What comes to mind when you see the word “legumes”? Baked beans, hummus, bean nachos, french stew, black bean brownie?! Black beans are one of my favourite legumes. I first encountered black beans on a high school exchange to Costa Rica. In Central and South America black beans and rice are often a staple dish and was served daily at my school canteen. Black beans and rice is also a common breakfast dish as is a black bean soup made with the bean cooking water. Legumes are a staple food in most latin American cuisines. On my return to New Zealand all those years ago I couldn’t find black beans in any supermarket, health food shop and specialty grocers barely existed! Now, however, black beans are a common canned bean. Yippee!

What are legumes and pulses?

A legume is the fruit or seed of a plant. Legumes can be dried, to increase their shelf life, and then cooked or eaten fresh (e.g. edamame beans or broad beans). Legumes are an important food for humans and animals and, in horticulture, legumes are a rotation crop used to improve soil quality. The legume food group includes beans (soya beans, kidney beans, cannelloni beans, black beans etc), peas (chickpeas, green peas, split peas), lentils (puy, green, brown, red) but also alfalfa, carob, peanuts and tamarind. Pulses are the dry seed of legume plants e.g. lentils, dried split peas, gram.

Are there any health benefits of eating legumes?

Nutritional benefits

Legumes are a nutritious and versatile food group that are an essential source of protein for many populations in the world. Legumes are a great source of plant protein and when combined with a grain (e.g. rice, wheat) provide all the essential amino acids (protein building blocks) that we need. Legumes are also a source of slowly digested (low GI) carbohydrate. Eating slowly digested carbohydrate foods help the body maintain more stable blood glucose levels and may help you to feel satisfied for longer.

Gut health benefits

Legumes are a rich source of a range of fibre types that are broken down in the large intestine by your gut bacteria or microbiota. Eating whole foods that are naturally higher in dietary fibre can help to create and maintain a more diverse gut microbiota. A diverse gut microbiota creates a gut environment unfavourable for harmful bacteria and helps to maintain the health and integrity of the gut lining.

Should you eat legumes when you have IBD?

Butyrate and gut health

Butyrate is a short chain fatty acid produced by specific groups of bacteria in the large intestine. These groups of bacteria are often reported to be less prevalent in stool samples from people with IBD; however, why this is the case, is not yet confirmed. What we do know is that butyrate is produced during the fermentation of undigested dietary fibre such as resistant starch and galacto-oligosaccharides (GOS) found in legumes. Butyrate has a protective role in maintaining the health of the large intestine. Research studies are investigating whether increasing butyrate in the large intestine reduces gut inflammation in both ulcerative colitis and Crohn’s disease. Preliminary results with butyrate capsules or capsules of inulin and oligosaccharides have both shown positive reductions in gut inflammation in both ulcerative colitis and Crohn’s disease. We don’t know yet whether your gut microbiota produces more butyrate if you start eating more foods containing fibre but, we do know that eating the recommended 25 - 30 g per day of fibre is associated with a more diverse gut microbiota with more butyrate producing groups of bacteria. Watch this space!

FODMAPs

Most legumes contain galacto-oligosacchardes (GOS), a FODMAP* carbohydrate, that is not digested in the small intestine and moves into the large intestine where it is broken down and fermented by your gut bacteria. For approximately 30% of people with IBD the fermentation of GOS in the large intestine can result in abdominal pain, bloating, diarrhoea and/or excessive flatulence. Such symptoms after eating foods that contain GOS, or other FODMAPs, is not thought to be harmful to your gut but is not pleasant. If you experience these symptoms within 2-3 hrs of eating of legumes you may find that eating a smaller portion size helps to reduce the severity of these symptoms.

*FODMAP is an acronym for fermentable oligosaccharides, disaccharides, monosaccharides and polyols. All of these are types of carbohydrate found in foods. Oligosaccharides and polyols normally enter the large intestine undigested whereas lactose (a disaccharide) and fructose (a monosaccharide) are normally digested in the small intestine but can enter the large intestine undigested if your small intestine does not produce enough lactase enzyme or lacks sufficient fructose carriers to absorb the fructose.

How to eat legumes more often: Practical tips

Start small. The high fermentable fibre content of legumes means that eating a whole can of beans in one sitting is going to be challenging for the gut of most people.

• Add whole, or blended, cooked legumes into mince dishes or tomato sauces e.g. bolognaise, meat balls, soups or stews

• Try a bean dip e.g. hummus or white bean dip and use it in sandwiches or on crackers

• Add a tablespoon of canned legumes to a salad

• Make, or use a canned version, of mixed bean salad with a vinaigrette (see previous blog for vinaigrette recipe)

• Add legumes to baking to help increase your fibre intake in a delicious treat (see one my favourite recipes below)

• Aim to include a small serving (small handful) of legumes in your meals twice a week and increase the portion size slowly and as tolerated

Black bean browniE

NZ food and nutrition guidelines recommend that we should all be eating legumes twice a week. In addition to being highly nutritious they are also an affordable source of protein and complement, and even enhance, many meat containing dishes and baking. One of my favourite legume containing treats is black bean brownie. This is a feel good brownie and not overly sweet and sickly like most chocolate brownies. This recipe is adapted from Eleanor Ozick’s brownie recipe in My Petite Kitchen Cookbook - simple wholefood recipes.

Ingredients

1 x 400g can black beans drained and rinsed

1 cup dried dates

1/4 cup boiling water

1/2 cup cocoa powder

4 eggs

1 Tbsp white wine or apple cider vinegar

1 tsp baking soda

Method

Preheat oven to 160 degrees. Grease and line a medium sized slice tin.

Pour boiling water over dates and leave to soak for 5 minutes.

Put the remaining ingredients into a blender or food processor. Add the dates and soaking water last. Blend until smooth.

Pour mixture into lined tin and bake for 25 minutes until just cooked. Remove from oven and let stand for 5 minutes before moving brownie to a rack to cool.

Serve dusted with cocoa or icing sugar. It is extra delicious served with whipped or clotted cream! The brownie keeps well in the fridge for a few days and can be frozen.