Low serum B12, but normal MMA and tHcy (and low iodine)

[hawkis]

My serum B12 levels have been dropping slowly in the last 3 years with memory loss, poor cognitive function, exhaustion, continuous infections etc. However one off tests for methylmalonic acid and total homocysteine have been normal, so my new doctor is saying I do not have a true B12 deficiency. Has anybody experienced this? Are there any health conditions or tests which can cause a low serum B12 result?

Oddly, my iodine is low, but all other extensive tests are normal.

Luckily my doctor has recommended loading B12 injections to see if my symptoms resolve. So far I have only been given 3 injections with only a small improvement in fatigue.

Thank you!

[Gambit62 Administrator]

test results provide context. I'm not sure what the scope for error is on the MMA test but people vary with B12 as to which systems/processes develop first.

Have you been tested for any absorption problems - eg PA, coeliacs, h pylori?

though iodine is a difficult deficiency to track down as it is quite difficult to asses how much is in your diet as the amount in food can vary considerably. Being low in iodine can affect thyroid function - and symptoms of an underactive thyroid overlap considerably with those of B12 deficiency.

[hawkis in reply to Gambit62]

Thank you very much, yes I've had several consultations with gastroenterology including a gastroscopy and colonoscopy with biopsies. Only a 'trace' of gastric atrophy which could be in line with PA but this could have been caused by the sampling alone, so it's questionable, plus relevant antibodies all negative. But I've had IBS for 20 years, so maybe it's 'simply' this causing absorption issues. Everything else gastric related has been excluded.

My last serum B12 was 109pmol/l....... at a loss, but I appreciate what you say about the iodine, maybe it is all more related to this.

[hawkis]

Hi, yes, serum B12 dropping slowly from 160 - 109 pmol/l, over the past three years. Recent MMA 189 nmol/l, and homocystine 9.9 umol/l.

Thank you