Interrelation of vitamin B12 and iron

Iron and the folate-vitamin B12-methylation pathway in multiple sclerosis

Some subjects with multiple sclerosis (MS) present with low blood iron parameters. Anecdotal reports and a single patient study suggest that iron supplementation may be beneficial in these subjects. Myelin is regenerated continually, but prerequisites for this process are iron and a functional folate-vitamin B12-methylation pathway. The aim of this study was to determine iron status, folate and homocysteine in MS subjects, and to evaluate the effect on MS symptoms if deficiencies were addressed.

RESULTS

In relapsing-remitting MS subjects, serum iron concentration correlated significantly with age at diagnosis (r=0.49; p=0.008). In Caucasian female MS subjects, serum iron and ferritin concentrations were significantly lower than in matched controls. In a 6-month pilot study, 12 subjects taking a regimen of nutritional supplements designed to promote myelin regeneration, improved significantly neurologically as measured by the Kurzke EDSS (Total Score means 3.50 to 2.45, 29.9%; p=0.021). These were significantly improved (p=0.002) compared to 6 control group patients taking multivitamins (Kurzke Score increased by 13.9% from 4.83 to 5.50). Both groups had significantly reduced homocysteine concentrations at 6 months, suggesting that methylation is necessary but not sufficient for myelin regeneration.

Carbohydrates and sulphur-containing compounds in the anaemic buccal epithelium

Mucosal biopsies from the inside of the cheek show epithelial atrophy, glycogen depletion, and an occasional increase in sulphydryl content in both iron-deficiency and megaloblastic anaemias. These changes are the same in the two types of anaemia but are more marked in the latter group.

The tongue and oesophagus in iron-deficiency anaemia and the effect of iron therapy

Biopsies of the tongue and oesophagus were performed on 14 patients with uncomplicated iron-deficiency anaemia before and after treatment with iron. Haemoglobin and serum iron estimations were performed at the same time. Nine patients had clinical evidence of atrophic changes in the tongue before therapy was started. Evidence of regeneration appeared within one or two weeks of starting iron therapy. Two patients showed persistent atrophy. Angular stomatitis and koilonychia were longer in disappearing. Biopsies confirmed that filiform papillae and kerato-hyalin granules are frequently absent from the epithelium of the smooth tongues of iron-deficient patients. Iron therapy is followed by the re-appearance of keratohyalin granules and keratinized filiform papillae. Two patients complained of dysphagia, which disappeared after treatment. No abnormality in the oesophageal epithelium was found in any of the patients either before or after therapy. The relationship of oesophageal carcinoma to antecedent iron-deficiency epithelial changes is considered suspect.

Changes in serum vitamin B12 levels in patients with megaloblastic anaemia treated with folic acid

In 21 patients with megaloblastic anaemia associated with the tropical malabsorption syndrome serum vitamin B(12) levels have been measured serially before and during parenteral folic acid therapy. In 11 patients there was a significant rise in serum B(12) levels, reaching a peak three to 17 days after starting the folic acid. In three of these cases, absorption of labelled B(12) was the same before and after the administration of folic acid. In two cases there was a fall in serum B(12) levels and in seven there was no change. In one case small amounts of folic acid produced no change in serum B(12) levels, whereas larger doses produced a prompt but transient rise.

The significance of Howell-Jolly bodies and giant metamyelocytes in marrow smears

Howell-Jolly bodies in erythroid precursors can be found in the marrow in a variety of diseases. More than 1% in the later erythroblasts is rarely found except in vitamin B(12) or folic acid deficiency states.Giant metamyelocytes are probably always the result of vitamin B(12) or folic acid deficiency. A distinction is drawn between the deficiency of, and therapeutic need for, vitamin B(12) and folic acid.

The buccal mucosa in anaemia

The histological features of the buccal mucosa have been examined in 50 cases of iron-deficiency anaemia, 14 cases of megaloblastic anaemia, and 50 normal subjects. Differences between the anaemic and normal groups have been found and in some anaemic patients striking morphological changes have been seen. These might be due to a direct effect of iron or vitamin B(12) deficiency on the metabolism of the epithelial cells.

FOLIC ACID AND VITAMIN B12 LEVELS IN PREGNANCY AND THEIR RELATION TO MEGALOBLASTIC ANAEMIA

There is a significant fall in the serum folic acid level during pregnancy, reaching its lowest level at term. This is most pronounced in twin pregnancies. A similar but less spectacular fall occurs in the vitamin B(12) concentration. In megaloblastic anaemia both folic acid and vitamin B(12) levels are lower than in other pregnant women. The degree of megaloblastic change in the bone marrow, as measured by the type and number of megaloblasts, is reflected in the vitamin levels, cases with florid megaloblastosis showing the most marked depression of vitamin B(12) and folic acid activity. Although there is a significant difference in the mean folic acid levels between megaloblastic and normoblastic pregnant women, a considerable overlap exists between individual values in the two groups. When the labile folic-acid factor is determined separately the test becomes much more specific. In the present series, all cases of megaloblastic anaemia yielded labile-factor levels below 1.0 mmug. per ml., while a similar value was encountered in only one of 35 normal pregnancies. In five women with megaloblastic anaemia the vitamin B(12) concentration was less than 100 mumug. per ml. but rose to normal levels on folic acid therapy alone.

Influence of age and stomach function on serum vitamin B12 concentration

Serum vitamin B12 (B12), maximal gastric acid output (MAO), and B12 absorption were determined in 82 subjects, age 32 to 85 years, who had normal absorption of radiocyanocobalamin. In 46 of the patients the gastric intrinsic factor (IF) was also measured. Serum B12 concentration and MAO varied widely in all age groups from abnormally low to definitely normal. The mean values for serum B12 and MAO, however, declined very similarly with advancing age owing to an increased incidence of low values for these two measurerment in the aged. There was no significant fall in the mean B12 absorption or IF secretion as a function of old age. Achlorhydric and hypochlorhydric patients invariably had lower mean serum B12 concentrations than those with adequate MAO. Conversely, patients with normal MAO all had normal serum B12 levels. Serum B12 concentration, although correlating with both MAO and IF secretion, showed a closer relationship to the former than to the latter. These findings suggest that the stomach, aside from producing the IF, plays an important role in maintaining a normal serum B12 concentration.

Small intestinal malabsorption of vitamin B(12) in iron-deficient rats

Rats were rendered iron deficient by a combination of diet and bleeding to study its effects on vitamin B(12) absorption. Small intestinal loops were isolated in vivo and the absorption of -57Co-vitamin B(12) bound to a known quantity of intrinsic factor was measured. Iron deficiency resulted in the impairment of both uptake and transport of B(12). This malabsorption was corrected within 5 days by parenteral iron repletion. The findings were not due to a non-specific effect of anaemia since no correlation existed between haemoglobin levels and B(12) absorption in rats anaemic as a result of acute blood loss. No evidence was found for an altered small-intestinal microflora, bacterial counts being similar in iron-deficient and control rats. It is concluded that iron deficiency in the rat results in impaired absorption of B(12) by the small intestine, probably as a result of some defect produced in the enterocyte.

A survey of vitamin B-12 deficiency in an elderly psychiatric population

For many years, cases of pernicious anaemia associated with mental symptoms have been described, and interest in these symptoms was renewed following the introduction of liver therapy (Richardson, 1929; Phillips, 1931). Interest later appeared to decline, so that MacDonald Holmes (1956), almost 20 years after the last important clinical review of the subject, could comment with justification that although the cerebral lesions of pernicious anaemia had been recognized for more than a century they were still much less familiar than the lesions which occurred in the spinal cord and peripheral nerves. Since then vitamin B12 deficiency as a cause of mental symptoms has given rise to increasing interest, and this is reflected in recent suggestions that serum vitamin B12 assays should be carried out routinely in psychiatric patients and might be more informative nowadays than the routine Wassermann reaction (Strachan and Henderson, 1965; Hunter and Matthews, 1965).