The Effects Of Caffeine On Your Heart And Other Organs

May 03, 2017 5 min read
The Effects Of Caffeine On Your Heart And Other Organs

Caffeine is a compound primarily found in coffee but it is also present in lesser amounts in tea and certain sports drinks.  The average adult intake of caffeine daily around the world is about 300mg, which is equivalent to about 2 cups of black coffee. For some people, this amount of caffeine can be a miraculous energy booster, making them more productive at work or increasing their sporting abilities. For others, the same amount can make them feel anxious, really hyper with their hands shaking and lead to insomnia. In some people, it can cause constipation. In others, it can cause heart attacks.


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So, what dictates which group of people you fall into?

The Role of the CYP1A2 gene

The differences in the effect of caffeine in different people are to do with how their body’s metabolism is genetically pre-programmed. CYP1A2 is a gene that codes for 95% of the caffeine metabolism in the body. A person can fall into one of 3 groups: AA, CC or AC depending on which variant of the gene they have. AAs metabolize caffeine quickly and this variant is found in about 45% of the population. People with the AC (43% of the population) and CC (12% of the population) variants mean that caffeine is metabolized slowly.

What are the effects of caffeine on your heart? Can coffee and caffeine cause heart attacks?

An interesting study involving 2000 people was published in the Journal of the American Medical Association about the link between coffee and heart attacks. Overall, it concluded that having one cup of coffee per day could offer some form of protection, while 2-3 cups daily increased the risk by 10% and 4 cups of coffee per day increased the risk of getting a heart attack by 20%. However, when they further subdivided the participants into groups of fast and slow metabolizers, it showed that if the person was a slow metabolizer of caffeine (AC or CC variant), this increased risk of getting a heart attack was even more pronounced.

The fast metabolizers of caffeine actually hardly had any increased risk of getting heart attacks even with 3 cups per day. The overall effect of caffeine increasing the risk of a heart attack therefore was mostly contributed to by the slow metabolizers. This is not surprising since the caffeine would be hanging around the body exerting its effects for a longer period of time in this group of people.

Caffeine's impact on blood pressure

Another study looked at the relationship between caffeine and high blood pressure. In this study, it showed that people who inherently metabolized caffeine quickly had a lowered risk of getting high blood pressure by consuming caffeine daily (even up to 4 cups per day) as compared to abstainers. But, slow metabolizers of caffeine had an increased risk of high blood pressure with even just 2 cups of coffee daily when compared to people who took no coffee. As you can see, the response to caffeine is incredibly individualized.

Finding out which variant of the gene you carry, therefore, clearly will have an impact to how much coffee or caffeinated drinks you should be consuming on a daily basis. This is easily done using a nutrigenomic test kit. I can help you understand these tests and their results.

But it’s not just genes that dictate the effects of caffeine on your body

the effects of caffeine

If you do find out you are a slow metabolizer of coffee, take heart in knowing this is not the only factor that determines whether you can enjoy your daily cup of coffee or not.

If you have just eaten, your stomach contents can slow down the speed at which the caffeine and its effects gets distributed around the body. If you have a larger body mass, the effects are also weakened. Whether you have built up a tolerance to the effects of caffeine because you have been drinking it for a while is also another factor that is important to consider. The CYP1A2 gene is just one gene that has been linked to caffeine metabolism. There are others that have yet to be studied and the complex interplay between genetic and lifestyle factors continues to be a source of interest in the medical community.

Your flavor of coffee is also important

The other important aspect to remember is that when scientists talk about the health benefits of coffee, they’re talking about black coffee — not the fancy dressed up ones from your local cafe.

If you’re not simply drinking your coffee black, then chances are that all the other things you add to your morning cup of joe is just causing you more harm.

Calories from the teaspoons or packets of sugar add up over time, as do the calories from the added flavor shots.  Zero-calorie artificial sweeteners can still increase your risk of diabetes and other diseases. Non dairy creamers are full of corn syrup and partially hydrogenated vegetable oils used to replicate the feel of cream but, in reality, these are just added sugar and trans fats.

If you can’t take black coffee, try a healthier alternative like stevia or cinnamon instead for some natural sweetness. Otherwise, it’s really not the health drink you might be hoping for.

If you do take it black and your genes dictate that you can metabolize the caffeine quickly, then there are some great health benefits that have been associated with caffeine.

Besides the effects on the heart, caffeine also has been shown to:

  1. Aid in weight loss by boosting your resting metabolism. It also improves exercise performance which further aids in weight loss.
  2. Help boost brain function and memory due to its stimulant effect. It can prevent Alzheimer’s and Parkinson’s disease.
  3. Contain antioxidants that can help fight cancer.
  4. Help fight depression.
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How much caffeine is in your favorite drink?

All the same, it’s probably safest to stick to about 200-300 mg per day if you are unsure which genetic variant you have. This equates to:

30 ml Black espresso – 45 to 75 mg

240ml Brewed black coffee  – 100 – 200 mg

240 ml Black tea – 15 – 70 mg

240 ml Green tea – 25 – 45 mg

350 ml Coke – 35 mg

350 ml Mountain Dew – 40 to 55 mg

240 ml Redbull – 80 mg

The sugar added to Coke, Mountain Dew and Redbull likely cancel out any potential health benefits when taken on a regular basis, though. Watch out as well that certain brands of maximum strength cold and flu preparations could contain up to 200mg of caffeine.


denise karlyn hee

This guest post is written by Ireland-based Dr. Denise Karlyn Hee, a medical doctor practicing nutrigenomic medicine and certified integrative nutrition health coach. If you’d like to find out more about this topic, find out your genetically-determined sensitivity to caffeine or consult with Dr. Denise, feel free to message her via her RingMD profile (profile here).

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