Study puts coffee in the bad books again, if you drink this much

Can you get through the day without coffee? Is it your go-to pick-me-up in the morning or have you sworn off it altogether? It seems coffee is either reviled or revered – depending on what month it is.

Now, a University of South Australia study has found that drinking too much coffee may be linked to an increased risk of osteoporosis.

While investigating the effects of coffee on how the kidneys regulate calcium in the body, the researchers found that high doses of caffeine (800mg) consumed over a six-hour period almost doubled the amount of calcium lost in the urine.

They say their study is the first to report the impact of high-dose, short-term caffeine intake on how the kidneys clear calcium, sodium and creatinine.

Read: Are you drinking your coffee too early?

The university’s Dr Hayley Schultz says that given an ever increasing ‘coffee culture’, it’s important people understand the impact of what goes into their bodies.

“Caffeine is one of the most widely used recreational drugs in the world, with 80 per cent of adults consuming at least one caffeinated beverage per day,” she says.

“It’s a common stimulant, consumed by professionals, parents, shift workers and teenagers alike to start their day and stay alert – even the military use caffeine to help combat sleepiness.”

But Dr Schultz says that while coffee has its perks, it’s also important to acknowledge its drawbacks, with one being how our kidneys handle calcium when coffee consumption hits a certain level.

“Our research found that people who consume 800mg of caffeine over a typical working day will have a 77 per cent increase in calcium in their urine, creating a potential deficiency that could impact their bones,” she says.

Read: Why are we still debating whether coffee is good or bad for us?

To gain an understanding of how much coffee you need to drink to reach 800mg, a cup of brewed coffee contains 130 to 175mg, an instant coffee 70 to 135mg and a 150ml espresso 150mg.

Osteoporosis is a chronic, painful and debilitating disease that makes your bones less dense and more susceptible to fracture. It occurs when bones lose calcium and other minerals faster than the body can replace them and is more common in women.

An estimated 924,000 Australians have osteoporosis.

The researchers explained that in their double-blind clinical study, participants were asked to chew caffeine or a placebo gum for five minutes at two-hour intervals over a six-hour treatment period, ingesting 800mg of caffeine.

Read: Tips to help you kick the coffee habit

The primary objective was to examine the impact of caffeine consumption on wakefulness and other factors, but a sub-study aimed to evaluate how caffeine consumption affects the renal clearance of calcium.

Co-researcher Dr Stephanie Reuter Lange says understanding the long-term effects of high caffeine consumption is especially important for higher risk groups.

“People at risk could include teenagers who binge-consume energy drinks and are at risk because their bones are still developing; professional athletes who use caffeine for performance enhancement, as well as post-menopausal women who often have low blood calcium levels due to hormonal changes and lack sufficient daily dietary calcium intake.

“Increasingly, we are also seeing high levels of caffeine among shift workers who need to stay alert over the night-time hours, as well as those in the military who use caffeine to combat sleep deprivation in operational settings.”

Dr Reuter Lange says caffeine in moderation certainly has its pros, but understanding how excess consumption could increase the risks of a highly preventable disease such as osteoporosis is important.

The researchers say they will continue to explore and predict the impact of different levels of caffeine on short and long-term bone health.

Were you aware that high coffee consumption is being linked to osteoporosis? Do you drink more than two cups per day? Why not share your experience in the comments section below?

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