Breath Alcohol Level and Plasma Amino Acids: A Comparison between Older and Younger Chronic Alcohol-Dependent Patients

Aim: The aim of the present study is to examine the distribution of plasma excitatory and inhibitory amino acids, according to the age and current breath alcohol levels (BrAl +/-), of alcohol-dependent patients. Participants and Methods: 78 alcohol-dependent patients (mean age = 46.2 +/- 11 years, men/women = 54/24) were clinically tested, including the determination of the major excitatory as well as inhibitory amino acids. The independent variables were gender, age and current alcohol consumption measured with the breath alcohol level (BrAl +/- status). Results: In comparison to BrAl negatives, BrAl positives had higher plasma levels of glutamic acid (P = 0.01) and proline (P = 0.026), and lower levels of aminobutyric acid (P = 0.002), serine (P = 0.031) and urea (P = 0.01). In the BrAl positives, no age effect was found related to the plasma amino acids. In contrast, the BrAl negatives displayed age-related differences. The older (>= 50 years) BrAl negative patients had higher plasma levels of cystine, tyrosine, citrulline and urea, and lower histidine levels, compared to the younger group (< 50 years). In general, differences in plasma levels of certain amino acids were dependent on gender, BrAl status, age and biochemical markers (GGT, MCV) of alcohol abuse. Conclusions: Abstaining patients (BrAl-/) display age-related differences in AAs' distribution, while active drinking (BrAl+/) seems to even out those differences, underpinning the hypothesis that drinking mimics changes seen with advanced age.