Do you love coffee and drink it every day? A new study from scientists at the University of Toronto found that your body’s response to coffee might depend on your genes—and it could affect your kidney health.
Inside our bodies, we have tiny instruction books called genes. These genes help control how our bodies work. One gene in particular, named CYP1A2, helps break down caffeine—the main active ingredient in coffee.
Some people have a fast version of this gene, like a speedy race car, which means their bodies can handle coffee quickly and easily. These people can usually enjoy their daily cups of coffee without it harming their kidneys.
But not everyone has the fast gene. Others have a slower version, more like a snail. When they drink too much coffee, their bodies take longer to break down the caffeine, and this can put more stress on their kidneys.
So, how much coffee is too much? For most people, drinking about three cups a day is considered safe. Some adults may be okay with up to four cups. But if you have the “snail” version of the gene, even this amount might be too much.
What’s fascinating is that about half of people around the world have the “race car” gene, and the other half have the “snail” gene. It’s a perfect split—50/50! And now, there’s a genetic test available that can tell you which one you have. This can help you decide how much coffee is safe for you to drink.
This study teaches us that everyone is different. Just because your friend can drink five cups of coffee a day doesn’t mean it’s healthy for you. Understanding your body—and your genes—can help you make smarter choices, especially when it comes to protecting your kidneys.
Kidneys are very important organs. They help clean your blood, remove waste, and keep your body in balance. To keep them healthy, it’s important to drink enough water, eat healthy foods, stay active, and be careful with medications.
Scientists are always working to find better ways to protect kidney health. Some foods may help support kidney function, and new medicines are being developed to keep kidneys healthy.
This research was led by Dr. Ahmed El-Sohemy and was published in a scientific journal called JAMA Network Open. It’s a good reminder that even small daily habits—like drinking coffee—can affect our health in different ways depending on who we are.
If you care about kidney health, please read studies about how to protect your kidneys from diabetes, and drinking coffee could help reduce risk of kidney injury.
For more information about kidney health, please see recent studies about foods that may prevent recurrence of kidney stones, and eating nuts linked to lower risk of chronic kidney disease and death.
Copyright © 2025 Knowridge Science Report. All rights reserved.
