Just as the go-to drink for bone health — milk — has come under attack by New York Times’ food columnist Mark Bittman for not living up to its healthful reputation, a new study suggests an even more controversial beverage as an alternative: alcohol.
Previous research has linked moderate drinking with improved bone density — women who drink moderately have higher bone density than non-drinkers or heavy drinkers — but such observational studies connecting people’s dietary or drinking patterns to health effects have not been able to determine cause and effect. It’s possible, for example, that people who are healthier to begin with are more likely to drink moderately, rather than the other way around. However, experiments in animals that have been designed to show cause and effect have found that moderate doses of alcohol are indeed good for the bones.
Throughout life, bones constantly remodel themselves, building up new sections while breaking down old ones in turnover processes called formation and resorption. As we age, this turnover falls out of balance, leaving bones thinner and weaker. Moderate doses of alcohol seem to tip the scale back in the right direction.
The new study, which was published in the journal Menopause and led by Urszula Iwaniec of Oregon State University, sought to examine how alcohol might affect bone turnover in women, who are at especially high risk for fractures late in life. It included 40 healthy postmenopausal women under 65, just at the age at which the risk for osteoporosis and fractures starts to rise.
All of the women were daily or near-daily moderate drinkers, defined in the study as having one-half to two standard drinks per day. Most of the women preferred wine; in America, a standard drink of wine is defined as a 5-ounce glass, of which there are about five in a typical bottle.
For the study, the women were asked to abstain entirely from alcohol for two weeks, and then start drinking again for two days. Researchers tracked certain blood markers of bone health throughout, and found that these markers of bone density correlated positively with alcohol consumption: in other words, the more the women drank within the moderate range, the better their bone health looked.
During their period of abstinence, the scientists saw negative changes in measures of bone formation and resorption. “There was a significant increase in the bone turnover markers osteocalcin and CTx when alcohol was excluded for 14 days,” the authors write. That is, when the women weren’t drinking, their bones were breaking down more than they were being rebuilt.
But when they started drinking again, the healthier levels were restored. “Within 12-14 hours of resuming alcohol consumption, osteocalcin and CTx returned to values that did not differ from baseline,” the authors note, concluding that the “small but significant increases in [these chemicals] after short-term abstinence provide substantial evidence that moderate alcohol consumption decreases bone turnover.”
“Drinking moderately as part of a healthy lifestyle that includes a good diet and exercise may be beneficial for bone health, especially in postmenopausal women,” said lead author Urszula Iwaniec in a statement. “After less than 24 hours to see such a measurable effect was really unexpected.”
Of course, no one would suggest replacing milk with wine in school cafeterias to build strong bones — but older women who already drink moderately and are not at risk for heavier drinking may benefit. However, while the study links drinking with improvements in bone health, it doesn’t go so far as to show that alcohol can reduce women’s risk of breaking a bone. “Although there is substantial evidence that moderate alcohol consumption correlates with higher bone mass density in postmenopausal women, it is much less clear whether consuming alcohol lowers the fracture rate,” the authors note. “Therefore, even if drinking had no detrimental effects, it would be unwise to recommend drinking for the purpose of preventing fractures.”
Indeed, drinking more than two glasses of wine a day — and especially drinking them rapidly — is obviously more likely to increase the risk of falls and fractures through entirely different means. Also, while light to moderate drinking has been linked to a lower risk of death from all causes, particularly from heart attack and the most common type of stroke, it has also been associated with an increased breast cancer risk.
This means that for any individual women, her particular risk factors — from her risk of alcoholism to breast cancer and the effect of alcohol on balance and caution — will determine whether moderate drinking is beneficial or harmful. Still, having a glass of wine or two with dinner isn’t likely to harm our bones, and the research increasingly suggests that it could help.