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Correspondence PICA HYPOTHESIS
The definition of pica is controversial and the evidence in existing literature suggests that it is not a single entity. While sonie authors consider that pica is a natural habit, others associate it with either iron or zinc deficiency. Since these studies have been carried out on different populations (Neumann, 1970;McDonald & Marshall, 1964)the reports are neither complete nor comparable. Professor BonsdorfTs ‘Pica hypothesis’ (March 1977,p 476) is interesting in view of recent data published to the effect that iron deficiency affects the functional activity of monoainineneurotransmitters (5-hydroxytryptamine and dopamine) in the CNS. This disturbance is related to a change in post-synaptic events (Youdim & Green, 1977),leading to diminished or, possibly, abnormal motor activity. This abnormality can be reversed by restoring the iron to its normal level. However, if iron deficiency is at the root of abnormal eating patterns in infants and children, it is hard to explain why only a very small group of children suffer from pica, w l d e iron deficiency appears very frequently and universally. In addition, pica has been found in children without any nutritional disturbances, including iron deficiency (Gutelius et al, 1962).Furthermore, it has been reported that pica can be cured by administration of zinc (Hambidge & Silverman, 1973).Does this imply that zinc also effects the ‘appetite centre’? Professor Bonsdorffs suggestion of further study of pica in relation to iron and appetite centre is cspecially difficult in view of the lack of uniformity and distribution of this symptom. The effects of iron deficiency on appetite and behaviour in general which are under study may not necessarily elucidate the nature of this relationship. Department of Pharmacology, The Medical School, Technion, Ha@, Israel
MOUSSA B. H. YOUDIM
THEODORE C.IANCU
Department of Paediatrics, Lady Davis Carmel Hospital, Ha$, Israel
14 March 1977 REFERENCES
G u ~ m u s ,M.F., IvIm~cm,F.K.,LAYMAN,E.M., COHEN,G.J. & DUBLIN, C.C. (1962)Nutritional studies of children with pica. Pediatrics, 29, 1021. HAMBILGE, K.M. & SILVERMAN,A. (1973)Pica with rapid improvement after dietary zinc supplementation. Archives of Diseases in Childhood, 48, 567. MCDONALD, R. & MARSHALL, S.R. (1964)Value of iron therapy in pica. Pediatrics, 34, 558.
NBUMANN. H.H. (1970)Pica-symptom or vestigial instinct. Pediatrics, 46, 441. YOUDIM,M.B.H. & GREEN, R. (1977) Biogenic monoamine metabolism and functional activity in iron deficient rats: behavioural correlates. In : Iron Metabolism. Ciba Symposium No. 5 5 (ed. by R. Porter and D. FitzSirnmons). North Holland, Amsterdam.
Correspondence PICA HYPOTHESIS
The definition of pica is controversial and the evidence in existing literature suggests that it is not a single entity. While sonie authors consider that pica is a natural habit, others associate it with either iron or zinc deficiency. Since these studies have been carried out on different populations (Neumann, 1970;McDonald & Marshall, 1964)the reports are neither complete nor comparable. Professor BonsdorfTs ‘Pica hypothesis’ (March 1977,p 476) is interesting in view of recent data published to the effect that iron deficiency affects the functional activity of monoainineneurotransmitters (5-hydroxytryptamine and dopamine) in the CNS. This disturbance is related to a change in post-synaptic events (Youdim & Green, 1977),leading to diminished or, possibly, abnormal motor activity. This abnormality can be reversed by restoring the iron to its normal level. However, if iron deficiency is at the root of abnormal eating patterns in infants and children, it is hard to explain why only a very small group of children suffer from pica, w l d e iron deficiency appears very frequently and universally. In addition, pica has been found in children without any nutritional disturbances, including iron deficiency (Gutelius et al, 1962).Furthermore, it has been reported that pica can be cured by administration of zinc (Hambidge & Silverman, 1973).Does this imply that zinc also effects the ‘appetite centre’? Professor Bonsdorffs suggestion of further study of pica in relation to iron and appetite centre is cspecially difficult in view of the lack of uniformity and distribution of this symptom. The effects of iron deficiency on appetite and behaviour in general which are under study may not necessarily elucidate the nature of this relationship. Department of Pharmacology, The Medical School, Technion, Ha@, Israel
MOUSSA B. H. YOUDIM
THEODORE C.IANCU
Department of Paediatrics, Lady Davis Carmel Hospital, Ha$, Israel
14 March 1977 REFERENCES
G u ~ m u s ,M.F., IvIm~cm,F.K.,LAYMAN,E.M., COHEN,G.J. & DUBLIN, C.C. (1962)Nutritional studies of children with pica. Pediatrics, 29, 1021. HAMBILGE, K.M. & SILVERMAN,A. (1973)Pica with rapid improvement after dietary zinc supplementation. Archives of Diseases in Childhood, 48, 567. MCDONALD, R. & MARSHALL, S.R. (1964)Value of iron therapy in pica. Pediatrics, 34, 558.
NBUMANN. H.H. (1970)Pica-symptom or vestigial instinct. Pediatrics, 46, 441. YOUDIM,M.B.H. & GREEN, R. (1977) Biogenic monoamine metabolism and functional activity in iron deficient rats: behavioural correlates. In : Iron Metabolism. Ciba Symposium No. 5 5 (ed. by R. Porter and D. FitzSirnmons). North Holland, Amsterdam.
