The recommended daily allowance (RDA) levels for vitamin B12 should be increased by 500 per cent according to Danish researchers whose findings were published in the January 2006 issue of the American Journal of Clinical Nutrition (Vol. 83, pp. 52-58). They found that in order to correct all vitamin B12-related variables a RDA of 6 micrograms is needed.
Currently the RDA in Europe is only 1 micrograms for adults, while the US dietary reference intake (DRI) is 2.4 micrograms. RDAs are established at a level considered to be the minimum amount of the vitamin required to avoid the risk of developing vitamin deficiency disorders.
Vitamin B12 is necessary for:
- stimulating RNA synthesis in nerve cells,
- strengthening neurotransmitters, and increasing concentration and memory,
- myelin formation (the covering around the nerve cells),
- protecting arteries in the brain by metabolizing homocysteine,
- nervous system health,
- growth and development,
- the production of red blood cells,
- healthy digestive function, and
- detoxifying cyanide from foods and tobacco smoke.
Food sources of vitamin B12 include: brewer’s and nutritional yeast, liver, clams, eggs, meats, fish, and dairy products. Some vitamin B12 is available from sea vegetables, such as, dulse, kelp, kombu, and nori.
The current study involved calculation of dietary and supplemental intake of vitamin B12 for 98 post-menopausal women with an average age of 57 using three-day diet records, a method that does not rely heavily on memory and widely believed to give the most valid estimated of intake. Volunteers were divided into quintiles depending on B12 intake, then researchers measured four different vitamin B12-related serum markers.
Despite the range of intake varying from three to 15 micrograms, the researchers observed that the curves leveled off at a daily intake of about six micrograms for all variables analysed. Hence, a daily vitamin B12 intake of six micrograms appears to be sufficient to normalize all of the vitamin B12-related variables and this may be more adequate for the general adult population than the current RDA.
B12 is often deficient in vegans (strict vegetarians) because the predominant source of B12 is animal products. It is also prevalent among the elderly population. Further details about vitamin B12 are available at Healthy Vitamin Choice.
