30 min after ingestion. In summary, green tea polyphenols delivered in a beverage were shown to protect skin against harmful UV radiation and helped to improve overall skin quality of women.
PMID: 21525260 [PubMed – indexed for MEDLINE]