by Marina Komarovsky
“Za zdorovye!“ (Russian) “¡Salud!” (Spanish) “Gezondheid!” (Dutch) In a number of languages, the appropriate exclamation for clinking glasses during a toast translates literally as “To health!” During the conversation that ensues over drinks, a popular topic, speaking of health, is: Does moderate drinking confer a benefit? We have been hearing a lot about cardiovascular health benefits, but another important relationship under investigation is alcohol and bone health. Both men and women hit their peak bone mass (and probably their peak alcohol intake) during their twenties, so there is no better time to think about how we can keep our bones strong for the long term.
Why would alcohol be good for bone health in the first place? You have probably already heard about resveratrol in red wine, but this is just one of many polyphenolic compounds found in alcoholic beverages. Others include flavonols, flavanols, prenylflavonoids, anthocyanins, proanthocyanidins, hydroxycinnamic acids, and EGCG; some are found in wine, some in beer. Certain polyphenols may bind to estrogen receptor genes, which leads to increased estrogen action, which in turn inhibits bone breakdown. Others also decrease the production of TNF-α and IL-6, cytokines that promote bone breakdown. Beer in particular contains high concentrations of the silicon mineral, which is beneficial for bone and other connective tissue growth.
How do these biological effects play out at the population level? There have been a number of studies around the world showing associations between moderate alcohol intake and bone health. In Korea, where the rice liquor soju plays an essential role in business meetings, a large epidemiologic study found that men who drank between one and five small cups of soju per day were half as likely to be classified as having reduced bone strength than those who did not drink at all. But that risk was increased for men who drank more than eight cups. In Australia, famous for its Shiraz, researchers measured bone density in elderly men and women. They followed up two and a half years later, to find that men who drank alcohol in general – and red wine in particular – experienced less age-associated bone loss over that period. In Spain, where it’s common to sip from a bottle of a regional beer over a long lunch, women who drank beer had higher bone density.
Research with several large U.S. based cohorts like the Cardiovascular Health Study (in four communities around the U.S.) and the Framingham Osteoporosis Study (local in Massachusetts) has also yielded analyses of the relationship between alcohol and bone health. Cardiovascular Health Study participants who drank up to 14 drinks per week were 22% less likely to experience hip fractures over a 12-year period. Researchers at our very own Jean Mayer USDA Human Nutrition Research Center on Aging worked with Framingham cohort data. Comparing moderate drinkers to nondrinkers, they found that men who had one or two drinks per day had higher bone density, but having more than two reversed this relationship. For women, more than two drinks – especially two glasses of wine – were beneficial in the postmenopausal group only. Because estrogen has a role in inhibiting the breakdown of bone, the sharp drop which occurs after menopause takes a toll on bone. It’s possible that the protective effect of alcohol kicks in at this time, a welcome finding given concerns about osteoporosis after menopause.
These studies have primarily focused on the relationship between alcohol and bone density or fractures. However, the prerequisite of breaking a bone is falling, and intoxication may increase those chances. In an experiment, elderly participants were given alcoholic drinks and had to walk on a treadmill while researchers placed obstacles in front of them. After only two drinks, participants failed to step over the obstacles on the treadmill at twice their baseline rate. A muscular reaction test showed that response times for the biceps femoris – the muscle helps us to change our gait to step over something or to recover from a stumble – were also delayed after two drinks. Moderate intake does not reduce bone density, but it may increase the rate of falling, and hence the possibility of breaking a bone.
Meanwhile high alcohol intake does act via the endocrine system to reduce bone formation. A large international analysis combined a total of nearly 17 thousand participants from three major cohorts in Australia (Shiraz country), Canada (the place to enjoy Labatt’s and Molson beers during hockey games), and the Netherlands (home of well-known Heineken and the exotic-sounding brandewijn, kandeel, and Kraamanijs liquors) – all with strong traditions of social drinking. Results showed that among both men and women, drinking three to four beers per day significantly increased the risk for osteoporotic fractures. As with anything, moderation is key.
The international perspective in this research is significant for several reasons. First, because different populations have different genetic pools, biological reactions to any nutrient intake are not identical, and it’s important to learn whether associations are consistent across groups. Another point is that when it comes to bone health in particular, it all relates back to calcium. In the digestive tract, calcium absorption is dependent on vitamin D, whose availability is in turn dependent on sunlight. Sunlight exposure varies with geography, another reason to look at populations worldwide. A third concept is that, just like every country has its own exclamation for a toast and its own favorite libation, every country also has a unique drinking culture. “It’s not just the [amount of] alcohol. It’s all a matter of culture, it’s all a matter of pattern, a matter of moderation and habit,” expresses Dr. Katherine Tucker, Chair of the Department of Health Sciences at Northeastern University and investigator on the HNRCA study with the Framingham Osteoporosis cohort. Many factors are involved in the relationship between alcohol and bone health, but across the globe, studies are showing that one or two drinks per day may not be a bad thing.
Marina Komarovsky is a Friedman alumna (’11) with MS-Nutritional Epidemiology/MPH-Health Communication degrees from Tufts. Her goal in writing is to relate study findings from researchers who are into nutritional biochemistry and statistics to those who are not into those things at all. She currently works as a research coordinator at Northeastern University.