When the B-12-Intrinsic Factor complex arrives in the jejunum (the last part of the small intestine), special receptors bind the complex and ultimately B-12 is passed through the gut wall into the bloodstream.
Only active B-12 is utilized by all human cells, including red blood cells (RBCs). B-12 is crucial in the normal formation of DNA, the blueprint of our biochemistry. If the RBC has inadequate folate (Vitamin B7) and / or B-12, abnormal DNA is formed and delayed maturation of the RBC occurs.
This is called pernicious anemia. The prolonged development results in large, abnormally shaped cells called macrocytes. The cell wall of the macrocyte is flimsy and the cell is susceptible to hemolysis (destruction) in the capillaries.
The RBCs account for one of every four cells in the body, with a normal life span of 120 days. The size of an RBC can be seen microscopically. It is also measured on a routine complete blood count. Specifically the mean corpuscular volume (MCV) measures the average size of the RBC. Corpuscle is a synonym for red blood cell.
The red blood cell distribution width (RDW) is also measured in the complete blood count. An elevated RDW indicates that there is a large difference in the size from RBC to RBC. This could indicate the presence of small RBCs as well as large RBCs in the blood at the same time. This occurs most commonly when there are microcytes (small blood cells) due to iron deficiency as well as macrocytes due to folate, B-12 and / or intrinsic factor deficiency simultaneously.
Macrocytes live only one-third to one-half as long as normally formed RBCs. Therefore they have to be replaced at the same rate to keep the blood count normal. The extra biochemical energy involved in making up to three times as many red blood cells has to come at the expense of some other metabolic need. This is analogous to patients who have the figurative equivalent of the special forces of their white blood cells dealing with toxic chemicals and compounds. While part of the immune system is tied up, some other invader, such as cancer, may succeed in sneaking by the body’s defenses.
Obtaining adequate dietary B-12 is difficult for portions of the general population (animal-based eaters included), and can be challenging for most vegans.
B-12 is produced by soil bacteria.
B-12 is the only vitamin that most vegans cannot obtain in adequate quantity without supplementation because of modern day sanitation in farming practices. In addition, cyanocobalamin, hydroxycobalmin, methylcobolamin, adenosylcobalmin are the only biologically active forms, and therefore can be recognized by intrinsic factor. Cyanocobalamin should be avoided due to harmful metabolites. Most people would do well by taking a daily supplement of B-12 extracted from Saccharomyces cerevisiae. Preliminary studies demonstrate the cyanobacterium Aphanizomenon flos-aquae is a good source of active B-12. Sea vegetables are also thought to provide usable B-12. Vegans can obtain biologically active B-12 supplements synthesized by bacteria, a non-animal origin.
B-12 should be taken along with whole B complex for proper utilization by the cell.
B-12 levels can be measured in the blood, but there is a pitfall. Blood levels of B-12 may represent active as well as inactive B-12, the latter of which cannot be utilized by human cells. Blood B-12 can actually paradoxically increase because it cannot be taken into the cell, where it has its physiologic effect. Intracellular analysis of B-12, or measuring Homocysteine (HC) in the blood can be evaluated to give a clearer picture of what is occurring at the cellular level.
HC, an amino acid, is a proxy measure of B-12 function intracelluarly because B-12 is a cofactor in its metabolism. A normal HC establishes that adequate active B-12 is absorbed, circulates through the blood, and is utilized biochemically in the cell. Those with inadequate active B-12 will have a buildup of HC and therefore elevated blood levels. Excess HC can have grave consequences throughout the body. In the brain homocysteine can cause neuron (brain cell) DNA damage and neuronal mitochondria (cellular powerhouse) damage. It can cause neuro and neuropsychiatric disorders including memory problems and Alzheimer?s dementia. Elevated HC is much more predictive as a risk factor for heart disease versus cholesterol testing. Elevated HC can cause abnormal cross-linking of collagen, leading to defective bone matrix, and hence lead to osteoporosis.
Normal reference values reported by the larger laboratories are often unacceptable. The ideal level of blood HC is 6 – 7. Levels of HC 8 – 10 are okay, and any level above 10 is unacceptable. An MCV value on the complete blood count above 90 is suspicious for inadequate folate or B-12 utilization. An MCV above 100 should certainly warrant further investigation and intervention. Often lifestyle, nutritional, and hormonal interventions can bring physiology into balance. Additional testing into toxic load may be indicated. A trained anti-aging practitioner can make recommendations if the above or other abnormalities are present.