Disorders of Cobalamin (Vitamin B12) Absorption and Transport

Kapadia, Cyrus R.; Donaldson, Robert M.

doi:10.1146/annurev.me.36.020185.000521

Cited by 26 publications

(7 citation statements)

References 72 publications

(57 reference statements)

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“…Therefore, although the concentration of cobalamin may be adequate in the intestinal lumen, it is unavailable to the host. 41,42 Because cats harbor large numbers of duodenal bacteria, the higher concentration of cobalamin recorded during antibiotic administration is not a surprise and may be associated with the lower numbers of intestinal microbes.…”

Section: Discussionmentioning

confidence: 99%

Effects of oral administration of metronidazole on small intestinal bacteria and nutrients of cats

Johnston

Lamport²,

Ballèvre³

et al. 2000

ajvr

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Oral administration of metronidazole decreased the number of aerobic bacteria and altered indigenous flora in the small bowel of cats. Normal duodenal flora appeared to be stable, because species of bacteria were re-established by 9 months after cessation of metronidazole. Bacterial flora appeared to have an impact on nutrients, because albumin and cobalamin increased during antibiotic administration and returned to preadministration concentrations after cessation of the antimicrobial.

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Section: Discussionmentioning

confidence: 99%

Effects of oral administration of metronidazole on small intestinal bacteria and nutrients of cats

Johnston

Lamport²,

Ballèvre³

et al. 2000

ajvr

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“…For diagnostic purposes, the so-called "blocking" type, directed against the B 12 binding site, is measured, as this type not only is highly specific for pernicious anemia but also is the species present in 70% of patients. 96 Antibodies to parietal cells, although present in 90% of patients with pernicious anemia, are less specific, as they can occur in simple atrophic gastritis and in autoimmune thyroid disease. 97 …”

Section: -83mentioning

confidence: 99%

Vitamin B12 deficiency from the perspective of a practicing hematologist

Green

2017

Blood

264

197

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B12 deficiency is the leading cause of megaloblastic anemia, and although more common in the elderly, can occur at any age. Clinical disease caused by B12 deficiency usually connotes severe deficiency, resulting from a failure of the gastric or ileal phase of physiological B12 absorption, best exemplified by the autoimmune disease pernicious anemia. There are many other causes of B12 deficiency, which range from severe to mild. Mild deficiency usually results from failure to render food B12 bioavailable or from dietary inadequacy. Although rarely resulting in megaloblastic anemia, mild deficiency may be associated with neurocognitive and other consequences. B12 deficiency is best diagnosed using a combination of tests because none alone is completely reliable. The features of B12 deficiency are variable and may be atypical. Timely diagnosis is important, and treatment is gratifying. Failure to diagnose B12 deficiency can have dire consequences, usually neurological. This review is written from the perspective of a practicing hematologist.

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“…The discrepancy between the behavior of MMA and 2-MCA levels on the one hand and serum vitamin levels on the other hand may therefore be explained if the influence of the vitamins stored in storage pools, such as liver tissue, on tHcy metabolism is considered. Proceeding from these considerations, it is most likely that stored cobalamin [21,22] has a major influence on MMA and 2-MCA levels. On the other hand, storage pools of folate or pyridoxal phosphate have not been identified yet.…”

Section: Discussionmentioning

confidence: 99%

Long-Term Effects of Vitamin B12, Folate, and Vitamin B6 Supplements in Elderly People with Normal Serum Vitamin B12 Concentrations

Henning

Tepel

Riezler³

et al. 2001

Gerontology

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Background: In the elderly, deficiencies of folate, cobalamin (vitamin B₁₂) and pyridoxal phosphate (vitamin B₆) are common. The metabolites homocysteine, methylmalonic acid, 2-methylcitric acid and cystathionine have been reported to be sensitive markers of these vitamin deficiencies. Objective: The long-term (269 days) effect of an intramuscular vitamin supplement containing 1 mg vitamin B₁₂, 1.1 mg folate, and 5 mg vitamin B₆ on serum concentrations of homocysteine (tHcy), methylmalonic acid (MMA), 2-methylcitric acid (2-MCA), and cystathionine (Cysta) was studied in 49 elderly subjects with normal levels of vitamin B₁₂. Methods: Vitamin supplement was administered 8 times over a 21-day period, metabolite concentrations were measured until day 269 (e.g. 248 days after the end of vitamin supplementation). Results: From day 0 to 21, the serum levels of the 3 vitamins increased significantly, after cessation of supplementation the levels returned to baseline within the follow-up period. The MMA, 2-MCA and tHcy levels decreased during the treatment period significantly and did not reach baseline values within the 248-day period. Cysta levels did not differ significantly from baseline, either during or after treatment. Conclusion: MMA and 2-MCA levels rather reflect the availability of vitamins, especially cobalamin, than the actual serum levels. Since deficiencies of folate, cobalamin and pyridoxal phosphate in the elderly may cause hyerhomocysteinemia and hence may have unfavorable effects on mental performance, determination of MMA and 2-MCA levels in elderly patients with mental disturbances may be a cost-effective measure to improve or maintain mental performance.

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Disorders of Cobalamin (Vitamin B12) Absorption and Transport

Cited by 26 publications

References 72 publications

Effects of oral administration of metronidazole on small intestinal bacteria and nutrients of cats

Effects of oral administration of metronidazole on small intestinal bacteria and nutrients of cats

Vitamin B12 deficiency from the perspective of a practicing hematologist

Long-Term Effects of Vitamin B<sub>12</sub>, Folate, and Vitamin B<sub>6</sub> Supplements in Elderly People with Normal Serum Vitamin B<sub>12</sub> Concentrations

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