There's nothing like a cool pint after exercise on a warm day. But is this a good idea? In a previous blog I discussed the effects of binge drinking on recovery and these effects were not positive. However, others have argued that beer drinking, in moderation, can have positive effects, beer adds to hydration, it contains vitamins, especially B-vitamins and chromium. The malt and hops used in both lager and bitter contain flavonoids, which counter cell damage and help reduce the risk of cancer and heart disease.
Recently I was contacted by the producers of a TV program on Channel 4 (UK) called Food Unwrapped. This program looks into the origin of our foods and tries to find out the truth behind some common beliefs about food. In this series they were interested in finding out whether small amounts of beer could have positive effects after exercise.
Testing the hydrating properties of beer
We set up a little study with a few rugby players at the University of Birmingham and focused on the hydrating properties of beer. The group was divided in two and they all performed the same training. Afterwards they received either beer or water and we measured some markers of hydration. It turned out that water was slightly better than beer. Of course this was not a very well controlled clinical trial and really just used for illustration purposes but how does it compare to the real research out there?
What does the research say?
In a previous blog I presented the results of a study by Professor Ron Maughan and colleagues who compared the hydrating properties of various beverages. It demonstrated that the beverage hydration index (how well fluid is retained in the body after consuming a drink) for beer (lager) was perhaps slightly lower than water and other beverages but this difference was small and not statistically significant.
Similar findings were reported by Dr Ben Desbrow who performed a number of studies (1,2) looking at the effects of alcohol containing beers on post exercise hydration. In their studies, beer failed to completely restore fluid balance within 4 hours, independent of the strength of the beer and the electrolyte content. They did observe however that a light beer (with 2.3% alcohol) combined with 50 mmol/L of added sodium was a more effective rehydration solution than the same beer with half the sodium content or a mid strength beer with or without 25 mmol/L of added sodium. (50 mmol/L would be roughly 3 grams of table salt per liter and 25 mmol/L, 1.5 grams per liter).
Beer failed to completely restore fluid balance within 4 hours, independent of the strength of the beer and the electrolyte content
There are other claims as well. Claims about vitamin content, especially B vitamins but these content if generally low. There are also claims about phytonutrients in beer and especially the polyphenols within nonalcoholic beer have suggested to have some positive effects following endurance exercise (3). Such effect include reductions in inflammation and incidence of respiratory tract illness. These results have not yet been confirmed as far as I am aware and therefore we may need to be a little cautious with the interpretation of these findings.
It is sometimes suggested that beer provides a good source of calories. In most beers, however, most of the calories are derived from alcohol and alcohol is metabolized in the liver and not in the muscle. There are carbohydrates in beer but the carbohydrate content is relatively low (0.5-4 g/100ml). In one pint you will find 2.5-20 grams of carbohydrate giving you 10-80 kcal. Alcohol in the same drinks will give you 22-28 kcal. Beer can certainly help a little towards restoring carbohydrate stores.