The Effect of Green Tea and Vitamin C on Skin Health

There is little information on the effect of oral catechin, a nutritionally relevant bioactive compound, on skin health in humans in vivo despite considerable evidence for protective effects in experimental studies. Vitamin C is essential for skin health and stabilises catechins in the gut lumen. Ultraviolet radiation (UVR) in sunlight is a key environmental stressor impacting on skin health. Effects include acute inflammation and longer term photodamage.

OBJECTIVE: To examine the protective effect of catechin and vitamin C on UVR-induced inflammation.

STUDY DESIGN

(1) A double-blind randomised controlled nutritional study in 50 healthy volunteers. Volunteers will receive 3 months dietary supplement with high dose bioactive (n=25),or placebo (n=25).

The aim is to quantify the influence of catechin/vitamin C on:

• UVR-induced inflammation
• Leukocyte infiltration
• Inflammatory mediators
• Markers of photoageing
• DNA damage
• Bioavailability will also be assessed

(2) Bioavailability of catechin and vitamin C in skin and blood. Volunteers will receive active dietary supplement. Blood and urine samples will be taken over a period of 6 hours to determine blood bioavailability. Skin biopsies will also be taken to assess skin bioavailability. Volunteers will then receive 3 months of active dietary supplement followed by repeated sampling.

Inclusion criteria

• Healthy adults
• Sun-reactive skin type I / II

Exclusion criteria

• History of skin cancer
• History of a photosensitivity disorder
• History of a generalised skin disorder
• Sunbathing (including sunbeds) in the past 3 months
• Pregnancy
• Taking photoactive medicine
• Drink tea > 2 cups/day
• Taking nutritional supplements