Moderate beer consumption may help fight osteoporosis, suggests a study by the University of California's department of food science and technology.
Dietary silicon is important for the growth and development of bone and connective tissue, according to the National Institutes of Health (NIH). It has been known for years that beer is a significant source of dietary silicon, but there was little specific information about the levels in various types of beer.
"The factors in brewing that influence silicon levels in beer have not been extensively studied," Prof. Charles Bamforth, the study's lead researcher, said in a statement.
Bamforth and a team of researchers conducted the first major study to determine the relationship between beer production methods and levels of silicon content. The results of the team's examination of 100 types of beer were published in the February issue of the Journal of the Science of Food and Agriculture.
The average silicon levels found in different types of beer (milligrams per litre):
- Indian pale ale (IPA): 41.2 mg/L.
- Ales: 32.8 mg/L.
- Pale ale: 36.5 mg/L.
- Sorghum: 27.3 mg/L.
- Lagers: 23.7 mg/L.
- Wheat: 18.9 mg/L.
- Light lagers: 17.2 mg/L.
- Non-alcoholic: 16.3 mg/L.
(Source: "Silicon in beer and brewing," published in the February issue of the Journal of the Science of Food and Agriculture.)
The researchers "studied the impact of raw materials and the brewing process on the quantities of silicon that enter wort and beer," Bamforth said.
They found that pale-coloured malt beers have a higher silicon content, while darker products, such as chocolate, roasted barley and black malt brews, all have much lower silicon content.
The report says the reasons for the differences are not yet known, but it pointed out that hops have as much as four times more silicon than is found in malt. Beers such as IPAs tend to use more hops, while wheat beers generally have fewer hops than other brews.
"Beers containing high levels of malted barley and hops are richest in silicon," says Bamforth. "Wheat contains less silicon than barley because it is the husk of barley that is rich in this element."
Bamforth discovered the average silicon content of beers sampled was between 6.4 and 56.5 mg per litre. Beer drinkers could expect an average silicon intake of 29.4 mg/L.
There is no specific recommended daily intake of silicon, but nutrition experts say an average daily intake of 20 to 50 mg is considered good.