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.
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: 1. UVR-induced inflammation 2. Leukocyte infiltration 3. Inflammatory mediators 4. Markers of photoageing 5. DNA damage 6. 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.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
TRIPLE
Enrollment
95
One green tea capsule (1250mg catechin) and one vitamin C tablet (100mg) daily for 3 months
One capsule daily for 3 months
Salford Royal NHS Foundation Trust
Manchester, United Kingdom
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.
Time frame: 3 months
Intergroup comparison of inflammatory mediators (cytokines/chemokines) in skin biopsy sections and blister fluid.
Time frame: 3 months
Intergroup comparison of histological biomarkers (leucocytes, markers of photoageing, DNA damage) in skin biopsy sections.
Time frame: 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.
Time frame: 3 months
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