Wednesday, October 9, 2013

Vitamin B12 – Are You Deficient?

In a word, YES, you may very likely be deficient in vitamin B12. The most common food source is red meat. So if you are a vegetarian, or limit your animal foods to fish and chicken, you need to supplement. But even if you are an “all American red meat eater”, a real carnivore, the odds are pretty high that you are still deficient.

Much has been written about how hard it is to absorb B12. You need adequate HCl (depleted by Prilosec and all the other protein pump inhibitors). You need intrinsic factor and healthy epithelial lining in the small intestine. While these are significant issues, the real issue is conversion.

The food form of vitamin B12 is cyanocobalamin. If all the factors listed above are working and B12 is absorbed into the lining of the small intestine, it must be converted to one of the bio-available forms to be used by the body. Methylcobalamin and adenocobalamin are the two bio-available forms that are produced by those small intestine cells. Once converted, both forms are released into the blood stream and go to work. Vitamin B12, folic acid, and vitamin B6 are involved in many, many chemical pathways in the body.

The ability to convert vitamin B12 is controlled by our genetics and unfortunately many of us have a genetic impairment that limits or prevents us from converting B12. Eight percent of the population have inherited a defective gene from both parents and will never make the conversion. These patients are easy to identify as they are always be anemic (have a low red blood cell count, low hemoglobin, or low hematocrit) because B12 is necessary to make red blood cells. The more common issue is the person who inherited a defective gene from just one parent. Sometimes they can convert B12, sometimes not. If they are under stress from illness, poor diet, lack of exercise, long work hours, etc., they may not convert B12. Twenty-five percent of the population is afflicted with this genetic defect. That’s one of every four people!

So, looking at all the issues with vitamin B12, it’s a pretty good guess that you are deficient. Not quite 50/50, but close. Fortunately, the solution is quite easy. The bio-available forms of B12 – methylcobalamin and adenocobalamin are readily available in supplement form. You can also take a sublingual form that is absorbed without passing through the digestive tract. Clinically, I find that that supplementing the patient with partial impairment for 30 days will often restore normal conversion, eliminating the need to supplement.

Let’s discuss B12 shots briefly. Most of the injections contain cyanocobalamin, the food quality form. When you inject the food quality form into the tissues of the body, where does the conversion occur? The vitamin never has an opportunity to be converted by the cells of the small intestine. All injections of B12 should be either methyl or adenocobalamin, not cyanocobalamin.

If you look at your last blood test, the lab probably ran a CBC (complete blood count). It’s a common lab test. If the RBC count, hemoglobin, or hematocrit are low, you might need more vitamin B12. If the MCV (mean corpuscular volume) is above 92, you are probably deficient in B12 and/or folic acid.