“All disease begins in the gut” – Hippocrates said it long ago and still we underestimate the power of our gut! Your gut hosts the majority of the immune cells in your body plus trillions of bacteria that play an important role in regulating your immune system.
Short-Chain Fatty Acids (SCFAs) are prebiotic elements that adhere to healthy gastrointestinal and immunological functioning. The SCAFs are modulators for the colon, immune and metabolic processes of the body.
The importance of healthy Gastrointestinal functioning is peculiar for nutritive physiological and psychological well-being. A healthy gut is the chief aspect of a well-maintained and healthful core and is often called our second brain. In addition, short-chain fatty acids may also play an essential role in health and disease.
Short-Chain Fatty acids play an essential role in influencing the habitat of the gut microbiome and metabolism. As a result, they may reduce the risk of inflammatory diseases, type 2 diabetes, obesity, heart disease, and other conditions.
They are an energy source for the colonic microbiota (the largest population of microbes colonizing humans from birth) and intestinal epithelial cells.
In addition, they promote good immunity and repress several inflammatory diseases. Short-chain fatty acids have been shown to protect against colon cancer in animal and lab studies. However, more research is required.
Read along to explore and understand in-depth information about Short-Chain Fatty Acids and how they affect your health.
Table of Contents
What are Short-Chain Fatty Acids?
The Short-Chain Fatty Acids are fatty acids with five or fewer carbon atoms in the aliphatic chain. SCAFs are the primary metabolites that are synthesized by the intestinal microbiota through indigestible polysaccharide fermentation.
The less complicated answer is they are the primary products of the breakdown of nondigestible carbohydrates by gut bacteria.
The most popular SCFAs that are known to have beneficial effects on human health are Acetate, Butyrate, and Propionate. They are produced when the friendly gut bacteria ferment fiber in your colon and are the main source of energy for the cells lining your colon.
Before delving further into the concept of SCAFs, let’s discuss a bit about their base compound, which is Fatty Acids.
What are Fatty Acids?
Fatty Acids are organic compounds constituting a Carboxyl functional group (–COOH) and a long Hydrocarbon chain (a chain made of carbon and hydrogen atoms linked together with covalent bonds).
The hydrocarbon chain (also known as the aliphatic chain) contains an even number of carbon atoms ranging from 4 to 28 and may either be saturated or unsaturated. Additionally, the Carboxyl functional group is the section that makes the entire compound an acid (Carboxylic acid).
Fatty Acids are represented as [R-COOH], where ‘R’ stands for the aliphatic chain. The general formula is denoted with [CH3(CH2)nCOOH], where ‘n’ is a variable number for the methylene (CH2) group that is usually an even number between 4 to 28.
Moving on to general biochemistry from the scientific definition of Fatty Acids—Fatty Acids are the fundamental functions of one of the essential macronutrients of our body—Fats. They belong to a subclass of lipids known as Triglycerides or Triacylglycerols.
Fatty Acids play a distinct role in various bodily functions such as being the building blocks and energy source for the cells, protein modification and storing energy in the form of Triglycerides in fatty tissues.
Pertained to the saturation of hydrogen atoms and the nature of the carbon to carbon covalent bond, Fatty Acids are classified as:
1. Saturated Fatty Acids: They are the fatty acids with the maximum saturation of hydrogen atoms in the aliphatic chain and single covalent bonds between the carbon atoms (C–C).
Examples of saturated fatty acids are palmitic acid and Stearic acid.
2. Unsaturated Fatty Acids: They are the fatty acids with double covalent bonds between the carbon atoms (C=C) and twice fewer hydrogen atoms than the number of double bonds.
- Monounsaturated Fatty Acids: They are unsaturated fatty acids with only one double bond.
- Polyunsaturated Fatty Acids: They are unsaturated fatty acids with more than one double bond.
Examples of unsaturated Fatty Acids are Omega-3 and Omega-6.
Respective to the number of carbon atoms in the aliphatic chain, Fatty Acids are categorized as:
1. Short-Chain Fatty Acids (SCFAs): They have five or fewer carbon atoms in the aliphatic chain. Butyric acid and Acetic acid are examples of SCFAs.
2. Medium-Chain Fatty Acids (MCFAs): They have an aliphatic chain of 6 to 12 carbon atoms. Caproic acid and Lauric acid are examples of MCFAs.
3. Long-Chain Fatty Acids (LCFAs): They constitute 13 to 21 carbon atoms in the aliphatic chain. Linoleic acid and Palmitic acid are examples of LCFAs.
4. Very Long-Chain Fatty Acids (VLCFAs): They have 22 or more carbon atoms in the aliphatic chain. Citric acid and Montanic acid are examples of VLCFAs.
Proceeding further, so far, we have discussed that:
- SCFAs are saturated aliphatic fatty acids with fewer than six carbon atoms in the hydrocarbon chain.
- SCAFs are the main metabolic entities produced by the intestinal bacterias through anaerobic fermentation of nondigestible dietary fibers and resistant starch.
- SCAFs are essential for healthy gut and immune cells, influencing metabolic processes in the body, being the functional and structural components of cells, and a source of energy production and storage.
Synthesis of Short-Chain Fatty Acids
SCFAs are organic anions and the key metabolites produced by friendly bacterial species that inhabit our body’s small and large intestines. Production of short-chain fatty acids, their amount, rate, and molecularity depends on the variety of the gut microbiota, respectively.
The intestinal microbiota present in the body of healthy individuals contributes to maintaining balance and regulating the immune and inflammatory responses of the body. They coexist in harmony and protect the body from various pathogens and pathobionts.
The short-chain fatty acids are synthesized by anaerobic fermentation of carbohydrates and proteins by the gut bacteria. These bacteria ferment the indigestible food components from your small intestine into the large bowel. This process of fermentation plays a significant role in the synthesis of SCFAs.
The factors that affect the production of SCFAs are:
- The gut microbiota composition
- Dietary sources
- The duration of passage of the food content through the digestive system
Further, these SCFAs are absorbed in the bloodstream for energy metabolism, storage, and other human body functions.
Functions of Short-Chain Fatty Acids
Short-Chain Fatty Acids play a central role in influencing various bodily processes that are essential for healthy and sustainable physiological and psychological functionality.
Some of these functions are as follows:
- SCFAs influence the environment of the gastrointestinal region for proper fermentation of dietary substances.
- They play a pivotal role in being an energy source for the colonocytes and intestinal microbiota.
- SCFAs are required for the gut-brain axis community in the body. The Gut-brain axis community is a bidirectional transmission of signals between the center and enteric nervous system. It influences the biochemical linking of emotional and cognitive brain centers to the Gastrointestinal tract.
- They have influential structural segments in the formation of cells and cell walls.
- Excess SCAFs are stored in fatty tissues in the form of Triglycerides and retrieved when the body needs instant energy.
Benefits of Short-Chain Fatty Acids
In recent years, the research on Short-Chain Fatty Acids and the gut microbiota has expanded the horizons of our knowledge about the involvement of SCFAs and intestinal microbes in shaping the physical and mental health of humans.
Some of the positive effects of SCFAs are:
- SCFAs have anti-inflammatory and anti-cancer properties. Based on human and animal research, they are exceptional at preventing and treating various inflammatory diseases and certain cancers (colon cancer).
Short-Chain Fatty Acids prevent colon cancer by promoting the health of colonocytes, destruction of cancer cells, and averting tumor cell formation.
Clinical studies have shown that short-chain fatty acids, along with a high-fiber-containing diet, effectively prevent and improve the symptoms of Ulcerative Colitis, Crohn’s disease, and colon and colorectal cancer.
- Short-Chain Fatty Acids regulate blood sugar levels by increasing enzyme activities in the liver and muscle cells. Due to this, SCFAs have been shown to improve glucose homeostasis in people struggling with diabetes Mellitus and insulin resistance.
Various human studies and clinical trials have significantly highlighted SCFAs and high-fiber food intake in improving blood sugar concentration and insulin sensitivity.
- Short-Chain fatty acids and intestinal microbiota prevent diarrhea by fermenting non-degradable carbohydrates and fibers. The consumption of antibiotics represses the SCFAs products and microbial activities in the intestinal lumen, causing diarrhea.
This is why increasing the production of SCFAs by administering a starch resistant, high-fat diet and oral rehydration solutions effectively cure and treat diarrhea.
- SCFAs inflect metabolic processes and influence energy regulation and nutrition absorption. Several animal research and previous studies have presented that SCFAs promote fat and adipose storage reduction, decreasing the risk of obesity.
However, there is no evidence of human research reported regarding the effects of SCFAs on fat and adiposity regulations.
- SCFAs in association with fibrous-rich diets reduce the production of cholesterol and inflammatory problems. The inhibition of cholesterol production in the body and its absorption in the bloodstream promotes cardiovascular health and significantly decreases the risk of heart diseases.
- In terms of lipid metabolism, SCFAs drastically increases fatty acid oxidation and heat production, inhibits fatty acid synthesis, and reduces fat storage.
Short-Chain fatty acids involved in health paradigm
Short-Chain Fatty Acids have been an exciting subject of study in the context of human health. Several recent studies and research on human and animal models have been done to interpret the role of SCFAs in influencing human health.
The majority of Short-Chain Fatty Acids, precisely 95%, that are involved in nurturing health parameters are Acetate, Butyrate, and Propionate. In this section, we’ll be addressing these three SCFAs, their significance, and their role in shaping our physiological and psychological health.
A non-fatty acid that has terrific contributions toward health is Lactic acid or Lactate. Though it is technically not a fatty acid, it is imperative as it’s produced by the intestinal microbes, just like short-chain fatty acids.
Acetate or Acetic acid is a short-chain fatty acid produced in the highest concentration by gut bacteria. Acetate is predominantly accountable for maintaining the gastrointestinal biome and nourishment of other species of intestinal microbiota.
The production of Acetate is necessary for the comprehensive wellness and maintenance of our physical and mental health. It also reflects the dependence and construction of various microbial species.
Microbiota involved in the synthesis of Acetic Acid:
The mass of bacterial species ferments the indigestible fibers and resistant starch in our bodies to synthesize SCFAs.
They provide nourishment to the colonic lumen and other bacterial species and are codependent to produce different types of SCFAs. The microbial species involved in the production of Acetate are:
- Akkermansia muciniphila,
- Prevotella spp.,
- Ruminococcus spp.
Bifidobacteria and Lactobacillus are the primary producers of Acetate, whereas Akkermansia muciniphila, Prevotella spp., and Ruminococcus spp. produce Acetate in comparatively fewer concentrations.
Functions and Benefits of Acetate:
Acetate has various beneficial functions that are essential for a healthy digestive system, like preventing diseases such as diabetes and obesity and maintaining the diverse bacterial colony in the gut. Below are some of the several benefits that Acetate offers:
- Acetate stabilizes the gut microbiome by regulating the pH of the intestinal cavity. It creates an acidic environment to enhance the activities and survival of the friendly bacteria while restraining the entrance and productivity of disease-causing pathogens.
- Acetate helps in regulating appetite and fat accumulation by binding to hormone receptors present in the gut cavity. These receptors are responsible for promoting the release of hormones, Peptide YY (PYY) and Glucagon-like Peptide-1 (GPL-1) that regulate hunger cravings and control appetite.
PYY and GLP-1 have anti-obesity and anti-diabetic properties that maintain and regulate blood sugar levels and insulin secretion. Thus, Acetate helps prevent obesity and diabetes by assisting in the secretion of these peptides and hormones.
- Acetate improves cross-feeding that enhances the biodiversity of the gut-microbiome by enabling other microbiotas to survive and thrive. It helps in nourishing other bacterial species and contributes to the production of other SCFAs.
For instance—the Acetate molecules produced by Bifidobacteria acts as an energy source for Firmicutes bacterial species, which are responsible for the production of another SCFA—Butyrate.
Butyrate or Butyric Acid is a short-chain fatty acid essential for a healthy digestive system and a defense mechanism against physiological and neurological diseases.
The production of Butyrate in the body is significantly less as compared to Acetate and Propionate. Butyrate has anti-inflammatory properties and is vital for combating gut dysbiosis (disbalance in the intestinal microbiome), a root cause of various diseases, neurological problems, and digestive disorders.
Butyrate production can be increased by consuming a fiber-rich diet. Incorporating fibrous dietary substances in your diet will increase SCFAs production and protect you from various diseases.
Microbiota involved in the synthesis of Butyric Acid:
The anaerobic bacterial species that inhabit that GI tract and are involved in the synthesis of Butyrate are:
- Members of Firmicutes bacterial family
- Faecalibacterium prausnitzii
- Eubacterium rectale
- Roseburia spp.
The Firmicutes bacterial family members ferment carbohydrates and use the Acetic acid produced by Bifidobacteria to synthesize Butyric acid.
Functions and Benefits of Butyrate:
Butyrate is a versatile short-chain fatty acid because it incubates several benefits for both physical and mental health. It is associated with the following functions:
- Butyrate accounts for yielding about 70% of the total energy requirements of colonocytes. It provides nourishment to the colon cell and the microbes present in the gut.
- Butyrate is a fundamental part of intestinal walls’ structural molecularity that acts as a blood-brain barrier and separates the gut microbiome from the rest of the body. Butyrate supports and strengthens the barrier to maintain an uninterrupted flow of vitamins and minerals in the bloodstream and prevent dangerous pathogens, food particles, and toxic elements from entering the blood.
- Butyrate is rich in anti-inflammatory, anti-cancer, and antioxidant properties. It reduces the symptoms and prevents inflammatory diseases such as Crohn’s disease and Irritable Bowel Syndrome (IBS). Butyrate efficiently targets and destroys carcinogenic cells and prevents the growth of tumors that may cause colon cancer.
- Butyrate assists in controlling the blood sugar levels and insulin secretion in the body and helps prevent and cure Type-2 Diabetes and insulin sensitivity. It is also effective in reducing diet-induced obesity.
- Butyrate’s molecular mechanism is associated with collaborating with the gut-brain axis for signal transmissions. It connects the emotional and cognitive centers of the brain to the peripheral intestine and promotes neuroprotective functions. Butyrate plays a defensive role against neurodegenerative diseases and mental disorders.
Propionate or Propionic acid is a short-chain fatty acid that is a firm promoter of appetite regulation and obesity reduction phenomenons. It holds anti-obesity, anti-inflammatory, anti-cancer, and cholesterol degrading properties that prevent adiposity, inflammatory diseases, cancer, and cardiovascular disorders.
Microbiota involved in the synthesis of Propionate:
The anaerobic fermentation of nondigestible dietary fibers and resistant starch by intestinal bacterias produces Propionic acid. The primary microbes involved in Propionate synthesis are:
- Bacteroides eggerthii
- Bacteroides fragilis
- Veillonella parvula
- Bacteroidetes phyla
- Firmicutes phyla
- Lachnospiraceae phyla
Functions and Benefits of Propionate:
Propionate is a crucial SCFA with tremendous health benefits. Some of these advantages are:
- Propionate exhibits anti-inflammatory properties and protects the digestive system and other body parts from serious inflammatory diseases. It has vast potential for promoting health and treating various diseases like atherosclerosis.
Atherosclerosis is a medical condition in which arteries are obstructed by cholesterol plaques which cause blockage and interrupt blood flow. This condition is vastly concerning as it may lead to heart attack and stroke.
- Propionate has analogous appetite regulation and obesity reduction properties. Similar to Acetate, it also promotes the release of hormones Peptide YY (PYY) and Glucagon-like Peptide-1 (GPL-1).
These hormones are responsible for regulating the appetite by satiating your hunger cravings and reducing your energy intake. Propionate minimizes the risk of obesity by stimulating fat decimation and decreasing the amount of fat storage.
- Propionate encourages protective and defensive mechanisms against carcinogenic cells. It stimulates the destruction of cancerous cells and prevents colon cancer.
Lactate or Lactic acid is an organic compound with a Carboxyl (-COOH) and Hydroxyl (-OH) functional group. Its formula is C3H6O3 and is technically not a short-chain fatty acid.
However, similar to SCFAs, it is a product of anaerobic fermentation of nondigestible polysaccharides by friendly intestinal bacterias. Lactate has several health benefits and disease-resistant qualities.
Microbiota involved in the synthesis of Lactate:
Lactic acid is a versatile compound with health-promoting and fermentation properties. It has several functions, including fermented food development and the protection and enhancement of gastrointestinal health.
The major producers of Lactate are the Lactobacillus or Lactic acid bacteria. They inhabit the colonic microbiome and synthesize Lactate by anaerobic fermentation of dietary substances.
Lactic acid is also produced in the muscles as a result of physical training and exercise. It is the accumulation of Lactic acid in the muscles that makes us feel the pain and soreness after a good workout.
Functions and Benefits of Lactate:
- Lactate is an important intestinal acid because it nourishes the Butyrate-producing bacterial species and maintains the diversity of the gut microbiome. It indirectly assists in promoting colon health by being an integral part of Butyrate production.
- Lactate improves digestive functions and enhances the immune system by creating defense mechanisms against disease-causing pathogens. It promotes the development and strengthening of the gut lining by maintaining the integrity of the cell wall.
- Lactate has anti-inflammatory properties and helps in the repression of various substances. It reduces inflammation in the GI tract by suppressing the release of pro-inflammatory elements like Interleukin-6 protein (IL-6) and an anti-inflammatory myokine. It also assists in the regulation of immune system responses.
- Similar to Butyrate, Lactate helps in the gut-brain axis signal transmissions and promotes neurological health. It enhances mood and brain function by linking the brain and gastrointestinal pathways for a better communication system.
Foods Beneficial for SCFAs Production
Consuming a diet with high roughage content is a beneficial factor for improving and maintaining a healthy digestive system.
Roughage is an indigestible fibrous-rich nutrient that contains insoluble fibers and resistant starch. It is an essential factor for the production of SCFAs.
The production of Short-Chain Fatty Acids depends on the type of fibers incorporated in our diet. A clinical study conducted regarding ‘High-level adherence to a Mediterranean diet beneficially impacts the gut microbiota composition and associated metabolome’— inferences that an intake of a high fibrous diet is directly proportional to SCFA production in the body.
Dietary fibers and food substances that play a vital role in Short-Chain Fatty Acid synthesis are:
Inulin is a prebiotic fermentable fiber present in a wide variety of fruits and vegetables. It is a rich source of SCFAs production and possesses several health benefits.
Inulin reduces many digestive problems like diarrhea, constipation, and inflammatory bowel diseases. It also helps lower blood cholesterol, obesity, oxidative stress, and neurodegenerative disorders. Moreover, Inulin increases glucose sensitivity and maintains the system of an immune response.
Foods that are rich in Inulin are:
- Chicory (which is used in salads)
- Dandelion root
- Jerusalem artichokes
Processed foods that contain Inulin are:
- Candy bars
- Ice cream
Fructooligosaccharide is a naturally occurring oligosaccharide (carbohydrate) and is a prebiotic compound with various health benefits. FOS are low-calorie, nondigestible fibers that are essential for SCFAs synthesis in the body.
It is fermented by the gut microbiota to produce short-chain fatty acids and provide nourishment to the bacterial species of the gut microbiome.
Fructooligosaccharide is further known to reduce blood sugar levels and digestive problems like constipation and diarrhea and prevent the growth and development of cancerous cells.
Foods that are rich in Fructooligosaccharide are:
- yacon root
- blue agave
Resistant starch is the nondigestible content of the starch, which is not absorbed in the small intestine and is fermented in the large bowel by the gut microbiota to synthesize SCFAs.
Resistant starch is an excellent source of Short-Chain Fatty Acids production. It is involved in many health factors such as reducing appetite and obesity, improving insulin sensitivity, lowering blood sugar levels, and assisting in the digestive process.
Foods that are rich in Resistant starch are:
- Cooked and cooled rice and potatoes
- Green Bananas
- Raw potato starch
- Cooked and cooled starchy carbs ( sweet potatoes, corn tortillas, pasta)
Pectin is a heteropolysaccharide that has an acidic structural molecularity. It is a soluble fiber with gelatinous properties.
Pectin promotes intestinal health and acts as a nourishment source for the gut microbiota. It also improves blood pressure, cholesterol, digestive functions and prevents colon and Prostate cancer and gastrointestinal disorders.
Food sources for pectin are:
- Oranges and other citrus fruits
- Green Beans
- Sweet potatoes
Arabinoxylan is a dietary fiber and a type of polysaccharide (cellulose). It is a soluble and non-digestible fiber found in major cereal grains. It has medicinal properties and is beneficial for many health factors.
Arabinoxylan prevents digestive problems like constipation and smoothens the movement of food through the digestive system. It also prevents cardiovascular disease, diabetes, metabolic diseases and improves weight loss.
Food sources for Arabinoxylan are:
- Pangola grass
- Bamboo shoot
Guar Gum is a polysaccharide extracted from guar beans. It is a soluble and fermentable fiber with laxative properties.
Guar gum helps in weight maintenance, obesity control, diabetes, diarrhea, constipation, and Irritable Bowel Syndrome. It is widely used in industrial food production because of its moisture-retaining, stabilizing, and thickening properties.
Food sources for Guar Gum are:
- ice cream
- salad dressing
- gluten-free baked goods
- breakfast cereals
- vegetable juices
Dairy products such as milk, yogurt, curd, and cheese are also essential sources for Short-Chain Fatty Acid production.
Have you ever thought about how tiny microscopic organisms and compounds can be such great providers for so many health benefits?
The intestinal microbiome constituting enormous microbiotas that synthesize Short-Chain Fatty Acids are a vast reservoir for several beneficial health effects.
Short-chain fatty acids have many advantageous mechanisms such as anti-inflammatory, anti-cancer, antioxidant, anti-obesity, nourishment, structural and disease projective properties. In addition, they are essential for healthy physiological, neurological, and cardiovascular well-being and functioning.
A well-balanced and dietary fibers-rich diet improves SCFA concentrations and production. Thus, consuming fibrous-rich substances benefits us by increasing the SCFAs synthesis, maintaining the intestinal lumen’s biodiversity, and preventing several diseases and disorders.
Taking care of your gut bacteria can open the door for an entire sky of health benefits. Of course, the best way to do this is by eating plenty of foods that are high in fermentable fiber!
High-fiber foods, such as fruits, veggies, legumes, and whole grains encourage the production of short-chain fatty acids.
There are also supplements you can take to help increase your intake of SCFA. One brand that we trust is BodyBio.
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