Nutrition Beneficial gut bacteria that produce vitamins B2, B9, B12 and K2


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Our intestines are home to between 500 to 1000 of bacterial species. The delicate balance between these play an important role in our well-being, digestion, immunity, mood, but also in the production of certain vitamins. After writing about how to interpret your microbiome, I got curious as to which particular species produced vitamins.

Vitamin K[SUB]2[/SUB] (menaquinones), a highly beneficial vitamin that is known to prevent and even reverse arteriosclerosis, is notoriously difficult to obtain from food sources, except in fermented products like cheese and Japanese nattō (pungent fermented soybeans). Not all cheese are rich in K[SUB]2[/SUB], and in fact only a few species types like Gouda or Brie have the rare vitamin. In the case of both these cheeses and nattō, it is the Bacillus subtilis bacteria that produces the K[SUB]2[/SUB], a species that is also commensal to the human gut.

Digging a bit deeper, I found a study by Cooke et al. (2009) that identified as Enterobacter agglomerans, Serratia marcescens and Enterococcus faecium as the main producers of Vitamin K[SUB]2[/SUB]. However these are pathogenic bacteria so useless as probiotics.

Another common K[SUB]2[/SUB] producer is Escherichia coli, which has a bad reputation for being a cause of food poisoning, but is usually harmless in small quantities.

Vitamin B[SUB]12[/SUB] (cobalamin) in food is almost exclusively found in animal products, and especially in shellfish, crustaceans and beef. But vegetarians are not necessarily deficient as B[SUB]12[/SUB] and other B-vitamins can be produced bytypical probiotics like Bifidobacterium, Lactobacillus. The most famous B[SUB]12[/SUB] producer is Lactobacillus reuteri, which is found in many probiotics brands, but is naturally found in human intestines. Another indirect bacterial source is Propionibacterium. It is normally found on the skin rather than in the gut, and one species is known for causing acne. But the B[SUB]12[/SUB]-producing strain Propionibacterium freudenreichii subsp. shermanii is used in cheesemaking to create CO[SUB]2[/SUB] bubbles that become the round holes in cheese like Emmental cheese, and to some extent, Jarlsberg cheese, Leerdammer and Maasdam cheese.

According to Wikipedia, species from the following genera are known to synthesize B[SUB]12[/SUB]: Acetobacterium, Aerobacter, Agrobacterium, Alcaligenes, Azotobacter, Bacillus, Clostridium, Corynebacterium, Flavobacterium, Lactobacillus, Micromonospora, Mycobacterium, Nocardia, Propionibacterium, Protaminobacter, Proteus, Pseudomonas, Rhizobium, Salmonella, Serratia, Streptomyces, Streptococcus and Xanthomonas.

Most of these are proteobacteria that are potentially pathogenic or anyway not commensal to the human gut. Other pathogens include Mycobacterium (some species are the causative agents of tuberculosis and leprosy), and Corynebacterium (common on the skin, but can cause diphtheria in the gut). The only commensal gut bacteria would be Acetobacterium, Bacillus, Clostridium, Flavobacterium and Lactobacillus, although Bacillus and Clostridium both have a few pathogenic species too.

Vitamin B[SUB]9[/SUB] (folate or folic acid) is usually found in fresh (uncooked, unfrozen) leafy vegetables. Like B[SUB]12[/SUB], folate can be produced by lactic acid bacteria like Lactobacillus and Bifidobacterium. Rossi et al. (2011) compared the different strains and found that 'within the genus Lactobacillus, the strains belonging to the species Lactobacillus plantarum are expected to produce folate in the presence of preformed pABA, while the other species cannot be regarded as folate producers' and that several folate‑producing Bifidobacterium strains were found to produce folate, 'but the release of high amounts of vitamin does not seem to be widespread within the genus'.

L. Plantarum is found in sauerkraut, fermented sausages, pickles, brined olives, Korean kimchi, sourdough, stockfish, as well as in some cheeses. That may explain why people who never eat fresh leafy vegetables are not necessarily deficient in folate.

LeBlanc et al. (2011) reported that other strains of bacteria have the ability to produce folates in addition to L. Plantarum. These include:

- Bifidobacterium animalis (used in Danone's Bifidus yoghurts like Activia)
- Bifidobacterium longum (used a a probiotics)
- Lactobacillus acidophilus (most common probiotics)
- Lactococcus lactis (used to make buttermilk and many cheeses including Brie, Camembert, Cheddar, Colby, Gruyère, Parmesan, and Roquefort)
- Leuconostoc lactis (used to make kefir and sauerkraut)
- Streptococcus thermophilus (used to make yoghurt)

Vitamin B[SUB]2[/SUB] (riboflavin), which is mostly found in meat, eggs, dairy products and legumes, is synthesised especially by bacteria that belong to the Lactobacillus, Streptococcus and Enterococcus genera, but also in Bacillus subtilis (Perkins and Pero 2002) and Escherichia coli (Bacher et al. 1996).

One of the most efficient at producing riboflavin is Lactobacillus fermentum, which is found in sourdough and in many probiotics. It is also noted for its ability to reduce cholesterol levels and to act as an antimicrobial and antioxidative. Other good producers are the above-mentioned B[SUB]12[/SUB] synthesisers P. freudenreichii and L. reuteri.
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I find this very interesting. I had been having Irritable bowel problems for 2 years. I was given the impression by my GP that its something I just have to live with since I went Lactose free, Gluten free even stopped having sugar as I thought these might have been the culprits.

Of course they were not as I still had the condition. Finally I decided to visit an Alergy Dr (having little hope that anything would change). He told me to take 1 probiotic a day and I can confidentially say after 6 weeks taking them that it has given my my life back.

I also read once that while we think that the appendix is useless, it might actually serve as a beneficial bacteria reserve. So there might be some kind of co relation. I had mine removed 22 years ago. However I am not sure if this is proven or not or its relevant.
I'm absolutely flabbergasted that anyone would think yo-yos are edible.

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