RESUMEN
BACKGROUND: No studies have yet been undertaken to determine the effect of aloe gel on the clinical signs and biochemical changes of aging skin. OBJECTIVE: We wanted to determine whether dietary aloe vera gel has anti-aging properties on the skin. METHODS: Thirty healthy female subjects over the age of 45 were recruited and they received 2 different doses (low-dose: 1,200 mg/d, high-dose: 3,600 mg/d) of aloe vera gel supplementation for 90 days. Their baseline status was used as a control. At baseline and at completion of the study, facial wrinkles were measured using a skin replica, and facial elasticity was measured by an in vivo suction skin elasticity meter. Skin samples were taken before and after aloe intake to compare the type I procollagen and matrix metalloproteinase 1 (MMP-1) mRNA levels by performing real-time RT-PCR. RESULTS: After aloe gel intake, the facial wrinkles improved significantly (p<0.05) in both groups, and facial elasticity improved in the lower-dose group. In the photoprotected skin, the type I procollagen mRNA levels were increased in both groups, albeit without significance; the MMP-1 mRNA levels were significantly decreased in the higher-dose group. Type I procollagen immunostaining was substantially increased throughout the dermis in both groups. CONCLUSION: Aloe gel significantly improves wrinkles and elasticity in photoaged human skin, with an increase in collagen production in the photoprotected skin and a decrease in the collagen- degrading MMP-1 gene expression. However, no dose- response relationship was found between the low-dose and high-dose groups.