Want to know what the one food that is truly deserving of the title ‘superfood’ is? It is legumes. Packed with nutrients, offering a host of health benefits and good for the environment too, you’ve probably been overlooking these foods for years. It is time to give them another look. Oh, and they also store really well, making them ideal doomsday prepping foods which is on-trend in today’s times. In this podcast, I’ll talk about the foods that make up the legume family, uncover those health benefits and give you tips on how you can get more of them in your diet.
Looking for a food that is packed with nutrients, offers a host of health benefits and is good for the environment? Then it is time to rediscover a love for legumes. These powerhouse foods are staples in cultures the world over making them rightly deserving of a place in any diet.
A legume is a plant belonging to the botanical family of Fabaceae (also called the Leguminosae family). A legume can also refer to the part of any plant from the Fabaceae family and that includes its leaves, stems, and pods. Just to confuse things a little though, you may sometimes see the term ‘pulses’ used interchangeably with legume. While the two words mean similar things, a pulse is strictly the edible seed from a legume. Examples of pulses include kidney beans, lentils and peas.
For thousands of years, legumes have been right up there with grains in their importance to humans. Evidence of the cultivation of lentils has been found in Egyptian pyramids. Legumes were also among the first cultivated plants in the Mediterranean. The large seeds of many species of legumes are easy to gather and store for extended periods. This makes them a valuable source of nutrition in times of food scarcity and for those doomsday prepping for the Zombie apocalypse that is probably next to descend upon us after coronavirus.
The legume family is a diverse and hardy one. Found on all continents except Antarctica, they are the third-largest family of flowering plants on the planet with almost 20,000 different species. Some of the best-known examples include:
Legumes come in a variety of shapes, sizes and colours. They can be enjoyed in many forms including split, ground into flour, dried, canned, cooked or frozen. When mixed together, they make a vibrant and colourful display and colour is a great guide to food variety.
Heath benefits
So, onto those health benefits. Legumes are one of the few foods deserving of the title ‘superfood’. A list of their nutritional and health benefits makes for a long read. For starters, they are a good source of B-group vitamins like folate. Then there is the iron, phosphorus, zinc, calcium and magnesium they contain. They are also low in fat, rich in carbohydrates and a superior source of protein than most other plant foods. Then there are the antioxidants making legumes a true superstar with some of the highest levels of antioxidants of any food. In fact, red kidney beans top the list with even more antioxidants than blueberries.
Legumes, when eaten as part of a healthy balanced diet, may help prevent the development of numerous chronic diseases. The type of fibre in legumes can help to lower cholesterol and reduce spikes in blood glucose after a meal. High cholesterol and blood glucose elevate the risk of heart disease. A review of research studies in this area found that people who eat legumes four times each week had a 14 percent lower chance of developing heart disease. I’ll link to the study in the show notes. https://www.ncbi.nlm.nih.gov/pubmed/24898241
Legumes can also be an important food to help control body weight which is valuable considering the high rates of overweight and obesity in a country like Australia. A combination of their protein and fibre content can help increase feelings of fullness after a meal which helps curb the desire to overeat. A 2016 meta-analysis of 21 studies looking at legumes and body weight, found that including legumes in the diet was able to significantly lower body weight. And that weight loss was over-and-beyond weight loss seen in a comparator diet that was just lower in calories or a comparator diet that was designed to keep body weight stable. I'll link to the study in the show notes. https://www.ncbi.nlm.nih.gov/pubmed/27030531
Legumes are rich in potassium, magnesium, and fibre, all nutrients that have a positive influence on blood pressure. A 2014 review of eight clinical trials found that regularly eating legumes could lower blood pressure. And the benefit was seen both in people with high blood pressure and those with normal blood pressure to begin with. Again, you’ll find the study in the show notes. https://www.ncbi.nlm.nih.gov/pubmed/24014659
Gut bacteria also profit from a meal of legumes. The fibre diversity found in legumes provides a great fuel source for the growth of beneficial bacteria like Bifidobacteria and Lactobacillus. This can translate into improvements in gut barrier function which provides a defence against harmful invaders. A healthy gut means improved immunity and greater regularity of bowel movements. With more beneficial probiotic bacteria in the gut, they turn up the production of fibre fermentation by-products called short-chain fatty acids (SCFAs). These SCFAs are linked to a range of health benefits including lowering the pH in the bowel, improving the bioavailability of calcium and magnesium, and inhibiting the growth of potentially harmful bacteria.
Environmental impact
Food choices are more than just about health. Food sustainability and the environment are now important considerations in the food choices many people make. Legumes rank highly in any environmental assessment of their merits. Greenhouse gases released from the growing of legumes are up to seven-times less than for a similar area of land compared to crops such as wheat. Because of their hardiness in many different environments, legumes can be grown in more arid environments when other crops would fail.
The environmental benefits don’t stop there. Legumes can utilise nitrogen from the atmosphere through a process called nitrogen fixation. This means less nitrogen-based fertilisers need to be used in the farming process. It also leaves nitrogen in the soil after harvesting, which can benefit the crop that is planted in the soil next.
The ability of legumes to fix nitrogen from the atmosphere is shared by no other cultivated plant. Although the plant can’t take all the credit here as it is done as part of a symbiotic relationship with a soil-borne bacterium known as rhizobia. Nitrogen fixation is one of the key reasons why legumes became such a successful family of plants. It also explains why legumes are such a great source of protein. Because of their protein content, legumes appear in the Australian Guide to Healthy Eating twice: once in the vegetable group and a second time in the protein group along with meat, fish, eggs and nuts.
Tips to enjoy them
With so many different legumes to choose from, there is no shortage of ways to enjoy them. Legumes have a unique texture that gives them a mouth feeling similar to meat. Combine that with being an excellent source of protein all makes for legumes being a great plant-based substitute for meat, chicken and fish.
Soups and stews are tailor-made for legumes as they get plenty of time to cook. Classic bean soups can include split peas, lentils, black beans and navy beans. Use your favourite combination of legumes and vegetables, simmer them together for 30 to 40 minutes, add in a few herbs and some lemon juice, and you will have a delicious and healthy Mediterranean soup.
A basic legume salad can be made from a combination of any kind of cooked legumes, together with chopped herbs, lemon juice, olive oil, salt, and pepper. Then add chopped vegetables or fruit, cheese cubes, or even slices of chicken breast.
A traditional Indian dhal with either green, red or brown lentils makes for the quintessential legume curry. Hummus made from chickpeas makes for a great healthy snack that you can buy pre-made or make from scratch. Don’t just save legumes for lunch and dinner, legumes make a great breakfast addition and go well with many egg dishes such as frittatas and omelettes.
You may think that dried legumes are hard to prepare and need hours of soaking and boiling before you can use them. While it is true that soaking dried legumes can make them easier to digest and absorb, it is not essential in every case. Split peas and lentils never need soaking and cook quickly. Although it takes some time, soaking and cooking legumes does not take much planning or effort. You can also prepare slow-cooking legumes in advance and store them in the freezer. For added convenience, canned legumes are a handy alternative to dried legumes as they’re ready to consume almost straight out of the can.
Gas can sometimes be a problem for someone adding more legumes in their diet. This is actually a good sign as shows that your gut bacteria are doing their job fermenting the fibre for the benefit of your health. To help ease any gut discomfort, introduce legumes gradually over several days to weeks. Soaking dried beans for at least three hours before cooking them may help reduce this side effect. Changing the water several times during soaking and discarding the final soaking water also will help.
So, I hope I’ve convinced you. Legumes make a great addition to any diet. They are a sustainable and inexpensive source of food that are high in protein and fibre and a host of other nutrients. They’re also great for your health.
Research Wrap Up
Now on to my research wrap up segment where I profile a study that has grabbed my attention during the week. And for this week, it is a quirky study looking at how sitting and standing posture can influence not just how much we eat, but also the perceived temperature of the food and even how the food tastes.
There is a growing trend for more and more food to be eaten ‘on the go’. That can mean less traditional meals eaten at a table and more eaten while moving from place to place or even getting a quick meal standing up before moving on to the next pressing engagement of the day. The business of life aside, scientists are now questioning if there could be something inherently different about standing up that can affect perception and consumption of food.
The traditional five senses of taste, sight, sound, touch and smell can all affect the eating experience. So could an additional sense system, that being the vestibular system responsible for balance and posture, also influence eating sensations?
The theory is that when people experience some form of stress or discomfort, food does not taste as good. Standing up is thought to cause a mild stress to the body so how much could this stress influence the experience of eating? Over a series of six different experiments involving several hundred volunteers, researchers explored standing versus sitting on food taste and enjoyment, temperature perception, and volume of food consumed. And I’ll link to the study in the show notes. https://academic.oup.com/jcr/article-abstract/46/4/708/5488173
Here is the summary of all the studies. People sitting down rated delicious tasting food such as freshly baked brownies more highly compared to when the same food was eaten standing up. When the same food was made ‘less delicious’ by adding too much salt to the recipe, people sitting down rated the food poorly. Surprisingly, those standing up did not notice the difference.
It wasn’t just taste perception that was affected. Temperature perception of hot beverages such as coffee was rated stronger and more intense when sitting down compared to standing up. And then there was the effect on how much was drunk. Drinking coffee while standing lead to less of it being drunk.
Just to raise the stakes for how mild stress can alter the eating experience, volunteers tried fruit snacks while carrying a shopping bag. The stress of the extra weight meant that regardless of if people were either sitting and standing, they rated the food to be less tasty when they were carrying some full shopping bags.
Whether it’s standing or engaging in some form of extra exertion such as carrying a heavy bag, the low-level stress placed on the body is enough to mute taste buds and affect appetite. This makes sense from a physiological point of view as when the body is under some form of stress, the body is primed in a more ‘fight or flight’ direction rather than in the opposite ‘rest and digest’ direction.
How to translate this into your life? Take the time to appreciate eating for the experience it is which means being in the right space both mentally and physically and that means sitting down and giving your attention to the food at hand.
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.