Vitamins in Beer by Dr Caroline Walker of Brewing Research International

A few generations ago, the nutritional benefits of beer were well known. Beer was safer to drink than water and was thought of more as a liquid bread and hence was a staple in the family's diet. These days we buy foods without really knowing how they are made, and this has changed our perception of which foods are healthy.

So where do the vitamins in beer come from? The key is that beer isn't just made from cereal, its made from malted cereal.

Malting is a very simple process; seeds are soaked in water and allowed to sprout. This is an ancient method for increasing the nutritional content of seeds and quite likely originates in prehistoric times. Sprouting may have happened initially by accident, but our canny ancestors knew a good thing when they came across it!

As the seedling begins to germinate it actually makes vitamins. Figure 1 gives a few examples of the types of increases in vitamins seen after a few days of germination. For brewing, the major ingredient is barley malt. A premium grade of barley will typically be germinated for 4-5 days after first soaking in water. The maltster then stops the germination process by drying in a kiln. The drying process is gentle and thus preserves many of the vitamins, although some less stable ones such as vitamin C are destroyed .The overall result is a dried grain with a high vitamin content the barley malt.

In the first stages of making beer, the malt is milled into a flour, and then mixed with hot water. For beer making both the bran and the flour are used, and so beer is a whole grain product. Considering the vitamins only, at this point all of the vitamins that can dissolve in water are released into the liquid. The result is a vitamin enriched broth a liquid bread. Inevitably, some vitamins will be lost during brewing and will not make it to the finished product, as during fermentation, some vitamins will be used by the yeast for growth. Despite this, several vitamins remain in the beer by the time it gets to the bottle, and table 1 gives some typical values which may be found in beer.

In typical Western diets, vitamin deficiency is not generally a problem. However, there's still room for improvement! For example, the typical intake of folate is about 200 micrograms/day, but nutritionists believe that our health would be improved by increasing this figure to 300 microg./day. This is because over the last ten years medical researchers have found that folates may help protect against chronic diseases such as heart disease, cancer and Alzheimers.

Folates are found in fruit and vegetables, with the highest levels being found in dark green leafy vegetables. Unfortunately, we do not generally eat enough fruit and vegetables. Therefore, nutritionists are focusing their attention on the nutritional value of some commonly consumed folate-containing foods. This forms the basis of a new EU project Folates, from food to functionality which is being led by the Institute of Food Research at Norwich. Among the foods being looked at are rye breads, orange juice, fermented milk products, gazpacho and beer.

The BRI are participating in this project by measuring the levels of folates in beer. Our initial results on the folate content of beer are incorporated in Table 1; a litre of beer contains between 10 to 45 % of the recommended daily intake (i.e. 20 to 90 microgr. of folate). To put this into context, one litre of the highest folate beer contains approximately the same amount of folate as 100g broccoli, 0.5 kg tomatoes, 0.25 kg potatoes or 1.5 litres of 2% milk.

However, there is quite a variation in the levels of folate in beer, due to differences in how these beers are made. The BRIs part of the project will involve working out why there is such variation, and to offer brewers guidelines on the best way to preserve the folate in beer. For further details on the EU folate project, please visit the website at www.ifr.bbsrc.ac.uk/folate/.

Folates are also known to help in the prevention of neural tube defects, and pregnant women are consequently advised to increase their intake of folates. It should be emphasised that since beer contains alcohol, it is not a suitable dietary folate source for pregnant women.

Nutritionists must always consider bioavailability that is our ability to absorb nutrients from food. Even although a food may contain quantities of a vitamin, it doesn't mean we can absorb it. For example, researchers have shown vitamin A is more readily absorbed from cooked carrots than raw ones i.e. boiled vegetables may in some cases be more nutritious than their raw counterparts. While this is a big hurrah for traditional British cooking techniques, it still leaves the question of whether vitamins in other foods can be absorbed.

In beer, the question of bioavailability has already been answered in part. In a study at the TNO Nutrition and Food Research Institute, in the Netherlands, a small group of volunteers were asked to drink wine, beer, spirits or water with their evening meal for three weeks (Van der Gaag et al 2000). The researchers checked the volunteers blood at the end of this time and found that the beer drinkers had bigger increases in the amount of vit.B6 in their blood compared to those drinking the other beverages. This result may have been expected, in that beer was the only one of the beverages given to the volunteers which contained vitamin B6! However, it does help to answer the question of whether we can absorb this vitamin from beer.

In conclusion, culturally the knowledge that beer is made from highly nutritious malt has been lost to the general public. Hopefully new research will restore the image of beer to one that earlier generations would recognise, and the message that moderate beer consumption can make some positive contribution to a balanced diet will be delivered.