We all know people who can drink coffee late at night and still sleep soundly. Then there are those who can hardly tolerate half a cup of coffee. This range of effects is influenced by variations in a gene (polymorphisms), that affect the speed of caffeine metabolism. But these polymorphisms may affect more than just sleep and the jitters. Studies are finding that they may affect the risk of heart attack.

This example of the effect of a polymorphism (gene variation) on how we metabolize a food (coffee) is called nutrigenetics. If you need a refresher, last week’s post outlined the difference between nutrigenetics and nutrigenomics.

Most studies on coffee/caffeine don’t divide the volunteers up according to their gene polymorphism that affects caffeine metabolism. Instead, they just analyze everyone as the same. This study (Cornelis et al, 2006) looked at the effect of caffeine on risk of heart attack according to 3 different caffeine metabolism polymorphisms.  The results are interesting. Let’s take a look at my infographic that summarizes the study:

Infographic looking at genotype and coffee consumption in relation to heart attack risk from CALMERme.com

* Statistically significant difference compared to <1 cup coffee/day

While previous studies found inconclusive or conflicting effects regarding coffee consumption and heart attack risk, they were looking at all genotypes together. They missed the clear variations this study shows. In this study, moderate coffee consumption looked like it increased the risk of heart attack in the total population (the first part of the first graph: “all genotypes”).  But when the results were teased apart into different genotypes (i.e., fast and slow metabolizers) a very different picture was seen: in AA genotypes, moderate coffee consumption appeared protective of heart attack, while in AC and CC genotypes moderate and high coffee consumption was associated with increased heart attack risk, especially in the younger population. 

Personalized nutrition

This study is an excellent example of the power of personalized nutrition.  Using genetic testing to assess which polymorphisms we have, can help us determine the best environment for optimal health. Just based on these results, if you are in your 40s, for example, and you have the AC or CC genotype, it would seem prudent to switch to decaf coffee after your first one in the morning.

In this example with coffee metabolism, we may be able to guess what our genotype is from our phenotype (i.e., can we tolerate coffee easily or not) but a gene test would give us a definitive answer.


What these gene tests show is that having a particular polymorphism doesn’t mean you will get a certain disease. Rather, knowledge of your genes shows you how best to control your environment (toxic exposure, diet, exercise, sleep, stress, etc.,) to optimize your health based on your genes.  

It is likened to genes loading a gun, but the environment pulls the trigger.  You may have genes that affect a function, but in a favorable environment, there won’t be an impact.  i.e., the CYP1A2 CC genes in someone who only drinks one coffee a day will likely not have an impact on their risk of heart attack relating to caffeine intake. The gene loaded the gun, but the environment didn’t pull the trigger. 

Interpreting your genetics summit

As a reminder, there is an ‘interpreting your genetics’ summit online later this month.  This is a great way for you to learn more. Here’s a link to sign-up.  I’ll also be covering a few more example of nutrigenetics and nutrigenomics in the next couple of weeks. 

Interpreting Your Genetics Summit


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