Beta-carotene plasma levels and content in oral mucosal epithelium is skin type associated

Beta-carotene is one of the important antioxidants in the defence mechanisms of the body against reactive oxygen species and, in particular, against UV radiation in the skin. The aim of our study was to measure if differences of beta-carotene in the peripheral blood and oral mucosa exist in relation to skin types I-IV (according to Fitzpatrick). One hundred and seventy-four subjects were studied with regard to beta-carotene plasma levels. Out of these, 63 healthy volunteers (24-28 years) with skin type I-IV were studied with regard to plasma levels and content of beta-carotene in the oral mucosa. Ten millilitres of venous blood was obtained and oral mucosa cells (OMCs) were taken by gently brushing the oral cavity without contamination of capillary leak blood. A modified method by Stich et al. was used for preparing cells and measuring beta-carotene in OMCs by HPLC. Plasma levels of skin type I were 0.1565 micromol/l and increased via skin types II with 0.2989 and III with 0.5457 to 1.221 micromol/l in skin type IV. A similar skin type-dependent increase in beta-carotene could be measured in the oral mucosa epithelium (OMC) either when measured in micromoles/litre (0.0056-0.0217) or in nanograms/10(6) cells (0.2090-0.9989). Smokers had significantly lower levels of beta-carotene in plasma and OMC as compared with non-smokers. Non-melanoma and melanoma skin cancer patients also showed lower beta-carotene plasma levels and in the OMCs as well. From our results, we conclude that plasma levels and content of beta-carotene in the cytoplasm of OMCs show marked and significant differences with regard to skin types I-IV. The question arises whether these differences are genetically controlled.