Effect of an antioxidant drink on homocysteine levels in Alzheimer's patients

Abstract

Background A large body of evidence supports a role of oxidative stress in Alzheimer disease (AD) and in cerebrovascular disease. Blood levels of homocysteine may be increased in AD and hyperhomocysteinemia may contribute to disease pathophysiology by vascular and direct neurotoxic mechanisms. Even in the absence of vitamin deficiency, plasma total homocysteine (tHcy) concentration may be influenced by administration of polyphenols. Objective To determine the effect of an antioxidant beverage rich in polyphenols on the plasmatic levels of tHcy in Alzheimer's patients. Design, setting, and patients A multicenter, randomized, double-blind controlled clinical trial of polyphenols supplementation in 100 subjects (52 of control group, 24 AD patients in initial phase and 24 AD patients in moderate phase) (Mini-Mental State Examination scores between 14 and 26, inclusive). Fasting plasma concentrations of tHcy, folate and vitamin B 12 were measured before (Ti) and after (Tf) the ingestion of the beverage. The study was conducted at clinical research places of the Catholic University San Antonio and University Hospital Virgen de la Arrixaca of Murcia (Spain). Intervention Participants of the three groups were randomly assigned to 2 groups of the same size: 50% treated with antioxidant beverage rich in polyphenols and 50% treated with an identical placebo beverage. Subjects consumed 1 brick (200 mL/day) of antioxidant drink or placebo drink for 8 months. Results Higher tHcy levels were observed in the AD moderate phase patients (Ti:12.65 ± 1.21 μmol/L) than in the AD initial phase patients (Ti:9.13 ± 1.24 μmol/L) and in the control group (Ti:9.86 ± 0.77 μmol/L). Lower folate levels were observed in the AD moderate phase patients (Ti:8.20 ± 1.29 ng/mL) than in the AD initial phase patients (Ti:9.41 ± 1.56 ng/mL) and in the control group (Ti:12.32 ± 0.67 ng/mL). Antioxidant drink vs placebo drink attenuated the tHcy increase in the control group (Tf values of 11.74 ± 0.45 vs 15.63 ± 1.79 μmol/L) and AD patients, especially in the moderate phase (Tf: 10.49 ± 0.73 vs 16.58 ± 2.73 μmol/L). Conclusions The regular ingestion of polyphenols contained in an antioxidant beverage may decrease tHcy plasmatic concentrations in Alzheimer's patients.