32. 33. lamic expression of ART, a novel gene related to agouti, is up-regulated in obese and diabetic mu- tant mice. Genes Dev 19973 1 593-602 Ollmann MM, Wilson BD, Yang YK, et al. Antago- nism of central melanocortin receptors in vitro and in vivo by agouti-related protein. Science 1997;278: Graham M, Shutter zyxwvuts JR, Sarmiento zyxwvut U, et at. Overex- pression of Agrt leads to obesity in transgenic mice. 34. 35. 135-8 Nat Genet 1997;17:273-4 Yaswen L, Diehl N, Brennan MB, Hochgeschwender U. Obesity in the mouse model of pro-opiomelano- cortin deficiency responds to peripheral melano- cortin. Nat Med 1999;5:1066-70 Zemel MB, Moore JW, Moustaid N, et al. Effects of a potent melanocortin agonist on the diabetidobese phenotype in yellow mice. Int J Obes 1998;22:678- 83 zyxw Is Fruit Juice a “No-no’’ in Children’s Diets? zyxw In addition to milk and other beverages, juices in reasonable quantities (12 fl ozlday or less) pro- vide nutrients infants need while keeping sugar and food energy intakes adequate. The rising prevalence of obesity in preschool and school children has immediate health consequencesand may lead to health problems later in life.’ In 1997, Dennison et al? reported that young children’s high fruit juice intakes (> 12 fl odday; approximately 194caloriesdependingonjuice) were associated with slightly shorter stature and heavier weights compared with lower intakes (4-12 fl odday). The study was small, however, and failed to recognize that both obesity and short stature have multiple causes, as Troiano and Flegal have Recent observations of children by Skinner et a1.4 failed to confirm Dennison et al.’s above-mentioned findings. The two studies do agree on several other points about juices in children’s diets. Fruit juice was not substituted for milk in either study.2~~ Even among children consuming greater than 12 fluid ounces ofjuice per day, milk consumption was sufficient to meet children’s calcium needs. Soft drink intake was inversely associated with both milk and juice intake in both st~dies.~,~ Both of these studies raise several questions about the role of various beverages containing sugar in the di- ets of young children. What sugars and what beverages are young children consuming today? What is an appro- priate daily intake of milk,juices, and soft drinks? What is the effect ofjuice consumption on total sugar and caloric intake? The report of the Year 2000 Dietary Guidelines for Americans Advisory Committee5 recommended “choos- ing beverages and foods to limit your intake of sugars,” and the 1995Guidelinescalled for “choosing a diet moder- This review was prepared by Rachel Emerson Doucette, M.S., and Johanna T. Dwyer, DSc., R.D., Tufts University Schools of Nutrition and Medicine and New England Medical Center Hospital, Boston, MA 02111, USA. ate in sugar^."^ Within recommended intake levels and with appropriate oral hygiene, foods and beverages con- taining sugars cause few specific health problems in most children, even though these foods and beverages and all tasty and calorically dense foods may increase the risk of obesity. Although cases are rare, in some children other health problems are associated with dietary sugars. Table 1 presents a zyxwv summary of specific disorders associated with certain sugars in the diets of preschool children. Fermentable sugars such as sucrose, fructose, glu- cose, and lactose; cooked starches; and inverted sugars if retained in the mouth can be fermented by Streptococ- z cus mutans and other cariogenic bacteria via glycolysis to pyruvic acid, which destroys tooth enamel and leads to dental caries.’ Lactose or milk sugar, a naturally occurring fermentable sugar that is in all mammalian milks, is the carbohydrate consumed in largest quantities by breast- fed infants.aMilk-based infant formulas are also relatively high in sugars, most of which is lacto~e.~ Lactose occurs in the matrix of other nutrients, however, including cal- cium phosphate, which act as a buffering systemthat remin- eralizes the tooth enamel after acid-associated deminer- alization. Moreover, the fat content in milk may also be cariostatic or anticariogenic. Various types of milks and milk products are very high in lactose. Lactase deficiency and lactose intoler- ance may cause large amounts of lactose to ferment in the colon resulting in a chronic, nonspecific, osmotic diar- rhea. Lactose-fiee formulasand milks are now widely avail- able for persons with such problems. Table 2 presents the sugar content of commonly con- sumed fruit juices. Sorbitol, a sugar alcohol present in relatively large amounts in pear, apple, grape, and prune juices and some sugar-free candies, but not in citrusjuices, is not absorbed in the gut. In high doses it also causes a chronic, nonspecific, osmotic diarrhea.%“ Consumption of sorbitol-containing juices should be limited to zy 8 fluid ounces per day, especially in the diets of children with fructose malabsorption, nonorganic failure to thrive, or other gastrointestinal problem^.^,^^ Fructose is a commonly consumed monosaccharide that must be limited in children with fructose deficiency. 180 Nutrition Reviewsa, Vol. 58, No. z 6