Drinking moderate amounts of black coffee daily not only boosts energy but may also have positive health effects, especially for people with diabetes. Clinical observations have found that diabetic patients who manage their blood sugar, blood pressure, and cholesterol while drinking moderate amounts of black coffee daily can see improvements in kidney function and slower progression of kidney disease. One inspiring case involved a 60-year-old diabetic woman who, after following her doctor’s advice and drinking black coffee daily for three months, experienced a reversal in kidney function decline, with improved glomerular filtration rate and nearly vanished proteinuria.
Renowned nephrologist Dr. Hong Yongxiang recently shared on the program “Healthy Good Life” that recent studies increasingly show coffee can boost the glomerular filtration rate and reduce urine protein levels. He recounted a patient who had diabetes for 15 years and was referred from metabolism specialists due to a decreased glomerular filtration rate of 50 and early signs of diabetic kidney disease, including microalbuminuria.
Dr. Hong advised the patient to strictly control blood sugar, blood pressure, and lipids, increase intake of anti-inflammatory foods like colorful fruits and vegetables, olive oil, and bitter tea oil, and to drink 1 to 2 cups of black coffee daily. After three months, the patient’s microalbuminuria was nearly undetectable, and her filtration rate improved to over 60, much to her surprise and delight—proving that black coffee can help protect kidney function.
However, Dr. Hong cautions adults not to exceed 300 milligrams of caffeine per day. For example, a 360ml cup of dark roast coffee contains about 235mg of caffeine, while the same amount of Americano has about 150mg, so the daily maximum is about two cups.
Timing also matters: Dr. Hong recommends drinking coffee between 9:30 and 10:30 a.m. to stimulate the brain and enhance work focus, and again from 2:30 to 3:30 p.m. to fight afternoon drowsiness and boost alertness. He also advises avoiding coffee after 5 p.m. to prevent sleep disturbances.
