Different Causes of a Vitamin B12 Deficiency
If a vitamin B12 deficiency is found, the cause must then be identified so that the most suitable treatment option can then be chosen. The possible causes are as follows:
Inadequate dietary intake
The B12 supply from food is not high enough – common among vegans.
Temporarily, more B12 is required than is supplied through the diet, e.g. in cases of prolonged stress.
There is sufficient B12 intake but it cannot be absorbed. This is often the result of minor gastrointestinal inflammations.
Depending on the cause, the treatment will differ. How does this look in detail?
Treating a B12 Deficiency Caused by Low Intake
If the diet does not provide sufficient vitamin B12 supplies, the body’s liver and cell storage will eventually be used up. As this develops, a number of signs and symptoms indicating a deficiency can manifest. When storage levels are seriously low, severe symptoms are likely to appear.
Vegans and vegetarians are commonly affected by nutritional deficiencies. If this is due to inadequate dietary intake then implementing a daily supplement should fix this.
It is also possible that a deficiency is caused by improper absorption, which cannot simply be fixed by beginning daily supplement intake. To determine this, there are vitamin B12 deficiency tests available. To check this, it is possible to run a personal test by taking supplements for a number of weeks to see if the expected changes take place or not.
The treatment of diet related deficiencies are carried out in two phases:
1. Initial therapy (high dose to refill the body’s B12 store)
2. Maintenance therapy (standard dose to meet daily requirements)
After the initial high dosage course of therapy (typically 1000 μg daily for 2-3 months) a much lower maintenance dose of 10 – 300 μg per day should be adopted, preferably taken at three intervals. While this is well above the daily requirement of 3 μg, only a small quantity will be absorbed by the body; the majority is passed through the urine.
The body is able to absorb 1.5 μg of vitamin B12 from each oral dose. A further 1% is absorbed via passive diffusion. Because of this, you must either take relatively high dosages to optimize passive diffusion, or multiple dosages spread throughout the day.
If there is also malabsorption at play, an even higher dosage may be required. Some studies have concluded that to successfully treat patients suffering from anemia, an oral cyanocobalamin dose 200 times higher than the standard recommendation would be required.1 In such cases 500 – 1000 μg would be required.
Since a toxic overdose is not possible, it is quite common for vitamin B12 to be taken long-term daily at dosages of such quantities. As a result there are a variety of products available on the market to accommodate such use. However, this permanent state of overdose has been criticized, as it serves to disturb the nutrient balance.
Treating a B12 Deficiency Caused by Malabsorption
If malabsorption is affecting the body’s utilization of vitamin B12, daily oral doses of cobalamin will not produce any sustainable outcome, as absorption via intrinsic factor is completely redundant here.
Long-term high dosage vitamin B12 as either shots (typically 500 – 1000 μg), lozenges or drops (500 – 2000 μg) are usually administered to those suffering from an absorption disorder and resulting acute deficiency. From this a rich supply of B12 is guaranteed for the cells, while the source of the issue is identified. The oral mucosa is well suited to obtaining vitamin B12 from lozenges or drops. Additionally, passive diffusion is possible in the intestine from really high doses. In chronic or non-curable cases, such as surgeries removing essential sections of the small intestine, treatment must be continued permanently, otherwise a deficiency will result.
When the cause of the absorption problems is unclear, it is advisable to begin a course of supplementation, while further tests are ran. The most common causes are chronic disorders affecting the gastrointestinal mucosa, alcohol or drug use, malnutrition and stress (both physical and mental). Some other less common causes include helicobacter pylori infections, drug interactions and genetic diseases.
Selecting the Right Vitamin B12 Supplement
There are a number of different supplementary forms of vitamin B12 available containing different active ingredients. The most common forms include cyanocobalamin, hydroxocobalamin, methylcobalalmin and adenosylcobalamin.
Cyanocobalamin is the synthetic form of vitamin B12 and is broken down by the body into methylcobalamin and toxic cyanide, which can cause strong allergic reactions in some cases. This artificial form has been leading the US market in B12 supplements for many years, primarily because it is easy to manufacture. Increasingly, however, it is becoming a less popular as its disadvantages are more widely acknowledged. Some even argue that the product should be taken of the market entirely, as it is so inferior to other forms.
Hydroxocobalamin is one of the natural forms of vitamin B12. It can be produced by a number of bacteria. The body must first convert hydroxocobalamin, but in contrast to disadvantages of cyanocobalamin, it has the advantage of staying in the body far longer and not being excreted so readily. Hydroxocobalamin is currently the international standard for vitamin B12 supplements and is also the drug of choice as recommended by WHO.3
Our personal recommendations for vitamin B12 when used for medicinal purposes are methylcobalamin and adenosylcobalamin, which are both readily bioavailable. Both cyanocobalamin and hydroxocobalamin must first be converted into methylcobalamin and adenosylcobalamin before they can be used in the body. These forms are referred to as B12 coenzymes or bio-identical vitamin B12 forms.
Further information on this topic can be found in our article vitamin B12 supplements.
Vitamin B12 Produced by Algae
Algae such as spirulina, chlorella and nori are often marketed as alternative vegan vitamin B12 sources, however, this is currently a controversial topic. As well as vitamin B12, algae has been shown to contain large amounts of pseudovitamin B12. Studies indicate that these these vitamins can block the absorption of actual B12, resulting in a negative B12 balance.4
By contrast, other studies show that B12 serum levels can be raised significantly through the consumption of algae. However, it cannot be stated in any certain terms just how much of this may be available to cells.
Minerals and Trace Elements to Accompany and Support Vitamin B12
Alongside vitamin B12, it is highly beneficial and recommendable that other vitamins belonging to the B complex are taken in supplementary form to treat diseases. Folic acid is considered the most important of these as the pair work closely together during metabolism. Biotin, magnesium and calcium are also important indirectly, as they interact with B12.
The use of B12 for medicinal purposes may temporarily result in an iron deficiency, because blood formation is increased. It is therefore advised that iron supplements are also taken during initial treatments of very severe anemia related diseases.
1Eussen SM, de Groot LM, Clarke R, et al. Oral Cyanocobalamin Supplementation in Older People With Vitamin B12 Deficiency: A Dose-Finding Trial. Arch Intern Med. 2005;165(10):1167-1172. doi:10.1001/archinte.165.10.1167.
2Freeman AG. Cyanocobalamin—a case for withdrawal: discussion paper. J R Soc Med 1992; 85: 686-771. PubMed
3WHO Model List of Essential Medicines. 18th list (April 2013) http://www.who.int/medicines/publications/essentialmedicines/en/4. Dagnelie PC, van Staveren WA, van den Berg H. Vitamin B-12 from algae appears not to be bioavailable. Am J Clin Nutr. 1991;53:695-7.