Hatte ich vor 2-3 Jahren mal für ein anderen Forum zusammengstellt:
Norialgen
To clarify the bioavailability of vitamin B12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B12 and vitamin B12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B12-deficient rats were investigated. The amount of total vitamin B12 in the dried purple laver was estimated to be 54.5 and 58.6 (se 5.3 and 7.5 respectively) microg/100 g dry weight by Lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively. The purple laver contained five types of biologically active vitamin B12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin B12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin B12. When 9-week-old vitamin B12-deficient rats, which excreted substantial amounts of methylmalonic acid (71.7(se 20.2) micromol/d) in urine, were fed the diet supplemented with dried purple laver (10 microg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) became undetectable and hepatic vitamin B12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B12 in dried purple laver is bioavailable to rats.
http://www.ncbi.nlm.nih.gov/pubmed/11430774?dopt=Abstract
Pilze
Mushrooms are unique in that they contain Vitamin B12, something that vegetables can't produce at all. Since B12 is mainly of animal origin, deficiency is commonly associated with vegetarian diets. Mushrooms were found to contain 0.32-0.65 mg per gram of B12, allowing just 3 g of fresh mushrooms to provide the RDA of this vitamin. Vegetarians may find this a useful way of getting this important nutrient.
http://www.world-of-fungi.org/Mostly_Medical/Stephanie_Ingram/NUTRITIONAL_VALUE.htm
Verschiedene Algen
http://www.nzetc.org/tm/scholarly/tei-Bio14Tuat01-t1-body-d5.html
Ungekeimte und gekeimte Hülsenfrüchte
http://jn.nutrition.org/content/56/3/403.full.pdf
Spirulina und AFA habe ich ausgelassen, da widersprüchliche Angaben vorlagen. Bier hat sein B12 aus der Besiedlung der Hefe und/oder Symbionten der gekeimten Gerste, was beides ein "wildes" Entstehen von B12 bedeutet, was kobaltabhängig und daher stark variabel ist. Die letztgenannten Beispiele stellen definitiv keine geeigneten Quellen dar, da entweder die Werte stark veränderlich sind oder die Menge der Analoga die der aktiven B12-Formen übersteigt; Cyanobakerien wie Spirulina und AFA können außerdem mit Stämmen kontaminiert sein, die gesundheitsschädliche Microcystine produzieren.
Über die Vorangegangenen könnte man nachdenken.
Die umfassendste und meiner Meinung nach gewissenhafteste Zusammenstellung und Darstellung:
http://www.veganhealth.org/b12/plant
Norialgen
To clarify the bioavailability of vitamin B12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B12 and vitamin B12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B12-deficient rats were investigated. The amount of total vitamin B12 in the dried purple laver was estimated to be 54.5 and 58.6 (se 5.3 and 7.5 respectively) microg/100 g dry weight by Lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively. The purple laver contained five types of biologically active vitamin B12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin B12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin B12. When 9-week-old vitamin B12-deficient rats, which excreted substantial amounts of methylmalonic acid (71.7(se 20.2) micromol/d) in urine, were fed the diet supplemented with dried purple laver (10 microg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) became undetectable and hepatic vitamin B12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B12 in dried purple laver is bioavailable to rats.
http://www.ncbi.nlm.nih.gov/pubmed/11430774?dopt=Abstract
Pilze
Mushrooms are unique in that they contain Vitamin B12, something that vegetables can't produce at all. Since B12 is mainly of animal origin, deficiency is commonly associated with vegetarian diets. Mushrooms were found to contain 0.32-0.65 mg per gram of B12, allowing just 3 g of fresh mushrooms to provide the RDA of this vitamin. Vegetarians may find this a useful way of getting this important nutrient.
http://www.world-of-fungi.org/Mostly_Medical/Stephanie_Ingram/NUTRITIONAL_VALUE.htm
Verschiedene Algen
http://www.nzetc.org/tm/scholarly/tei-Bio14Tuat01-t1-body-d5.html
Ungekeimte und gekeimte Hülsenfrüchte
http://jn.nutrition.org/content/56/3/403.full.pdf
Spirulina und AFA habe ich ausgelassen, da widersprüchliche Angaben vorlagen. Bier hat sein B12 aus der Besiedlung der Hefe und/oder Symbionten der gekeimten Gerste, was beides ein "wildes" Entstehen von B12 bedeutet, was kobaltabhängig und daher stark variabel ist. Die letztgenannten Beispiele stellen definitiv keine geeigneten Quellen dar, da entweder die Werte stark veränderlich sind oder die Menge der Analoga die der aktiven B12-Formen übersteigt; Cyanobakerien wie Spirulina und AFA können außerdem mit Stämmen kontaminiert sein, die gesundheitsschädliche Microcystine produzieren.
Über die Vorangegangenen könnte man nachdenken.
Die umfassendste und meiner Meinung nach gewissenhafteste Zusammenstellung und Darstellung:
http://www.veganhealth.org/b12/plant