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Caffeine Cravings - Blame Your Genes?

Why is it that some people need multiple cups of coffee to get through the day, while others get that wired or jittery feeling after just one cup?  It may be your genes.  

Researchers at five institutions, including UNC-Chapel Hill and the Harvard School of Public Health have identified two genetic variants that may help explain why some people have more caffeine cravings than others.  

Caffeine is ahead of nicotine and alcohol in use. Nearly 9 out of 10 adults in America use caffeine daily, in some form, with the average consumption of 210-240 mg daily. That amount of caffeine is approximately 3 cups of coffee, or 5-6 cans of soda.  

The researchers scanned the genomes of nearly 50,000 Americans of European descent.  The researchers were looking for tiny variations in DNA, called single-nucleotide polymorphisms, or SNPs ("snips") that show up repeatedly in people with higher caffeine intake. The data used was collected from U.S. nutritional surveys (taken between 1984 and 2001) in which participants reported how often, and how much, they consumed caffeine (including coffee, tea, soda and chocolate, among other foods and drinks). 

The "Scientific" Information

Pooling all the data, the researchers identified two variable snippets of DNA,out of the more than 2.5 million examined, that differed consistently with caffeine consumption. One of the variants was located near a gene called CYP1A2, which plays a role in caffeine metabolism. The second was near a gene dubbed AHR, which regulates CYP1A2. Everyone has two copies of each of these genes, one inherited from each parent.  The copies vary subtly from one person to the next. These findings are important in understanding why the health benefits/effects vary from person to person.  

How Does Caffeine Work?

Caffeine blocks the brain chemical Adenosine that promotes our urge to sleep.  This is one of the reasons people love caffeine.  Among the effect on countering fatigue, caffeine enhances mood improves concentration and alertness and quickens reaction time.  

Among the effects experienced from caffeine, many studies suggest that there are also many benefits from caffeine, including reduced risk of developing Alzheimer's, Parkinson's and certain types of cancer.

Additional, larger studies are being conducted with a focus on coffee drinkers, including more than 90,000 people and a wider range of ethnic groups. Researchers say the results will give a better understanding why the effects of caffeine vary from person to person, as well as help indentify patients who are more likely to suffer negative side effects.


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