Supplementing Vitamin K2: Why You Must Take MK-7 (not MK-4)

[Mito]

MK7 didn’t stop aspirin bleeding. On,y mk4.

There is reason to think MK-7 would be better at supporting blood clotting.

“MK-7 is not just three times better than K1 at reaching bone; it’s also five times better at supporting blood clotting (Schurgers, 2007). This may be because the greater fat-solubility of MK-7 makes it hold on more tightly to the membranes within liver cells, making it stay active in the liver much longer rather than being released and broken down (Shearer, 2008). The liver is where clotting proteins are made, so more extended activity in the liver would explain why MK-7 could better support blood clotting. If this is correct, other long-chain MKs such as MK-8 and MK-9 probably share this property as well.”
https://chrismasterjohnphd.com/blog/2016/12/09/the-ultimate-vitamin-k2-resource/

 

[tankasnowgod]

Sorry for the sensationalist headline. Just thought I’d post the official title. More for discussion than anything else.

Btw, since switching to mk7, I’ve grown to like it more. Regarding benefits of mk4, I never experienced noticeable effects but that doesn’t mean they were occurring physiologically.

I noticed Kiran starts off by claiming that the body can just make whatever MK-4 it needs from MK-7. The same argument is made about Beta Carotene and Vitamin A, that the body can just make whatever Vitamin A is needed from Beta Carotene. I think both ideas are flawed. Then he goes on to cite the Rotterdam study as proof of his claim that MK-7 is better than MK-4, but that study was simply observational in nature, and no such conclusion could be drawn. So, I'm very skeptical of his overall claim. If he has a list of studies to review for MK-7, I would be curious to see how it compares to the studies Haidut listed in favor of MK-4 in his initial post on Kuinone.

 

[BigChad]

I’ve never found a clean source of K1. I have found one for K2 MK4.

What do you mean by clean source

 

[lampofred]

I’ve never found a clean source of K1. I have found one for K2 MK4.

You don't think LifeExtension's Super K is a good source?

 

[BigChad]

You don't think LifeExtension's Super K is a good source?

Life extensions is soy sourced mk7, geraniol mk4, not sure of k1 but iirc the product has lots of fillers. They did say theyll be changing mk7 to chickpea source

 

[Tarmander]

I have heard some rough stories from Mk7, people having weird issues.

 

[Amazoniac]

A fairer comparison between vitamers requires the same route and similar doses. The tails affect distribution, but the effects being concerned here are due to the core/ring, therefore it's worth adjusting for it. Regardless if the weight is concentrated in one part of the molecule more than other, mk-7 is heavier than mk-4, it's 150% of mk-4, therefore you either multiply mk-4 or divide mk-7 amounts by 1.5 to make sure you're dealing with similar number of.. cores. Comparing for example 200 mcg of mk-4 to 300 mcg of mk-7.

Otherwise you'll find people injecting themselves with 135 mg of mk-4 and reporting without being specific that it's better than mk-7.

By the way, some experiments such as the following used graded doses but with a wide gap between them. It's usually not a comprehensive approach.

- Menatetrenone - Wikipedia

"Administered daily doses of 15, 45, 90, and 135 mg revealed that 45 mg was the minimum effective dose for improving bone mass parameters evaluated by microdensitometry and/or single photon absorptiometry in postmenopausal women with osteoporosis." The study referenced is available in Japanese[9][10]. Briefly, 15mg, 45mg, 90mg, 135mg and a 5th group with 0.75ug of alfacalcidol were evaluated. The counts of people who had a 'moderate improvement' or greater were recorded. The 15mg group had 26.9%, the 45mg 46%, the 90mg 49% and the 135mg had 50.9% of subjects with a moderate improvement or greater.. It was therefore determined that doses above 45mg as much as 135mg have the same effectiveness as 45mg and that 45mg was much better than 15mg. Therefore 45mg was determined to be the ideal dose.

Spoiler

 

[Roselynne]

I'm only able to take Mk4 2-3 drops a day otherwise I experience nose bleeding. This amount seems effective.
Id like to take Mk7 for my teeth however I experience water retention and swelling in my lower extermities. I tried different doses of Mk7 however I haven't had any luck. Any idea why I would retain water after taking one dose?

 

[baccheion]

I'm only able to take Mk4 2-3 drops a day otherwise I experience nose bleeding. This amount seems effective.
Id like to take Mk7 for my teeth however I experience water retention and swelling in my lower extermities. I tried different doses of Mk7 however I haven't had any luck. Any idea why I would retain water after taking one dose?

Nose bleeding? Are you getting enough calcium and vitamin C?

Swelling can be due to thrombosis, lower potassium, insufficient protein, low magnesium (can lead to lower potassium)..

 

[Roselynne]

Nose bleeding? Are you getting enough calcium and vitamin C?

Swelling can be due to thrombosis, lower potassium, insufficient protein, low magnesium (can lead to lower potassium)..

Nose bleeding? Are you getting enough calcium and vitamin C?

Swelling can be due to thrombosis, lower potassium, insufficient protein, low magnesium (can lead to lower potassium)..

I'm working on increasing my calcium. It's been difficult to find a good source of low fat milk. I tried whole milk however I get sinus congestion from milk and cheese. I only have so much time to squeeze oranges for vitamin C.
Are there supplements I can take in the mean time for C and calcium? I know I need more of both.

I tried MK7 before when I was eating low carb and fasting most of the day. It's possible I was low in potassium, protein and magnesium. Right now I'm taking potassium and magnesium in supplements. I've been able to get my protein intake up to about 100grams.

 

[baccheion]

I'm working on increasing my calcium. It's been difficult to find a good source of low fat milk. I tried whole milk however I get sinus congestion from milk and cheese. I only have so much time to squeeze oranges for vitamin C.
Are there supplements I can take in the mean time for C and calcium? I know I need more of both.

I tried MK7 before when I was eating low carb and fasting most of the day. It's possible I was low in potassium, protein and magnesium. Right now I'm taking potassium and magnesium in supplements. I've been able to get my protein intake up to about 100grams.

There's talk on this forum about using egg shells. Unsure if a good idea. There's bound to be some good calcium supplement. I used calcium bisglycinate in the past an liked it. There's also calcium AEP and calcium orotate.

Doctor's Best sells Quali-C. There's also the whole food version made from acerola cherries (eg, in Naturelo's multivitamin or one daily).

 

[Roselynne]

There's talk on this forum about using egg shells. Unsure if a good idea. There's bound to be some good calcium supplement. I used calcium bisglycinate in the past an liked it. There's also calcium AEP and calcium orotate.

Doctor's Best sells Quali-C. There's also the whole food version made from acerola cherries (eg, in Naturelo's multivitamin or one daily).

Thank you. I have been lurking here awhile. I just started looking in to the vitamins and minerals. I will check out the sources you suggested as well.
I've used egg shell before so I may try that.

 

[Amazoniac]

I have heard some rough stories from Mk7, people having weird issues.

What are these? This form has always been a hit-or-miss for me, it's challenging to predict how it's going to be next response. I did experience weird issues at times, such as a sustained drop in temperature for the period that it takes for it do leave the body with only a small dose. I think it's a toxin.

 

[Tarmander]

What are these? This form has always been a hit-or-miss for me, it's challenging to predict how it's going to be next response. I did experience weird issues at times, such as a sustained drop in temperature for the period that it takes for it do leave the body with only a small dose. I think it's a toxin.

yes I have heard similar things...dizziness and the like. I would avoid

 

[ecstatichamster]

K2 MK4 is very reliable, physiological and vastly preferred over MK7.

 

[Amazoniac]

K2 MK4 is very reliable, physiological and vastly preferred over MK7.

Indeed. But since mk-7 occurs in foods, many people consume it without issues and the reaction is not always a miss, there has to be something else involved. The piece of cheese that you're holding makes me wonder if it's worth trying other forms, it contains more long-chain menaquinones than mk-4:
- Vitamin K1 Vs. K2 And How Much To Take With Aspirin?


- From Protein Folding to Blood Coagulation: Menaquinone as a Metabolic Link between Bacteria and Mammals (posted elsewhere, but we don't care)

"The metabolic flexibility of quinones means that their use is not limited simply to the respiratory chains of microbes or the photosynthetic centers of plants. Many higher‐order organisms not only incorporated quinones into their respiratory chains, but have utilized these highly effective molecular wires in many different redox‐dependent reactions. While the quinones are ancient, they remain very important to life on this planet."

"The canonical pathway for menaquinone biosynthesis in bacteria is well‐established and has been reviewed in great detail elsewhere [7]. Of particular interest to this review, however, is the prenylation reaction mediated by MenA in which the lipophilic tail is attached to 1,4‐dihydroxy‐2‐naphthoic acid (Figure 2). In essence, this is the critical step that links the redox‐active quinone to the membrane. The lipophilic substrate of MenA is made up of repeating isoprenal subunits, the exact number of which is determined by the octaprenyl pyrophosphate (OPP) synthase encoded by the particular microbe. The ultimate chain length of these products is determined by a molecular ruler mechanism wherein bulky amino acid residues at the bottom of each of OPP's active sites block chain elongation [8], and it is this step that controls the identity of the primary MK produced by an organism. There is some evidence to suggest, however, that growth temperature also plays a role in the length and degree of saturation of the aliphatic side chain [9]. Phylloquinone biosynthesis in cyanobacteria is predicted to proceed via a pathway very similar to that of MK biosynthesis. However, the cyanobacterial MenA incorporates a mostly saturated phytyl tail at position C‐3 rather than the partially unsaturated isoprenyl side chain associated with MK [10]. Recently, an alternative pathway for menaquinone biosynthesis has been described in several Achaea and Gram‐negative bacteria, including Helicobacter pylori, Chlamydia species, and spirochetes [11]. While both pathways start with chorismate, the formation of the quinone proceeds via completely different reactions. The diversity of pathways for biosynthesis of MKs serves to underscore the importance of its role in metabolism."

"While the reactions requiring vitamin K in human metabolism are becoming clearer, the source of the vitamin K is still not completely understood. The presence of large numbers of bacteria in the human colon capable of synthesizing K2 would perhaps suggest that absorption of this bacterial byproduct might fulfill the human requirement. In fact, MK‐6 is made by Eubacterium lentum, MK‐7 by Veillonella, MK‐8 by Enterobacteria, and MK‐10 and MK‐11 are made by Bacteroides [19, 20]. The bacterial contribution to vitamin K pools in humans is supported by studies done with gnotobiotic rats fed vitamin K‐free diets. The rapidly developing hemorrhagic conditions in these rats could be reversed by supplying bacteria from conventionally raised rats, suggesting that absorption from the bowel provided sufficient quantities of K2 [21]. Concordant with this is the observation that taking broad‐spectrum antibiotics can reduce vitamin K production by more than 70% [22]. However, K2 is embedded within the bacterial inner membrane, and as such would appear to be inaccessible to passive absorption. MKs have been shown to be secreted by some organisms [23], and it is also possible that water‐soluble precursors of MK biosynthesis might be more readily available [7]. However, this scenario is further complicated by the fact that there is very little evidence that the large intestine is capable of absorption of MKs. Uptake has been shown to be poor in rats [24] and infants [25]. Even the finding that antibiotic treatment lowered vitamin K production does not conclusively identify bacteria as a major source of human vitamin K2 pools, as some antibiotics have been shown to inhibit the human enzymes necessary for recycling vitamin K2 [26]. The role of the microbiome in the production of K2 is therefore questionable and would suggest that perhaps vitamin K stores in humans might be the result of dietary intake."

"Measurements of the concentrations of vitamins K in various tissues [show] that K1 levels are low in the brain, kidneys, and lungs but high in the liver, heart, and pancreas; K2 (in the form of MK‐4) was found to be in high concentration in the brain, kidneys, and pancreas but in low concentration in the liver, heart, and lungs. As for longer chain K2s, MK6‐11 were found in the liver and trace amounts of MK6‐9 were found in the heart and pancreas [30]. MK10 and MK11 may be major contributors to the hepatic pool of K2 [26], and the presence of these long‐chain MKs again raise the possibility that the commensal population of colonic bacteria may somehow contribute to overall vitamin K levels in the host, as analysis of tissue samples has only shown the ability to synthesize MK‐4 from K1. However, the presence of potential homologs for other prenyl diphosphate synthases in the genome further suggests that humans may be capable of producing longer chain MKs as well."​

- The Ultimate Vitamin K2 Resource | Chris Mitorjohn

"Some bacteria, such as those used to make Jarlsberg cheese, produce partially saturated menaquinones wherein some of the repeating subunits have double bonds and others don’t. For example, Jarlsberg is very rich in tetrahydromenaquinone-9, which is similar in structure to MK-9 except the second and third units of the tail are saturated. As Shearer (2014) pointed out, even phylloquinone has a double bond in the first unit of its tail and could be seen as a partially saturated form of MK-4. Thus, rather than forming two categories of K vitamins, it makes more sense to say that vitamin K comes in a wide diversity of forms that are distinguished by the length and saturation of their tails."​

- Synthesis and Characterization of Partially and Fully Saturated Menaquinone Derivatives

"MK analogues that contain partially and fully saturated isoprenyl side chains of various lengths are found in eubacteria and archaea. These characteristics are evolutionarily conserved and have long been used in taxonomic classification efforts and phenotypic organization of bacteria.[13−15] MK analogues with one or more saturated isoprene units are found in some members of Gram-positive and Gram-negative bacteria, and the systematic preparation and characterization of a few selected truncated partially and fully saturated MK derivatives are described in this manuscript.[14−17] In contrast to partial saturation, the fully saturated MK-7(14H) has been observed in archaea, which are single-celled microbes comprising part of the human microbiota.[18,19] It is thought that the full saturation of the isoprenyl side chain observed in archaea makes the cellular membrane more tolerant to extreme environments (e.g., high temperature, high salinity, and low/high pH).[18] Thus, many MK homologues that contain various degrees of saturation in their isoprenyl side chains have been isolated, but there is a limited understanding of the function of partially saturated derivatives.[16,20] Menaquinone-9(II-H2) [abbreviated as MK-9(II-H2), Figure 1A], which is saturated at the second isoprene, has been observed in a number of bacteria including Mycobacterium phlei and pathogenic Mycobacterium tuberculosis.[14,16,17,21,22] The biological significance of the partial saturation of MK-9 has remained unclear even 50 years after its first description.[20] Remarkably, the synthesis of MK-9(II-H2) was recently shown to be essential for M. tuberculosis survival in host macrophages (white blood cells of the immune system); thus, MK-9(II-H2) represents a potential novel virulence factor involved in tuberculosis (TB) disease progression.[23]"

"Part of our ongoing studies includes why partial saturation of MK-9 increases the virulence of pathogens such as M. tuberculosis.[23] Therefore, we need access to MK analogues containing partially and fully saturated isoprenyl side chains. However, in general, they are neither commercially available nor sold as a pure geometric isomer as in the case of vitamin K1. The potential for the formation of cis and trans MK isomers and the separation and characterization of these geometric isomers are sometimes overlooked in the literature, but it is critical for their applications in biological systems. The use of cis/trans MK mixtures in biological systems would lead to inaccurate biological activities. Recently, the separation and nuclear magnetic resonance (NMR) analysis of cis/trans mixtures of the dietary supplement menaquinone-7 (MK-7) was reported, demonstrating the importance in understanding the different chemical, biochemical, conformational, and physical properties exhibited between cis and trans MK isomers.[24,25] Truncated MK analogues (i.e., one to three isoprene units) have the advantage of being less hydrophobic, which can improve their biological activity compared to longer isoprenyl MK analogues (e.g., MK-7 and MK-9) and can be prepared using a similar methodology described in this manuscript and reports elsewhere.[26,27]"

"In this manuscript, we have synthesized and characterized four partially and fully saturated truncated isoprenyl MK derivatives (Figure 1B−E) as well as separated and characterized the geometric isomers formed in the reactions. We have adopted the simple naming system where MK-2 with a saturated double bond at the second isoprene unit is denoted as menaquinone-2(II-H2) and abbreviated as MK-2(II-H2), where II denotes the second isoprene unit and H2 denotes the saturation of one double bond (Figure 1B).[23,28] This naming system follows for higher degrees of saturation such as MK-2(I,II-H4), that is, saturated at isoprenes I and II and MK-3(I,II,III-H6), that is, saturated at isoprenes I, II, and III (Figure 1C,E). Although MK-2(II-H2) and menaquinone-3(IIH2) [abbreviated as MK-3(II-H2)] were known in literature reports mostly in the 1950s[29−34] and MK-2(II-H2) was considered in a computational model study,[35] there are no modern syntheses reported, and these analogues have not been extensively characterized nor have their geometric isomers been resolved and characterized in the literature. Evidence supports the trans MK isomer as the only biologically active isomer.[27] Therefore, the separation and isolation of geometric isomers of MK derivatives is critical when testing these compounds in biological assays."

"An interesting feature of MKs is the possibility of geometric isomer formation (Figure 2A,B). The biologically active trans isomer of vitamin K1 is the natural biological form of vitamin K1.[27]"

Changing dogma regarding the conformation of electron transferring menaquinone (MK)​

"The separation and characterization of an MK analogue’s trans isomer is essential for use of these compounds in biological systems or for understanding biological systems that use MK because evidence shows that the cis isomer is not biologically active. The partially and fully saturated MK analogues synthesized in this manuscript are substrate analogues for enzymes involved in MK/vitamin K metabolism and are essential for understanding the structure−activity relationships of these biological systems.[49] They are also critical for understanding the function, reactivity, and conformation of partially saturated MK analogues as little is currently known. These MK analogues are also of interest from a therapeutic and medicinal standpoint. For instance, MK-4 (vitamin K2) was recently shown to be a potential new therapeutic strategy to treat rheumatoid arthritis; it is a proposed drug for the effective treatment of osteoporosis and has anticancer properties. Nevertheless, the synthesis of partially saturated MK analogues remains a challenge as there is currently not a suitable catalyst to selectively saturate an individual isoprene unit on an MK analogue while leaving the other double bonds unaffected. Importantly, the synthesis and characterization of these partially and fully saturated MK substrate analogues is essential for understanding why they are necessary for various organisms to survive, and most importantly, understanding the reason MK-9(II-H2) (i.e., saturated at the second isoprene unit) is a potential virulence factor for pathogenic M. tuberculosis, which is responsible for the deaths of ∼1.3 million people annually."​

Will is common menaquinones antibiotics?

 

[Grapelander]

I’ve never found a clean source of K1. I have found one for K2 MK4.

Superior Source has additive free products for Vitamin K:

K1

K4

K7

K1, K4, K7 blend

 

[ecstatichamster]

Thanks but these contain excipients @Lewis Acid

 

[Homo Consumericus]

Indeed. But since mk-7 occurs in foods, many people consume it without issues and the reaction is not always a miss, there has to be something else involved. The piece of cheese that you're holding makes me wonder if it's worth trying other forms, it contains more long-chain menaquinones than mk-4:
- Vitamin K1 Vs. K2 And How Much To Take With Aspirin?


- From Protein Folding to Blood Coagulation: Menaquinone as a Metabolic Link between Bacteria and Mammals (posted elsewhere, but we don't care)

"The metabolic flexibility of quinones means that their use is not limited simply to the respiratory chains of microbes or the photosynthetic centers of plants. Many higher‐order organisms not only incorporated quinones into their respiratory chains, but have utilized these highly effective molecular wires in many different redox‐dependent reactions. While the quinones are ancient, they remain very important to life on this planet."

"The canonical pathway for menaquinone biosynthesis in bacteria is well‐established and has been reviewed in great detail elsewhere [7]. Of particular interest to this review, however, is the prenylation reaction mediated by MenA in which the lipophilic tail is attached to 1,4‐dihydroxy‐2‐naphthoic acid (Figure 2). In essence, this is the critical step that links the redox‐active quinone to the membrane. The lipophilic substrate of MenA is made up of repeating isoprenal subunits, the exact number of which is determined by the octaprenyl pyrophosphate (OPP) synthase encoded by the particular microbe. The ultimate chain length of these products is determined by a molecular ruler mechanism wherein bulky amino acid residues at the bottom of each of OPP's active sites block chain elongation [8], and it is this step that controls the identity of the primary MK produced by an organism. There is some evidence to suggest, however, that growth temperature also plays a role in the length and degree of saturation of the aliphatic side chain [9]. Phylloquinone biosynthesis in cyanobacteria is predicted to proceed via a pathway very similar to that of MK biosynthesis. However, the cyanobacterial MenA incorporates a mostly saturated phytyl tail at position C‐3 rather than the partially unsaturated isoprenyl side chain associated with MK [10]. Recently, an alternative pathway for menaquinone biosynthesis has been described in several Achaea and Gram‐negative bacteria, including Helicobacter pylori, Chlamydia species, and spirochetes [11]. While both pathways start with chorismate, the formation of the quinone proceeds via completely different reactions. The diversity of pathways for biosynthesis of MKs serves to underscore the importance of its role in metabolism."

"While the reactions requiring vitamin K in human metabolism are becoming clearer, the source of the vitamin K is still not completely understood. The presence of large numbers of bacteria in the human colon capable of synthesizing K2 would perhaps suggest that absorption of this bacterial byproduct might fulfill the human requirement. In fact, MK‐6 is made by Eubacterium lentum, MK‐7 by Veillonella, MK‐8 by Enterobacteria, and MK‐10 and MK‐11 are made by Bacteroides [19, 20]. The bacterial contribution to vitamin K pools in humans is supported by studies done with gnotobiotic rats fed vitamin K‐free diets. The rapidly developing hemorrhagic conditions in these rats could be reversed by supplying bacteria from conventionally raised rats, suggesting that absorption from the bowel provided sufficient quantities of K2 [21]. Concordant with this is the observation that taking broad‐spectrum antibiotics can reduce vitamin K production by more than 70% [22]. However, K2 is embedded within the bacterial inner membrane, and as such would appear to be inaccessible to passive absorption. MKs have been shown to be secreted by some organisms [23], and it is also possible that water‐soluble precursors of MK biosynthesis might be more readily available [7]. However, this scenario is further complicated by the fact that there is very little evidence that the large intestine is capable of absorption of MKs. Uptake has been shown to be poor in rats [24] and infants [25]. Even the finding that antibiotic treatment lowered vitamin K production does not conclusively identify bacteria as a major source of human vitamin K2 pools, as some antibiotics have been shown to inhibit the human enzymes necessary for recycling vitamin K2 [26]. The role of the microbiome in the production of K2 is therefore questionable and would suggest that perhaps vitamin K stores in humans might be the result of dietary intake."

"Measurements of the concentrations of vitamins K in various tissues [show] that K1 levels are low in the brain, kidneys, and lungs but high in the liver, heart, and pancreas; K2 (in the form of MK‐4) was found to be in high concentration in the brain, kidneys, and pancreas but in low concentration in the liver, heart, and lungs. As for longer chain K2s, MK6‐11 were found in the liver and trace amounts of MK6‐9 were found in the heart and pancreas [30]. MK10 and MK11 may be major contributors to the hepatic pool of K2 [26], and the presence of these long‐chain MKs again raise the possibility that the commensal population of colonic bacteria may somehow contribute to overall vitamin K levels in the host, as analysis of tissue samples has only shown the ability to synthesize MK‐4 from K1. However, the presence of potential homologs for other prenyl diphosphate synthases in the genome further suggests that humans may be capable of producing longer chain MKs as well."​

- The Ultimate Vitamin K2 Resource | Chris Mitorjohn

"Some bacteria, such as those used to make Jarlsberg cheese, produce partially saturated menaquinones wherein some of the repeating subunits have double bonds and others don’t. For example, Jarlsberg is very rich in tetrahydromenaquinone-9, which is similar in structure to MK-9 except the second and third units of the tail are saturated. As Shearer (2014) pointed out, even phylloquinone has a double bond in the first unit of its tail and could be seen as a partially saturated form of MK-4. Thus, rather than forming two categories of K vitamins, it makes more sense to say that vitamin K comes in a wide diversity of forms that are distinguished by the length and saturation of their tails."​

- Synthesis and Characterization of Partially and Fully Saturated Menaquinone Derivatives

"MK analogues that contain partially and fully saturated isoprenyl side chains of various lengths are found in eubacteria and archaea. These characteristics are evolutionarily conserved and have long been used in taxonomic classification efforts and phenotypic organization of bacteria.[13−15] MK analogues with one or more saturated isoprene units are found in some members of Gram-positive and Gram-negative bacteria, and the systematic preparation and characterization of a few selected truncated partially and fully saturated MK derivatives are described in this manuscript.[14−17] In contrast to partial saturation, the fully saturated MK-7(14H) has been observed in archaea, which are single-celled microbes comprising part of the human microbiota.[18,19] It is thought that the full saturation of the isoprenyl side chain observed in archaea makes the cellular membrane more tolerant to extreme environments (e.g., high temperature, high salinity, and low/high pH).[18] Thus, many MK homologues that contain various degrees of saturation in their isoprenyl side chains have been isolated, but there is a limited understanding of the function of partially saturated derivatives.[16,20] Menaquinone-9(II-H2) [abbreviated as MK-9(II-H2), Figure 1A], which is saturated at the second isoprene, has been observed in a number of bacteria including Mycobacterium phlei and pathogenic Mycobacterium tuberculosis.[14,16,17,21,22] The biological significance of the partial saturation of MK-9 has remained unclear even 50 years after its first description.[20] Remarkably, the synthesis of MK-9(II-H2) was recently shown to be essential for M. tuberculosis survival in host macrophages (white blood cells of the immune system); thus, MK-9(II-H2) represents a potential novel virulence factor involved in tuberculosis (TB) disease progression.[23]"

"Part of our ongoing studies includes why partial saturation of MK-9 increases the virulence of pathogens such as M. tuberculosis.[23] Therefore, we need access to MK analogues containing partially and fully saturated isoprenyl side chains. However, in general, they are neither commercially available nor sold as a pure geometric isomer as in the case of vitamin K1. The potential for the formation of cis and trans MK isomers and the separation and characterization of these geometric isomers are sometimes overlooked in the literature, but it is critical for their applications in biological systems. The use of cis/trans MK mixtures in biological systems would lead to inaccurate biological activities. Recently, the separation and nuclear magnetic resonance (NMR) analysis of cis/trans mixtures of the dietary supplement menaquinone-7 (MK-7) was reported, demonstrating the importance in understanding the different chemical, biochemical, conformational, and physical properties exhibited between cis and trans MK isomers.[24,25] Truncated MK analogues (i.e., one to three isoprene units) have the advantage of being less hydrophobic, which can improve their biological activity compared to longer isoprenyl MK analogues (e.g., MK-7 and MK-9) and can be prepared using a similar methodology described in this manuscript and reports elsewhere.[26,27]"

"In this manuscript, we have synthesized and characterized four partially and fully saturated truncated isoprenyl MK derivatives (Figure 1B−E) as well as separated and characterized the geometric isomers formed in the reactions. We have adopted the simple naming system where MK-2 with a saturated double bond at the second isoprene unit is denoted as menaquinone-2(II-H2) and abbreviated as MK-2(II-H2), where II denotes the second isoprene unit and H2 denotes the saturation of one double bond (Figure 1B).[23,28] This naming system follows for higher degrees of saturation such as MK-2(I,II-H4), that is, saturated at isoprenes I and II and MK-3(I,II,III-H6), that is, saturated at isoprenes I, II, and III (Figure 1C,E). Although MK-2(II-H2) and menaquinone-3(IIH2) [abbreviated as MK-3(II-H2)] were known in literature reports mostly in the 1950s[29−34] and MK-2(II-H2) was considered in a computational model study,[35] there are no modern syntheses reported, and these analogues have not been extensively characterized nor have their geometric isomers been resolved and characterized in the literature. Evidence supports the trans MK isomer as the only biologically active isomer.[27] Therefore, the separation and isolation of geometric isomers of MK derivatives is critical when testing these compounds in biological assays."

"An interesting feature of MKs is the possibility of geometric isomer formation (Figure 2A,B). The biologically active trans isomer of vitamin K1 is the natural biological form of vitamin K1.[27]"

Changing dogma regarding the conformation of electron transferring menaquinone (MK)​

"The separation and characterization of an MK analogue’s trans isomer is essential for use of these compounds in biological systems or for understanding biological systems that use MK because evidence shows that the cis isomer is not biologically active. The partially and fully saturated MK analogues synthesized in this manuscript are substrate analogues for enzymes involved in MK/vitamin K metabolism and are essential for understanding the structure−activity relationships of these biological systems.[49] They are also critical for understanding the function, reactivity, and conformation of partially saturated MK analogues as little is currently known. These MK analogues are also of interest from a therapeutic and medicinal standpoint. For instance, MK-4 (vitamin K2) was recently shown to be a potential new therapeutic strategy to treat rheumatoid arthritis; it is a proposed drug for the effective treatment of osteoporosis and has anticancer properties. Nevertheless, the synthesis of partially saturated MK analogues remains a challenge as there is currently not a suitable catalyst to selectively saturate an individual isoprene unit on an MK analogue while leaving the other double bonds unaffected. Importantly, the synthesis and characterization of these partially and fully saturated MK substrate analogues is essential for understanding why they are necessary for various organisms to survive, and most importantly, understanding the reason MK-9(II-H2) (i.e., saturated at the second isoprene unit) is a potential virulence factor for pathogenic M. tuberculosis, which is responsible for the deaths of ∼1.3 million people annually."​

Will is common menaquinones antibiotics?

So there are evil MK analogues. Verily, the plot thickens.

 

[Ras]

Ideally I would like to get k2 from food sources, are there any good ones besides liver?

Masterjohn's resource has a searchable database of Vitamin K2 MK# amounts found in various foods.