Statistics show that people who abuse alcohol suffer reduced bone mass. Although this is not surprising, the reasons are still not understood in full. There are probably many. Alcohol may directly damage bone and does seem to interfere with the bone renewal cycle .
From a lifestyle point of view, alcoholics tend to eat poorly, which certainly contributes to poor bone condition. The negative effect of heavy alcohol use on the liver is well known. Poor liver function in turn affects the body’s ability to metabolize vitamin D and leads to impaired calcium absorption.
Also, chronic alcohol use affects the nervous system and makes long term drinkers more susceptible to falls. Heavy drinking affects the bone-renewal cycle by impairing the function of osteoblasts, responsible for bone growth. The bone depleting action of osteoclasts does not seem to be affected. Heavy drinkers who quit using alcohol generally regain their osteoblast function, all other conditions being equal.
A study conducted in Barcelona, Spain, focused on a group of heavy drinkers with no significant liver disease. The lack of liver problems minimized the possibility that metabolic bone disorders were
caused by poor vitamin D absorption. Researchers noted increased blood calcium levels and reduced levels of parathyroid hormone, suggesting that alcohol has the primary effect of removing calcium
from bone and releasing it in the blood. However, they concluded that moderate use of alcohol does not seem to cause significant damage.
On the other hand, research by D. T. Felson and others in a Framingham, Massachusetts, study revealed that postmenopausal women drinking at least seven ounces per week (one drink per day) of alcohol had higher bone density at most sites than women drinking less than one ounce. They concluded that the alcohol increased their estrogen levels and this in turn reduced net bone loss. A slight but less significant advantage was also seen for male drinkers.
Another study by D. Hemenway and others showed that women over fifty who were both very thin and who consumed at least fifteen grams of alcohol per day were particularly susceptible to fractures. Thinness is already known to be a serious risk factor for osteoporosis, especially in women.
In spite of studies implying the apparent advantages of moderate alcohol consumption, the overall statistical picture shows that habitual alcohol intake is associated with decreased bone mass. Considering its general negative effect on metabolism, alcohol abuse (but not necessarily alcohol use) may combine with other risk factors to worsen imbalances in the bone renewal cycle.
Nevertheless, research results on this subject remain widely divergent and quite contradictory, some researchers reporting the positive effects of drinking on bone, others asserting the negative effects. It is important to clearly distinguish between alcohol use and abuse and to moderate its use. Although American cultural sensibilities often equate alcohol use with abuse, moderate drinking does not seem to be a significant risk factor for bone loss and osteoporosis.