SCFA: Bacterial Boosters
When people talk about probiotic bacteria, the “magic word” SCFA is always mentioned. These are short-chain fatty acids that are a product of the helpful and good bacteria. But what exactly are SCFA, how do they work and why are they so unique?
Probiotic bacteria are on the rise. Increasing knowledge about the microbiome and the positive effects of good, i.e. beneficial, bacteria means that more and more interested people are looking at their diet and the bacteria found in their bodies. This raises the question: What actually makes the good bacteria so useful? One answer is that the microbiome produces short-chain fatty acids (SCFA).
What are the SCFA of bacteria?
First, some basic but very simple chemistry: SCFA stands for “short chain fatty acids” and refers to substances that are mainly formed in the large intestine when bacteria living there ferment fiber from our food, i.e. process it. In chemical terms, they are a short hydrocarbon chain with a methyl group and a carboxyl group at their ends. They usually consist of two to six carbon atoms. Short-chain fatty acids are acetic acid (acetate, two carbon atoms), propionic acid (propionate, three carbon atoms), butyric acid (butyrate, four carbon atoms), valeric acid (valerate, five carbon atoms) and caproic acid (capronate, six carbon atoms).
In the case of acetate with its two carbon atoms, the entire chain consists only of the methyl group and the carboxyl group. The longer the chain, the more carbon atoms there are in between. That is all. They are simply quite short carbon chains.
Brevity is the spice of life
And this is precisely the advantage of these short chains. As they are so small and handy, they can penetrate human cells relatively easily and bind to receptors. This gives them an important function in the metabolism and immune system. For example, they can be quickly absorbed by the cells of the intestinal mucosa in the large intestine, where they serve as the main source of energy.
Due to their shortness, they are water-soluble and can therefore spread easily. In the intestine, the SCFA that were formed by the microbiome and are not absorbed by the intestinal epithelial cells pass directly through the intestinal wall or with the help of transporters directly into the blood. However, the majority of the remaining SCFA are first transported to the liver via the portal vein and only enter the systemic circulation from there.
The systemic cycle
The systemic circulation is the “large” circulation that distributes the oxygen-rich blood from the left side of the heart via the aorta to all regions of the body and then brings the used, i.e. oxygen-poor, blood back to the right side of the heart via the veins, from where it is pumped into the lungs (small circulation), where it is enriched with oxygen and returns to the left side of the heart via the small circulation.
The systemic circulation is the “large” circulation that distributes the oxygen-rich blood from the left side of the heart via the aorta to all regions of the body and then brings the used, i.e. oxygen-poor, blood back to the right side of the heart via the veins, from where it is pumped into the lungs (small circulation), where it is enriched with oxygen and returns to the left side of the heart via the small circulation.
Effect of the SCFA of the bacteria
SCFAs have a variety of effects in the body.
Energy source
Butyrate is the main source of energy for the epithelial cells of the large intestine, the so-called colonocytes. It supports the integrity of the intestinal mucosa and prevents microorganisms from entering the bloodstream.
Anti-inflammatory
SCFAs have an anti-inflammatory effect by influencing various signaling pathways. For example, they inhibit the excessive release of cytokines, the messenger substances of the immune system. Although these are necessary when the body reacts to infections and injuries, SCFA ensure that the immune response is balanced and does not go into overdrive or cause chronic inflammation.
Immune-boosting
By regulating a balanced release of cytokines, SCFA have an immune-boosting effect and ensure that the body can react better to threats.
Better blood sugar levels
Reduced inflammation promotes better insulin sensitivity because the body’s cells react more strongly to insulin again and can absorb glucose efficiently.
Weight control
SCFA act on certain cells, which then release more hormones, which in turn reduce the feeling of hunger by signaling to the brain that enough energy has been absorbed. In addition, more insulin is released, which stabilizes blood sugar levels and further reduces the feeling of hunger. SCFAs are therefore perfectly suited to preventing cravings in a natural way.
Intestinal flora
SCFA generally support a healthy balance of intestinal flora and ensure a high level of diversity.
Reduction of the risk of bowel cancer
Butyrate can reduce the risk of bowel cancer by stimulating degenerated intestinal cells to undergo programmed cell death. This prevents them from developing into cancerous tumors.
Cholesterol level
Propionate in particular can reduce the activity of certain enzymes in the liver that are responsible for cholesterol formation. It also has a positive effect on LDL cholesterol.
Brain health
The gut communicates continuously with the brain, for example via nerve connections such as the vagus nerve. SCFAs can serve as signaling substances that support this communication.
Support of the bone metabolism
Butyrate reduces inflammation and thus prevents excessive activation of osteoclasts, which are responsible for the breakdown of bone tissue. This has a positive effect on the balance between bone formation and bone resorption.
SCFA therefore have a number of positive effects. It is worth activating and promoting the good bacteria that produce these fatty acids.
7 tips for promoting the formation of SCFA by the microbiome
The formation of SCFA by the microbiome can be specifically promoted. In principle, it does not matter whether the SCFA are produced by bacteria or introduced into the body by other means. But as always, it is not just the end products that matter. The bacterial populations fulfill many other important functions than just the formation of SCFA. The body must always be considered as a whole. Therefore, the aim should always be to specifically stimulate the natural production of SCFA by the microbiome.
Tip 1: Dietary fiber
Make sure your diet is high in fiber. Whole grains, vegetables and legumes are full of food for your good, SCFA-producing bacteria.
Tip 2: Probiotics
Eat more probiotic foods such as yogurt, kefir, sauerkraut and other fermented products. Commercial probiotics can also help.
Tip 3: Exercise
Sorry if we always come back to that: But you have to move. There’s no way around it. Physical activity supports intestinal health.
Tip 4: Sugar
Don’t. Give up sweets and simple sugars. If you can’t, then reduce your consumption. Every piece of cake less helps. Reward yourself with a piece of dark chocolate instead.
Tip 5: Processed food
Processed foods are not good for you. You know it, and yet you eat them because they can be prepared quickly. Just don’t.
Tip 6: Stress
Engage in meditation or autogenic training to reduce your stress. Give it a try. It will do you so much good!
Tip 7: Hydration
Drink. Drink. Drink. Preferably an electrolyte-containing liquid such as medicinal water. Or at least add a pinch of salt to your glass of water.
You will already know much of the advice. But the secret is not to know the solution, but to put it into practice. SCFAs, which are produced by the microbiome, are real health boosters. It’s worth supporting the bacteria to promote your health and better protect you from disease.
The choice is yours. As always. (JS)
Sources and further reading
Zhang et al (2023). Short-chain fatty acids in diseases. Cell Communication and Signaling, 21:212. DOI: 10.1186/s12964-023-01219-9
Silva, Y.P., Bernardi, A., & Frozza, R.L. (2020). The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Frontiers in Endocrinology, 11:25. DOI: 10.3389/fendo.2020.00025
Kopczyńska, J. & Kowalczyk, M. (2024). The potential of short-chain fatty acid epigenetic regulation in chronic low-grade inflammation and obesity. Frontiers in Immunology, 15:1380476. DOI: 10.3389/fimmu.2024.1380476
Portincasa et al (2022). Gut Microbiota and Short Chain Fatty Acids: Implications in Glucose Homeostasis. International Journal of Molecular Sciences, 23:1105. DOI: 10.3390/ijms23031105
Motăţianu, A., Şerban, G., & Andone, S. (2023). The Role of Short-Chain Fatty Acids in Microbiota-Gut-Brain Cross-Talk with a Focus on Amyotrophic Lateral Sclerosis: A Systematic Review. International Journal of Molecular Sciences, 24:15094. DOI: 10.3390/ijms242015094
Fusco et al (2023). Short-Chain Fatty-Acid-Producing Bacteria: Key Components of the Human Gut Microbiota. Nutrients, 15:2211. DOI: 10.3390/nu15092211
Tan et al (2014). The Role of Short-Chain Fatty Acids in Health and Disease. Advances in Immunology, 121:91-119. DOI: 10.1016/B978-0-12-800100-4.00003-9
