Microbiome - Prebiotics vs Probiotics

and what about Postbiotics? or Synbiotics? GOS, FOS, fructans, inulin or arabinoxylans? No worries, pomegranate peel can help. And gobo - burdock root.

Probiotics refers to foods with active cultures of bacterial species. Think ‘pro-’ for providing beneficial microbiota species - like planting seeds in a farm field. Fermented foods that have live cultures can be a source of beneficial microbiome species. Prebiotics refers to foods or fiber that help feed the bacterial species of the microbiome in the gut. ‘Pre-’ might be for eating foods that ‘precede’ microbial growth, but that is a grammatical stretch. Prebiotics are like giving a farm field plenty of fertilizer to help the crops grow better.

Postbiotics refers to chemicals that are ‘post-metabolites’ of food nutrients that we ate but microbes digested instead of our enzymes and the microbes formed another chemical from the food nutrient that hadn’t been in our diet. Butyrate and short chain fatty acids are postbiotic metabolites formed in the colon from resistant starches that are hard for us to digest. Urolithins are postbiotics formed by butyrate producing species from ellagic acid in pomegranate peel.

Synbiotics is a newer term, jargon within the capsule market, which refers to products that provide both a probiotic species and some sort of prebiotic nutrient that would support that species’ growth within the gut. Synbiotics provide both the seeds and some fertilizer.

*This post is a follow-up to the post: We are symbionts with our mitochondria and microbiome, (Substack). I had mentioned the study by (Singh, et al, 2022) but hadn’t linked it, see the next section.

The post Bifidobacterium, CoV, Sabine Hazan, and butyrate producing colon species, (Substack) contains food sources of fibers/resistant starches that help promote butyrate producing species (names of the species are included). An excerpt of the food sources is included later in this post.

Postbiotic Microbiome metabolites – urolithin A and B.

Urolithins can cross the blood brain barrier and reduce neuroinflammation and may promote hippocampal neurogenesis. Mitochondrial health was helped in a clinical trial in older adults. (Liu, et al, 2022)

Postbiotic Urolithin A an B: In a study by Singh, et al, (2022) with 500 mg Urolithin supplements (MitoPure ^TM) in comparison to 8 oz pomegranate juice daily, microbiome species were tested in the juice group and urolithin producers versus not urolithin producers were identified. At baseline only 12% of the participants had urolithin present, after the pomegranate juice treatment – 40% did. The urolithin producers had more diverse microbiomes and a better Firmicutes/Bacteroides ratio of butyrate species. Having more Bacteroides in ratio to Firmicutes was associated with non-production of urolithin A in response to 8 ounces of pomegranate juice daily. Species that help produce urolithin A and B from ellagitannins may include Firmicutes, Clostridiales and Ruminococcaceae families, and Akkermansia muciniphlia. (Singh, et al, 2022)

Localized prostate cancer, phase II randomized placebo-controlled trial with pomegranate fruit extract; postbiotic metabolites observed in urine and plasma with pomegranate fruit extract. Pomegranate fruit extract was given, 1000 mg (n = 15), or placebo (n = 15), daily for twelve months. Urine and plasma samples were found to have the postbiotic metabolites urolithin A and urolithin A-gluc more frequently in the pomegranate treated group. (Jarrad, et al, 2021)

Fermented foods versus a capsule probiotic product that has live cultures

Fermented foods with live cultures may provide more benefits for gut health than capsule probiotic products. Reputable companies and fresh, refrigerated storage may be needed for product viability. There is some evidence that even if the product is no longer viable, that providing the gut with the capsule product may still promote better microbial balance. It may be providing ready to use building block/templates for similar species in the gut to readily take up and use for their growth. That is kind of expensive way to feed our gut though. Adequate zinc is essential for their health.

Researchers in the area of microbiome and health seem to use fermented foods and fiber rich prebiotic plant foods to promote their own gut health more than taking a capsule product (*my opinion from reading a lot of #microbiome Tweets years ago). People with histamine excess or MCAS problems may need to use a capsule product though as fermented foods are high in histamine content and that could worsen symptoms of histamine excess. Pomegranate can help reduce mast cell activation and improve ratios of beneficial gut microbes.

Fermented Foods

Fermented foods that seem to help our gut microbiome include live culture yogurt, pickles, Kim-chee, sauerkraut, and the beverages Kefir and Kombucha. Miso and tempeh also may benefit gut microbial species. See a webinar: FERMENTED FOODS AND HEALTH: DOES TODAY'S SCIENCE SUPPORT YESTERDAY'S TRADITION?, (Youtube), (ISAPP - a pdf of the webinar slides)

Be aware that heat treating kills the live species. Pickle or sauerkraut with live cultures will be a refrigerated product with a fairly short Use-By date compared to the jars that sit on a pantry shelf. Other types of pickles are made with vinegar or brine instead of by fermentation and would not be ‘probiotic’ foods. Sourdough bread is a fermented bread that no longer has live cultures after baking but the process of fermentation can improve digestibility, and possibly gluten content, and increase some nutrients. Wine and beer are fermented but then heat treated. The fermentation process can increase or modify nutrient content. (ISAPP - a pdf of the webinar slides)

Pomegranate wine can be a source of the beneficial postbiotic urolithin A and B which can help reduce inflammation within the brain. The postbiotic remains even after the heat of bottling would kill the fermentation microbes.

Prebiotic foods and fibers

Prebiotic rich foods include pomegranate/peel and “asparagus, onions, and wheat […] salsify, Jerusalem artichoke, artichoke, leek, onion, garlic, and scorzonera” and well-studied soluble fibers studied as prebiotics include “inulin, FOS, GOS, and synthesized version of human milk oligosccharides (HMOs).” (Holscher, Hutkins, Sanders, 2021) Scorzonera is also called black salsify. Recipe: (whereismyspoon.co/black-salsify)

“Over the years, the concept of prebiotics has evolved. It has expanded beyond the gut to include beneficial microorganisms associated with other colonized body sites, even though the majority of current prebiotics focus solely on utilization in the gut. Although most commercially available prebiotics are fermentable carbohydrates, the definition is broad enough to include compounds such as polyphenols and phytochemicals.

The most commonly-studied prebiotics are the soluble fibers

• inulin,

• fructooligosaccharides (FOS),

• galactooligosaccharides (GOS), and more recently

• synthesized versions of human milk oligosaccharides (HMOs).

Prebiotics may be present naturally in certain foods or in synthesized forms in foods or supplements. The majority of research into their health effects has focused on isolated substances, and less on prebiotics as part of whole plant foods (e.g., asparagus, onions, and wheat). However, recently a dietary interventions focusing on prebiotic rich foods, including salsify, Jerusalem artichoke, artichoke, leek, onion, garlic, and scorzonera, demonstrated that consumption of these foods increased fecal Bifidobacterium, increased satiety, and reduced participants’ desire to consume sweet and salty food. 38” (Holscher, Hutkins, Sanders, 2021)

How much fiber to eat each day - probably more than we are getting currently on average.

“Although there is an adequate intake recommendation for fiber (14 g/1000 kcal), at present, there are no official dietary recommendations for adequate intake or recommended daily allowance for prebiotics in healthy individuals. Research has suggested that an oral dose of ≥3 g per day of prebiotics is needed to elicit a bifidogenic effect, 51 although even lower levels were effective in children with autism. 52 Typically, around 5 g is the target for FOS and GOS in the daily diet—and this includes plant sources of prebiotics. Larger doses of up to 20 g/day may be necessary to facilitate certain health outcomes such as weight loss or improved glycemic control. 53-57”

• Evidence-Based Use of Probiotics, Prebiotics and Fermented Foods for Digestive Health, (Holscher, Hutkins, Sanders, 2021) and ISAPPscience.org.

Fructooligosaaccharides (FOS) - ‘fructo-oligo-saccharides’

Fructooligosaccharides (FOS) may be used as a low glycemic index sweetening alternative called ‘calorie free’. It is a natural fiber in some plant foods and it seems to help balance blood sugar, reduce cholesterol and is not a calorie source for cancer cells. Too much could cause gassy bloating from microbial over growth. Up to twenty grams per day or less is likely safe and tolerable. (medicalnewstoday.com/Is FOS safe?) Otherwise 4-15 grams per day is recommended for constipation. (Sabater-Molina, et al., 2009)

“FOS have a number of interesting properties, including a low sweetness intensity; they are also calorie free, non-cariogenic and are considered as soluble dietary fibre. Furthermore, FOS have important beneficial physiological effects such as low carcinogenicity, a prebiotic effect, improved mineral absorption and decreased levels of serum cholesterol, triacylglycerols and phospholipids. Currently FOS are increasingly included in food products and infant formulas due to their prebiotic effect stimulate the growth of nonpathogenic intestinal microflora. Their consumption increases fecal bolus and the frequency of depositions, while a dose of 4-15 g/day given to healthy subjects will reduce constipation, considered one of the growing problems of modern society, and newborns during the first months of life.” (Sabater-Molina, et al., 2009)

Fructans

Fructans are another type of fiber that has been studied as a probiotic. Fructans are a chain of fructose sugar molecules connected together. Galacto-oligosaccharides are similar but are a chain of galactose sugar molecules connected together. People with bowel issues or Small Intestine Bacterial Overgrowth (SIBO) may feel better by avoiding foods rich in the fibers that feed our microbiome. The diet has the acronym FODMAP. (monashfodmap.com/blog/what-are-oligos)

Staying on restrictive diets very long can become boring and may lack adequate nutrients. Pomegranate peel can help rebalance positive and negative microbiome species and reduce mast cell degranulation. It might benefit people with digestive difficulties even though it has fiber and can promote microbiome growth. Moderation versus excess is often the key to better health.

Galacto-oligosaccharides (GOS)

Legumes such as lentils, chickpeas and beans contain galacto-oligosaccharides (GOSs). Ten grams per day might be used of a refined product for medicinal purposes. (ScienceDirect/GOS)

“Studies in elderly subjects, a population with known decreases in bifidobacteria, confirm a bifidogenic effect of GOS. Men and women over 50 years of age consumed 4 g/day GOS and placebo in a crossover study for 3 weeks each. Bifidobacteria levels were increased with GOS compared to placebo [48]. Men and women around 70 years of age taking 5.5 g/day of GOS also experienced a beneficial modulation of their gastrointestinal microbiota. Bifidobacterium spp., Lactobacillus–Enterococcus spp., and the Clostridium coccoides–Eubacterium rectale increased while Bacteroides, Clostridium histolyticum, Escherichia coli, and Desulfovibrio spp. decreased [49].” Prebiotics: Inulin and Other Oligosaccharides (Mitmesser and Combs, 2017) viewable at (ScienceDirect/GOS)

Inulin

Food sources of inulin include: chicory root, 41.6 gr., Jerusalem artichokes (aka sunchokes), 18 gr., dandelion greens, 13.5 gr., garlic, 12.5 gr., leeks, 6.5 gr., asparagus, 2.5 gr., wheat bran, 2.5 gr., bananas, 0.5 gr.. (Livestrong.com) *The grams of inulin fiber is per 100 grams of the food, about 3.5 oz. We are more likely to eat 3.5 ounces of Jerusalem artichoke tubers or dandelion greens than wheat bran or chicory root. Asparagus doesn’t have as much as leeks but more people eat them and would eat a half cup compared to a spoonful of wheat bran sprinkled on something else. Onions in general are also a source of inulin and rye and barley are mentioned in another source.

Foragers can go look for burdock and dig up the roots which are starchy and a good source of inulin. The Japanese cultivate burdock root as a favored food called Gobo. Burdock grows in ditches, gets enormous leaves and then grows taller stems with burrs that get caught on clothes or fur. (healthline.com) Foraging identification guide: (ediblewildfood.com) More about the medicinal benefits: Burdock – A Common Weed with Powerful Plant Medicine - The Back Yard Herbalist (thebackyardherbalistschool.com)

Burdock has prickly burrs as seed pods which cling to fur or clothing. Photo by Anna Gavrilova on Unsplash

*I dug some burdock root and tried it - a little tougher than a carrot and not quite as starchy as a potato or parsnip. It seemed inedible, tough, as I cleaned it and peeled it but it did cook up to a softer but still firm texture. It is said to be iron rich and the broth was a very vivid blue green. The cooked roots turned grayish brown after a couple days which may be the polyphenol chlorogenic acid revealing itself. The peel is rich in glutamic acid which is favored for a umami flavor so traditional methods of preparation simply lightly scrub the root instead of peeling it. Slicing it into rounds or thin lengths is a traditional way to cut the roots and they may be added to Miso soup or stir-fried or deep fried into thin chips. (simplyoishii.com/gobo) I would prefer to peel the burdock root then as glutamic acid might lead to its anionic form glutamate and excitotoxicity for my brain.

Arabinoxylan‐oligosaccharides (AXOS)

Food sources of arabinoxylans include: psyllium, flax seed, bamboo shoots, and all cereal grains including rice.

“Arabinoxylans have been found in all major cereal grains, including rye, wheat, barley, oats, rice, sorghum, maize, millet (Izydorczyk and Biliaderis, 1995), as well as in other plants, such as psyllium (Fischer et al., 2004), flax seed, pangola grass, bamboo shoots, and rye grass.”

Arabinoxylans, M.S. Izydorczyk, in Handbook of Hydrocolloids (Second Edition), 2009.

Foods first!

In general refined fiber products are not superior to eating more onions, and other vegetables and fruits, beans, whole grains, and cooked and chilled starchy foods that have more resistant starch content than the initial hot food. Any raw fruit or vegetable will have a much larger percentage of resistant starch and that is why eating raw green apples can leave a person with a very gassy belly — too much resistant starch overfed the microbiome causing a sudden increase in gas as a waste product from their fermentation of the starches that were to hard for us to fully digest.

Disclaimer: This information is being provided for educational purposes within the guidelines of Fair Use and is not intended to provide individual health guidance.

Reference List

Arabinoxylans, M.S. Izydorczyk, in Handbook of Hydrocolloids (Second Edition), 2009.

Evidence-Based Use of Probiotics, Prebiotics and Fermented Foods for Digestive Health, (Holscher, Hutkins, Sanders, 2021) and ISAPPscience.org

FERMENTED FOODS AND HEALTH: DOES TODAY'S SCIENCE SUPPORT YESTERDAY'S TRADITION?, (Youtube) (ISAPP - a pdf of the webinar slides)

Galacto-oligosaccharides, (ScienceDirect/GOS)

(Jarrad, et al, 2021) Jarrard, D., Filon, M., Huang, W., et al., 2021. ‘A phase II randomized placebo-controlled trial of pomegranate fruit extract in men with localized prostate cancer undergoing active surveillance’. Prostate. Jan;81(1):41-49. doi: 10.1002/pros.24076. Epub 2020 Oct 23. PMID: 33095939. Available at: https://pubmed.ncbi.nlm.nih.gov/33095939/

(Liu, et al, 2022) Liu, S., D’Amico, D., Shankland, E., et al., (2022). ‘Effect of Urolithin A Supplementation on Muscle Endurance and Mitochondrial Health in Older Adults: A Randomized Clinical Trial’. JAMA Netw Open. 5(1):e2144279. doi:10.1001/jamanetworkopen.2021.44279 https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2788244

(Mitmesser and Combs, 2017) S. Mitmesser, M. Combs, Chapter 23 - Prebiotics: Inulin and Other Oligosaccharides, Editor(s): Martin H. Floch, Yehuda Ringel, W. Allan Walker, The Microbiota in Gastrointestinal Pathophysiology, Academic Press, 2017, Pages 201-208, ISBN 9780128040249, https://doi.org/10.1016/B978-0-12-804024-9.00023-9. https://www.sciencedirect.com/science/article/pii/B9780128040249000239) excerpt viewable at (ScienceDirect/GOS)

(monashfodmap.com/blog/what-are-oligos)

(Sabater-Molina, et al., 2009) Sabater-Molina M, Larqué E, Torrella F, Zamora S. Dietary fructooligosaccharides and potential benefits on health. J Physiol Biochem. 2009 Sep;65(3):315-28. doi: 10.1007/BF03180584. PMID: 20119826. https://pubmed.ncbi.nlm.nih.gov/20119826/

(Singh, et al, 2022) Singh, A., D’Amico, D., Andreux, P.A., et al., (2022), Direct supplementation with Urolithin A overcomes limitations of dietary exposure and gut microbiome variability in healthy adults to achieve consistent levels across the population. Eur J Clin Nutr 76:297–308. Available at: https://doi.org/10.1038/s41430-021-00950-1