It can only be used as food for our intestinal inhabitants, which our digestive tract or small intestine does not absorb. More here: prebiotics
The secondary plant compounds also benefit the large intestinal flora to a large extent…
- What are secondary plant compounds?
- Polyphenols (phytochemicals)
- Short and flush
- Studies and findings on the prebiotic effect of individual polyphenols
- Study results on the influence of food containing polyphenols on the intestinal flora
- Short and concise: polyphenol influence on bacteria
- Glucoinsolates (mustard oil glycosides)
- Isoflavones (phytoestrogens)
- Resveratrol (one stilbene)
- Polyphenol-rich diet
- Continuing links
What are secondary plant compounds?
The name says it all. Similar to dietary fibres, they have been neglected in their importance for our body for a long time. But why and what we know by now, I will explain below. Here is a small list from this book “Intestines and secondary plant substances” (Amazon*), which I have extended by the point tannins. You can’t expect completeness here, also I have seen lists with a different hierarchical order in the internet, e.g. the term flavonoids is missing completely in the upcoming list. But for the book, from which the list is taken, I spent money and the content is otherwise short, concise and good. Therefore I like to help myself:
- Lycopene (e.g. from the tomato)
- Alpha- and beta-carotene (e.g. from the carrot)
- Phenolic acids (e.g. from coffee, tea, wholemeal)
- Hydroxybenzoic acids: gallic, protocatechu, vanillin, syringa acid
- Hydroxycinnamic acids: p-coumaric, caffeic, ferulic and sinapic acids
- Flavonols (e.g. from onions, apples, berries)
- Flavone (e.g. from herbs)
- Anthocyanins (e.g. from red, purple fruits and vegetables)
- Flavanols (e.g. from tea, cocoa)
- Epicateching gallate
- Epigallocatechin gallate
- Flavanones (e.g. from viral fruits)
- Phenolic acids (e.g. from coffee, tea, wholemeal)
- Sulfuraphane (e.g. from broccoli, cress, mustard)
- Isoflavones (e.g. from soya, cereals)
- Isoflavones (e.g. from soya, cereals)
If you want to deal more with secondary plant compounds, especially the polyphenols, I recommend this book: Amazon*
From polysaccharides (dietary fibres) to polyphenols, polysaccharides are mainly used by our useful intestinal bacteria but also partly by the bad guys as food you can read everything here: prebiotics). The second group of substances mentioned, the polyphenols, have not been on everyone’s lips for so long or have not been brought into connection with our intestinal flora. Until now, it was only known that the polyphenols e.g. from red wine have a healthy effect on our body. They are said to have a antioxidative effect against so-called radicals. But the most important thing is probably that most of the polyphenols are not absorbed in the small intestine or are chewed up in the small intestine, similar to the polySACCHARIDs, and also end up in the large intestine.
The bioavailability and effects of polyphenols depend on their transformation by our intestinal bacteria.For example, polyphenols and their metabolites (synthesized by bacteria) can also inhibit pathogenic bacteria while stimulating the growth of beneficial bacteria and exerting prebiotic-like effects. (source)
I think that for thousands of years we humans or our animal ancestors have been eating vegetable food, occasionally also animal food like meat/eggs or in former times probably insects or other arthropods, but probably chew the milk of other species. Our digestive system is used to this predominantly vegetable food, or our large intestine is used to what the small intestine does not resorb. Thus our intestines have become accustomed above all to the intestinal bacteria, which can cope with our mostly vegetable food. With all the ingredients that are contained in plant foods, including the polyphenols and saccharides (More about: prebiotics).
Pure carnivores have an intestinal flora that is adapted to animal protein and a life span that is shorter than that of herbivores (e.g. elephants), depending on their diet.
While polysaccharides are the energy reserves of plants, polyphenols have the task of fending off pests and bacteria or simply to colour the flowers. There are of course other effects/tasks, such as protection against UV radiation, aroma etc.
Maybe it’s thought too simple, but I’m allowed to, because I’m a layman and make the world as I like it. If you look at the groups of substances without the prefix Poly, you will see:
- Saccharose = energy carrier = growth
- Phenol = disinfectant = defence (Phenol was used as disinfectant in the 19th century. Nowadays derivatives of phenol are used)
Our physiological intestinal microbiome or the desired intestinal bacteria, which have lived in symbiosis with us and our ancestors for thousands of years, are thus able to convert the polyphenols into antibodies by means of enzymes. They themselves or bacteria with which they live in symbiosis are immune to these. Bacteria that are hostile to them die or are strongly inhibited in their growth. A microbiologist or chemist would now probably “facepalms”, but some things are easy to explain.
In various sources on the Internet, one reads of a prebiotic effect of polyphenols. Concerning growth, however, I would primarily think of polysaccharides, because they provide (more) energy. Therefore I rather think that polyphenols give the “good” bacteria a growth advantage over the “bad” (pathogenic) bacteria. A similar growth advantage that we give to the “evil” intestinal bacteria when we take antibiotics. I will mention later, further down, a few studies I have researched that show the following:
The metabolites, i.e. the substances produced from the polyphenols, are mainly phenolic acids, which are said to have antioxidant and antibacterial effects.
Short and flush
- Polyphenols are healthy and have an antioxidant effect if the corresponding intestinal bacteria are present in sufficient numbers.
- Some polyphenols are absorbed without bacterial help in our small intestine or even already in the stomach.
- Effects of polyphenols: bactericidal, anti-inflammatory, cancer preventive, cancer growth inhibiting
- The positive effect of polyphenols develops in interaction with other substances (including polyphenols) found in the same plant. FOR EXAMPLE: Quercetin has a high-dose mutagenic effect, but in combination with other polyphenols it has an antimutagenic effect.
- Taking polyphenols individually therefore makes no sense. Always as an extract from the plant/fruit, this is then called (active substance) matrix.
- A single intake of a high dose has no effect, because the intestinal bacteria that make the polyphenols available to us may not yet be present in sufficient quantities. From this follows:
- Long-term ingestion would be wise.
- Probably the best way would be to sneak in, because otherwise you would be throwing pearls before swine. One must first slowly multiply the polyphenol processing bacteria.
- Here, too, I see parallels to the intake of prebiotics, whose dosage should also be slowly increased.
- There are different polyphenols. The polyphenols with a low bioavailability have more influence on the intestinal microbiome.
- It is the same with saccharides/saccharose and polysaccharides, polyphenols are quasi the dietary fibres of phenols or phenolic acids. However, some phenols like benzene or even the phenol are actually toxic. Phenols include many aromatic substances, e.g. of wine or vanillin. Phenolic acids are said to have antioxidant and antibacterial effects.
If you want to know how you can use the latest research findings to build up your intestinal flora, then I recommend this blog article: intestinal flora nutrition
Studies and findings on the prebiotic effect of individual polyphenols
Before we get to the hard facts.
There are now good nutritional supplements with secondary plant substances, which consist of extracts of the well-known superfoods such as green tea, red/blue berries, soya etc. (Source: Amazon*)
In this way the carotenoids, polyphenols, isoflavones, etc. are not taken as individual substances but in their natural matrix, i.e. the substances that are supplied by nature. It is now known that these are better processed by the body (and the bacteria) and the effect is healthier. Nevertheless, I do not want to withhold from you the studies on the individual polyphenols.
Back to the food supplements. Since, as you know, I am also taken with another product by Dr. Wolz (you can read about it here: Intestinal Cure), I myself have tested Vitalkomplex Dr. Wolz (Amazon*) and found it to be good value for money. So you do not have to resort to the very expensive noble products. Vitalkomplex Dr. Wolz is expensive enough.
Critics of these vital substance complexes explain that only a very small part of these secondary plant substances are absorbed in the small intestine anyway. In my opinion, these people are the same people who missed the “strong” prebiotics and the negative name “strong” fiber, or thought that breastfeeding an infant was worse than prenutrition because of the “bacterial contamination” of breast milk. (Well, that hit home! Letting off steam does you good! :-))
So, dear critics, even if the secondary plant compounds or their metabolites (degradation products after contact with the intestinal bacteria) are excreted with the stool, they are at least beneficial to the intestinal bacteria.
It is very difficult to evaluate and recognize which secondary plant substance is metabolized by which bacterium to which degradation substance and which other bacteria further convert these substances into a (molecularly smaller) substance and which other substances must still be contained in the “matrix” so that the degradation product can finally be absorbed by our intestine. Almost as difficult to understand as this long sentence. 😉
Degradation products are a variety of benzoic acids, phenolic acids, urolithines and phytoestrogen (S) -equol, enterodiol and enterolactone. In most cases, a complex network of different intestinal bacteria species is required for complete remodelling. How well secondary plant substances, i.e. polyphenols & Co., can be used by the body is therefore individual and can be trained by an appropriate nutrition . The more diverse and “healthy” the intestinal microbiome is, the better the secondary plant substances can be processed.
This and the following is all here to read.
“Final absorbed bioactive derivatives have shown antimicrobial properties against viruses (as HBV), Gram-positive bacteria (as S. aureus, L. monocytogenes), and Gram-negative bacteria (S. enterica, P. aeruginosa), but also against eukaryote species as fungi (Candida spp., T. mentagrophytes) or protozoans (T. cruzi, P. falciparum).”
What does this tell me? The consumption of foods with a high polyphenol content in combination with a high intestinal flora diversity is therefore of great importance in the fight against infectious diseases.
In this source I found a very interesting statement of the scientists, which I summarize like this:
The intestinal flora has a great potential to convert polymeric flavonoids into low molecular weight phenols and these may have protective biological activities in the colon. On the one hand for the metabolic pathway and on the other hand for the biological activities in vivo. (By which I assume the intestines will also be meant.)
In this study by Dacre, J. C. & Williams, R. T. from 1968 was metabolized by a stool sample (the intestinal flora) of rats Protocatechuic acid to CO2 and in small amounts Hydroxybenzoic acid, whose esters are used as preservative according to Wikipedia. However, the conversion rate was very low, because almost 90% of the protocatechuic acid remained unmetabolized.
However, this study is very old and I imagine that nowadays better conditions can be created to artificially simulate the anaerobic conditions of the colon. Likewise, today we will have found ways to get the stool, with all the bacteria that die from oxygen, relatively isolated in such an artificial intestine.
Anyway, preservatives inhibit the growth of bacteria, in this case the “bad guys”. For as I have argued above/above, we humans have become accustomed to the bacteria that metabolize our originally predominantly vegetable food. And only vegetable food provides secondary plant substances such as polyphenols.
Eubacterium ramulus is a quercetin metabolizing anaerobic intestinal bacterium which is listed as “positive bacterium” in the intestinal test of BIOMES. So it makes sense to multiply it, or at least not to starve it, if you already have a sufficient amount. It is a microorganism present in human faeces in an amount of about 108 in one gram of dry stool.
Eubacterium is able to degrade luteolin-7-glucoside, rutin, quercetin, kaempferol, luteolin, eriodictyol, naringenin, taxifolin and phloretin to phenolic acids. Catechin and epicatechin were not degraded. (Source) So for catechin and epicatechin you need other bacteria, let’s see what else I can find …
In this study, polymeric proanthocyanidins were metabolized by human intestinal flora into phenolic acids, phenylacetic acid (a derivative of acetic acid), phenylpropionic acid and phenylvaleric acid.
In this study polyphenols were administered to various groups of rats for 8 days and the urine was searched for metabolites of the rat intestinal flora. Catechin was metabolized by the intestinal flora of rats into 3-hydroxyphenylpropionic acid and 3-hydroxyhippuric acid. In the urine of rats fed with red wine polyphenols (proanthocyanidins, phenolic acids, flavanols, anthocyanins and flavonols) 3-hydroxyphenylpropionic acid, 3-hydroxybenzoic acid and 3-hydroxyhippuric acid as well as hippuric, p-coumaric, vanillinic, 4-hydroxybenzoic and 3-hydroxyphenylacetic acid) were found, which also could only have entered the bloodstream through the help of the intestinal flora of the rats in the urine and before.
In the research of the absorption, metabolism and bioavailability of flavonoids, one has stumbled upon an important aspect. Most flavonoids, with the exception of catechins, are bound to sugar in plants as beta-glycosides. Glucosides are the only glycosides that can be absorbed in the small intestine and end up in the blood plasma. Absorption in the small intestine is more efficient than in the large intestine and leads to higher plasma levels. (source)
Further studies on the degradation of polyphenols to phenols or phenolic acids by our intestinal flora:
Study results on the influence of food containing polyphenols on the intestinal flora
According to this source, the polyphenols from green tea have a positive influence on our intestinal flora. The growth of certain pathogenic bacteria like Clostridium perfringens, Clostridium difficile and Bacteroides spp. is inhibited. This effect has had little effect on Bifidobacterium spp., Lactobacillus sp., but also Clostridium spp.
It has been found, for example, that catechin significantly inhibits the growth of catechins and inhibits the growth of clostridium histolyticum. coli and members of the group Clostridium coccoides – Eubacterium rectale, while the reproduction of Bifidobacterium and Lactobacillus spp. remained relatively untouched (Tzounis et al). To promote bifidos and lactos, other polyphenols are needed. More on this in the chapter berries/grapes.
According to this study, the polyphenols from green tea lead to a decrease in Firmicutes and an increase in Bacteroidetes ( slimming bacteria, see: Slim with intestine) . The relative proportions of Blautia, Bryantella, Collinsella, Lactobacillus, Marvinbryantia, Turicibacter, Barnesiella and Parabacteroides correlated significantly with the weight loss induced by tea extracts.
A Proanthocyanidin-rich extract from grape seeds, administered to healthy adults for 2 weeks, significantly increased the number of bifidobacteria (Yamakoshi et al.)
Rats, when treated with red wine polyphenols, had significantly lower concentrations of Clostridium spp. and higher concentrations of Bacteroides, Bifidobacterium and Lactobacillus spp.
Similarly, resveratrol, the well-known polyphenol of grapes, led to higher levels of Bifidobacterium spp. and Lactobacillus. (Dolara et al)
A human study showed that the consumption of polyphenols from red wine increased the number of Enterococcus, Prevotella, Bacteroides, Bifidobacterium and Bacteroides uniformis, while the amount of Lactobacillus spp. remained unchanged .
In another study, the growth of pathogenic bacteria such as Clostridium perfringens, Clostridium difficile and Bacteroides spp. was significantly suppressed.
The polyphenols of a wild blueberry drink caused a significant increase in the amount of Bifidobacterium. (Vendrame et al. )
The flavanols from grape seeds (known as OPC) promote the growth of Lactobacillus/Enterococcus and inhibit the growth of the Clostridium Histolyticum group in the intestinal microbiome (Cueva et al)
In rats whose diet was supplemented for 16 weeks with a dealcoholised proanthocyanidin-rich red wine extract, the composition of the intestinal flora changed: before treatment, there was a dominance of Bacteroides, Clostridium and Propionibacterium spp., then a dominance of Bacteroides, Lactobacillus and Bifidobacterium spp.
Source of the study results just summarized: https://www.sciencedirect.com/science/article/pii/S0955286313000946
In this study, the feeding of grape seed extract to mice led to a growth of Lactobacilli and Bacteroides.
In this study, the influence of the different polyphenols of red wine on the intestinal flora was investigated. It was found that the following groups of intestinal bacteria could numerically benefit from the polyphenols in red wine:
- Bacteroides uniformis
- Eggerthella lenta
- Blautia coccoides
- Eubacterium rectale
Polymers of catechin and epicatechin are not digested by human enzymes, and epicatechin and catechin are processed by the microbiota to produce healthy short-chain fatty acids through the activity of the microbiota. (Source)
The four-week daily intake of a drink containing cocoa-derived flavanols led to an increase in the population of bifidobacteria, while the number of clostridia was reduced. (study)
Cistus inacanus is a herb from which one can make a tea or strong brew.
Cistus Incanus contains a large number of polyphenols. (Source)
Cistus Incanus is my personal “strong polyphenol bomb.” A tea that can be drunk in large quantities because, unlike green tea, it does not contain caffeine or teaine.
In this study the efficacy of polyphenol extracts from 4 different Cistus Incanus teas on Streptococcus mutans (one of the primary cariogenic bacterial species) was demonstrated. So it makes sense to rinse the mouth with a Cistus Incanus Sud.
I have not found any studies on intestinal flora. But after what I have just said, I think that we can assume a generally positive effect of polyphenols on our intestinal flora, and many of these are present in Cistus incanus.
The source just mentioned on the effect of Cistus incanus ingredients on Strepptococcus mutans provided us with much more important information, namely a list of the 29 polyphenols found in Cistus Incanus. The identified polyphenols were divided into three groups: Ellagitannins (including gallic acid), flavanols and flavonols. Of course, you can now look for studies on the effectiveness of the individual polyphenols, which I have simply done for punicalin and quercetin. But as just mentioned, it depends on the interaction of different substances.
- Hexahydroxydiphenyl glucose isomer (HHDP)
- 4 different punicalin isomers
- Punicalin is a component of pomegranate extract and showed in combination with other polyphenols antimicrobial activity against Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Cryptococcus neoformans, methicillin-resistant Staphylococcus aureus (MRSA) and aspergum were tested against Mycobacterium intracellulare. Compounds 2 and 4 showed activity against P. aeruginosa, C. neoformans and MRSA (study).
- Punicalagin showed a strong activity against Candida albicans and Candida parapsilosis. (Study)
- Gallic acid
- 4 different punicalagin gallate isomers
- Cornusiin B
- Quercetin in the form of:
According to this study, quercetin supplementation has a major impact on the composition of the intestinal microbiota by reducing the ratio of Firmicutes to Bacteroidetes and inhibiting the growth of bacterial species (Erysipelotrichaceae, Bacillus, Eubacterium cylindroides) previously associated with diet-related obesity.
- Quercetin-3 rutinoside
- Myricetin in the form of:
- Myricetin pentoside
- Myricetin-3 ramnoside
- Kaempferol in the form of:
Short and concise:
polyphenol influence on bacteria
Catechins (green tea)
- Clostridium histolyticum
- Clostridium coccoides
- Eubacterium rectale
- Clostridium histolyticum
- Clostridium spp.
- Bifidobacterium spp
- Lactobacillus spp
Berries / proanthocyanidin (e.g. in cranberries)
- Clostridium spp.
- Lactobacillus spp
- Akkermansia muciniphila
Grape polyphenols/resveratrol (red wine)
- Clostridium spp.
- Clostridium perfringens
- Clostridium difficile
- Bacteroides (esp. Bacteroides uniformis)
- Bifidobacterium spp.
- Lactobacillus spp.
Grape seed flavanols (known as OPC – oligomeric proanthocyanidins)
The gallotannins and ellagitannins are hydrolysable tannins and can be consumed by eating fruits such as raspberries, cranberries, strawberries, walnuts, grapes and pomegranates.
Gallotannins are converted by intestinal microbial hydrolysis to glucose and gallic acid. Ellagitannins are metabolized to ellagic acid, which in turn are metabolized to urolithins. Which bacteria produce these metabolites is unknown so far.
Extracts (main component: ellagic acid) from the plant Pteleopsis hylodendron act against …
- Klebsiella pneumoniae
- Bacillus cereus S. aureus
- L. monocytogenes
- E. coli
- E. coli
- S. typhi
Ellagitannins present in pomegranate peel effectively inhibit …
- S. aureus
- L. monocytogenes
- E. coli
Ellagic acid extract from pomegranate inhibits the formation of biofilms by the bacteria …
- S. aureus (MRSA)
- E. coli
Punicalaginic, punicalinic, gallaginic and ellagic acid show antimycotic properties against …
- Candida albicans
- C. neoformans
- Aspergillus fumigatus
In addition to inhibiting biofilm formation, pomegranate extracts interfere with pre-formed biofilms and inhibit the formation of germ tubes in Candida albicans.
Glucoinsolates (mustard oil glycosides)
These fat-soluble substances are responsible for the pungent and bitter taste in e.g. radish, horseradish, mustard, cress and cabbage. They have a relatively high bioavailability, which is why I have not further investigated this group of substances. But they will also have an influence on the intestinal flora.
Isoflavones are mainly found in strong legumes. They are famous as an ingredient of the soya bean, but other beans, lentils and peas can also provide isoflavones.
Most isoflavones (daidzein, genistein and formononetin) cannot be absorbed in the small intestine or are already processed in the small intestine by small intestinal bacteria such as Lactobacillus or Bifidos or end up in the large intestine as food for the bacteria there. Metabolites are naturally absorbed in the small intestine in greater quantities than in the large intestine, where they are involved in the formation of a good intestinal flora.
Daidzein, one of the more active isoflavones, is metabolised in two different ways depending on the intestinal microbiota.
…who are producers of equol.
- Streptococcus intermedius B. ovatus
- Ruminococcus productus
- Lactobacillus mucosae EPI2
- E. faecium EPI1
- Veillonella spp
- Eggerthella sp. Julong732Finegoldia magna EPI3
O-demethylangolensin (O-DMA) via 2′-dehydro-O-demethylangolensin from …
- Clostridium spp.
(S)-Equol has a high antioxidant activity. The sugar substitute xylitol can influence the metabolism of daidzein by altering the metabolic activity of the intestinal microbiota. The proportion of bacteroides was increased by the combined consumption of xylitol and daidzein/strong. (source)
The isoflavone genistein is reduced by intestinal microbes to dihydrogenistein, which in turn is further metabolised to 6′-hydroxy-O-desmethylangolensin.
Other isoflavones are also converted by gut flora bacteria.
In addition, isoflavones appear to inhibit S. aureus (MRSA = Multi Resistant Streptococcus Aureus).
Resveratrol (one stilbene)
Resveratrol is found in Strong red wine, grapes, peanuts, pistachios, berries and Japanese Itadori tea (Reynoutria japonica).
Chinese scientists confirm (study) that resveratrol changes the intestinal flora in such a way that more Lactobacillus, Bifidobacteria and Bacteroidetes grow.
In this study an attempt was made to find out which bacteria are responsible for which metabolites of resveratrol. Besides the already known dihydroresveratrol, 3,4′-dihydroxy- trans- stilbene and 3,4′-dihydroxybibenzyl (lunularin) were identified. These two bacterially produced resveratrol metabolites were previously unknown. Unfortunately, the intestinal bacteria responsible for this could not be found. However, at least the two strains Slackia equolifaciens and Adlercreutzia equolifaciens could be identified as dihydroresveratrol producers.
In this study, the ratio of Strong> Bacteroidetes to Firmicutes was increased by the intake of Resveratrol. Furthermore, there was a significant inhibition of Enterococcus faecalis and an increased growth rate of Lactobacillus and Bifidobacterium.
It is a phytoalexin and is only used by plants to defend themselves against infections in certain areas. In other words, phytoalexin such as resveratrol are not a basic component of the plant, but are used, for example, in areas that require particularly high levels of UV protection or defence against fungi.
The fat-soluble carotionoids have a relatively high bioavailability, so I have not examined them further. But carotenoids will also have a certain influence on the intestinal flora.
Like soap (hence the name) saponins have a fat-soluble and a water-soluble part. Can form stable foam when shaken in water. They are partly harmful to insects and cold-blooded animals, but they are also beneficial to mammals, because saponins have the following effects: they are antibiotic, antifungal, immunostimulatory, are generally regarded as antinutrients. E.g.: from legumes … bitter taste!
Pulses are only digestible when they are cooked. I have not found any studies on a positive influence on the intestinal flora.
I will soon summarize in an article how you can do something good for your intestinal flora with food supplements, teas etc. and how an intestinal flora friendly nutrition looks like. The blog article is already in the making!
Ah yes, in this context I would like to mention the term nutraceuticals. Nutraceutical is a combination of the words “nutrition” (nutrition) and “pharmaceutical” (drugs). In the end, they are products with medical effectiveness, according to the motto “Let your food be your medicine!” (I could google now for safety’s sake, but that’s roughly how Hippocrates’ saying went, right?)
Extracts from superfoods, which often contain a high proportion of polyphenols, are the ingredients of these nutraceuticals, such as the Vitalkomplex from Dr. Wolz.
- Secondary plant compounds | Polyphenols for the intestinal flora & Nutraceuticals
- Intermittent fasting & autophagy
- Feed the intestinal flora: Food & prebiotics | polyphenols & supplements
If you want to get to know all polyphenols now, you can spend some days in the Polyphenol-Explorer pleasure. Have fun, this is too much technical language even for me! 🙂
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