Caffeine is a bitter alkaloid chemical that acts as a central nervous system (CNS) stimulant. It is most commonly consumed by humans after being extracted from the cherries of the coffee plant and the leaves of the tea bush, as well as from various foods and drinks containing products derived from the kola nut. Beverages containing caffeine, such as coffee, tea, soft drinks, and energy drinks make caffeine the world's most widely consumed psychoactive substance, as well as one that is considered relatively safe and therefore legal as well as mostly unregulated.Wikipedia
Several genetic variations affect how much of a buzz caffeine will give you, as well as whether caffeine consumption may alter your risk for various diseases. In particular:
- Caffeine metabolism: Individuals who are homozygous for the CYP1A2*1A allele are "rapid" caffeine metabolizers, whereas carriers of the variant CYP1A2*1F are "slow" caffeine metabolizers.
- (see CYP1A2 SNPs for details)
- Myocardial infarction risk:
- Intake of coffee was associated with an increased risk of nonfatal MI only among individuals with slow caffeine metabolism.[PMID 16522833]
- Hypertension risk:
- Carriers of slow *1F allele are at increased risk and should thus abstain from coffee, whereas individuals with *1A/*1A genotype can safely drink coffee.[PMID 19451835]
- Breast Cancer risk:
- Breast size:
- Among healthy premenopausal non-hormone users, 3+ cups of coffee per day was associated with lower breast volume only in CYP1A2*1F (slow) allele carriers (p=0.02), consistent with reports that coffee reduces breast cancer risk only for these allele carriers.[PMID 18813311]
- Alzheimer's disease risk:
- Two studies (Caffeine Reverses Cognitive Impairment and Decreases Brain Amyloid-? Levels in Aged Alzheimer's Disease Mice and Caffeine Suppresses Amyloid-? Levels in Plasma and Brain of Alzheimer's Disease Transgenic Mice published in the July 2009 issue of the Journal of Alzheimer's Disease point to caffeine as reducing a protein (beta amyloid) that is a sign of Alzheimer's disease.