Excess caffeine intake may be linked to increased risk of osteoporosis University of South Australia researchers have a bone to pick when it comes to drinking too much coffee as new research finds that excess caffeine may be linked to an increased risk of osteoporosis. Investigating the effects of coffee on how the kidneys regulate calcium in the body, researchers found that high doses of caffeine (800 mg) consumed over a six-hour period almost doubled the amount of calcium lost in the urine. This is the first study to report the impact of high-dose, short-term caffeine intake on renal clearance of calcium, sodium, and creatinine in healthy adults.