Taking too much folic acid - over 1mg a day - can mask signs of vitamin B12 deficiency.

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An early symptom of B12 deficiency is anaemia, but taking large amounts of folic acid treats the anaemia without treating the B12 deficiency.

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Professors Brian Wharton and Ian Booth, from the Institutes of Child Health in London and Birmingham, warned that in people with vitamin B12 deficiency, consumption of folic acid may mask a condition called megaloblastic anaemia - which if not picked up can lead to degeneration of the spinal cord.

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We see high HgA1Cs that are accurate measurements, but not reflective of glucose control in people with low red cell turnover from iron, vitamin B12 or folate deficiency.

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Her exam revealed inordinately high levels of gastrin--an indicator of atrophic gastritis or pernicious anemia, a deficiency of vitamin B12.

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