Re: Methylcobalamin vs cyanocobalamin excretion

[Guest guest]

To , Carol and Kim...

Thank you all for your replies.

Kim...if MB12 injections are retained I am no doubt way over the top. This is

not at all good, from what I understand. I was told it was water soluble and one

excreted the excess. I think I shall ask to have my levels retested before

proceeding.

Thanks again...

Dinah

>

> Dinah

>

> I've done a bit of research, and wanted to report on what I've found so far.

It is an interesting subject, so I'll continue exploring.

>

> http://en.wikipedia.org/wiki/Vitamin_B12 has a good discussion on

methylcobalamin and cyanocobalamin. The body takes cyanocobalamin and converts

it to methylcobalamin and adenosylcobalamin, leaving behind the cyanide

(miniscule amount).

>

> An additional wikipedia article on methylcobalamin says that one study

suggests that methylcobalamin is better retained in the body. Which implies

that more cyanocabalamin is excreted than absorbed, perhaps.

>

> The wikipedia article I cited above goes on to say that for those patients who

lack the intrinsic factor to absorb B12, there is 80-100% excretion of oral

doses in the feces vs 30-60% excretion in feces in individuals who have adequate

intrinsic factor. I didn't find a discussion of the excretion factor from serum

injections, or which form of B12 serum is better absorbed. Or if there is

difference in urinary or feces excretion levels. So I'll keep looking.

>

> Here's a quote from the wikipedia article discussing how much B12 is excreted

per day:

> *******************

> " The total amount of vitamin B12 stored in body is about 2,000-5,000 mcg in

adults. Around 50% of this is stored in the liver. Approximately 0.1% of this is

lost per day by secretions into the gut as not all these secretions are

reabsorbed. Bile is the main form of B12 excretion, however, most of the B12

that is secreted in the bile is recycled via enterohepatic circulation. Due to

the extremely efficient enterohepatic circulation of B12, the liver can store

several years' worth of vitamin B12; therefore, nutritional deficiency of this

vitamin is rare. How fast B12 levels change depends on the balance between how

much B12 is obtained from the diet, how much is secreted and how much is

absorbed. B12 deficiency may arise in a year if initial stores are low and

genetic factors unfavourable or may not appear for decades. "

> ***********************

>

> In another article abstract on PubMed, a study of urinary excretion in 30

patients given cyanocobalamin injections indicated that there was a wide

variation in the amounts excreted and a wide variation in the capacity of

tissues to retain injected cyanocobalamin.

>

> There is a lot more research to come. This is enough for now, though [grin].

>

> Kim M.

>

>

> I cannot determine if the Methylcobalamin is stored as is the cyanocobalamin

or is it excreted. Do either of you know?

>

> Thank you...

> Dinah

>

[Guest guest]

Good idea to have your B12 levels checked regularly; I do. Currently I get tested twice a year by my primary care physician, and once a year by my neurologist. That frequency is based on my original B12 deficiency diagnosis, along with the levels I maintain due to the regular injections. My doctors weigh the test results with the knowledge that I give myself a 1cc injection once a month. At least once a year I hold off on the monthly injection so that I can get my blood drawn when it has been 4+ weeks since my last injection so the doctors see how low the levels are.

Initially I went through 4 months of taking high levels of oral B12 to see if my levels improved; they did not. It was difficult as I have interstitial cystitis, and B vitamins really aggravate my bladder lining. It was obvious that my body wasn't absorbing much B12 and excreting most of it. My blood levels certainly didn't move up after 4 months; actually they'd dropped a few points.

We all excrete a certain percentage of B12 daily. If you are missing the intrinsic factor to utilize B12 found in foods, then you will need regular injections to maintain a minimal amount within your body. Or if you aren't eating the foods that provide your body with B12, you'll need the supplementation, either through injection or oral doses.

All depends on your test results, and what other issues you are dealing with. And your symptoms. I point to my difficulties with balance and coordination when my B12 levels drop below 450, even though the minimal "normal" limit is around 250 according to the labs my doctors use.

I'll keep looking into this issue, and report.

Kim M.

>>>>>>>>>>

Kim...if MB12 injections are retained I am no doubt way over the top. This is not at all good, from what I understand. I was told it was water soluble and one excreted the excess. I think I shall ask to have my levels retested before proceeding. Thanks again...Dinah