Drinking coffee has been linked to a number of health benefits, as well as certain risks. Studies show that coffee drinkers with type 2 diabetes may be at lower risk for diabetic retinopathy (eye disease), and drinking coffee may reduce the risk for liver disease — a benefit that is especially relevant to people with type 2, who are at higher risk for liver disease. People who drink coffee may also be at lower risk for heart failure, heart rhythm problems, stroke, and dementia. But drinking coffee — or at least too much of it — is also linked to sleep disruption, certain heart rhythm problems, dementia, and elevated blood cholesterol.
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For the latest study, researchers looked at a group of 3,805 adults with type 2 diabetes who were followed for a median of 5.3 years. The average age of participants was 64.2 at the beginning of the study, and all participants initially had an eGFR (estimated glomerular filtration rate, a measure of kidney function) of 60 or higher. Participants had their coffee intake assessed at the beginning of the study using a dietary survey.
Higher intake of coffee linked to reduced risk of kidney function decline
During the follow-up period, 840 participants saw their kidney function decline to an eGFR below 60. But a higher intake of coffee appeared to reduce the likelihood of this happening — compared with participants who drank no coffee, those who drank less than a cup per day were 23% less likely to see their kidney function decline below this threshold. Those who drank one cup per day were also 23% less likely to experience a decline in eGFR to below 60, while those who drank two cups or more per day were 25% less likely to see this decline in kidney function.
When they researchers adjusted for participants’ eGFR at the beginning of the study, it didn’t meaningfully change the results — those who drank coffee were still less likely to see their kidney function decline, at all levels of coffee consumption. The average decline in eGFR per year was 2.16 for participants who didn’t drink coffee, 1.89 for those who drank less than a cup per day, 1.80 for those who drank one cup per day, and 1.78 for those who drank two or more cups per day.
“To our knowledge, this is the first prospective study to show a significant inverse association between coffee consumption and a decline in eGFR in patients with type 2 diabetes,” the researchers wrote. “Patients with diabetes are at higher risk of [kidney] dysfunction than individuals without diabetes; therefore, these findings might be important for their clinical care.”
Want to learn more about keeping your kidneys healthy with diabetes? Read “Managing Diabetic Kidney Disease,” “How to Keep Your Kidneys Healthy,” “Protecting Your Kidneys,” and “Kidney Disease: Your Seven-Step Plan for Prevention.”