Nutr. Metabol. 20: 9 13 (1976)

Serum Vitamin B , 2 Levels in Protein-Malnourished Children Bola O .A . Osifo and B.K. Adadevoh' Departments o f Nutrition and Chemical Pathology, Faculty o f Medicine, University o f Ibadan,Ibadan

Key Words. Children ■ Protein-malnourished • Vitamin Bu • Liver enlargement Abstract. Serum vitamin B ,2 levels were assayed in 25 healthy and 35 protein-malnour­ ished children aged I 6 years. Serum proteins and haematocrit values o f the children were also measured. Liver enlargement was estimated clinically. The mean serum vitamin Bw activity among protein-malnourished children was slightly higher than that for the control group. Serum vitamin Bu activity o f the healthy Nigerian children was, however, high, and possible reasons for this are discussed in detail. There was some correlation between very high serum vitamin B u levels among the protein-malnour­ ished children and incidence o f liver enlargement.

High serum vitamin B|2 level has been proposed as a diagnostic index for the fatty liver degeneration that accompanies kwashiorkor (Spector et al., 1966). Satoskar et al. (1962) were able to correlate the high serum vitamin B|2 levels with the fatty liver change in hypoproteinaemic children in India. They also observed that there was a marked fall in the serum vitamin B|2 levels when definite improvement was established. This observation was confirmed by Spcrtor et al. (1966) in their study in South Africa. Since liver damage is almost always present in protein malnutrition (Gillman and Gillman, 1951), it would be expected that vitamin B 12 metabolism might be impaired as this vitamin is stored in the liver. Some workers have even suggested that liver dysfunction of sufficient degree might interfere with the storage o f the vitamin (Merrit et al., 1962).

' The authors are grateful to Alim i Jeje and Alaba Adeyetni for their technical assis­ tance.

Downloaded by: University of Connecticut 132.174.250.220 - 1/6/2020 1:09:08 PM

Received: October 15, 1974; accepted: October 13. 1975.

Osifo/A dadevoh

10

This paper deals with the study o f serum vitamin B ,2 in both healthy and protein-malnourished children. The study was set up to compare the serum vitamin B 12 levels o f protein-malnourished and healthy children and see whether the results could be correlated with the incidence o f enlarged liver in the pro­ tein-malnourished children. Materials and Methods 60 children aged 1 6 years were involved in this study. 25 o f them were normal healthy children and they served as the control group. The remaining 35 were proteinmalnourished, with well-marked symptoms such as oedema, muscle wasting and growth retardation. Collection o f samples. 2 ml o f venous blood were taken from each child before any treatment was given, using disposable syringes and needles. The sample was allowed to clot at room temperature and the separated serum was used for vitamin B 12 assay. Serum vitamin B ,, was assayed by the microbiological method described by Spray (1962). The test organism was ¡Mctobacillus leichmannii (National Collection o f Industrial Bacteria, Torry Research Station, Aberdeen, Catalogue No. 8117). Serum proteins were measured by the method o f Wool ton (1964). Haematocrit was determined in duplicates with the use o f heparinized capillary tubes and a microhaematocrit centrifuge. Since enlarged liver is usually present in protein malnutrition, the simple clinical test used to diagnose the enlarged liver was based on the measurement o f liver size. This was done by palpating the abdomen in the midline and in the nipple line as described by Oomen (1957).

Results The serum vitamin B|2 concentrations in control and malnourished children are shown in table 1. The mean values for both groups are very high but slightly higher in the malnourished group. There was wide individual variation within Table 1. Vitamin B l2 and protein in the serum o f normal and protein-malnourished children and haematocrit values Controls, n = 25

Serum vitamin B l2, pg/ml Serum protein, g/100 ml Haematocrit, %

Protein-malnourished n = 35

mean range

SD

mean range

SD

735 7.30 35

506 0.14 3.9

932 4.4 32

476 0.6 6.6

150 1,512 6 .6 -8 .1 23 -44

225 1,825 3 .2 -5 .9 20 45

Downloaded by: University of Connecticut 132.174.250.220 - 1/6/2020 1:09:08 PM

t-test for serum vitamin B tJ levels: p < 0.10.

Scrum Vitamin Bu Levels in Protein-Malnourished Children

11

Table II. Distribution o f serum vitamin Bl: levels in the control and malnourished group Serum vitamin B 12, pg/ml

Controls, %

Malnourished, %

400 4 00-800 800 1,200 1.200 1,600 1,600 2.000

20 40 30 10 -

10 25 40 20 5

Table ///. Relationship between serum vitamin B ,2 levels and incidence o f enlarged liver among protein-malnourished children Serum vitamin B l2, pg/ml

Number o f subjecls

Number with enlarged liver

400 400 800 800 1.200 1.200-1,600 1,600 2,000

4 8 14 7 2

_ 1 5 5 2

each group. The concentration o f serum protein was much lower in the malnour­ ished group. The distribution of serum vitamin B i 2 levels in the control and malnour­ ished children is shown in table II. The relationship between enlarged liver and serum vitamin B )2 levels in the protein malnourished group is shown in table 111.

Discussion

Downloaded by: University of Connecticut 132.174.250.220 - 1/6/2020 1:09:08 PM

The results in this study suggest that serum vitamin B ,2 levels in proteinmalnourished children were slightly higher than in healthy controls, but there was wide individual variation within each group. A similar difference has been reported by various workers (Satoskar et ai. , 1962; Spector et al., 1966: Khalil et a i, 1973). In this study, the healthy control children had high senim vitamin B|2 levels (mean = 735 pg/ml). High levels among Nigerian children were first observed by Edozien (1965), and have also been observed in adults (Fleming. 1968; Osifo, 1973). Many theories have been put forward to explain these high serum B ,2 concentrations among Nigerians, for dietary intakes o f this vitamin are very low.

12

The possibility o f medication with vitamin B n can be safely ruled out in this population. Brandt et at. (1963) suggested that hepatic disease was the likely cause o f high serum vitamin B n concentrations observed in Africans, and this suggestion has been supported by Smith (1966). This explanation does not seem tenable among the normal control children because total serum proteins were within normal limits even among those who had serum vitamin B )2 concentra­ tions above 800 pg/ml. Renal failure as being a cause o f high serum B|2 (R elief et aL, 1965) was also excluded from this study by routine methods. Fleming (1968) has suggested that high serum vitamin B 12 observed among Nigerians could be due to high serum-binding capacity. This suggestion becomes difficult to accept in view o f the even higher values for protein-malnourished children with low serum proteins but no clinical sign o f hepatic damage. Recent work by Osuntokun et al. (1974) has shown that methyl B i2 is the predominant serum form o f cobalamin among Nigerians. Hence, the accumulation o f inactive cyanocobalamin being the cause o f high serum B ,2 in this population is very unlikely. A possible explanation for the high serum vitamin B|2 concentrations among Nigerians is microbial synthesis o f this vitamin in the gastrointestinal tract. While there is no doubt about possible synthesis, the site o f synthesis has not been confirmed. Since the absorption o f the vitamin is confined to the ileum, tlie synthesis must occur proximal to it. Another possible explanation for these high serum vitamin B 12 levels is a genetic one. A study thereof is in progress. Satoskar et al. (1962) were able to correlate the incidence o f liver damage with high serum vitamin B i2 levels among protein-malnourished children in India. Spector et al. (1966) confirmed this and they suggested that raised serum vitamin B )2 could serve as a diagnostic index for the liver damage that accom­ panies protein malnutrition. Their argument was based on the fact that the damage done to the liver would interfere with the storage o f the vitamin in the liver. In this study, some o f the protein-malnourished children had enlarged livers, and enlarged livers occurred more frequently in children who had serum vitamin B )2 levels above 1,000 pg/ml. It should also be noted that enlarged liver oc­ curred more often in the younger children below 3 years o f age. It is suggested that when the liver can no longer store the vitamin, the vitamin accumulates in the serum, and must be secreted into the urine since the vitamin is water-soluble. We have not studied vitamin B !2 output in the urine in this investigation. Our present work continues, but so far it seems that our results support the observations o f Satoskar et al. (1962) and Spector et al (1966). Since not all the protein-malnourished children with high serum vitamin B i2 levels had enlarged livers, we recommend that other diagnostic methods to assess liver damage should accompany measurement o f serum vitamin B 12.

Downloaded by: University of Connecticut 132.174.250.220 - 1/6/2020 1:09:08 PM

Osifo/A dadevoh

Scrum Vitamin B ,¡ Levels in Protein-Malnourished Children

13

References Brandt, V.: Kerrich, J.E ., and Metz, J .: The distribution o f serum vitamin Bu concentra­ tions in some population groups in South Africa. S. Afr. J . med. Sci. 28: 125-131 (1963).

Edozien, J .C .: establishment o f biochemical norm for the evaluation o f nutritional status in west Africa. Jl W. Afr. Sci. Ass. 10: 3 - 9 (1965). Fleming, A .F .: Serum vitamin Bu and vitamin-B,¡-binding capacity o f southern Nigerian blood donors. W. Afr. med. J . 17: 2 5 -3 0 (1968). Gillman, J. and Gillman, T. : Perspectives in human nutrition, p. 230 (Gruñe & Stratton, New York 1951).

Khalil, M .: Tanios, A .: Moghazy, M.: Aref, M .K .: Mahmoud, S., and El Lozy, M .: Serum and red cell folates, and serum vitamin B)2 in protein calorie malnutrition. Archs Dis. C'hildh. 48: 366 369(1973). Merrit, A .D . , Rucknagel, D .L : Silverman, M ., and Gardiner, R .C .: Urinary urocanicacid in man. The identification o f urocanic acid and the comparative excretion o f urocanic acid and N-formiminoglutamic acid after oral histidine in patients with liver disease. J . clin. Invest. 41: 1472 1483(1962). Oomen, H .A .P .C .: The relationship between liver size, malaria and diet in Papuan children. J . trop. Geogr. Med. 9: 84 -93 (1957). Osifo. B .O .A .: Vitamins and brain function. Proc. Int. Sem. on the Nutritional Influences on Function o f the Nervous System , Ibadan 1973. Osuntokun, B .O .: Mathews, D.M . . Hussein, H .A .A .: Wise, I.J., and Linnell, J .C .: Plasma and hepatic cobalamins in tropical ataxic neuropathy. Clin. Sci. mol. Med. 46: 563-567 (1974). Satoskar, R .C . , Kutkarni, B.S.: Mehta, B.M.: Sanzgiri, R .R ., and Bamji, M .S.: Scrum vitamin B ,j and folic acid (PGA) levels in hypo-proteinaemia and marasmus in Indian children. Archs Dis. C'hildh. 37: 9 16 (1962). Smith, A .D .: Plasma thiocyanate and vitamin B 1S in neurological disease. Lancet i: 1207 1208(1966). Spector, 1.: Faloke, H .C.: Yoffe. Y., and Metz, J .: Observations on urocanic acid and formiminoglutamic acid excretion in infants with protein malnutrition. Am . J . clin. Nutr. 18: 42 6 -4 3 6 (1966). Spray. G .H .: The estimation o f significance o f the level o f vitamin B, 2 in serum. Post-grad, med. J .3 8 : 35-40(1962 ). Wootton, I.D .P .: Micro-analysis in medical biochemistry (Churchill, London 1964).

Downloaded by: University of Connecticut 132.174.250.220 - 1/6/2020 1:09:08 PM

Dr. Bola O.A. Osifo. Department o f Nutrition, Faculty o f Medicine. University o f Ibadan, Ibadan (Nigeria)