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1:11:2003 |
| Methyl-B12 Can Improve Alertness and Concentration Vitamin B12 was isolated from a liver extract in 1948 and identified as the nutritional factor in liver which prevented pernicious anemia - a deadly type of anemia characterized by large, immature red blood cells. Vitamin B12 works with folic acid in many body processes including the synthesis of DNA, red blood cells, and the insulation sheath (the myelin sheath) that surrounds nerve cells and speeds the conduction of the signals along nerve cells. Vitamin B12 deficiency is most often due to a defect in absorption, not a dietary lack. In order for vitamin B12 from food to be absorbed, it must be liberated from food by hydrochloric acid and bond to a substance known as intrinsic factor within the small intestine. Intrinsic factor is secreted by the parietal cells of the stomach. These same cells are responsible for the secretion of hydrochloric acid. Hence, the secretion of intrinsic factor parallels that of hydrochloric acid. The B12-intrinsic factor complex is absorbed in the small intestine with the aid of the pancreatic enzyme trypsin. In order for vitamin B12 to be absorbed, an individual must secrete enough hydrochloric acid and intrinsic factor and adequate pancreatic enzymes, including trypsin, and have a healthy and intact ileum (the end portion of the small intestine, where the vitamin B12-intrinsic factor complex is absorbed). Lack of intrinsic factor results in a condition known as pernicious anemia. The defect is rare before the age of thirty-five, and it is more common in individuals of Scandinavian, English, and Irish descent. It is much less common in southern Europeans, Asians, and Blacks. Since vitamin B12 is found only in animal foods, it appears that it is very important that vegetarians supplement their diets with vitamin B12. Vitamin B12 is available in several forms. The most common form is cyanocobalamin, however, vitamin B12 is most active in the form of methylcobalamin. This form is the best to use. B12 Deficiency Unlike other water-soluble nutrients, vitamin B12 is stored in the liver, kidney, and other body tissues. As a result, signs and symptoms of vitamin B12 deficiency may not show themselves until after five or six years of deficient intake or lack of intrinsic factor. While anemia is most often thought of as the primary sign of vitamin B12 deficiency, it appears that a deficiency of vitamin B12 will actually first affect the brain and nervous system. Vitamin B12 deficiency can cause depression, especially in the elderly. It can also produce such symptoms as numbness, pins and needles sensations, or a burning feeling in the feet as well as impaired mental function that in the elderly can mimic Alzheimer's disease. In addition to anemia and nervous system symptoms, a vitamin B12 deficiency will also result in a smooth, beefy red tongue; and diarrhea due to the fact that rapidly reproducing cells such as those which line the mouth and entire gastrointestinal tract will not be able to replicate without vitamin B12 (folic acid supplementation will mask this deficiency symptom). Correcting Low B12 Levels Improves Mental Performance Although it is popular to inject vitamin B12 in the treatment of anemia and B12 deficiency, injection is not required as the oral administration of an appropriate dosage has been shown to produce as good of results as injectable preparations in treating vitamin B12 deficiency. The most common forms are cyanocobalamin and hydroxycobalamin, however, vitamin B12 is active in only two forms - methylcobalamin and adenosylcobalamin. These later forms are active immediately upon absorption, while cyanocobalamin and hydroxycobalamin must be converted to either methylcobalamin or adenosylcobalamin by the body. Methylcobalamin is preferred over adenosylcobalamin as 90% of the body's active B12 is in this form and methycobalamin is easily converted to adenosylcobalamin. To highlight the superiority of methylcobalamin, let's take a look at one study specifically evaluating the effects of methylcobalamin versus cyanocobalamin on circadian rhythms, well-being, alertness, and concentration in healthy subjects.1 The twenty subjects (mean age 36 years) were randomly assigned to treatment for 14 days with 3 mg cyanocobalamin or methylcobalamin after 9 days. The results indicated a significant advantage for methylcobalamin. Methylcobalamin supplementation led to a significantly improved sleep quality, shorter sleep cycles, increased feelings of alertness, better concentration, and a feeling of waking up refreshed in the morning. Some of the interesting findings included the fact that methylcobalamin was significantly more effective even though blood levels of cobalamin increased more significantly in the cyanocobalamin than the methylcobalamin group. Clearly, this finding indicates that methycobalamin is much more biologically active than cyanocobalamin. Methylcobalamin has also shown to help some people suffering from what is referred to as sleep-wake disorder. This disorder is characterized by excessive daytime sleepiness, restless nights, and frequent nighttime awakenings. It is very common in shift workers. In people with sleep wake disorders, taking methylcobalamin (1.5 to 3 mg daily) has often led to improved sleep quality, increased day time alertness and concentration, and improved mood. Much of the benefit appears to be a result of methylcobalamin influencing melatonin secretion.2,3 The low levels of melatonin in the elderly may be a result of low vitamin B12 status. However, benefit may also be a result of unmasking low brain levels of methylcobalamin. A low level of methylcobalamin is one of the most common nutrient deficiencies, especially in the elderly. In people with low levels of B12, supplementation is very effective in improving mental function as well. In one large double-blind study, a complete recovery was observed in 61% of cases of these patients exhibiting significant mental impairment. It was thought the reason why the remaining 39% did not respond was due to irreversible damage to the brain as a result of long-term low levels of vitamin B12.4 Several studies have shown the best clinical responders are those who have been showing signs of impaired mental function for less than 6 months. Usual Dosage: In the treatment of vitamin B12 deficiency with oral preparations the recommended dosage is 2,000 mcg (2 mg) daily for at least one month followed by a daily intake of 1,000 mcg (1 mg). For the applications of methylcobalamin discussed in this newsletter, I would recommend 3 mg upon awakening for one month followed by a maintenance dosage of 1 mg per day. I would recommend that all vegetarians supplement with 1 mg of methylcobalamin daily. The specific product that I recommend is a well-formulated sublingual
(under the tongue) tablet from Natural Factors that is available
as B12 Methylcobalamin in your local health food store. Key References:
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