Re: B12 Supplements and RDA

John Sankey said:

The problem with elderly absorption of B12 is for natural sources
of B12 where it is bound to proteins. Everything I have read
shows that pure B12 in pills IS absorbed by all.

Please provide examples of this information.

You must not have read clinical trial PMID: 12755792
Only 87% normalized their serum B12 levels after
250 to 1000ug/day for a month (only 54% had
corrected their anemia).

Quoted message said:

So, taking a
pill once a weekshould be entirely adequate.

This seems to be a separate claim for bioavailability beyond
the 'absorbed by all' one above. Please provide examples
of this information, also, and what dose is it which will do
for a week. (are you talking about a really massive dose?)

Quoted message said:

I'm a senior and
have my blood B12 level checked every few years - a can of clams
once a month is keeping my level right up to par. If I develop
any problems, I expect to take 3x the RDA in pills and have no
further problems.

So pernicious anemia and all other problems can be treated by
just 3x RDA! Please provide this data.

The authors of PMID: 12743340 who gave 1000ug/day oral to B12
deficiency patients for 18 months will look silly.

clinical trial PMID: 15911731
Oral cyanocobalamin supplementation in older people with vitamin
B12 deficiency: a dose-finding trial
"CONCLUSION: The lowest dose of oral cyanocobalamin required
to normalize mild vitamin B(12) deficiency is more than 200 times
greater than the recommended dietary allowance, which is
approximately 3 mug daily."
(study done in the Netherlands)