ABSTRACT
I. Introduction ..................................................................................................449 II. Choline Chemistry, Metabolism, and Function ............................................ 450 III. Choline De ciency ....................................................................................... 451 IV. Nutritional Importance of Choline during Pregnancy ................................. 452 V. Dietary Recommendations for Choline ........................................................ 453 VI. Choline and Folate Interrelationship ............................................................ 453
A. Metabolic Implications ............................................................................ 453 1. Folate Intake and Biomarkers of Choline Status ................................. 453 2. Genetic Variation in Folate-Metabolizing Enzymes and Biomarkers of Choline Status .............................................................. 455 3. Choline Intake and Biomarkers of Folate Status ................................. 457
B. Potential Health Implications................................................................... 458 VII. Summary and Conclusions ........................................................................... 459 References ..................................................................................................... 459
The nutritional importance of choline was recognized in 1932 by Charles Best, codiscoverer of the hormone insulin. In a series of elegant experiments, Best et al. [1-3] demonstrated the essential role of choline in the prevention of fatty liver in rodents and depancreatized dogs. A decade later, Schaefer et al. [4] provided evidence of the metabolic intermingling of choline and folate by demonstrating that folate had a choline-sparing effect in rats and chicks. The term lipotropic was subsequently coined to describe dietary agents such as choline and folate that prevented or reduced accumulation of fat in liver [5,6]. More recently, the possible use of choline as a homocysteine (Hcy)-lowering agent [7,8] and the establishment of a dietary recommendation [9] have stimulated immense interest in choline, its interplay with
folate, and its role in disease prevention. The objectives of this chapter are to provide an overview of the metabolism, function, and essentiality of choline; describe the interrelationship between folate and choline; and consider the potential health implications of this reciprocal relationship.
