Are Beans Prebiotic? The Magical Microbiome Boosters

Dietary pulses, such as dry beans, lentils, chickpeas, and dry peas, have the most fiber of all the different types of legumes. They are also cheap, easy to find, and last a long time. To get the recommended fiber intake and keep your gut and overall health in good shape, adding pulses to your regular diet is a simple and effective way to do it. Dietary pulses-derived resistant starch (RS) is a relatively less explored prebiotic ingredient. Several in vitro and preclinical studies have shown how important RS is for promoting and shaping the gut microbiota composition toward homeostasis, which in turn improves the metabolic health of the host. Instead, only the cereals and tubers derived RS has been tested on people and old animal models to see what effect it has. In this case, this review gathers research about how dietary pulses and their RS can improve gut microbiome-metabolome signatures in both preclinical and clinical studies. It also thinks about their potential and prospects for better gut health related to getting older. In short, adding dietary pulses and their RS to your diet encourages the growth of good bacteria in your gut and greatly increases the production of short-chain fatty acids in the colon.

Pulses are valuable dry grains from leguminous crops. Pulses were first tamed around 10,000 years ago and are now a main source of protein and energy, especially in developing countries where they are grown as a staple crop [1]. But over the past 100 years, people’s eating habits have changed. For example, fewer people are eating pulses every day, and the number of people with chronic diseases has gone up [2]. Researchers have found that eating a lot of whole grains and legumes or pulses is linked to living longer and having better heart, metabolic, and brain health [3]. Instead, eating a lot of refined grains, red meat, and sugar has been linked to a higher risk of death and bad heart and metabolism outcomes [3].

People all over the world can buy different kinds of pulses, but the Food and Agriculture Organization (FAO) has named 11 main types: chickpeas, lentils, cowpeas, peas, pigeon peas, vetches, lupins, and other “minor” pulses [4]. Among them, lentils (Lens culinaris L. ), beans (Paseolus vulgaris L. ), chickpeas (Cicer arietinum L. ), and peas (Pisum sativum L. ) are the most frequently consumed pulses worldwide [5]. Pulses possess superior nutritional properties and harbor various bioactive compounds, viz. , fermentable fibers, bioactive peptides, and phytochemicals [6]. Pulses have a lot of health benefits because they have a lot of good protein and soluble and insoluble fiber [7]. It has been suggested that people can improve their health by eating at least 14 grams of fiber per 1000 calories every day [8]. Still, a developed country like the US is a long way from reaching this level, and the size of the gap is almost 20% of the total shortfall [9]. Adding pulses to your diet could be a good way to make up for this lack. Pulses have a lot of fiber—up to 30 grams per 100 grams of dry weight for peas, 18 to 20 grams for lentils, 18 to 22 grams for chickpeas, and 23 to 32 grams for beans. The main type of fiber in pulses is insoluble fiber, which makes up 10 to 15 grams for peas, 11 to 17 grams for lentils, 10 to 18 grams for chickpeas, and 20–28 grams for beans [4].

Starch is the major carbohydrate in pulses accounting for nearly 50% portion of carbohydrates [10]. Some of the starches in raw and/or cooked pulses are found as dietary fiber instead of as carbs that can be used. This is because foods that are heated change the structure of the starch in some or all of their parts, creating resistant starch (RS). RS goes through the upper digestive tract without being broken down. It then goes to the large intestine, where microbes there break it down into a variety of metabolites that help keep people healthy [11]. Studies in the past have also shown that RS can help improve the body’s post-meal glucose and insulin levels, make people feel fuller, lower cholesterol and stored fat, and help them lose weight. This makes it a useful ingredient, especially for treating metabolic disorders that are linked to the gut [12,13,14,15]. So far, studies that looked at the health benefits of RS in humans only looked at RS from cereals and tubers. Pulses derived RS got very little to no attention. Recently, work was done in our lab to separate and clean the starches from 18 pulses. These starches were then tested for their usefulness so that they could be used more widely as better food ingredients [16]. Because selected pulse RS has better sensory properties than common fibers like whole cereals, fruit fibers, and so on Adding this functional ingredient to your diet could help control metabolic diseases [17].

These days, a lot of people know that the gastrointestinal (GI) tract is an important part of the body’s defense system. Intestinal bacteria help break down the nutrients in food and make bioactive molecules with low molecular weight, which is very important for our health and well-being [18]. The human digestive tract is home to more than 1014 microorganisms from more than 1000 species, and the bacterial genome is about 100 times bigger than the human genome [19]. About 95% of the total microbes present in the human body are colonized in the GI tract. The GI tract is home to bacteria, eukaryotes, and archaea. This group of living things is called gut microbiota [20]. Different parts of the gut have different microbiota and different types of microbes that live there. These differences are caused by things like the shape of the gut, the availability of nutrients, the pH level, and the presence or absence of oxygen. Gut bacteria mostly belong to the four main phyla. Firmicutes are the most common, making up 65% of all gut bacteria. Bacteroidetes come in at 25%, followed by proteobacteria at 8%, and actinobacteria at 5%. The GI tract is home to three main groups of extremophile anaerobes: the Clostridium coccoides group (also called Clostridium cluster XIVa), the Clostridium leptum group (also called Clostridium cluster IV), and Bacteroides [21]. Gut microbes and the byproducts they make when they break down different substrates play many roles in maintaining the health of the host, including immune, metabolic, and neurobehavioral functions.

Gut microbiota is dynamic in nature and changes continuously during the lifespan of an individual [22]. During the aging process of an individual, dynamic changes occur in behavioral, environmental, biological, and social processes. Genomic instability, epigenetic changes, and telomere attrition are the main signs of aging. They cause cells to die, have trouble sensing nutrients, and have mitochondrial-related problems, all of which make it harder for cells to talk to each other and stem cells to work properly [23]. As people get older, their immune systems and cells stop working as well as they used to. This causes low-level inflammation to last for a long time and makes the gut more permeable. This can lead to a number of digestive problems, heart and metabolic diseases, weak muscles, memory loss, and gut dysbiosis [24]. problems that come with getting older are made worse by western diets that are high in fat and sugar, which may make gut dysbiosis more likely [25]. One important thing that can help lower the risk of many age-related diseases is keeping a healthy and varied gut microbiota that changes over time. Our group has already found that gut dysbiosis is worse in older people than in younger people in earlier studies [26].

Over 20% of baby boomers are at nutritional risk, and that number could rise to over 30% by 2020. This shows how expensive health care is in the United States and how important it is to eat foods that are high in nutrients and good for you as a way to stay healthy. In this way, pulses might be the “perfect” food for older adults because they are low in saturated fat and high in fiber. They are also easy to buy, cook, and eat, making them a cheap way to improve gut health and overall health in people of all ages, including older people [27]. Gut health is when the host’s immune system works together with a balanced gut microbiota to protect the integrity of the mucosal epithelial barrier and lower harmful inflammatory responses [28]. This connection is thrown off by gut microbiota dysbiosis, which speeds up the development of many long-term gut-related illnesses, such as diabetes, obesity, inflammatory bowel disease (IBD), and colorectal cancer [29]. Gut dysbiosis is mainly marked by a lack of species diversity among beneficial and commensal gut microbes, along with an overgrowth and/or proliferation of native pathobionts or opportunistic pathogenic microbes. This leads to immune system dysregulation and a low-grade pro-inflammatory response in the gut [30]. This off-balance (dysbiotic) balance in the two-way communication between the gut microbiota and the epithelial immune system makes intestinal epithelial (altered gut barrier function; “leaky gut”), immunological (chronic hyper-inflammation of intestinal mucosa) and neurological (gut–microbiota–brain axis) dysfunctions worse, which can lead to a number of gut-related and systemic diseases [31]. In this case, the goal of this review is to gather information on how eating RS pulses affects changes in the gut microbiome and metabolome profile in different groups of people, as well as the health effects these changes have. Also, a lot of attention is paid to the research that has already been done on how RS affects gut and metabolic health that comes with getting older.

Resistant Starch and Human Health

Starch is a dietary carbohydrate that is commonly found in everyday food. It is the second most abundant chemical compound in the plants after cellulose. Chemically, starch is composed of two monosaccharide molecules that are amylose (linear chain) and amylopectin (branched chain). These molecules are linked together with alpha 1-4 and/or alpha 1-6 glycosidic bonds. Starch can be broken down into three groups based on its physical and physiological properties: rapidly digestible starch, slowly digestible starch, and resistant starch (RS) [32]. Englyst and colleagues’ (1982) in vitro study showed that even after enzyme treatment, some of the starch was still not broken down. More research confirmed that these starches were not broken down by amylases in the small intestine and went to the colon, where they were used by gut microbes. They named this starch fragment “resistant starch” [33]. The structure of the starch molecule and the amount of amylose to amylopectin have the most impact on how easily the starch is broken down in the small intestine. Chemically, RS has a low molecular weight (12 KDa) and a straight structure made up of α-1,4-D-glucan parts that come from the amylose fraction that has been broken down backwards [17].

Resistant starch is further subdivided into five types depending upon its structural features. RS type 1 (RS1) starch is physically inaccessible and has the most complicated structures because it is often found trapped within the protein matrix or non-starch parts of the plant cell wall (e.g. g. , whole grains or pulses) [11]. Compared to RS1, the cellular structure is absent in RS type 2 (RS2). The RS type 2 possesses native, uncooked, and semi-crystalline starch granules having a B- or C-type polymorph (e. g. , high-amylose starch, raw potato starch) [11]. The RS type 3 (RS3) is obtained by retrogradation process upon cooking and cooling of starch-containing foods. It might be hard to digest because pancreatic α-amylases don’t work as well on starch double helices as they do on fully gelatinized starch molecules (e.g. g. , retrograded high amylose maize starch) [34]. RS type 4 (RS4) is starch that has been changed chemically through esterification, crosslinking, hydroxypropylation, acetylation, and phosphorylation [35]. Because the functional groups block the site where starch-digesting enzymes work, RS4 is not easily broken down. The RS type 5 (RS5) starch is made when high amylose starch combines with lipids to form a complex. This makes high amylose even more resistant to enzymes by stopping granules from swelling up while they’re cooking [17].

Resistant starch possesses many desirable functional and health-promoting properties [32]. A summary of the effects of resistant starch from the pulses on the health of people and rodents can be found in RS fermentation in the lower GI tract produces different starch oligomers and SCFAs. SCFAs are actively involved in reducing the risk of diabetes, cancer, obesity, and other cardiovascular diseases [8,19,25]. Among them, acetate, propionate, and butyrate have been extensively studied for their health benefits. Acetate is the main SCFA that is made at a level of 65% in the colon, which causes big drops in pH. So, it stops the growth of harmful microorganisms and indirectly helps the body absorb minerals like calcium, iron, and sodium. Butyrate, on the other hand, gives colonocytes energy, reduces inflammation, protects against colon cancer, and is an important part of gut homeostasis as well as keeping the epithelium healthy [36]. Butyrate is also responsible for lower levels of glycolysis and glycogenolysis (Ashwar et al. , 2017). Propionate is another important metabolite that is partially absorbed via portal veins and reaches the liver. It is then broken down as a glucogenic substrate, which stops pathways that lead to less 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) activity and stops acetyl-CoA reductase from working. This lowers the amount of cholesterol in the blood [37]. The serum cholesterol-lowering effect of RS was demonstrated in rats when they were fed a cholesterol-free diet [38].

Benefits of Dietary Beans and Pulses on Gut Health

New research that shows how dietary fibers can help with a number of diseases has made people more interested in pulse-based foods. Various types of fibers present in pulses include long-chain soluble and insoluble polysaccharides, resistant starch, and galactooligosaccharides. In addition, these components can act as prebiotic precursors, which are digested by beneficial microorganisms in the gut. Researchers have found that eating pulses can lower serum cholesterol, make you feel fuller, and keep your blood sugar levels low after a meal. All of these things lower the risk of metabolic diseases like heart disease, diabetes, obesity, and more. [59,60]. In fact, several meta-analyses found that eating about two-thirds of a cup of pulses every day could lower total and LDL cholesterol by a large amount [61]. The low glycemic response of pulses is due to the intact cell wall of whole pulses that acts as a barrier between the starch and digestive enzymes. Additionally, pulse consumption is closely linked to lowering blood pressure and protecting against reactive oxygen species because it contains a lot of polyphenols [62].

In the past few years, there has been more research on pulses as a possible long-term source of plant protein instead of animal protein to feed the growing population and solve the problem of food insecurity [4]. Whole pulses are also high in plant-based protein and dietary fiber, which supports the idea that they are good for the gut microbiota. summarizes the effects of eating different types of pulses, such as cooked, ground, meals, or as a supplement, on the gut microbiota in rodents and humans. A study on pulse flour showed that the genera Bifidobacterium, Faecalibacterium, Clostridium, Eubacterium, and Roseburia grew better, and the production of butyrate and acetate also went up [63]. Adding pulses to the diet of mice has been shown in several studies to increase the number of Prevotella, Dorea, and Ruminococcus flavefaciens and decrease the number of Ruminococcus gnavus [18,29,64,65,66]. Prevotella is a genus that has a wide range of glycoside hydrolases and is known for being able to make SCFAs after carbohydrates are fermented [29]. The species Ruminococcus flavefaciens had been found to decrease in overweight (BMI: 25. 0–29. 9) and obese (BMI: >30. 0) subjects [67]. A species of bacteria called Ruminococcus gnavus that breaks down mucus has been linked to more gut-barrier problems in people who are overweight or have inflammatory bowel disease [65]. One more good thing about eating pulses is that they increase the number of Akkermansia muciniphila bacteria in the gut. These bacteria are often called “next-generation probiotics” [8,68]. Interestingly, this bacterium is also mucolytic but has an inverse correlation with R. gnavus [69]. Majority of the studies reported herein demonstrated a decrease in the ratio of Firmicutes to Bacteroidetes. This lower ratio of two major phyla has been linked to lessening obesity, possibly because of changes in how energy is taken from carbohydrates in the colon [70]. Among the Bacteroidales, the members representative of the pulse-based diets includes Muribaculaceae (S24-7), Rikenellaceae and B. acidifaciens [18]. Lentil consumption was found to be associated with increased prevalence of Roseburia in mouse feces [64]. Roseburia helps make butyrate and is linked to a number of diseases that are bad for you, like Crohn’s disease and colitis [71]. Even though these studies showed that pulses can change the gut microbiome for the better, the effects on different gut genera are complicated and may depend on things like the type of pulse, the dose, the age, the health of the participants, the length of the study, and the sequencing method used.

It has been shown that common beans, chickpeas, and lentils can change the microenvironment of the colon in animal models for the better [18,29,64,66]. These include (i) more crypt mucus and higher levels of mucin mRNA; (ii) higher levels of epithelial tight junction proteins; (iii) longer crypts, more epithelial cells, and more goblet cells; (iv) higher levels of SCFAs (acetate, propionate, and butyrate); (v) higher levels of G protein-coupled receptors in the intestine; and (vi) lower levels of pro-inflammatory cytokines in the blood. Having more G protein-coupled receptors in the colon is linked to detecting high SCFA production by gut microbes, which plays a role in fat metabolism and controlling hunger [81]. Researchers have used clinical trials to look into the beneficial effects of eating whole pulses on the microbiota and metabolite profile of humans in the past [72,73,74,75,76]. Some of these are a decrease in pathogenic and putrefactive gut bacteria species and an increase in Bacteroidetes and Faecalibacterium prausnitzii; a decrease in total serum cholesterol, LDL-cholesterol, and HDL-cholesterol; an increase in the variety of microbes; and a major change in the profile of metabolites (e.g. g. , ophthalmate) in colorectal cancer survivors.

This Benefit Of Beans & Lentils Will ‘Blow Your Mind!’

FAQ

Are beans high in prebiotics?

Are beans good for gut bacteria?

What beans are high in probiotics?

Are beans a prebiotic?

Beans are also a prebiotic, the fiber that feeds the probiotics in your digestive system. To understand what prebiotics are, we first need to know what they are feeding – probiotics. Probiotics are good bacteria in your gut microbiome that have numerous health benefits to keep your body working optimally.

What type of beans should one eat?

The most healthy beans are chickpeas, lentils, peas, kidney beans, black beans, soybeans, pinto beans, and navy beans. They contain a lot of fiber and proteins.

Are pinto beans prebiotic?

According to The Bean Institute, yes, pinto beans are prebiotic. They are the most popular bean in the United States. The United States Department of Agriculture (USDA) provides the following nutritional value of 1 cup of pinto beans: The recommended daily intake (RDI) of protein is between 15 to 25 grams, while fiber is 25 to 30 grams.

Are legumes a good prebiotic?

All legumes, including beans, peas, and lentils, offer tons of prebiotic benefits —they’re rich in oligosaccharides, resistant start, and plant compounds. Plus, they’re packed with protein, helping to boost the satisfaction level of any meal or snack they star in, whether you’re plant-based or not.