In a double-blind clinical study, researchers investigated the effects of high-dose, short-term caffeine intake on renal clearance of calcium, sodium, and creatinine in healthy adults.
Reuter et al. found that high doses of caffeine (800 mg) consumed over a six hour period almost doubled urinary calcium loss. Photo credit: Sci-News.com.
Osteoporosis is a chronic, painful, and debilitating disease that makes bones less dense and more prone to breakage.
More often in women, it occurs when the bones lose calcium and other minerals faster than the body can replace them.
Caffeine consumption has been linked to osteoporosis, which is believed to be due to increased bone resorption as a result of increased urinary calcium excretion.
However, the amount of calcium in the urine does not necessarily have to reflect the true effect of caffeine on calcium clearance.
“With the rise of an increasing ‘coffee culture’, it is important for people to understand the effects of what they put into their bodies,” said study co-author Dr. Hayley Schultz, researcher at the University of South Australia.
“Caffeine is one of the most widely consumed recreational drugs in the world, with 80% of adults consuming at least one caffeinated drink per day.”
“It’s a common stimulant used by professionals, parents, shift workers, and teenagers alike to start their day and stay alert – even the military uses caffeine to combat drowsiness.”
“But while coffee has its benefits, it’s also important to acknowledge your relapses – one of which is how our kidneys handle calcium.”
In a double-blind clinical study, participants chewed caffeine or placebo gum (800 mg total caffeine) for 5 minutes at 2-hour intervals over a 6-hour treatment period.
While the primary research objective was to examine the influence of caffeine consumption on wakefulness and other factors, this sub-study aimed to assess the influence of caffeine consumption on renal calcium clearance.
“Our research has shown that people who consume 800 mg of caffeine on a typical work day have a 77% increase in calcium in their urine, leading to a potential deficiency that could affect their bones,” said Dr. Schultz.
“Understanding the long-term effects of high caffeine consumption is particularly important for risk groups,” added the study’s lead author, Dr. Stephanie Reuter Lange, also from the University of South Australia, added.
“The average daily intake of caffeine is around 200 mg – roughly two cups of coffee. Drinking eight cups of coffee may seem like a lot (800 mg caffeine), but there are groups that would fall into this category. “
“People at risk could be teenagers who consume energy drinks who are at risk because their bones are still developing; Professional athletes who use caffeine to improve performance; as well as postmenopausal women who, due to hormonal changes, often have low blood calcium levels and do not have sufficient daily calcium intake from food. “
“We are also seeing increasing levels of caffeine in shift workers who have to remain vigilant at night, as well as in military personnel who use caffeine to combat sleep deprivation while on duty.”
“Caffeine in moderation certainly has its advantages. But it’s important to understand how excessive consumption could increase the risk of a very preventable disease like osteoporosis. “
The results appear in the British Journal of Clinical Pharmacology.
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Stephanie E. Reuter et al. The effect of high-dose, short-term caffeine intake on renal clearance of calcium, sodium and creatinine in healthy adults. British Journal of Clinical Pharmacology, published online April 14, 2021; doi: 10.1111 / bcp.14856
