Caffeine intake and the plasma proteome

Abstract

Caffeine intake has been associated with both an increased and decreased risk of various health conditions. However, the physiological pathways affected remain unclear. CYP1A2 is the major enzyme that metabolizes caffeine and a single nucleotide polymorphism (rs762551) affects the rate of caffeine metabolism. The objective of this study was to determine whether caffeine intake is associated with proteins in the plasma proteome, and whether CYP1A2 genotype modifies any of the associations observed. Subjects (n=1095) aged 20–29 years completed a 196‐ item semi‐quantitative food frequency questionnaire and provided a fasting blood sample from which DNA and plasma were obtained for genotyping and proteomic analysis with 54 plasma proteins. Subjects were categorized into three groups according to habitual caffeine intake (<100mg/d, 100–200mg/d, and >;200mg/d) and later stratified by CYP1A2 genotype. Among individuals with A/C or C/C genotypes (slow metabolizers), plasma concentration of complement component 3 (p=0.03) and gelsolin isoform 1 (p=0.005), were significantly lower in the highest category of caffeine intake. No differences in protein concentration were observed for A/A individuals (fast metabolizers). These results suggest certain plasma proteins are affected by caffeine intake, but only among slow metabolizers.Grant Funding Source: Canadian Institutes of Health Research