Comparison between erythroid aplasia in marasmus and kwashiorkor and the experimentally induced erythroid aplasia in baboons by riboflavin deficiency

Correcting a marginal riboflavin deficiency improves hematologic status in young women in the United Kingdom (RIBOFEM)

BACKGROUND

Moderate riboflavin deficiency is prevalent in certain population groups in affluent countries, but the functional significance of this deficiency is not clear. Studies have indicated a role for riboflavin in the absorption and use of iron.

OBJECTIVE

We investigated the effect of riboflavin supplementation on hematologic status in a group of moderately riboflavin-deficient women aged 19-25 y in the United Kingdom.

DESIGN

One hundred twenty-three women with biochemical evidence of riboflavin deficiency [erythrocyte glutathione reductase activation coefficient (EGRAC) >1.40] were randomly assigned to receive 2 or 4 mg riboflavin or a placebo for 8 wk. Measurements of hematologic status were made pre- and postsupplementation, and dietary intakes were also assessed; iron absorption was measured in a subgroup of women.

RESULTS

One hundred nineteen women completed the intervention. The use of a riboflavin supplement for 8 wk elicited a significant improvement in riboflavin status with a dose response (P < 0.0001). For women who received supplemental riboflavin, an increase in hemoglobin status correlated with improved riboflavin status (P < 0.02). Women in the lowest tertile of riboflavin status at baseline (EGRAC >1.65) showed a significantly greater increase in hemoglobin status in response to the supplement than did women in the first and second tertiles (P < 0.01). Dietary iron intake and iron absorption did not change during the study.

CONCLUSIONS

Moderately poor riboflavin status can affect iron status: the lower the riboflavin status, the greater the hematologic benefits of improving status. The results also suggest that consideration should be given to raising the currently accepted EGRAC threshold for deficiency. This trial was registered at controlled-trials.com as ISRCTN35811298.

Riboflavin (vitamin B-2) and health

Riboflavin is unique among the water-soluble vitamins in that milk and dairy products make the greatest contribution to its intake in Western diets. Meat and fish are also good sources of riboflavin, and certain fruit and vegetables, especially dark-green vegetables, contain reasonably high concentrations. Biochemical signs of depletion arise within only a few days of dietary deprivation. Poor riboflavin status in Western countries seems to be of most concern for the elderly and adolescents, despite the diversity of riboflavin-rich foods available. However, discrepancies between dietary intake data and biochemical data suggest either that requirements are higher than hitherto thought or that biochemical thresholds for deficiency are inappropriate. This article reviews current evidence that diets low in riboflavin present specific health risks. There is reasonably good evidence that poor riboflavin status interferes with iron handling and contributes to the etiology of anemia when iron intakes are low. Various mechanisms for this have been proposed, including effects on the gastrointestinal tract that might compromise the handling of other nutrients. Riboflavin deficiency has been implicated as a risk factor for cancer, although this has not been satisfactorily established in humans. Current interest is focused on the role that riboflavin plays in determining circulating concentrations of homocysteine, a risk factor for cardiovascular disease. Other mechanisms have been proposed for a protective role of riboflavin in ischemia reperfusion injury; this requires further study. Riboflavin deficiency may exert some of its effects by reducing the metabolism of other B vitamins, notably folate and vitamin B-6.

Effects of antibodies against chicken riboflavin carrier protein on fetal hepatic cell ultrastructure

Day 12 pregnant mice administered antibodies to cRCP exhibited riboflavin deprival, which resulted in progressive alteration in the fetal hepatic cell structure, which eventually led to fetal wastage and termination of pregnancy. These changes were evident as early as 1 h following antiserum treatment. Three hours following treatment, other degenerative changes such as disorganization of glycogen particles and endoplasmic reticulum and degranulation of mitochondria were observed. Nuclear pycnosis, and increased myelin figures, accumulation of lysosomes, all indicative of autolytic changes, occurred 6 h following treatment.

Effect of the protein content of the diet on the vitamin B12 status in rats

1. The effects of the protein content of the diet on the vitamin B12concentration of serum and of various tissues were studied in rats by means of microbiological and radioisotopic techniques.

2. Protein starvation reduced tissue weights and nitrogen contents, serum protein concentrations and haemoglobin values.

3. The vitamin B12contents of the serum and of several organs and tissues were greater in the protein-starved animals for reasons that remain unexplained.

4. The retention of radioactive cyanocobalamin per g fresh weight was significantly greater in liver, kidney, spleen and brain in the protein-depleted rats than in those given adequate protein. However, the total tissue retention was not significantly different between these groups, so that there was a greater capacity for tissue binding and for body conservation of vitamin B12in the protein-starved animals.