Vitamin b12

B12 is an essential vitamin. I thought getting enough b12 was only an issue for vegans, but that's not true.

processing b12

 * requires Magnesium

Who gets a B12 deficiency

 * older people. Your stomach gets less acidic over time.
 * Vegetarians (I have seen a range of statistics about b12 deficiency in India where vegetarianism is totally normal, the highest number I saw was 80% of adults are deficient, I don't remember the lowest number I saw)
 * vegans - vegans and vegetarians don't get enough b12 from their diet. you get more efficient at extracting b12 the less you have access to, but you have to have access to something to extract anything.
 * people with gut issues
 * low stomach acid
 * hypothyroid
 * etc.

speculation

 * probably people with Ehlers danlos syndrome because EDS means you're not processing the vitamins and minerals you need to make collagen, and one of those is Magnesium. You also need magnesium to process B12

Supplements

 * cyanocobalamin, synthetic. Some people say it's fine, others say it isn't.  Lots of people say "anything but this"
 * methylcobalamin - whatever article I read most recently says this kind is the best, and that's probably the popular thinking because the only two options at the local natural foods store are methyl- and cyano-
 * hydroxocobalamin is the version that's on the WHO model list of essential medications, not sure why.


 * deoxyadenosylcobalamin is also apparently a type of b12 but nobody ever mentions it, no idea if it's a supplement or anything else about it

Natural sources
Animal liver is by far the way highest source of b12. All the other top sources are meat. Then there's dairy. And you might be able to get some from ferments, depends who you ask and whether your particular ferment has any, not reliable. Also nutritional yeast, but wtf even IS nutritional yeast?!

Maintenance
Something I read somewhere seemed authoritative, I forget what all I learned, but it was a good one. My takeaway was that for vegetarians, a 1000mcg or whatever it's measured in, the one that's like a 41,667% DV or RDA or something dose 1-2 times per week is about right. Or a smaller dose every day, but I forget the dosage for that.

Loading doses
Oh also people who are deficient need to take "loading doses" to get back up to normal. An example loading dose would be 1000mcg (or whatever it's measured in) daily. Seems like the main way to know when you're done with loading doses is when your symptoms stop improving. But not everybody reacts positively to getting their b12 levels up!

According to https://www.godfire.net/vitamin_b12_folic_acid.htm " The authors conclude that the lowest dose needed to normalize vitamin B12 deficiency is more than 200 times higher than the recommended dietary allowance." Here is their citation: ''Eussen, S. J. P. M., et al. Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency. Archives of Internal Medicine, Vol. 165, May 2005, pp.1167-1172''

Pernicious anemia
People with pernicious anemia will always need high doses.

Recovering from deficiency

 * Some marker or other goes up within a week
 * Blood cells recover within like 8 weeks
 * Nerve stuff in like 3 months? Not sure about this.
 * "So having enough B12 not only removes the depression chemical [homocysteine], but actually converts it to the happiness chemical [SAMe]."

Loading doses are for like 6-12 weeks. But neurological symptoms can take longer to clear up. Something I read said it could take up to a year. Elsewhere I read that it could take 2+ years. But most people (according to the author who said it could take up to one year) should see neurological improvement within 3-6 months.

Seems like there is a controversy over whether it matters to get injections or not. Up your nose is apparently also an option.

Staying in your system
B12 is water soluble, but apparently it can hang out in your liver for years! It ... like, attaches to protein or something? '' If your blood levels are high and it's not due to high-dose supplements, your body may have difficulty using B12, which can cause a buildup in the blood. In this case, you may actually have a B12 deficiency, even though you have high blood levels. ''

Pineal gland
B12 has something to do with your sleep system

thyroid
People keep talking about b12 and thyroid

gut
You need a gut in good working order to get your b12

Misc

 * B12 is light-sensitive, keep it in a dark container.
 * I read somewhere that there are 4 different ways to test for a b12 deficiency. But it's hard to test for.  I forget the details.

I started reading this but didn't get around to finishing.

 * This was super-interesting https://www.godfire.net/vitamin_b12_folic_acid.htm
 * This had some some stuff that was at one end of the range of opinions about b12 https://www.ncbi.nlm.nih.gov/labs/pmc/articles/PMC2532799/
 * https://pubmed.ncbi.nlm.nih.gov/8534965/
 * https://kresserinstitute.com/postprandial-somnolence-why-a-food-coma-happens/
 * https://search.marginalia.nu/search?query=vitamin+b12&profile=yolo&js=default
 * B12 book (free online) by a doctor who seems to be the center of the b12 movement in the UK (just guessing here) http://www.b12d.org/book

Questions

 * Why is it pink in supplements? I thought it was cyan? Maybe that's only the synthetic one?
 * Why is it light-sensitive?
 * Understanding the cyanobalamin controversy
 * Understanding the injection/oral controversy
 * Why is hydroxocobalamin the WHO-preferred variety of b12?
 * What is methylation and what does it have to do with b12?
 * They say there's no upper limit but there's an upper limit to everything. What's b12's upper limit and what are the circumstances for it?