...the more you eat the more you toot!
Everyone knows that beans make you fart. It's something that's basically assumed to be a fact of life. Beans have high fiber, high fiber does things to your intestinal tract, and the net result is a chorus of flatulence and stink that makes you unfit company. I know many people who won't touch beans on a first date, for fear of the farts. So we think beans must cause farting...but is it TRUE?
(Oh sure, they look so innocent. Source)
Winham and Hutchins. "Perceptions of flatulence from bean consumption among adults in 3 feeding studies" Nutrition Journal, 2011.
Why study whether beans make you gassy? Well...why not? I mean, what else is science for!? But really, the authors of this study were interested in whether beans really make you cut the cheese because they are interested in health. A diet high in vegetables, including legumes (beans) is thought to be good for the prevention of chronic disease. And beans really are a wonderful
fruit legume. They are high in protein (which is what they are most known for), but they are also high in vitamins and minerals and are a good source of fiber. Really, you can't go wrong with a bean.
But people avoid beans because of their wind-making prowess, and this means they could be missing out on an important addition to a healthy (and possibly gassy?) diet. So the authors wanted to determine if eating beans really did cause gas.
And beans can definitely cause gas. They not only contain a lot of fiber, they also contain resistant starches, which aren't easily broken down. This means they end up getting digested by bacterial fermentation in your intestines, and a side effect of fermentation? That's gas. But gas production could vary from person to person. There's also the possibility of adapting to the gas producing qualities (or maybe just losing your sense of smell and dignity). After all, many other cultures eat way more beans on a daily basis than most Americans do.
But we still worry. And so, to put the idea of beans and gas to bed, the authors conducted a series of three experiments.
In the first study, they had participants eat 1/2 cup of beans (either black eyed peas or pinto), or 1/2 cup of carrots as a control. They could eat them alone or put them in a recipe as they wished, for 8 weeks. Because of the blacked-eyed peas and pinto beans in this study, they referred to it as the BEP study, which reminds me forcibly of this:
In the second study, they did the same 8 week treatment, only this time with 1/2 cup of vegetarian baked beans (with the carrots as control). And the final study was either 1/2 can of pinto beans or a control soup per day for 12 weeks. All the patients were told not to eat any other beans during the course of the study.
And the results? When it comes to farting, bean type matters. Only 19% of patients complained of farting after black-eyed peas, while 47-50% complained the magical fruit gave them too many toots when they ate pinto beans or baked beans (one unfortunate carrot eating control did complain of really bad gas). But this was only in the first week. Farting reports dropped off in week two and by the end of the 8 weeks, they might as well have been eating carrots. But keep in mind, all the subjects who were eating beans KNEW what they were eating, and the psychological expectation of a mass o'gas could have affected the results.
It's important to note that they weren't just studying farts here. This study was part of a larger study on the effects of beans on heart disease risk, and they found significant improvements in things like lipoprotein profiles and cholesterol. So 1/2 cup of beans per day could definitely do some good, without causing too much bad air.
So it seems that low levels of beans are safe. But it's important to note that in all three experiments, people were consuming only 1/2 cup of beans per day. This isn't a lot, I mean, a good sized Taco Bell anything will pack at least double the punch. While the people in this study didn't fart excessively, I have to wonder if it's a result of low bean dose.
Finally, the authors do note that farting occurs most often when people increase fiber from a low fiber diet, and goes away as you get used to it. And this is basically what they saw. So if you need more beans in your diet, better to get them on the daily and suffer it out for a week or two (maybe in the middle of a desert or something if you think it will be really bad), and then maybe life will return to normal. And if you're really worried? Stick to black-eyed peas. They look a little safer.
Winham, D., & Hutchins, A. (2011). Perceptions of flatulence from bean consumption among adults in 3 feeding studies Nutrition Journal, 10 (1) DOI: 10.1186/1475-2891-10-128