Caffeine cravings may be brewing in your genes

by Aimee Keenan-Greene

Are you a java junkie?

The need for a daily dose of Joe, diet soda, or energy drinks could be linked to your DNA,  according to a new study in the journal PloS Genetics.

Caffeine is the most widely consumed psychoactive substance in the world, says scientists involved in the study.

Now for the first time a genome-wide association study of habitual caffeine intake reveals a 'large heritable component;.

Researchers included 47,341 people of European descent based on five population-based studies in the United States. 

Through a comprehensive search of the human genome, scientists discovered two loci associated with habitual caffeine consumption: the first near AHR and the second betweenCYP1A1 and CYP1A2.

Both the AHR and CYP1A2 genes are biologically plausible candidates, as CYP1A2metabolizes caffeine and AHR regulates CYP1A2. 

Researchers write:  

In a meta-analysis adjusted for age, sex, smoking, and eigenvectors of population variation, two loci achieved genome-wide significance: 7p21 (P = 2.4×10⁻¹⁹), near AHR, and 15q24 (P = 5.2×10⁻¹⁴), between CYP1A1 and CYP1A2. Both the AHR and CYP1A2 genes are biologically plausible candidates as CYP1A2 metabolizes caffeine and AHR regulates CYP1A2.

Caffeine intake was assessed using semi-quantitative food frequency questionnaires (FFQ) that included questions on the consumption of caffeinated coffee, tea, soft drinks, and chocolate.