Vitamin B12 lozenges

[jonsi]

I learned something new today from my doctor when I stopped by to get a tbm tune-up on my vitamins.

Did you know that Vitamin B12 is virtually ineffective when taken in pill form and processed in the digestive track? As adults, 99% of B12 effectiveness is lost in digestion (something about the liver).

The effective way to get B12 into our systems is either by injection (ouch and expensive) or sub-lingually, under the tongue.

So buy B12 in lozenge form if you want the same results as the shots. (remember "I Love Lucy" mmmm, tasted good too. ?)

~jonsi

[EvDownJr]

Actually I have those at home. Got the el-cheepo Vitamin B12 under-the tongue tablets at Wal-Mart. They taste like cherry candy.

Wow, never guessed there was a problem absorbing in a regular multivitamin. Will have to whip mine out and have an energy party.

[2manyfibers]

Hey Jonsi - What your doctor told you about vitamin B12 not being absorbed effectively by the body didn't sound just right to me (and didn't make sense based on what I know of vitamins) so I did some research. Vitamin B12 is apparently absorbed in the body quite well as long as your stomach and digestive system works relatively well. The 1% effective absorption rate your doctor mentioned is what is absorbed through a process called passive diffusion (basically whatever is absorbed as the B12 dissolves in your stomach and digestive tract without enzyme activity from stomach acids). The B12 absorbed through this process is in addition to the amount of vitamin B12 the body normally absorbs as long as the digestive tract works relatively well and if you eat foods that contain B12 (or take it in supplemental form as in a good multivitamin). Thus, the body does a more effective job of processing vitamin B12 than what your doctor told you.

The following information comes from the Linus Pauling Institute at Oregon State University. It will tell everything you ever wanted to know about vitamin B12 and then some . This site has extensive information on practically any micronutrient (vitamins, minerals and amino acids) you want to research. Here's the link:

http://lpi.oregonstate.edu/infocente...ns/vitaminB12/

Vitamin B12 deficiency is estimated to affect 10%-15% of individuals over the age of 60 (4). Absorption of vitamin B12 from food requires normal function of the stomach, pancreas, and small intestine. Stomach acid and enzymes free vitamin B12 from food, allowing it to bind to other proteins called R proteins (3). In the alkaline environment of the small intestine, R proteins are degraded by pancreatic enzymes, freeing vitamin B12 to bind to intrinsic factor (IF), a protein secreted by specialized cells in the stomach. Receptors on the surface of the small intestine take up the IF-B12 complex only in the presence of calcium, which is supplied by the pancreas (5). Vitamin B12 can also be absorbed by passive diffusion, but this process is very inefficient—only about 1% absorption of the vitamin B12 dose is absorbed passively (2).

From all the information I can find it is only people that can't or don't produce the "Intrinsic Factor" (IF) noted in the excerpt above that don't "absorb" B12 through the digestive tract effectively. In these cases people need either an injection or sublingual delivery of vitamin B12 and these methods do allow quicker absorption than through the digestive tract. Most sources note than sometimes people that are strict vegetarians can have a vitamin B12 deficiency because the best sources of it are generally from meats. By all accounts it apparently doesn't hurt to take the B12 sublingually though even in addition to the "normal" amounts you would get from food.

[jonsi]

Thank you 2many!

I guess I didn't clarify supplemental B12 in pill form compared to natural B12 in foods. I get enough B12 in food but I was interested in a healthy "boost" the supplemental B12 in lozenge form can offer.

From your reply I understand it to say ... Absorption of vitamin B12 from food requires normal function of the stomach, pancreas, and small intestine. Stomach acid and enzymes free vitamin B12 from food,...

I went to the link you suggested and also found under Toxicity: When high doses of vitamin B12 are given orally, only a small percentage can be absorbed, which may explain the low toxicity.

I still stand with my doctor in that 99% of B12 effectiveness is lost when taken in pill form.

I did learn a lot though ~jonsi

[2manyfibers]

Hey Jonsi - I don't mind if you want to stand with your doctor........even though he is wrong in this case, I'm sure he would appreciate your company . The absorption of vitamin B12 doesn't depend so much on whether the B12 is from a food source or supplemental. It is true that the body only processes a small percentage of the amount of vitamin B12 that is consumed either from food or supplements. Only a relatively small amount of the B12 (cobalamin)is actually processed and used by the body. However the passive diffusion process is apparently where your doctor gets that 99% of the B12 consumed is not absorbed in the body. This is from the link I posted above:

Methylcobalamin and 5-deoxyadenosyl cobalamin are the forms of vitamin B12 used in the human body (1). The form of cobalamin used in most supplements, cyanocobalamin, is readily converted to 5-deoxyadenosyl and methylcobalamin in the body. In mammals, cobalamin is a cofactor for only two enzymes, methionine synthase and L-methylmalonyl-CoA mutase (2).

The form of vitamin B12 in supplements is readily converted to the forms normally used by the body. Whether the B12 is from food or supplements though, the body only uses part of the B12 consumed. This is because vitamin B12 is only used as a co-factor in the production of 2 specific enzymes - whatever amount consumed that isn't used for this is eliminated as waste or stored in organs such as the liver for later use. One reason people can have a vitamin B12 deficiency is that they may have an autoimmune condition known as "pernicious anemia". This is a condition caused by the autoimmune system attacking the lining of the stomach which interferes with the production of the "Intrinsic Factor" (IF). The other most common reason for not being able to absorb vitamin B12 properly is from the inability of some people's body's to "break out" the vitamin B12 when it is bound up in foods or proteins (thus, vitamin B12 supplements can be more effective in this case than foods because the B12 is not "bound up" in proteins). This section from the link explains this better than I can:

Food-bound vitamin B12 malabsorption is defined as an impaired ability to absorb food or protein-bound vitamin B12, although the free form is fully absorbable (11). In the elderly, food-bound vitamin B12 malabsorption is thought to result mainly from atrophic gastritis, a chronic inflammation of the lining of the stomach that ultimately results in the loss of glands in the stomach (atrophy) and decreased stomach acid production. Because stomach acid is required for the release of vitamin B12 from the proteins in food, vitamin B12 absorption is diminished. Decreased stomach acid production also provides an environment conducive to the overgrowth of anaerobic bacteria in the stomach, which further interferes with vitamin B12 absorption (3). Because vitamin B12 in supplements is not bound to protein, and because intrinsic factor (IF) is still available, the absorption of supplemental vitamin B12 is not reduced as it is in pernicious anemia. Thus, individuals with food-bound vitamin B12 malabsorption do not have an increased requirement for vitamin B12; they simply need it in the crystalline form found in fortified foods and dietary supplements.

The following excerpt from the section on "pernicious anemia" notes that only about 1% of the B12 can be absorbed by the body in the absence of IF (as is characterized by pernicious anemia).

High-dose oral supplementation is another treatment option (for pernicious anemia), because consuming 1,000 mcg (1 mg)/day of vitamin B12 orally should result in the absorption of about 10 mcg/day (1% of dose) by passive diffusion (4). In fact, high-dose oral therapy is considered to be as effective as intramuscular injection (7-10).

Some good news from the above excerpt is that taking high doses of B12 orally can be as effective as taking a shot - although the oral administration requires you to take 1 mg per day for a month to get a similar concentration as contained in a single 1 mg shot. The section you referred to on toxicity notes that it is the condition of pernicious anemia that limits the body to absorbing only 1% of the vitamin B12 consumed (although it isn't as clear as it could be) because by definition the body can't produce the IF that is responsible for most of the absorption of B12 under normal circumstances. This is from the toxicity section:

No toxic or adverse effects have been associated with large intakes of vitamin B12 from food or supplements in healthy people. Doses as high as 1 mg (1000 mcg) daily by mouth or 1 mg monthly by intramuscular (IM) injection have been used to treat pernicious anemia without significant side effects. When high doses of vitamin B12 are given orally, only a small percentage can be absorbed, which may explain the low toxicity.

The last sentence illustrates why you have to take 1 mg daily for a month to be the "equivalent" of taking B12 in the form of a shot. Even in healthy people, the body only absorbs a fraction of the vitamin B12 consumed orally, but the 1% figure specifically applies only when the body doesn't have the "Intrinsic Factor" available (as happens with pernicious anemia) to help absorb the B12 as it would under normal conditions.