Effects of a soy isoflavones extract on acute Alcohol Intoxication

Soy extracts contain isoflavones, polyphenolic compounds that perform their biological effects mainly through modulation of estrogenic receptors. Their consumption has been associated with many health benefits, including protection against hormone-dependent cancers, menopausal symptoms, heart disease, and osteoporosis. Daidzein, and its glycoside form daidzin, can act as natural inhibitors of the aldehyde-dehydrogenase-2 enzyme and might be useful to treat alcohol and cocaine dependence. The aim of the study was to assess the potential interaction between a soy extract in the pharmacokinetics and pharmacodynamics of alcohol. The protocol was approved by the local research ethics committee and registered with ClinicalTrials.gov, number NCT02309801. Ten healthy male volunteers participated in two experimental sessions. They received a single dose of alcohol (0.5 g/kg) and four capsules of Super-Absorbable Soy Isoflavones (Life-Extension, US) followed by the same dose of alcohol (2 h later). The study was randomized and crossover. They soy extract contained 216 mg of total isoflavones, 80 mg of daidzin-daidzein, 108 mg of genistein, and 24 mg of glycitein. Blood samples were obtained. Ethanol subjective and adverse effects (Visual Analogue Scales, Addiction Research Center Inventory) and vital signs were also measured along a 10-hour period. No differences were found in blood ethanol concentrations between both treatment conditions. Isoflavones showed several peaks in plasma suggesting enterohepatic recirculation. The soy extract did not modify the subjective and adverse effects of ethanol. Vital signs were also very similar in both sessions. The administration of a soy extract, at a dose twice the daily recommended for menopausal symptoms, did not interact with ethanol.