The Effect of Green Tea and Vitamin C on Skin Health

Study Overview
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Brief Summary
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There is little information on the effect of oral bioactive compounds on human skin clinically despite evidence of a beneficial effect from laboratory studies. The aim of this study is to examine the effect of oral bioactive compounds (green tea and vitamin C) on the health of human skin by measuring markers of skin health directly and skin nutrient uptake.

Detailed Description
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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.

Official Title
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The Effect of Dietary Bioactive Compounds on Skin Health in Humans in Vivo

Conditions
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Skin Cancer

Intervention / Treatment
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* Dietary Supplement: Green tea + vitamin C high dose
* Dietary Supplement: Placebo capsule


Participation Criteria
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Eligibility Criteria
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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

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Green tea + vit C high dose<br> | Dietary Supplement: Green tea + vitamin C high dose<br>* One green tea capsule (1250mg catechin) and one vitamin C tablet (100mg) daily for 3 months<br>|
| Placebo Comparator: Placebo<br> | Dietary Supplement: Placebo capsule<br>* One capsule daily for 3 months<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in the minimum erythemal dose (MED) of ultraviolet radiation. | The UV minimum erythemal dose (MED) will be determined for each study volunteer before and after nutritional supplementation to examine if the intervention can increase the MED and therefore protect against UV-induced erythema. | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Intergroup comparison of inflammatory mediators (cytokines/chemokines) in skin biopsy sections and blister fluid. |  | 3 months | 
| Intergroup comparison of histological biomarkers (leucocytes, markers of photoageing, DNA damage) in skin biopsy sections. |  | 3 months | 
| Nutrient (polyphenol) bioavailability in samples of skin, blood and urine. | Bioavailability will be assessed in volunteers participating in both the first (RCT) and second (non-randomised bioavailability) parts of the study. | 3 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Green tea, Vitamin C, Ultraviolet radiation, Inflammation, Photoageing