Vitamin B12 Study Shows Meat Not Effective in Preventing Deficiency

August 10, 2000

by Dan Murphy

on 8/4/00

for www.meatingplace.com

Nearly two-fifths of the U.S. population may be flirting with marginal

vitamin B12 status if the population of Framingham, Mass., is any

indication, according to USDA's Agricultural Research Service, the

department's chief scientific agency.

But while red meat is acknowledged as one of the best dietary sources of

vitamin B12, a major investigative study found " puzzling " deficiencies of

the essential vitamin -- which cannot be manufactured by the body --

among red meat eaters.

Read on for more about this medical mystery.

The study, focused on 3,000 men and women in the ongoing Framingham

Offspring Study of people from 26 to 83 years old, found 39 percent had

blood levels of vitamin B12 in the " low normal " range. This is above the

currently accepted deficiency level of 148 pmol/L ( " parts per mole per

liter, " a clinical measurement of molecular concentration), according to

study leader Katherine Tucker, a nutritional epidemiologist at the Jean

Mayer USDA Human Nutrition Research Center on Aging at Tufts University in

Boston. But at that level, some people do exhibit neurological symptoms,

Tucker said.

Nearly 9 percent of the study population fell below the current deficiency

level; more than 16 percent fell below 185 pmol/L.

" I think there is a lot of undetected vitamin B12 deficiency out there, "

Tucker said. " There is a question as to what the clinical cutoff for

deficiency should be. "

Vitamin B12 deficiency can cause a type of anemia marked by fewer but

larger red blood cells. It can also cause walking and balance disturbances,

a loss of vibration sensation, confusion, and in advanced cases, dementia.

The body requires vitamin B12 to make the protective coating surrounding

nerve tissue, so inadequate levels of B12 can expose nerves to damage.

Now for the mysterious part.

" The good news [about the study], " said ARS administrator Floyd Horn, " is

that most people can improve their B12 status by eating more fortified

cereals and dairy products, " adding that Tucker's data suggest that these

foods are nearly as effective as B12 supplements for getting people's blood

levels above the danger zone.

The really good news: Red meat is a significant source of bioavailable

vitamin B12, along with certain dairy products and fortified breads and

cereals containing added vitamin B12.

But the puzzling part is that the researchers, who expected to find a

connection between dietary intake of vitamin B12 and serum plasma levels,

found no association between plasma B12 levels and meat, poultry, and fish

intake, even though these foods supply the bulk of B12 in the diet.

" It's not because [those] people aren't eating enough meat, " Tucker said.

" It's that the vitamin isn't getting absorbed. "

Among the elderly, it is probably because they don't secrete enough stomach

acid to separate the vitamin from the meat proteins that tightly bind it,

the researchers theorized. But Tucker could not provide a definitive

explanation for poor absorption of the vitamin from dietary meat among

younger adults or why B12 appears to be better absorbed from dairy products

than from meats.

Perhaps the answer is to switch to cheeseburgers.

August 10, 2000

Thanks for posting this Maynard. It is exactly what I have been thinking,

that B12 is FAR from just a vegan issue because there are such a large number of

ways in which a person can have B12 absorption problems. It had been apparent

to me that absorption problems are relatively common, although I hadn't found a

figure to put on just how common.

Since the article you posted expresses some question about B12

malabsorption, I thought I would post the article I had published in the

Earthsaver in the fall of 1999, the newletter of the Vancouver Earthsave

Chapter, on that issue. This particular article was the second part of a 3 part

series on B12. If anyone wants my references, please email me for them.

Part 2: Conditions which interfere with the absorption of Vitamin B12

By Deborah A. Pageau B.Sc.

Assimilation of vitamin B12 is a complex process and many factors can

interfere. Tini Gruner, PhD (candidate) who is studying B12 at Lincoln

University in New Zealand sums them up in the following press release from

September 1999, reprinted with permission.

" If any of the transport proteins that must be present in the body are

lacking, vitamin B12 will not be carried to the tissues for metabolism, despite

it being in ample supply. Pernicious Anemia occurs when antibodies develop

against Intrinsic Factor, a vitamin B12 binding protein secreted by the stomach

in response to vitamin B12 in the diet. However, if there is inadequate

secretion of stomach acid, Intrinsic Factor will not, or only partially, be

released. Reduced stomach acid is common in older people (as part of the general

slowing down of their metabolism), in people with allergies and in those who

take antacids.

People who have part or all of their stomach removed will not be able to

secrete Intrinsic Factor. Removal of part of the small intestine, the site of

vitamin B12 absorption into the blood stream, can result in deficiency, as can

bacterial overgrowth of the small intestine or giardiasis. Pancreatic disease,

cystic fibrosis or any drugs that tie up free calcium interfere with vitamin B12

absorption, thus rendering the vitamin unavailable to the tissues.

In states of high metabolic need, like during pregnancy or in

hyperthyroidism, the vitamin is used up much more quickly and (supplementation

may be necessary) to meet the demand.

When there is damage to the liver from disease, toxins, drugs or alcohol,

the liver cannot retain and store the vitamin effectively. The person is then

more prone to deficiency.

(Genetic) predisposition to reduced stomach acid (and with that reduced or

absent Intrinsic Factor), pernicious anemia in the family and absence of any of

the other transport proteins can all contribute to a deficiency at some stage in

life.

Any thing that causes damage to the small intestine would limit the body’s

ability to absorb vitamin B12. "

It is estimated that approximately 1 in 250 people have a genetic tendency

towards an autoimmune reaction to gluten, a protein found in wheat, spelt,

kamut, triticale, rye, barley, and oats which results in damage to the small

intestine. This reduces ability to absorb B12 and other nutrients and commonly

contributes to developing B12 deficiency. Some researchers suggest that some

degree of reactivity to gluten may be quite common.

Apparently, 15% of people, who are sensitive to gluten, also react to soy.

All other legumes, all types of rice, teff, buckwheat, quinoa, millet, amaranth,

tapioca, all types of fruits and vegetables are generally considered safe for

gluten-free diet.

Nitrous oxide, which is sometimes used as anesthetia, is also known to cause

acute B12 deficiency.

With so many factors, which can result in a person developing a B12

deficiency, even if they eat meat, some researchers are suggesting that B12

deficiency may be more common than has been thought.