Bowl of Brussels Sprouts

The benefits of eating Brussels sprouts, and the problem

Brussels sprouts are a type of brassica meaning that they are related to cauliflower, broccoli and cabbage.  While there are autumn-ready varieties, we typically only eat them in winter and many of us only eat them at Christmas.  This is a real shame because sprouts are packed with nutrients including fibre, vitamin C, folate and vitamin K (if you are taking anticoagulant medication such as warfarin be careful not to consume more vitamin K over Christmas than you normally would to avoid complications with your medication).  The embarrassing problems begin however with the difficulty of digesting a type of sugar within sprouts: raffinose.

Raffinose can be found in brassicas, beans and some other vegetables.  It requires an enzyme called alpha-galactosidase to break it down which humans do not produce.  This means that raffinose passes into our large intestine undigested where it provides many of our important gut bacteria with a feast.  Unfortunately hydrogen, methane and carbon dioxide are side effects of this feast, and hence wind builds up in our gut until we let it out.  Individuals who are prone to problems with bloating, such as IBS sufferers, may prefer to avoid sprouts to reduce the effects of the gas build-up.

Smelly sprouts!

The smell that accompanies the escaped wind is mainly due to the sulfur* compounds that are found in all brassicas.  Again, our gut bacteria deal with these but produce hydrogen sulfide and methyl mercaptan as a result.  These are released with the other gases being produced to give our wind the distinct aroma.

It is believed that the sulfur compounds are not all bad – they may have anti-cancer properties.  But, high levels of hydrogen sulfide produced by the gut bacteria may contribute to inflammation within the gut and bowel-related diseases.  However, raffinose may lead to increased amounts of lactic acid bacteria which help to reduce the risk of gut inflammation and ulcerative colitis, potentially reducing the risks posed.  It is therefore best if you to eat these foods in moderation and in portion sizes appropriate to your own gut health status.

*the preferred spelling by the International Union of Pure and Applied Chemistry (IUPAC) adopted by the Royal Society of Chemistry.

Portion control

One method of reducing the problems associated with sprouts and other brassicas, while still getting the benefits, is to enjoy them in smaller quantities.  Do you remember the sprout eating competition between the Vicar of Dibley and David Horton?  I don’t recommend it!  One portion of vegetables is about 80g; that is just 8 medium-sized sprouts.

References/Further Reading