Beer is one of those things like red wine -- it's great for you in moderation, but bad in large amounts. Beer may not have the heart-protecting Resveratrol that makes red wine so popular, but it does have something that few other foods have in great quantities; dietary silicon. Yes, the human body uses silicon to help grow and firm up your bones.
If you're a menopausal woman worried about osteoporosis, for example,
drinking a less-processed beer like ale (as opposed to a lager) every
day can do huge amounts to keep your bones strong. Beer also has a
surprising amount of bioavailable calcium, though nothing like a glass
of fresh milk.
On the other hand, for your oral health, beer isn't the best thing to
finish a meal with. Beer is acidic, much like cola, and has similar --
if weaker -- effects. To put a technical side on it, acids start
demineralizing your tooth enamel at a pH of about 5.5. Coke comes in at a
very acidic 2.5. Depending on the darkness of the malt, beer can check
in around 5.4 for a weak brew like Budweiser all the way down to 3.2 for
a true sour like Rodenbach Grand Cru.
Beer, however, compounds the acidity problem by adding alcohol and
sugars to the mix. If you think about it, beer is created by bacteria
that consume the barley and hops, fermenting it and turning it into
alcohol. Of course, then, it's a great environment for bacteria to grow
in, especially once it gets warm in the mouth. Now, not much beer
remains in the mouth for hours at a time, but on the molecular level, if
it's the last thing you eat or drink before you start working or get
otherwise distracted, the alcohol and sugar that's left behind will
promote the growth of 'bad' oral bacteria quite readily.