- What are Short-Chain Fatty Acids?
- How do we Obtain SCFAs?
- Fibre and Bacteria – a Healthy Combination
- Benefits of SCFAs
- How Can I Boost my Production of SCFAs?
- Test, Don’t Guess
Have you heard of short-chain fatty acids?
In this article you’re going to become familiar with these incredible substances.
Despite being little-known outside of scientific literature, short-chain fatty acids (SCFAs) not only play a crucial role in the health of our digestive system, but are also involved in energy production, the control of inflammation, weight management and even cholesterol regulation.
Fatty acids are the building blocks of fat.
Chemically speaking, they’re straight chains of carbon atoms, along with hydrogen atoms and a group called a carboxyl group on the end - which is what makes them an acid.
A fat is formed when molecules of a fatty acid combine.
There are many types of fatty acids, some of which we’re quite familiar with - you may have heard of alpha-linolenic acid (ALA), which is an omega-3 fatty acid found in many seeds such as flax seeds.
Some of the carbon chains of fatty acids are really long - DHA, which is another omega-3 fat found in fish, has 22 carbon atoms.
SCFAs are specific types of fatty acids which contain less than six carbon atoms in their tails.
The most commonly encountered SCFAs are butyric acid, acetic acid and, propionic acid.
One SCFA - butyric acid - is found in dairy products, especially butter, ghee and some cheeses such as parmesan cheese.
In fact its name means ‘butter’ in Greek.
However, a major source of our SCFAs is from the fibre in our food.
Scientists have known for years that fibre is beneficial for our health, but it hasn’t been clear until recently exactly how it manages to benefit the body.
Fibre is any type of carbohydrate which we can’t digest.
However, fibre doesn’t simply pass out of our body unaltered and an important, but previously overlooked, role of fibre is to act as a food source for the bacteria living in our gut.
Science is starting to recognise what many naturopathic practitioners have believed for years – the bacteria residing in our digestive system have far reaching effects on our general health.
These bacteria, collectively known as our microbiome, can broadly be classified as beneficial and not so beneficial as far as our health is concerned.
Most of the time we’re relatively unaware of these trillions of bacteria hitching a ride along life with us, unless something goes wrong.
When the non-beneficial or pathogenic bacteria take over, the first symptoms tend to be digestive, such as IBS and food sensitivities.
However, fascinating research into our microbiome is revealing how the makeup of bacteria you play host to can affect the health of the whole body in previously unsuspected ways.
The question is, if the bacteria live in our digestive system, how do they influence our general health?
The answer may lie in SCFAs.
Bacteria, like us, need food to survive.
When we eat foods containing fibre we not only encourage the growth of the beneficial types of bacteria by providing them with a food source, but as the fibre is fermented by the bacteria, SCFAs are produced.
So-called friendly bacteria include those belonging to the species Lactobacillus and Bifidobacteria.
These types of bacteria produce large quantities of SCFAs.
The process happens in the large intestine or colon - the SCFAs in turn increase the acidity in the intestines which is an environment pathogenic bacteria don’t like, so they don’t grow as well (1).
In other words the production of SCFAs involves a cycle in which bacteria feed on fibre, then produce the acids which contribute to the environment they prefer to live in, so they can produce more SCFAs.
The amount and types of bacteria in the colon, the food source they are feasting on and how long it takes food to travel through the intestines all influence the amount and proportions of SCFAs which are produced.
The process of creating SCFAs needs the bacteria in the microbiome to work together, almost like a complex community.
Gut bacteria living in harmony with us and producing plenty of SCFAs result in wide-ranging health benefits.
SCFAs provide fuel for the cells of the intestines, and good levels of SCFAs have been linked to a healthy intestinal mucus lining. In fact studies have shown when no bacteria are present in the gut, the cells lining the colon were able to produce less energy (2).
Research suggests SCFAs can influence the genes which regulate the process of cell division and renewal in the gut, which may have implications for the prevention of colon cancer (3).
Other researchers have noted however that simply eating a high fibre diet, without the bacteria which produce SCFAs was ineffective at protecting against colon cancer.
Having a great population of bacteria in combination with a low fibre diet was equally ineffective.
It seems therefore it’s the combination of the fibre and the right type of bacteria which offers the protection.
Finally, SCFAs appear to control the muscular contractions which move food through the intestines during the process of digestion (4).
All this is good news for our digestive system, however science is now discovering SCFAs are also transported into the bloodstream where they are carried around the entire body.
There they act as signalling molecules and have been shown to have many beneficial effects on our overall health.
Research has linked low levels of SCFA production with increased intestinal permeability, otherwise known as leaky gut.
Low levels of butyrate have been found in studies to cause tiny gaps in the walls lining the small intestines to become larger, letting molecules through which shouldn’t gain access to the body (5).
Increased intestinal permeability has been linked to a range of health issues including food sensitivities, auto-immune diseases, skin problems and even mood disorders.
Because the health of the intestinal lining is crucial to the proper functioning of the immune system, it follows SCFAs also play a role in immune function.
Research has discovered SCFAs affect specific receptors involved in fat and glucose metabolism.
They seem to help to improve the body’s sensitivity to insulin, therefore helping us to regulate our blood sugar.
SCFAs can also inhibit fat storage and increase the amount of fat burned and so reduce body weight (6).
SCFAs also appear to encourage the release of a hormone called leptin, which regulates appetite and body weight over the long term (7).
Research concentrating on butyric acid concluded this SCFA has beneficial effects on blood sugar control with relation to Type 2 diabetes (8).
The specific types of bacteria which produce butyric acid were found to be low in people suffering from Type 2 diabetes (9).
We know eating more fibre is linked to lower levels of chronic inflammation in the body, and evidence suggests butyric acid may inhibit the production of certain inflammatory molecules (10). Inflammation is at the heart of many diseases.
Butyric acid has been used with success to reduce the inflammation in cases of Crohn’s disease and ulcerative colitis.
The SCFA propionic acid is metabolised by the liver. It’s thought it may reduce the liver’s production of cholesterol. In fact, SCFAs have been shown to reduce blood levels of cholesterol (11).
Certain types of fibre have been found to significantly boost the production of SCFAs. These include:
- Inulin - found in Jerusalem artichokes, chicory root, dandelion greens, onions, garlic, leeks and asparagus.
- FOS - short for fructo-oligosaccharides. This is a type of fibre found in plant foods especially garlic, onions, artichoke and banana.
- Pectin - good sources are apples, pears, apricots, carrots, guava and oranges.
- Resistant starch - in seeds, legumes, and unripe bananas - it is formed when starchy foods such as potatoes and rice are cooked and then cooled.
These types of fibre are often known as prebiotics because they serve as such good food sources for our gut bacteria.
Some people find they experience gas and bloating when they consume foods high in prebiotics.
This can be due to a condition called small intestine bacterial overgrowth, where the bacteria which should be in the colon migrate to the small intestine, where they aren’t usually found.
If this is the case for you, it’s best to introduce these foods very gradually, and to work with a therapist to correct the balance of bacteria throughout your digestive tract.
One of the most exciting aspects about our emerging knowledge of SCFAs are the clues they can give us about what is happening in the body. If we know how efficiently our bacteria are producing SCFAs, we can discover the state of health of our personal microbiome.
We know our individual genetic makeup exerts an influence over the precise ratio of the bacterial species in our microbiome, so we each play host to a different population which have a different capacity to produce SCFAs.
The ability of your microbiome to produce SCFAs can be assessed by a test which examines your stool. Analysis of the levels of the different types of SCFAs can tell us how effectively they’re being produced by our gut bacteria.
On the other hand, a urine test known as the OAT test - which stands for organic acids test - analyses your urine to detect the levels of other substances produced by our digestive bacteria which can give us a good picture of the makeup of our microbiome.
We now understand that SCFAs have profound effects on our body, and we also know their levels are affected by what we eat.
Research is still ongoing, but SCFAs may hold one key to the huge rise in inflammatory diseases seen in the modern Western world.
All this goes to show looking after your gut bacteria can have many benefits for your overall health.
A consultation with an experienced Amchara practitioner, with testing where appropriate, can recommend a nutritional plan to maximise the health of your microbiome and so improve your production of these wonderful SCFAs.
We’re dedicated to providing you with both insightful information and evidence-based content, all orientated towards the Personalised Health approach.
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