How Does Coffee Affect Bone Mineral Density?

Is drinking coffee a staple of your morning (and maybe even your afternoon) routine? If so, have you ever thought about how the caffeine in your coffee might be affecting your bone health?

A recent systematic review in Osteoporosis International aimed to determine whether caffeine consumption has an impact on bone mineral density (BMD) and fracture risk. Compiling data from all relevant studies, researchers found that the extent to which drinking coffee adversely impacts your bone health is largely dependent on the amount of caffeine you’re consuming. For example, researchers found that consuming 330 mg/day of caffeine (~3-4 cups of coffee) is associated with an increased risk of fracture, but drinking less than 220 mg of caffeine (~2 or fewer cups of coffee) is not associated with an increased fracture risk.

Curious why caffeine can have a negative effect on bone health? The exact mechanism by which caffeine impacts bone health is unknown, though two theories have gained lots of support in the past few years. One theory involves adenosine, a naturally-occurring substance in the body that stimulates bone formation by binding to adenosine receptors. Caffeine, however, competitively binds to these same adenosine receptors, blocking adenosine from binding and thus, inhibiting bone formation. Another way caffeine might adversely affect bone health is by promoting the urinary excretion of calcium from your body. As we rely on our calcium stores to build up bone, encouraging excretion of these stores by consuming caffeine can reduce both bone volume and BMD.

So, coffee-drinkers, the main takeaway here is that you do not have to cut coffee out of your routine (phew!). However, it might be worth limiting the number of cups of coffee you have daily to just one or two in order to minimize the effects caffeine could have on your bone health.