Carnitine has a fundamental biological role as a long-chain fatty acid carrier across the mitochondrial membrane and in ketone body formation. Although the body normally synthesizes carnitine, in certain circumstances such as total parenteral nutrition and haemodialysis a dietary supplement may be needed to maintain adequate levels. Several considerations suggest that carnitine is a truly essential nutrient in infancy and in other situations where the energy requirement is particularly high, e.g. pregnancy and breast feeding. There are, for example, congenital deficit syndromes due to enzymatic inadequacies. There is also the possible role of carnitine in serious metabolic disorders such as organic acidaemias and, above all, it has multiple physiological functions in major metabolic pathways which are essential for development and growth.
FrenkelG: The proposed vitamin role of carnitine. In: Carnitine Biosynthesis, Metabolism and Functions (FrenkelRAMcGarryJD, eds). New York: Academic Press, 1980; pp 1–5.
2.
RudmanDWilliamsPJ: Pathophysiologic principles of nutrition. In: Pathophysiology. The Biological Principles of Disease (SmithLHThierSO, eds). Philadelphia: WB Saunders, 1975; pp 440–452.
3.
BorumPRBennettSG: Carnitine as an essential nutrient. J Am Coll Nutr1986; 5: 177–182.
4.
BorumPR: Carnitine. Annu Rev Nutr1983; 3: 233–259.
5.
ReboucheCJPaulsonDJ: Carnitine metabolism and functions in humans. Annu Rev Nutr1986; 6: 41–66.
6.
FellerAGRudmanD: Role of carnitine in human nutrition. J Nutr1988; 118: 541–546.
7.
RudmanDAnsleyJDWhitaker SewellC: Carnitine deficiency in cirrhosis. In: Carnitine Biosynthesis, Metabolism and Functions (FrenkelRAMcGarryJD, eds). New York: Academic Press, 1980; pp 307–319.
8.
PennD.Schmidt-SommerfeldEPascuF: Decreased tissue carnitine concentrations in newborn infants receiving total parenteral nutrition. J Pediatr1981; 98: 976–978.
9.
HahnPAllardyceDBFrohlichJ: Plasma carnitine levels during total parenteral nutrition of adult surgical patients. Am J Clin Nutr1982; 36: 569–573.
10.
BowyerBAFlemingCRHaymondMW: l-Carnitine: effect of intravenous administration on fuel homeostasis in normal subjects and home-parenteral-nutrition patients with low plasma carnitine concentration. Am J Clin Nutr1989; 49: 618–623.
11.
BowyerBAFlemingCRIlstrupD: Plasma carnitine levels in patients receiving home parenteral nutrition. Am J Clin Nutr1986; 43: 85–91.
BöhlesHSegererHFekleW: Improved N-retention during l-carnitine supplemented total parenteral nutritionJ Parenter Enteral Nutr1984; 81: 9–13.
14.
YehYY: Antiketonemic and antiketogenic actions of carnitine in vivo and in vitro in rats. J Nutr1981; 111: 831–840.
15.
Anonymous: Metabolic effects of carnitine supplementation in subjects with low plasma carnitine levels. Nutr Rev1990; 48: 159–161.
16.
BremerJ: Carnitine: metabolism and functions. Physiol Rev1983; 63: 1420–1480.
17.
Jhan-SiddiquiLBamijMS: Plasma carnitine levels in adult males in India: effects of high cereal, low fat diet, fat supplementation and nutrition status. Am J Clin Nutr1980; 33: 1259–1262.
18.
LombardKAOlsonALNelsonSE: Carnitine status in lacto-ovo and strict vegetarian adult (Abstract). Am J Clin Nutr1987; 45: 862.
19.
ReboucheCJBroquistHP: Carnitine biosynthesis in Neurospora crassa: enzymatic conversion of lysine to α-N-trimethyllysine. J Bacteriol1976; 126: 1207–1210.
20.
BöhmerTMölstadP: Carnitine transport across the plasma membrane. In: Carnitine Biosynthesis, Metabolism and Functions (FrenkelRAMcGarryJD, eds). New York: Academic Press, 1980; pp 73–89.
21.
MarquisNRFritzIB: Enzymological determination of free carnitine concentrations in rat tissues. J Lipid Res1964; 5: 184–187.
22.
ReboucheCJ: Recent advances in carnitine biosynthesis and transport. In Clinical Aspects of Human Carnitine Deficiency (BorumPR, ed). New York: Pergamon Press, 1986; pp 1–15.
23.
BrooksDEMcIntoshJEA: Turnover of carnitine by rat tissues. Biochem J1975; 148: 439–445.
24.
BahlJJNavinTRBresslerR: Carnitine uptake and stimulation of carnitine uptake in the isolated beating adult rat heart myocyte. In: Carnitine Biosynthesis, Metabolism and Functions (FrenkelRAMcGarryJD, eds). New York: Academic Press, 1980; pp 91–113.
BorumPR: Disturbances in carnitine metabolism. Biochem Soc Trans1986; 14: 681–683.
30.
Di MauroG: Metabolic myopathies. In: Hand-book of Clinical Neurology, (VinkenPJBruynGW, eds). Amsterdam: Elsevier, 1979; pp 175–234.
31.
EngelAGAngeliniC: Carnitine deficiency of human skeletal muscle with associated lipid storage myopathy: a new syndrome. Science1973; 179: 899–902.
32.
RoeCRMillingtonDSMaltbyD: Status and functions of l-carnitine in Reye's syndrome and related metabolic disorders. J Natl Reye's Synd Found1983; 4: 58–59.
33.
SeccombeDWFarrellKJamesL: l-Carnitine treatment in a patient with Reye's syndrome. In: Clincial Aspects of Human Carnitine Deficiency (BorumPR, ed). New York: Pergamon Press, 1986; pp 155–156.
34.
EngelAG: Possible causes and effects of carnitine deficiency in man. In: Carnitine Biosynthesis, Metabolism and Functions (FrenkelRAMcGarryJD, eds). New York: Academic Press, 1980; pp 271–284.
35.
Rodriguez-SegadeSAlso de la PenaDPasJM: Carnitine deficiency in hemodialysed patients. Clin Chim Acta1986; 159: 249–256.
36.
BorumPRTaggartEM: Carnitine nutriture of dialysis patients. J Am Diet Assoc1986; 86: 644–647.
37.
RoeCRBohanTP: l-Carnitine therapy in propionic acidaemia. Lancet1982; ii: 1411–1412.
38.
SeccombeDWSnyderFParsonsHG: l-Carnitine for methylmalonic aciduria. Lancet1982; ii: 1401.
39.
RoeCRHoppelCLStaceyTE: Metabolic response to carnitine in methylmalonic acidura: an effective strategy for elimination of propionyl groups. Arch Dis Child1983; 58: 916–920.
RoeCRMillingtonDSMaltbyDA: Diagnostic and therapeutic implications of medium-chain acylcarnitines in the medium-chain acyl–CoA dehydrogenase deficiency. Pediatr Res1985; 19: 459–462.
42.
AllenRJHanschDBWuHLC: Hypocarnitinaemia in disorders of organic acid metabolism. Lancet1982; ii: 500–501.
43.
MandelHAfrickDBlitzerM: The importance of recognizing secondary carnitine deficiency in organic acidaemias: case report in glutaric acidaemia type II. J Inherited Metab Dis1988; 11: 397–399.
44.
HowatAJBennettMJViariendS: Defects of metabolism of fatty acids in the sudden infant death syndrome. Br Med J1985; 290: 1771–1773.
45.
AllenRHanschDBWuHLC: Hypocamitinaemia in disorders of organic acid metabolism. Lancet1982; ii: 500–504.
46.
ChalmersRARoeCRStaceyTE: Urinary excretion of l-carnitine and acylcarnitines by patients with disorders of organic acid metabolism: evidence for secondary insufficiency of l-carnitine. Pediatr Res1984; 18: 1325–1328.
47.
BougneresPFRocchiccioliFKolvraaS: Medium-chain acyl–CoA dehydrogenase deficiency in two siblings with a Reye-like syndrome. J Pediatr1985; 106: 918–922.
48.
HaleDEVariendSDe LeeuwSE: Reduced short-chain 3-hydroxyacyl–CoA dehydrogenase (HAD) activity in livers from sudden infant death syndrome victims. In: Abstracts of the Fifth International Congress on Inborn Errors of Metabolism.Asilomar: Society for Inherited Metabolic Disorders,. 1990; p 17.6.
49.
HahnPSeccombeD: Control of blood carnitine and carnitine acyltransferases in the perinatal period. In: Carnitine Biosynthesis, Metabolism and Functions (FrenkelRAMcGarryJD, eds). New York: Academic Press, 1980; pp 177–189.
50.
ScholteHRStinisJTJennekensFGI: Low carnitine levels in serum of pregnant women. N Engl J Med1984; 299: 1079.
51.
Bargen-LocknerCHahnPWittmanB: Plasma carnitine in pregnancy. Am J Obstet Gynecol1981; 140: 412–414.
52.
YoshidaTRouxJR: In vitro metabolism of palmitic acid in human fetal tissue. Pediatr Res1972; 6: 675–679.
53.
MeisamiETimirasPS: Normal and abnormal biochemical development of the brain after birth. In: Biochemcial Development of the Fetus and Neonate (JonesC, ed). New York: Elsevier, 1982; p 759.
54.
PageMAWilliamsonDH: Enzymes of ketone-body utilization in human brain. Lancet1971; ii: 66.
55.
MooreTJLioneAPSugdenMC: Hydroxybutyrate transport in rat brain: developmental and dietary modulations. Am J Physiol1976; 230: 619–623.
56.
BoothRFGPatelTBClarkJB: The development of enzymes of energy metabolism in the brain of precocial (guinea pig) and nonprecocial (rat) species. J Neurochem1980; 34: 17–23.
57.
SpitzerJJ: Application of tracers in studying free fatty acid metabolism of various organs in vitro. Fed Proc1975; 34: 2242–2246.
58.
RoeCRCoatesPM: Acyl–CoA dehydrogenase deficiencies. In: The Metabolic Basis of Inherited Disease, vol 1. New York: McGraw-Hill, 1989; pp 889–900.
59.
MorganBLGRossoP: Nutrition and brain development. In: A Quick Reference to Clinical Nutrition, 2nd edn (HalpernSL, ed). Philadelphia: Lippincote, 1987; pp 413–420.
60.
ClandidinMTChappellJEVan AerdeJEE: Requirements of newborn infants for long-chain polyunsaturated fatty acids. Acta Paediatr Scand [Suppl]1989; 351: 63–66.
61.
NeuringerMConnorWE: N-3-Fatty acids in the brain and retina: evidence for the essentiality. Nutr Rev1986; 44: 285–289.
62.
AngeliniEGovoniEBragagliaM: Carnitine deficiency: acute postpartum crisis. Ann Neurol1978; 4: 558–561.
