Scientists from the University of Toronto and other research centers recently studied how drinking a lot of coffee might affect kidney health. They also looked at whether a person’s genes could make a difference. They focused on a gene called CYP1A2, which helps the body break down caffeine.
To understand this better, imagine two friends, Alice and Bob. They both love coffee and drink several cups a day. However, their bodies handle caffeine differently.
Alice is a slow metabolizer, meaning her body takes a long time to get rid of caffeine. Bob is a fast metabolizer, so his body clears caffeine quickly. Even though they both drink the same amount of coffee, the effect on their kidneys could be very different.
The study found that people like Alice, who are slow metabolizers and drink a lot of coffee, showed almost three times more signs of kidney problems compared to fast metabolizers like Bob.
The researchers looked at several important health markers, such as proteins in urine, how well the kidneys filtered blood, and blood pressure—all of which are signs of how healthy the kidneys are.
In the past, studies on coffee and kidney health have shown mixed results. Some research suggested that too much caffeine might harm the kidneys, while other studies hinted that coffee might actually protect them.
This new study adds another important piece to the puzzle: your genes matter. Whether coffee helps or hurts your kidneys could depend on how quickly your body processes caffeine.
In the study, participants who drank a lot of coffee—more than three cups a day or about 300 milligrams of caffeine from espresso—showed different results depending on their genetic makeup.
This amount is close to the safe upper limit of daily caffeine intake suggested by health experts in places like Canada and the United States, where up to 400 milligrams per day is considered safe for most people.
The researchers paid special attention to heavy coffee drinkers who were slow metabolizers. In this group, they found more cases of albuminuria (too much protein in the urine), hyperfiltration (kidneys working too hard), and high blood pressure. All these signs suggest that the kidneys could be under stress or starting to have problems.
It’s important to note that about half the population carries the gene variant that makes them slow caffeine metabolizers, just like Alice. Because of this, some companies and clinics now offer genetic testing to check for the CYP1A2 gene. Knowing your results could help you make smarter choices about how much coffee you drink and how it could affect your health.
The findings highlight the idea of personalized nutrition—meaning that what’s healthy for one person might not be healthy for another because of genetic differences. Personalized nutrition tailors food and drink advice to each person’s body and genes instead of giving the same advice to everyone.
This research, led by Ahmed El-Sohemy and published in JAMA Network Open, encourages people to think about how their bodies respond individually to what they eat and drink. For people who love coffee, especially those who drink a lot of it, knowing your genetic profile could be important for protecting your kidney health.
Overall, this study shows how our genes can shape the way everyday foods and drinks affect us. It also points to a future where health care and nutrition advice could become more personalized, helping everyone make better choices for their own bodies.
If you care about kidney health, please read studies about pesticide linked to chronic kidney disease, and this drug may prevent kidney failure in people with diabetes.
For more health information, please see recent studies about drug duo that may treat kidney failure, and results showing these vegetables may protect against kidney damage.
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