Scientists from the University of Toronto and other research centers have found that drinking a lot of coffee may not be safe for everyone.
The risk of kidney problems from coffee depends on a person’s genes. This new study shows that people who drink three or more cups of coffee a day could harm their kidneys if they have a specific version of a gene called CYP1A2.
This gene helps the body break down caffeine. Some people have a “slow” version of the gene, which means their bodies take longer to remove caffeine.
When these people drink too much coffee, caffeine builds up in their system and can hurt their kidneys. Others have a “fast” version of the gene and can process caffeine quickly. For them, drinking coffee does not seem to cause kidney problems.
The researchers found that about half of the people in the study—and in the general population—have the slow version of the gene.
They tested three signs of kidney trouble: protein in the urine (called albuminuria), too much blood flowing through the kidneys (called hyperfiltration), and high blood pressure. All three problems were about three times more common in heavy coffee drinkers with the slow gene type.
This research shows why it’s important to understand how our bodies are different. One-size-fits-all health advice doesn’t always work. Personalized health tips based on genetics can help people avoid serious problems.
Today, many companies offer genetic tests that include information about the CYP1A2 gene. These tests can help people learn whether they are slow or fast caffeine metabolizers.
In Canada and the United States, health guidelines say that most adults can safely have up to 400 milligrams of caffeine each day. That’s about three to four cups of coffee. But this study suggests that for people with the slow gene, even this amount might be too much.
To keep your kidneys healthy, here are some helpful steps. First, live a healthy lifestyle. This includes eating nutritious foods, exercising often, and staying at a healthy weight.
Second, manage health problems like diabetes and high blood pressure, which can damage the kidneys if not treated properly. Third, drink enough water every day to help your kidneys flush out waste. Avoid smoking and drinking too much alcohol, as both can hurt the kidneys over time.
Also, be careful with over-the-counter pain medicines. Some can damage the kidneys if taken too often. Always read labels and follow your doctor’s advice. Finally, go for regular health check-ups, including tests for blood pressure and kidney function.
If you know that kidney disease runs in your family or you have other risk factors, talk to your doctor. You might benefit from extra tests or a more personalized health plan. This study is a reminder that even something as common as coffee may not be safe for everyone. Knowing your genes can help you make smarter choices.
If you care about kidney health, please read studies about drug that prevents kidney failure in 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 common painkillers may harm heart, kidneys and more.
The study was led by Dr. Ahmed El-Sohemy and published in JAMA Network Open.
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