Legumes are a cornerstone of traditional Greek cuisine, yet many people avoid them due to the bloating they can cause. In this article, we’ll explore various methods to help reduce bloating when consuming legumes.

Why is it important to include legumes in our diet?

There are many reasons why it’s worth improving the digestibility of legumes and incorporating them into our weekly meals. Specifically:

• Legumes are a primary source of plant-based protein and other essential nutrients.
• They are an integral part of the traditional Greek Mediterranean Diet, with a recommended consumption frequency of three times per week. The Mediterranean Diet is the most extensively studied dietary model, offering multiple health benefits, and is recommended for all Greeks to follow.
• Legumes are excellent sources of dietary fiber and are recommended for preventing constipation, controlling cholesterol levels, reducing the risk of diabetes and colon cancer, and supporting the growth of beneficial gut microbiota.
• They are a low-cost protein source.
• Finally, legumes are easy to cook in various ways, contain minimal fat, and can be a great ally in weight loss efforts.

Why do legumes cause bloating?

Legumes tend to be difficult for many people to digest and can lead to bloating and gas. This occurs because legumes contain sugars, specifically beta galactosides, with raffinose being the primary one, which are large molecules that cannot be absorbed. As a result, they pass undigested into the small intestine and reach the large intestine, where they are fermented by gut bacteria. This fermentation releases large amounts of carbon dioxide and hydrogen, which in turn causes the bloating, cramping, flatulence, and discomfort. Additionally, legumes contain anti-nutritional compounds that hinder the absorption of proteins, carbohydrates, and key dietary minerals like calcium and iron. However, the processing techniques discussed below can significantly increase both the digestibility and bioavailability of nutrients in legumes, making them a true superfood.

Processing techniques to improve legume digestibility

There are several techniques that can help make legumes easier to digest. Using one or a combination of the methods below can allow us to include legumes in our diet on a weekly or even daily basis.

1. Soaking legumes

Soaking legumes for 12–16 hours at room temperature reduces raffinose oligosaccharides by 9.8%. Ideally, the soaking water should be changed every 8 hours. You can also add baking soda or salt to the soaking water overnight, which promotes partial fermentation and improves digestibility.

2. Cooking legumes

Boiling legumes in fresh, clean water for 30–90 minutes significantly reduces the gas-producing sugars. Research shows that boiling (after soaking) for 30, 60, and 90 minutes reduced raffinose oligosaccharides by 44.4%, 46.6%, and 52.4%, respectively. Slow cooking with the lid off, pressure cooking, and microwave baking are also effective. Furthermore, baking legumes helps lower anti-nutritional compounds and increases nutrient bioavailability.

3. Sprouting legumes

Another method is sprouting legumes, known as legume sprouts. Creating and consuming sprouts from legumes (e.g., mung beans, chickpeas, lentils) allows us to obtain a highly absorbable form of nutrients. While sprouts contain slightly less protein than their unsprouted forms, the protein they do provide is more bioavailable, meaning it's easier for the body to absorb and utilize. Additionally, sprouts are rich in B-complex vitamins, vitamin C, polyphenols, flavonoids, and other antioxidants, as well as minerals in a more absorbable form. They also contain enzymes that support digestion.

4. Legume flours

Legumes can be ground into flour, which improves digestibility by breaking down their outer hulls and increasing the availability of their protein content. Legume flours are a simple way to include legumes in your diet without the unwanted side effects. You can use legume flour to make bread, pies, veggie patties, and even desserts.

5. Digestive enzymes

Finally, in extreme cases where none of the above methods are effective, digestive enzyme supplements containing α-galactosidase are recommended. This enzyme breaks down beta galactosides, helping improve the digestion of legumes after consumption.

Legumes are a highly nutritious food and should not be excluded from our diet. The symptoms they cause appear to be dose-dependent, so it's advisable to consume them in amounts we can tolerate. If symptoms occur, reduce your intake and gradually reintroduce them to your diet at tolerable levels. Additionally, simple practices such as chewing slowly and thoroughly or avoiding carbonated drinks alongside legumes can also help reduce bloating.

REFERENCES

Linares-Castañeda A, Jiménez-Martínez C, Sánchez-Chino XM, Pérez-Pérez V, Cid-Gallegos MS, Corzo-Ríos LJ. Modifying of non-nutritional compounds in legumes: Processing strategies and new technologies. Food Chem. 2025 Jan 15;463(Pt 3):141603. doi:10.1016/j.foodchem.2024.141603. Epub 2024 Oct 9. PMID: 39405829.

Khattab RY, Arntfield SD. Nutritional quality of legume seeds as affected by some physical treatments: 2. Antinutritional factors. LWT - Food Sci Technol. 2009;42(6):1113–8. doi:10.1016/j.lwt.2009.02.004.