Journal of Nutrition Education Volume 25 Number 6 November. December 1993 319

evaluacion amplia del consumo de nutrientes. Este estudio se baso en una encuesta por correo, entre adultos de 18 a 70 afios de edad, seleccionados al azar, en Perth, Australia Occidental, para investigar las relaciones que existen entre las densidades de nutrientes (consumo relativo, utilizando un cuestionario dietetico) y las variables relevantes de la personalidad. Estas ultimas induyeron las tres dimensiones del Cuestionano Eysenck de la Personalidad y dos mediciones del lugar de control. El lugar de control intemo, tanto para los hombres como para las mujeres, relacionado con la alimentacion se correlaciono positivamente con la densidad de fibra y negati­vamente con la densidad de azucar refinada. Las correlaciones significativas con las variables del Cuestionario Eysenck fueron en base al sexo. En los varones, el neuroticismo (N), se correlaciono negativamente con la densidad de fibra y posiu-

vamente con la densidad de colesterol; la despreocupacion inflexible (P) se correlaciono negauvamente con la densidad de carbohidratos complejos. Por otro lado, en la mujer, la despreocupacion inflexible (P) se correlaciono negativamente con la densidad proteinica y con la densldad de sodio y positivamente con la densidad del azucar refinada; la extraver­sion (E) se relaciono positivamente con la densidad de sodio. Se concluyo que diversas caracteristicas del consumo dietetico tienen relacion con factores de la personalidad que se consid­eran relevantes para el bienestar psicologico. El analisis de regresion indico que estos factores de la personalidad eran generalmente indicadores mas positivos del consumo de nutri­entes que las variables demograficas utilizads mas frecuente­mente tales como la edad, educacion y categoria ocupacional.

RESISTANT STARCH AND INFANT NUTRITION

Research by Bjork and Siljestrom (Journal of the Science of Food and Agriculture 58: 541-533, 1992) suggests that the high resistant starch content of at least some infant purees decreases their nutritional value because resistant starch acts in a similar manner to soluble dietary fiber. This results in a lower caloric density in many foods-including infant purees-than might be expected.

The purpose of the study was to evaluate the formation of in-vivo undigestible starch under conditions that are present during the canning of infant purees. To study the question, peas and potatoes were homogenized and then heated and cooled several times, while commercial peal potato infant puree was used as is. The authors then collected feces from rats fed these materials and analyzed them for starch. One group of rats had been treated with an antibiotic to kill the colonic microflora and allow the passage of all undigested carbohydrates. The other group of rats was untreated and was used to confirm that resistant starch was indeed fermented .

The results of the in-vivo trial show that large amounts of resistant starch are present in all three diets . The processed peas had the highest amount of resistant starch-30% of total starch-followed by the infant puree with 18% and the potato product with 7%. These numbers represent a notable amount of undigested carbohydrate. The authors found that the largest proportion of undigested starch was made up of retrograded amylose-a crystalline starch fraction unavailable to amylase. The amount of crystalline starch present in the infant puree diet could have been enhanced by the slow cooling that takes place when large numbers of cans are processed. The amount of calculated dietary fiber in the infant puree was 195 glkg DM. With the addition of the undigested starch fraction, the total amount of undigested carbohydrate in the puree rose to 251 glkg DM.

The ramifications of this study for infant nutrition are uncertain. The authors state that the present study should be used when discussing appropriate intakes of undigestible carbohydrates in infancy.

Unfortunately, no benchmark level for appropriate amounts of undigestible carbohy­drate in infant diets exists. The portions of dietary fiber, soluble dietary fiber, and resistant starch present in infant diets cannot be utilized by the infant, and it is lamentable that little is known about these items in infant nutrition. However, the fundamental question resulting from this study remains-does the increased level of un digestible carbohydrates from resistant starch in infant purees have a serious impact on the caloric intake, and therefore growth, of infants? Only further research on the effect of decreased caloric density on the health and growth of infants can answer this question.

Summary written by Paul Crawford

Penn State University