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Do Beans Make You Fart?

Ah, the age-old question: Do beans make you fart? I originally wrote this post in 2023, but I decided that now that I just finished my PhD, it was time to update it! So, updated: January 25, 2024. As you may well imagine, when I tell people I did my doctoral research on beans, it leads to many a conversation about flatulence, gas, farts, breaking wind – whatever your preferred term happens to be. But before we dive right into the science, an important aside about bean songs about farting.

If you are not up-to-date on recent bean ballads (yes, it is a genre), then maybe you have not yet heard the glorious Bean Song that Bush’s Beans commissioned Josh Groban to make as part of their delightful rebranding of beans as the beautiful food. Listening to Groban croon on about beans, I think we can all agree the world is a better place for having this song in it. But why do beans need to be rebranded when they are so perfect already, you are probably wondering? Well, that would be due at least in part to their reputation as the musical fruit.

Let’s address this issue and get into the science: Do beans make us gassy?

Do beans make you fart - A Legume a Day

What Does the Science Say: Do Beans Make Us Fart?

One of the main barriers to people eating more beans is their concern that they will experience flatulence (Doma et al., 2019; Didinger & Thompson, 2020). Here is the thing though: the science suggests this concern is way overexaggerated! Feeding studies in people show inconsistent results that vary with factors such as the type of bean. Also, if folks are not used to a high-fiber diet, it may take some time (a week or so, although it can vary among people) to adapt. If someone shifts from a diet low in fiber to one high in fiber, flatulence could happen even if the fiber is not coming from beans! All of a sudden, our gut microbes have more food to make them happy, and to celebrate… they produce wind.

What in Beans Causes Gas?

Various compounds in beans may cause gas. That is because these compounds are indigestible by the gastrointestinal enzymes that humans have. Instead of being digested, these compounds make it to our guts, where fermentation by gut bacteria can result in flatulence (Thompson 2019). A few of these compounds include resistant starch, fermentable dietary fiber, and galactooligosaccharides (also called GOS) like raffinose, stachyose, and verbascose (Brummer et al., 2015; Chen et al., 2016).

A Main Research Paper on Beans and Flatulence

One of the main research papers published on beans and flatulence is by Winham and Hutchins (2011). In this study, the researchers found a few key things:

  1. Many people did not experience increases in flatulence from beans in the first place (!!).
  2. Most of those individuals who did experience gas had those symptoms go away within 1 to 3 weeks of regular bean consumption. Something really important to note: flatulence was going away with regular, daily bean consumption. It’s important to make this a regular part of our diet!
  3. Interestingly, even a small percentage of people on a control diet (i.e., canned carrots instead of beans) reported increased flatulence. My takeaway: it’s high past time we stop blaming beans every time we have gas! Part of the problem seems to be that people believe that beans will cause gas, and this perception results in them focusing on this more and perceiving an increase in flatulence, even if that is not really the case.

Let’s dive a bit deeper into this paper, shall we?

What Did the Researchers Do?

The researchers examined three feeding studies, all of which had participants eat 1/2 cup of cooked beans – or a control – every day for 8 to 12 weeks. Participants then completed a weekly questionnaire that asked about symptoms like flatulence and bloating, to assess any potential gastrointestinal discomfort they may be experiencing during the study.

What Did the Researchers Find?

Guess what? Many people did not experience more flatulence! In fact, over half of study participants didn’t report any increases in gas even during the first week. And the good news is that people who did report increased flatulence reported that it quickly went away, with seventy percent or more of those individuals reporting that symptoms went away within the second or third week of regular, daily bean consumption. The researchers also observed that certain pulses, like black-eyed peas, were associated with lower reporting of increases in flatulence during the first week of regular consumption. I think this is likely largely due to differences in the fiber and galactooligosaccharide content and types, as black-eyed peas tend to have less fiber than other beans/pulses.

Below, you can see Table 2 from the paper, which shows the percentage of participants who reported increased flatulence. Notice how the numbers drop quickly and dramatically! Again, note that flatulence is going away with regular, daily bean consumption. Make beans a part of your routine!

study on "do beans make you fart" - flatulence reporting Winhams and Hutchins 2011
Source: https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-10-128

Why Does Flatulence Go Away with Regular Bean Intake?

You may be wondering just how flatulence goes away as we eat beans (or rather, returns to “normal levels” before we added more beans to our diets). There has been recent work on this topic! Plus, it looks like more research is being done on beans and flatulence, so I will provide updates as I seem them.

Mego and colleagues (2017a) examined the response of humans to galactooligosaccharides, and their work suggests that humans adapt to regular consumption of galactooligosaccharide prebiotics. Basically, the microbiota in the colon appears to adapt to the continued availability of the galactooligosaccharide, and this ultimately shifts the metabolism of the microbiota to pathways that produce less gas (Mego et al., 2017b). In addition, our body might absorb a larger proportion of the gas into the blood to be eliminated via the breath, or we could produce more gas-consuming bacteria (Mego et al., 2017b). How cool is that?!

Back to the Winhams and Hutchins (2011) paper, though. Curious and want to read more for yourself? Here is an image of the abstract and also the link to the full paper, titled Perceptions of Flatulence from Bean Consumption Among Adults in 3 Feeding Studies.

Winham and Hutchins 2011 abstract - study on "do beans make you fart"
Source: https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-10-128

How to Stop Beans from Giving You Gas?

I often show some variation of this slide in classes I teach about beans, with several tips about how to prevent flatulence from beans. (The title of the slide makes more sense in the context of the presentation.) Keep on reading below for more details.

Do Beans Make You Fart slide - A Legume a Day

Tips to Stop Beans from Giving You Gas

First of all, like I said, a lot of people do not experience any discomfort after eating beans and other pulses. However, if you are one of those who does feel these symptoms, or you are concerned that you – or a (smelly) loved one in close proximity – may get gassy, then here are a few tips to reduce gas:

  • If you can, give your body a little time. Once you get used to a higher fiber diet rich in beans, any gassiness may dissipate like the wind. Remember, research suggests that even people who do experience discomfort often see that disappear within 1 to 3 weeks of regularly eating beans, and flatulence returns to normal levels.
  • Work up to it. Start with smaller amounts and gradually add more pulses into your dietary pattern. Maybe a quarter-cup for a few days, then a half-cup for a few days, then one full cup, and so on – you get the idea. This is similar to the first recommendation but may help you avoid any discomfort to begin with.
  • Try other beans/pulses. Do mung beans make you feel less than stellar? Maybe try some pinto beans. Please note: these are just two random types of pulses I picked, this is not a scientific recommendation of a flatulence reducing substitution (sorry).
  • Discarding the soaking water may help. If you cook dry beans at home, consider discarding the soaking water and cooking the beans in fresh water. The galactooligosaccharides mentioned earlier – those indigestible compounds in beans that are associated with causing some of the flatulence – can leech into the soaking water (Fernandes et al., 2010). So, there may be less of those compounds if you dump the soaking water and cook in fresh water. The trade-off is that these very same compounds are prebiotics that are also associated with health benefits. Nothing is ever black or white – bummer, huh? Overall though, the approach to discard soaking water seems to be relatively well agreed upon.
  • Gas in natural. I hate to be the one to break it to you, folks, but gas is a natural byproduct of bacterial fermentation of compounds that are not digestible by human intestinal enzymes. This is not as much a tip as it is an important thing to recognize. Whether we like it or not, some level of flatulence is both natural and healthy. Why? Because we want – and need – fiber to feed our gut microbes, resulting in happy little fellows like the one shown on the slide above. More and more science is constantly coming out about how a healthy gut contributes to pretty much every other aspect of our health. So, cheers to more beans!

Still worried the musical fruit may make you sing? Honestly, my recommendation would be to enjoy beans and not worry too much about it because beans are simply too delicious and beneficial for both human and environmental health to let a little (perhaps unfounded) concern over flatulence stand in our way. The benefits we can reap generally very much outweigh the possibility of short-term flatulence as our bodies adjust to a healthful dietary pattern that includes beans on a regular basis. And try the tips above – they really can help!

Okay, that’s all for now. In the comments, I would love to hear your thoughts! Do beans make you fart (rhetorical you here, I’m not asking for any details!)? Are these tips helpful? Any other lingering questions about beans and flatulence?

References for Do Beans Make You Fart?

  1. Brummer, Yolanda, Mina Kaviani, and Susan M. Tosh. “Structural and functional characteristics of dietary fibre in beans, lentils, peas and chickpeas.” Food Research International 67 (2015): 117-125. (https://www.sciencedirect.com/science/article/pii/S096399691400698X)
  2. Chen, Yiran, et al. “Dietary fiber analysis of four pulses using AOAC 2011.25: implications for human health.” Nutrients 8.12 (2016): 829. (https://doi.org/10.3390/nu8120829)
  3. Didinger, Chelsea, and Henry Thompson. “Motivating pulse-centric eating patterns to benefit human and environmental well-being.” Nutrients 12.11 (2020): 3500. (https://doi.org/10.3390/nu12113500)
  4. Doma, Katarina M., et al. “Motivators, barriers and other factors related to bean consumption in older adults.” Journal of nutrition in gerontology and geriatrics 38.4 (2019): 397-413. (https://doi.org/10.1080/21551197.2019.1646690)
  5. Fernandes, Ana Carolina, Waleska Nishida, and Rossana P. da Costa Proença. “Influence of soaking on the nutritional quality of common beans (Phaseolus vulgaris L.) cooked with or without the soaking water: a review.” International journal of food science & technology 45.11 (2010): 2209-2218. (https://ifst.onlinelibrary.wiley.com/doi/full/10.1111/j.1365-2621.2010.02395.x)
  6. (B) Mego, M., et al. “Colonic gas homeostasis: Mechanisms of adaptation following HOST‐G904 galactooligosaccharide use in humans.” Neurogastroenterology & Motility 29.9 (2017): e13080. (https://onlinelibrary.wiley.com/doi/10.1111/nmo.13080)
  7. (A) Mego, M., et al. “Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof‐of‐concept‐study.” Alimentary Pharmacology & Therapeutics 45.5 (2017): 670-680. (https://onlinelibrary.wiley.com/doi/full/10.1111/apt.13931)
  8. Thompson, Henry J. “Improving human dietary choices through understanding of the tolerance and toxicity of pulse crop constituents.” Current opinion in food science 30 (2019): 93-97. (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7449238/)
  9. Winham, Donna M., and Andrea M. Hutchins. “Perceptions of flatulence from bean consumption among adults in 3 feeding studies.” Nutrition journal 10 (2011): 1-9. (https://nutritionj.biomedcentral.com/articles/10.1186/1475-2891-10128)

2 Comments

  1. Greg gambino

    2weeks ago I started to include more beans in my diet. Bought 4 three pound bags of beans – pinto, red, kidney and black. Have been eating a cup of cooked mixed beans every day and have not had any gas issues. I started some months ago adding a tablespoon of psyllium husk powder to my diet which my speak to your point of more prior fiber in diet not causing gas in bean consumption.

    • That’s wonderful that you are eating beans every day!! I think it’s a great idea to have variety, too. I would love to hear about any favorite bean dishes so far, and I’m glad you’re not experiencing any discomfort! Thanks for sharing. 🙂

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