[julleri]

I have another quick question:

I do not know if I have pernicious anemia. That is, I do not know if I lack Intrinsic Factor. Do you know how much of B12 gets absorbed if a person does NOT lack Intrinsic Factor? For example, if a person who does not lack Intrinsic Factor took a 1000mcg methylcobalamin sublingual pill (but swallowed the pill and didn't absorb it under the tongue), do you know if that person would absorb MORE than the 10mcg (or 1%)?

I hope my question makes sense.

[mrsD]

I would guess, that intrinsic factor is tied to the RDA for B12.

Biologically systems don't make "extra"...and only what you need.

So with that basic trait, I'd assume that enough intrinsic factor is made to deal with daily B12 absorption from animal foods.

The only difference is that intrinsic factor when latched onto B12 can work in the presence of food (as it arrives naturally) whereas passive absorption requires an empty stomach for best results. If intrinsic factor is broken, than passive absorption is all we have. Doctors don't even use the Schilling's test anymore to see if it is working. The labs have discontinued it.
http://en.wikipedia.org/wiki/Schilling_test

There is a test for autoimmune damage to the parietal cells in the stomach-- it looks for antibodies to the parietal cells:
http://en.wikipedia.org/wiki/Parietal_cell

B12 cobalamin is a very large molecule, difficult to absorb, so nature evolved this system of intrinsic factor helping because so little B12 is available in each meal.

The MMA test and homocysteine test show if the B12 is actually working in the tissues. The MMA test is specific for B12.
http://labtestsonline.org/understand...s/mma/tab/test

[julleri]

I found a sublingual with NO sugar alcohols that I don't react to negatively.
Has anyone had good results with this? It's Superior Source 1000 mcg methylcobalamin and only contains the B12 (methylcobalamin), lactose (milk), and acacia gum.

[julleri]

Here is a link to the product:
http://www.iherb.com/Superior-Source...-Tablets/26977

[mrsD]

If they work for you that is all that matters.

I'd still do them on an empty stomach, as sublingual
absorption is not all that great. That way you will get passive absorption from the intestine as well. (your swallowed saliva will contain much of the B12 dose).

[julleri]

Originally Posted by mrsD

If they work for you that is all that matters.

I'd still do them on an empty stomach, as sublingual
absorption is not all that great. That way you will get passive absorption from the intestine as well. (your swallowed saliva will contain much of the B12 dose).

Thank you.

I was even thinking taking two: one swallowed for the intestinal absorption and the other sublingually for the under-the-tongue absorption. This brand also makes the higher dose like other companies (Jarrow), in 5000 mcg. I would have to work up to a dose like that.

How come you say not much is absorbed under the tongue? I think it must be, as others see results with it and, despite the bad reactions I have had to others, I could feel some of the B12 effects (the upswinging) in others I have tried.

[mrsD]

Here is a study comparing oral with injectable.

Arch Intern Med. 2005 May 23;165(10):1167-72.
Oral cyanocobalamin supplementation in older people with vitamin B12 deficiency: a dose-finding trial.
Eussen SJ, de Groot LC, Clarke R, Schneede J, Ueland PM, Hoefnagels WH, van Staveren WA.
Source

Division of Human Nutrition, Wageningen University, Wageningen, The Netherlands.
Abstract
BACKGROUND:

Supplementation with high doses of oral cobalamin is as effective as cobalamin administered by intramuscular injection to correct plasma markers of vitamin B(12) deficiency, but the effects of lower oral doses of cobalamin on such markers are uncertain.
METHODS:

We conducted a randomized, parallel-group, double-blind, dose-finding trial to determine the lowest oral dose of cyanocobalamin required to normalize biochemical markers of vitamin B(12) deficiency in older people with mild vitamin B(12) deficiency, defined as a serum vitamin B(12) level of 100 to 300 pmol/L (135-406 pg/mL) and a methylmalonic acid level of 0.26 mumol/L or greater. We assessed the effects of daily oral doses of 2.5, 100, 250, 500, and 1000 mug of cyanocobalamin administered for 16 weeks on biochemical markers of vitamin B(12) deficiency in 120 people. The main outcome measure was the dose of oral cyanocobalamin that produced 80% to 90% of the estimated maximal reduction in the plasma methylmalonic acid concentration.
RESULTS:

Supplementation with cyanocobalamin in daily oral doses of 2.5, 100, 250, 500, and 1000 mug was associated with mean reductions in plasma methylmalonic acid concentrations of 16%, 16%, 23%, 33%, and 33%, respectively. Daily doses of 647 to 1032 mug of cyanocobalamin were associated with 80% to 90% of the estimated maximum reduction in the plasma methylmalonic acid concentration.
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.

PMID:
15911731
[PubMed - indexed for MEDLINE]

Because in the past it was believed that oral was not an effect route, injectable was the only treatment given for B12 deficiency. Now there are studies showing oral works as well.
Studies cost money to produce, and B12 is not a drug where lots of money or patents are at stake. So finding reliable data on sublingual is not common.
The size of the drug molecule and its lipid solubility, determine success with sublingual administration. Both of these traits are missing for B12, which is very water soluble, and a huge molecule.
Because of the lack of data that is reliable on sublingual forms, most comments on scientific sites are like this one:

In addition to oral dietary supplements, vitamin B12 is available in sublingual preparations as tablets or lozenges. These preparations are frequently marketed as having superior bioavailability, although evidence suggests no difference in efficacy between oral and sublingual forms.

from http://ods.od.nih.gov/factsheets/vit...hProfessional/

Certainly you can do whatever you like. I just suggest if you choose sublingual, keep it there for a LONG TIME and don't swallow. Most people find this difficult. Some complain of mucus membrane irritations, as well. To get the most potential from a sublingual given its lack of data ...do this on an empty stomach.