Increased caffeine consumption doubles renal calcium clearance, study finds

Previous studies have shown caffeine consumption to be associated with osteoporosis due to enhanced bone resorption as a result of increased excretion of calcium in the urine. However, calcium amount in the urine may not necessaritly reflect the true effect of caffeine on calcium clearance. Considering the same, Stephanie E. Reuter, UniSA Clinical & Health Sciences, University of South Australia, Adelaide, SA, Australia, and colleagues aimed to examine the impact of high-dose, short-term caffeine intake on renal clearance of calcium, sodium and creatinine in healthy adults in this double-blind clinical study. 

The participants were made to chew caffeine (n=12) or placebo (n=12) gum for 5 minutes at an interval of 2-hours over a 6-hour treatment period (800 mg total caffeine). 

They fund that caffeine increased renal calcium clearance by 77%. Furthermore, the effect was positively correlated with sodium clearance and urine volume. This suggests that caffeine may act through inhibition of sodium reabsorption in the proximal convoluted tubule. 

"This study confirmed that caffeine does increase renal calcium clearance and fosters further investigation into safe consumption of caffeine," concluded the authors. 

Reference:

The study titled, "The effect of high-dose, short-term caffeine intake on the renal clearance of calcium, sodium and creatinine in healthy adults," is published in the British Journal of Clinical Pharmacology.

DOI: https://bpspubs.onlinelibrary.wiley.com/doi/10.1111/bcp.14856