Coffee Brain and Bone Health

Coffee wakes up the brain but may water down aging bones.

That’s what a team of researchers at Southern Australia’s Flinders University concluded after reviewing data from an earlier Swedish and Dutch Study of Osteoporotic Fractures which tracked nearly 10,000 women aged 65 and older for 10 years. The Flinders folk used numbers from that study to measure female bone mineral density (BMD) at the hip and upper leg and then see if it were linked to regular coffee and tea consumption.

BMD, which is measured via a DEXA (dual energy X-ray absorptiometry) scan is an important measure used to estimate an individual’s risk of osteoporosis. This loss of skeletal bone is a major health problem affecting roughly one in three women over age 50 worldwide. As such, it is responsible for millions of debilitating and potentially lethal fractures every year.

In a world where numbers count, one oddity is the 25-word title of the Flinders itself -- ‘Longitudinal Association of Coffee and Tea Consumption with Bone Mineral Density in Older Women: A 10-Year Repeated-Measures Analysis in the Study of Osteoporotic Fractures’ – may accidentally attest to the importance of their observations.

The basic fact to surface when the results were published in the international journal Nutrients and referenced this month on the website sciencedaily.com is that while calcium and vitamin D remain the building blocks and cornerstones of bone health, and while both coffee and tea contain caffeine, tea appears to be associated with slightly higher hip bone density, giving aging bones a small boost, while drinking too much coffee could have the opposite effect. In short, to date, as Flinders’ Ryan Liu explained, laboratory studies have shown that coffee’s caffeine content interferes with the body’s ability to absorb calcium, thus adversely affecting bone metabolism (i.e. building and maintain bone tissue) while tea’s caffeine, for some yet-to-be-discovered reason does not. .

Happily for java junkies, there are several “buts” in the story. First, adding milk to the coffee seemed to mitigate its problematic effects. Second, how many daily cups a drinker consumes actually matters. Apparently, one or two wake-up cups to start or through the entire day did not appear to do harm, harmful, but upping that total to five cups was clearly linked to BMD problems, more so in women who drank alcohol than in teetotalers.

Given the popularity of caffeinated beverages, even a small link might offer an important pathway for protective prevention because, the Flinders folk say, for older women, enjoying a daily cup of tea rather than may be more than a comforting ritual, it could be a small step toward stronger bones.

Finally, the Flinders team offered only modest recommendations emphasizing that the differences themselves that they observed were modest. True, their findings were statistically significant, but for scientists they were not large enough to justify major changes in an individual’s daily habits. “Our results don’t mean you need to give up coffee or start drinking tea by the gallon,” says Associate Professor Liu. But they do suggest that moderate tea consumption could be one simple way to support bone health, and that very high coffee intake might not be ideal, especially for women who now and then lift a glass of wine or spirits.