Knowing how fast your body breaks down caffeine can save your life

It’s Wednesday afternoon and your brain is refusing to cooperate. You join your coworkers on their coffee run hoping caffeine will do the trick. Just a half an hour later you feel nauseous and lightheaded, you are gasping for breath clutching your chest. Next thing you know, you are waking up in the hospital to find out that you had a heart attack. Can coffee really cause a heart attack? In some people, it just might. The best predictors of this risk are genes that control how fast caffeine is broken down.

Caffeine is the most widely used psychoactive drug in the world. Unlike other drugs that affect brain functions, caffeine is legal, unregulated and is available in many different forms like coffee, tea, chocolate and energy drinks. More than 90% of adults in developed countries consume caffeine regularly. But individuals have different sensitivities to caffeine – the same cup of coffee that is a pick-me-up to one person is a sleep inducer to another. This depends on how long caffeine will stay around in the body, which is based on how fast caffeine is broken down.

One enzyme, cytochrome P450 1A2, is the main controller of caffeine levels in the body. It breaks down more than 95% of the caffeine. People with high levels of the enzyme can break down caffeine faster, compared to people with low levels of the same enzyme. Genetic changes in the CYP1A2 gene, which encodes cytochrome P450 1A2, are responsible for the differences in enzyme levels. “Fast” metabolizers carry a version of CYP1A2 that produces higher levels of enzyme whereas “slow” metabolizers have a version that lowers the amount of enzyme. Individuals with the “slow” version are more sensitive to caffeine, because it takes them much longer to break down and clear caffeine from the body.

Researchers have shown that caffeine intake can increase the risk of non-fatal heart attacks. This risk varied depending on whether you are a “slow” or a “fast” caffeine metabolizer. When a “slow” metabolizer drank 2-3 cups of coffee a day the risk of heart attack increases by 36%. They were 64% more likely to suffer a heart attack, if 4 or more cups were consumed. But “fast” metabolizers were 22% less likely to suffer a heart attack, even if they consumed 2-3 cups of coffee a day. Which means even a light coffee drinker may be at an increased risk of heart attacks, if they are genetically predisposed to metabolize caffeine slowly. The risk was enhanced by other risk factors for heart attacks, such as high blood pressure, high cholesterol, sedentary life style and family history.

On top of genetic changes, other lifestyle choices can also influence whether caffeine is harmful to your health. CYP1A2 levels are increased in people who use tobacco products or eat broccoli and cauliflower. Enzyme levels are decreased in people who consume herbal teas and spices like turmeric and cumin or in women who use oral contraceptives. Accordingly, a combination of genetic factors and lifestyle choices must be considered when trying to determine if caffeine – even at low levels – can be harmful to your health.

There are 32.4 million heart attacks and strokes worldwide every year. Cardiovascular disease is responsible for a quarter of all the deaths in North America. Given the vast quantities of caffeinated beverages consumed each year, along with diet and lifestyle habits, caffeine may be a main contributing factor to many of these deaths. Until you know which CYP1A2 version you have, the next time you need that pick-me-up, you might want to consider a healthy alternative, like a brisk walk or a healthy snack for the sake of your heart.