Close to 90% of Americans consume at least one cup of caffeine a day. But this same cup of caffeine may be a pick-me-up for one person while it is a sleep inducer to another. This variability is due to differences in caffeine sensitivity between people and it depends on how long caffeine stays around in the body.
Caffeine clearance is fairly rapid in fast metabolizers whereas caffeine stays in the circulation a lot longer if you are a “slow” metabolizer. Prolonged caffeine clearance is linked to increased risk of heart attacks and high blood pressure.
Slow metabolizers who consume more than 3 cups of caffeine a day maybe increasing their risk of a heart attack by 2-to-4 fold and their risk of hypertension by 3-fold.
The Caffeine sensitivity gene
The enzyme cytochrome P450 1A2 is the main controller of caffeine levels in the body. It breaks down more than 95% of the caffeine consumed. Genetic changes at the CYP1A2 gene results in making CYP1A2 enzyme with different activity levels. Those with the fast metabolizer variant make more CYP1A2. Enzymes levels are lower in slow metabolisers, who are more sensitivity to caffeine.
This DNA test detects a common genetic variant of the CYP1A2 gene linked to caffeine metabolism.
The “slow” variant is associated with lower levels of enzyme activity and slow clearance of caffeine. Reduced caffeine consumption is recommended for slow metabolizers to minimize health complications associated with lingering effects of caffeine.
Effects of caffeine
Caffeine is one of the most widely used unregulated psychoactive drugs in the world. Once in the body caffeine binds to receptors on nerve cells to increase their activity. The desired effects of caffeine, combating fatigue and drowsiness, are tackled using this mode of action.
However, as with any drug there are also side effects associated with increased consumption of caffeine. Excessive consumption may lead to symptoms such as
- Increased urination
- GI issues
- Irregular heart rate
- Muscle twitches