Probiotics Don’t Increase Short-Chain Fatty Acids
Where Probiotics Fall Short
Probiotics serve us by regulating the immune system, promoting anti-inflammatory pathways and supporting the environment for beneficial bacteria to thrive. However they do NOT quantitatively increase the number good bacteria in the colon. In order to increase beneficial bacteria we need to feed them with fermentable fibers, resistant starches and prebiotics. This increases short-chain fatty acids like butyrate which is key.
The Benefits of Probiotics
In the past decade the amount of research dedicated to probiotics is substantial. We know that they increase the absorption of:
1. omega 3 fatty acid
1. against leaky gut by nourishing the intestinal barrier
2. against small intestinal bacterial overgrowth
3. against acid reflux by reducing carbohydrate malabsorption
4. against histamine intolerance by reducing histamines
5. against inflammation by limiting cytokine production
Probiotics & the Gut-Brain Axis:
1. activate neural pathways
2. prevent stress induced changes to the gut
3. have microbial and neurochemical effects
There are an extensive number of strains and products available. In the functional medicine community we discuss when to use and avoid certain strains for specific conditions based on the latest research. We also use lab testing that shows which strains are present or absent and treat accordingly. This test has several inflammatory markers and shows any pathogenic bacterial or fungal growth.
Ferments Feed the Good Bacteria
The typical North American ingests only 10-15 grams of fermentable fiber each day. Jeff Leach from the American Gut Project is studying the Hadza hunter-gatherer people and estimates they consume an average of 100 grams per day. Archeological research shows the typical hunter-forager consumed around 135 grams per day. Fermentable fibers come from fruits, vegetables, legumes, starchy plants, nuts, and seeds.
The benefits of fermentable fiber are:
- they selectively stimulate Lactobacillus and Bifidobacterium
- they increase the production of short-chain fatty acids like butyrate which is key to gut health
- they increase the acidity of the colon making a less hospitable environment for pathogenic bacteria and a more hospitable for the beneficial species of bacteria
- they improve gut barrier function and host immunity
3 Types: soluble fiber, non-starch polysaccharides & resistant starch
Soluble fibre is mucilaginous and soothing to the digestive tract. Many are familiar with psyllium husk which is the main ingredient in Metamucil. It can be difficult to tolerate for many people causing bloating and discomfort. Glucomannan, acacia and partially hydrolyzed guar gum are inexpensive and better tolerated. Modified citrus pectin is expensive but has the added benefit of protecting against cancer and it also binds to heavy metals. Rotating between these is advised otherwise a reduction in good bacteria is likely. insoluble fibre like bran lack the same benefits. If you are familiar with the term FODMAP, soluble fibre are non-FODMAPS and generally people with digestive issues can tolerate them as long as they are integrated slowly into the diet.
Non-starch polysaccharide have an enormous list of benefits ranging from decreasing triglycerides and LDL particles to preventing obesity and hypertension. You may have heard of FOS, inulin, arabinogalactan, GOS or beta-glucan. Many of these are FODMAPS however GOS is not. It stands for galactooligosaccharide and is naturally occurring in human mother’s milk. It protects from pathogenic bacteria and feeds several strains of healthy bacteria. It can prevent allergies, reduce inflammation in gut conditions, increase the good short-chain fatty acids and protects against toxins which are linked to colon cancer.
Resistant Starch are foods that resist digestion in the small intestine and therefore are available to feed the good bacteria once they reach the colon. They include certain grains, seeds and legumes. Some sources of resistant starch you can integrate at home included cooked and cooled white rice and potatoes, green bananas/plantains and lentils. Bob’s Red Mill potato starch or green plantain flour are good additions to the kitchen and can be added to a soup or smoothie.
The benefits of resistant starch are:
1. growth of beneficial species like Bifidobacteria and Lactobacillus
2. increases the concentration of short-chain fatty acids
3. protect against colon cancer
4. improve metabolic health
5. reduce fasting blood sugar
6. reduce body weight
7. improve insulin sensitivity
8. improve sleep and mood
I’ll be talking more about short chain fatty acids. In particular the importance of butyrate stands out in the research. By following some of the guidelines and increasing the amount of fermentable fiber in your diet you will be significantly increasing butyrate levels and enjoying a number of associated health benefits. Enjoy!