Abstract
BACKGROUND: Vitamin A has different functions in the body and after being converted to acid form; it can play many roles in immune system regulation. Therefore, this vitamin can be used as a supplement in the treatment of diseases, such as cancer and autoimmune diseases. Vitamin A is a fat-soluble compound and its long-term consumption in high doses can have some adverse effects. OBJECTIVE: The current study aimed to investigate the possible complications and find solutions to minimize the adverse effects. PATIENTS AND METHODS: This study was a double blind randomized clinical trial. In the main study, vitamin A (as retinyl palmitate) was given to 35 multiple sclerosis (MS) patients in order to regulate their immune system with a dose of 25000 IU/day for a period of six months. To investigate the possible biochemical complications, lipid profiles, fasting blood sugar (FBS), liver enzymes, and C-reactive protein (CRP) were tested. RESULTS: Vitamin A did not have a significant difference in lipid profiles, FBS and liver enzymes between the two groups receiving vitamin A and the placebo, but CRP increased in patients who were taking vitamin A, 1.65±0.43 (mg/L) and 2.88±0.67, (Mean±SEM), before and after the intervention respectively (P=0.029), and statistical analysis showed significant differences with the group receiving placebo (P=0.011) and CRP level in vitamin A group was 1.3 mg/L more than those of the placebo group after intervention (P=0.011). CONCLUSIONS: Considering that no significant difference was found in the proven vitamin A side effects, due to the increase in CRP, frequent clinical and biochemical controls are required along with vitamin A supplementation.