There is no easy way to say this but beans (legumes) have a slightly unfortunate reputation for erm, causing flatulence. If like me you grew up watching the Mel Brooks classic 'Blazing Saddles' you will remember that quite memorable scene around the campfire.
Here comes the science. Donna Winham and Andrea Hutchins* report results following a study looking at whether bean consumption increases the reports of flatulence. The summary:
- A questionnaire was completed by participants already involved in various studies on beans and health (here and here and here) based on various parameters of flatulence, stool changes and bloating.
- Controlling for various other dietary factors and compared against a control portion of carrots, various types of beans differentially increased reported episodes of flatulence. It wasn't necessarily a uniform increase in reports of wind following bean consumption but nevertheless 1 week of pinto bean consumption correlated with 50% of people reporting flatulence, vegetarian baked beans (47%) and black-eyed peas (19%). Flatulence abated slightly in subsequent weeks.
- Reported flatulence was not necessarily followed by changes to stools, whether in consistency or frequency despite some slight alterations reported. Participant reports on individual beans were also not necessarily due to the fibre content of individual beans although black-eyed peas are reported to have the lower fibre content.
Joking aside, there are a few important points to take from this research. We now for example know that beans can cause flatulence. I know this is probably not new news to many consumers, particularly male consumers, but at least science has made its input. Having said that the reported rates of flatulence seemed to decrease as time eating beans consistently went on. I like the idea that some kind of adaptive process is at work, bearing in mind the study findings already indicated on bean consumption and biochemical and bacterial parameters. The authors also ask a few questions about the psychological effects of expectation with regards to flatulence and beans.
I hope I didn't offend anyone with this post. Science is science after all; and I suppose a study like this is a good way of bringing science to the masses. As it is Christmas, the BMJ have their usual 'interesting' studies which this year, rather un-Christmasly(?) includes how fast/slow the Grim Reaper walks and comparing grip strength and intelligence across different medical disciplines.
* Winham DM. & Hutchins AM. Perceptions of flatulence from bean consumption among adults in 3 feeding studies. Nutrition Journal. November 2011.