How to eat beans and lentils when your gut bloats easily

Beans have a reputation that arrives at the table before they do. Plenty of people skip them entirely because they expect gas. That's a shame, because a growing body of research supports plant-based eating, and legumes in particular, for lowering the risk of chronic disease (Winham and Hutchins, 2011).

If your gut bloats easily, you don't have to choose between beans and comfort. Here's a step-by-step way to bring legumes back into your meals.

Why beans cause gas

Legumes contain galacto-oligosaccharides, or GOS. These carbohydrates belong to the FODMAP family and are known triggers of digestive symptoms in people with IBS (Tuck et al., 2018a). The small intestine doesn't break them down well, so they travel to the colon, where bacteria ferment them and produce gas.

The amounts vary by legume. In a lab analysis of five legumes, total GOS in the raw seeds ranged from 2,500 mg per 100 grams in chickpeas to over 4,000 mg per 100 grams in fenugreek. The main types were stachyose and verbascose (Njoumi et al., 2019).

The fear may be bigger than the problem

In three feeding studies, adults ate half a cup of beans a day for 8 or 12 weeks. Fewer than half reported more flatulence from pinto beans or baked beans during the first week, and only 19% did with black-eyed peas. Meanwhile, 3% to 11% reported more flatulence on the control diets, which contained no beans at all (Winham and Hutchins, 2011).

The researchers concluded that concerns about gas from beans may be exaggerated, while noting that people respond differently to different types. That's useful: if one kind of bean bothers you, another may not.

Five steps to eating legumes more comfortably

Step 1: Start small and stay consistent

Begin with 2 to 3 tablespoons of beans or lentils at one meal, a few times a week. If that goes well, increase gradually toward half a cup over two to three weeks.

Consistency may matter as much as portion size. In a study of 20 healthy adults, a daily GOS supplement at first increased daytime gas episodes from 12 to 18 a day, and the volume of gas passed after a test meal from 160 to 236 mL. After three weeks of regular use, those numbers had dropped to 11 episodes and 169 mL, as the gut bacteria adapted (Mego et al., 2017). That was a supplement rather than beans, but it supports a small-and-steady approach.

Step 2: Choose canned legumes and rinse them

Canned beans and lentils are a convenient starting point. In a lab analysis of plant-based foods, canning and pickling were the processing methods that lowered FODMAP content the most (Tuck et al., 2018b).

Drain and rinse canned legumes before using them, and don't add the canning liquid to your recipe.

Step 3: If you cook dried beans, soak them first

Soaking and cooking both reduce GOS. In the legume analysis above, soaking lowered total GOS by between 10% (lentils and faba beans) and 40% (chickpeas), and cooking lowered it further (Njoumi et al., 2019).

Soak dried beans overnight, discard the soaking water, then cook them in fresh water until they're completely tender.

Step 4: Consider an enzyme with high-GOS meals

Alpha-galactosidase is an enzyme that acts on GOS. In a double-blind crossover trial, 31 people with IBS ate diets high in GOS along with either the enzyme or a placebo. Among the 21 who were sensitive to GOS, overall symptom scores were a median of 5.5 with the full enzyme dose (300 GALU) compared with 24.5 on placebo, and bloating scores were 6.5 compared with 20.5, on a 100 mm scale (Tuck et al., 2018a).

In that study, the enzyme was taken together with the high-GOS foods. noonlife's Meal Enzymes include alpha-galactosidase along with protease, amylase, lipase and lactase.

Step 5: Keep the rest of the meal simple

• Test one legume at a time so you learn which types suit you.
• Pair legumes with foods you already tolerate well, like rice, eggs, chicken or vegetables that don't bother you.
• Start with lentils or chickpeas in soups and salads before moving on to a big bowl of chili.
• Track your bloating from 0 to 10 a few hours after legume meals, and note the type and portion.

When it's more than beans

If you bloat most days no matter what you eat, or bloating is new and comes with early fullness, pelvic pain, urinary urgency, blood in your stool, unexplained weight loss or anemia, see your doctor. Those symptoms need a proper check rather than more food experiments.

Sources

1. Winham DM, Hutchins AM. Perceptions of flatulence from bean consumption among adults in 3 feeding studies. Nutr J. 2011;10:128. PMID 22104320
2. Tuck CJ, Taylor KM, Gibson PR, Barrett JS, Muir JG. Increasing symptoms in irritable bowel symptoms with ingestion of galacto-oligosaccharides are mitigated by α-galactosidase treatment. Am J Gastroenterol. 2018;113(1):124-134. PMID 28809383
3. Njoumi S, Josephe Amiot M, Rochette I, Bellagha S, Mouquet-Rivier C. Soaking and cooking modify the alpha-galacto-oligosaccharide and dietary fibre content in five Mediterranean legumes. Int J Food Sci Nutr. 2019;70(5):551-561. PMID 30614326
4. Mego M, Manichanh C, Accarino A, et al. Metabolic adaptation of colonic microbiota to galactooligosaccharides: a proof-of-concept-study. Aliment Pharmacol Ther. 2017;45(5):670-680. PMID 28078750
5. Tuck C, Ly E, Bogatyrev A, et al. Fermentable short chain carbohydrate (FODMAP) content of common plant-based foods and processed foods suitable for vegetarian- and vegan-based eating patterns. J Hum Nutr Diet. 2018;31(3):422-435. PMID 29473657

This article is for general information and isn't medical advice. If you have IBS or another digestive condition, a dietitian can help you test foods like legumes safely. Talk to your healthcare provider before starting a supplement.