ALEXANDRIA , Va. – Two new studies suggest that moderate beer consumption may help prevent osteoporosis, a disease in which bones becomes fragile and more likely to break.  Since there is no known cure for osteoporosis, prevention is the best medicine. 

The first study, published in the February 2004 issue of the Journal of Bone and Mineral Research , found a striking relationship between the intake of dietary silicon and bone mineral density in the hip sites of men and pre-menopausal women.  The second study, published in the March 2004 issue of the British Journal of Nutrition , shows that beer, in particular, is a highly-bioavailable source of dietary silicon. 

Journal of Bone and Mineral Research, February 2004

Researchers at Harvard Medical School and Tufts University, Boston, and the University of London, UK ( St. Thomas ’ Hospital and King’s College London) conducted a cross-sectional, population-based study involving 2,847 participants of the Framingham Offspring Cohort.  The researchers examined the association between silicon intake and bone mineral density in 1,251 men and 1,596 pre- and postmenopausal women (ages 30 to 87) at four hip sites and lumber spine.

Adjusting for all known potential confounding factors, the researchers found that silicon intake correlated positively with bone mineral density at four hip sites in men and pre-menopausal women, but not in postmenopausal women.  No significant association was observed at the lumber spine in any group.

Previous studies have indicated that moderate consumption of alcohol may play a role in increasing bone mineral density, although the mechanisms are not known.  Researchers noted that beer is a good source of silicon and that this may partly contribute to the beneficial effects of moderate alcohol consumption on bone.  By contrast, some research suggests that other alcoholic beverages are not a high source of silicon but still positively influence bone health when ingested in moderation, so an effect of ethanol per se is also likely.  Therefore, this research suggests that beer may have two advantages: its moderate alcohol content and its high silicon content. 

“Silicon is an often overlooked nutrient in the body and may well be useful for maintaining strong bones,” says Dr. Jonathan Powell, chair of Medicine and Nutrition, University of London and Cambridge , and primary investigator of the study.  “Unlike calcium, silicon potentially works on both sides of bone density – it appears to promote bone formation and may also prevent bone loss; whereas, calcium plays a role in preventing bone loss, but unless we are deficient, does not help in bone formation.”

As for the absence of findings with postmenopausal women, Dr. Powell explains: “We may not have seen a positive correlation between silicon intake and bone mineral density in postmenopausal women because this is when their bone structure is dominated by the process of bone loss, mainly due to the reduced estrogen effect.  Hormonal factors may overwhelm any nutrient effects on bone.”

Energy-adjusted silicon intake showed a large difference (10 percent) in the bone mineral density between participants with the highest intake of silicon (greater than 40 mg per day) and the lowest intake of silicon (less than 14 mg per day).  Researchers estimate that the average daily intake of silicon in the Western world is about 30 mg per day, and that silicon intake is lower in women than in men and decreases with age.

Although there is no daily reference intake for silicon in the U.S. , Powell thinks the current intake may be too low.  “Certainly as the diet has become more processed, including even most drinking water, it is likely that our silicon intakes have dropped,” suggests Powell.

Major sources of silicon have been identified in plant-based foods, such as whole grains and cereals (e.g. breakfast cereals, bread, rice and beer), some fruits and vegetables (e.g. bananas and string beans), and unfiltered drinking water.

A 12-ounce bottle of beer contains 7 mg of silicon; therefore, one beer can contribute as much as 20 to 25 percent of a person’s daily silicon intake.

British Journal of Nutrition, March 2004

In a second study, Powell as the primary investigator and colleagues at the University of London, UK (St. Thomas’ Hospital and King’s College London) investigated the silicon content of 76 different beers and then estimated the silicon absorption from beer in 17 healthy volunteers (nine males and eight females; mean age 25 years).

“We have known for some time that beer probably contains high levels of bioavailable silicon but formal studies were lacking on both the range of beer-silicon levels and the extent of absorption in humans,” says Powell. 

The silicon content of beer varied from 9 to 39mg/liter.  Although the researchers say the reason for the variability is not clear, they suggest that the final beer silicon levels may be due to variations in the way the malted barley is processed.  There was no association found between the silicon content of beer and the type of beer (wheat beer, stout, ale, lager, bottled, canned or draught), the concentration of ethanol or country of origin.

Subjects’ blood and urinary silicon levels were measured after ingesting comparable amounts of beer, a soluble silicon solution, ethanol or water.  The researchers found the subjects’ blood and urinary silicon levels increased considerably and similarly following the ingestion of beer or the soluble silicon solution, but not with the ingestion of ethanol or water. 

“We already knew that beer was likely to contain the highest source of silicon per serving because its manufacture uses the husk of the grain, where the silicon is contained,” says Powell.  “Now we have confirmed that beer is a readily bioavailable source of silicon.  Unlike some other high-silicon foods, the silicon in beer is readily absorbed because it exists as soluble silicate.”