The intrinsic factor is vital for B12 absorption

[Guest guest]

The Intrinsic Factor Is Vital for B12 Absorption

 

Putting vitamin B12 to work in the body requires adequate supplies

of the protein-based intrinsic factor

 

Like a temperamental opera prima donna, vitamin B12 (cobalamin) has

to have conditions exactly to its liking or it won't perform.

 

Because it prevents pernicious anemia, degenerating nerves and

mental disorders, cobalamin needs to be present in adequate

quantities.

 

Long before vitamin B12 reaches the stomach, it plays hard-to-get,

appearing in appreciable quantities in only these foods: sardines,

clams, mackerel, herring, croaker, snapper and flounder. And one of

those sources, clams, is shunned by many people because it is

considered a garbage collector of the sea, often full of pollutants.

 

 

Assuring a good intake of vitamin B12, whatever the source, does not

guarantee that it will be properly absorbed.

 

A good supply of what is called the intrinsic factor is necessary

for this vitamin to become available to the body.

 

The intrinsic factor, despite its rather cryptic name, is nothing

mysterious. It is innumerable tiny, open ended protein capsules

created by the stomach in the exact shape and size required to fit a

cobalamin molecule.

 

These capsules randomly weave and bob around amid digesting food.

 

When they bump into vitamin B12, they quickly trap it inside, snap

the open and shut, and transport it to the farthest end of the small

intestine, the only place in the gut where cobalamin can be absorbed.

 

Without intrinsic factor, most B12 could never reach its

destination, because bacteria which line the intestine are hungry

for this nutrient and would intercept it.

 

So you can be starved for vitamin B12 even when it is richly

supplied.

 

What happens if there's a dearth of intrinsic factor?

 

Intestinal bacteria gobble up much of the vitamin B12, and the rest

is excreted.

 

Ingesting enough vitamin B12, therefore, is not enough. The vitamin

has to be delivered to the right spot in the upper intestine for

absorption. Otherwise, the consequences can be serious.

 

One of the serious consequences is dementia, which can mean anything

from mild mental impairment to insanity.

 

A recent study by Ralph Carmel, M.D., a specialist in hematology and

a professor of medicine at the University of Southern California,

reveals the temperamental character of vitamin B12.

 

Carmel wrote that " a certain segment of the population, especially

the elderly, cannot absorb vitamin B12 from food ... Some of them go

on to develop low B12 levels with biochemical abnormalities that

cannot be detected by standard tests, and some develop dementia.

 

" In 99 percent of cases, B12 deficiency arises from an inability to

absorb the B12 ingested in food.

 

The Schilling test can determine the extent to which a person is

able to absorb the B12.

" However, in our study sample, 90 percent of the patients with

unexplained low levels of B12 had normal Schilling tests. How could

they have developed B12 deficiency if they were adequately absorbing

B12? "

 

An answer to Carmel's question came from a study done some years ago

by Dr. Doscherholmen at the University of Minnesota, showing that

certain people, particularly the elderly, can absorb B12 normally

when it is given in a pill in the Schilling test, but cannot absorb

it in food.

 

In his observation of cases at the Los Angeles County/USC Medical

Center, Carmel found that some people with low blood levels of

vitamin B12 may actually be suffering from a deficiency that, if

left undetected and untreated, can produce dementia.

 

Carmel said cobalamin deficiency is a growing problem and cites

statistics to make his case. Seven years ago, no more than 30 cases

of classical vitamin B12 deficiency were detected at this medical

center -- cases characterized by anemia or by problems in the spinal

cord nerves that supply the arms and legs.

 

Now each year several hundred cases of low levels of vitamin B12

show up at this medical center without the usual manifestations of

deficiency, leading Carmel to believe these patients might actually

have a vitamin B12 deficiency that was more subtle or different from

the usual form of deficiency.

 

When Carmel's group micro-scopically examined bone marrow blood

cells from patients with an unexplained low B12 levels, they

discovered that even though the cells didn't show the anemia of B12

deficiency, they behaved biochemically exactly like cells suffering

from a vitamin B12 deficiency.

[Guest guest]

What about sublingual B-12? That should be utilized well, shouldn't it?

 

Alobar

 

On 9/21/06, JoAnn Guest <angelprincessjo wrote:

>

> The Intrinsic Factor Is Vital for B12 Absorption

>

[Guest guest]

I agree with Alobar on the sublingual, and what's more the dosage is

thee too because sublingual b-12 is usually taken as the vastly more

bioavailable form, methylcobalamin.

 

Duncan

 

, Alobar <Alobar

wrote:

>

> What about sublingual B-12? That should be utilized well,

shouldn't it?

>

> Alobar