SUBSTITUTION OF SOY PROTEIN FOR MEAT PROTEIN MAY IMPAIR INTESTINAL CALCIUM ABSORPTION

Research has shown that increasing dietary protein from omnivorous sources increases intestinal calcium absorption and urinary calcium. Conversely, a low-protein omnivore diet results in reduced intestinal calcium absorption and urinary calcium. It has been assumed that soy consumption may improve bone health because of the isoflavones contained in some soy proteins and due to the reduced acidogenic capacity of soy protein compared to meat protein. A study reported in the Journal of Nutrition compared the effects of soy protein alone (i.e. without isoflavones) versus meat protein in both high- and low-protein diets fed to healthy women.

Soy contributed 68% of the protein in the high-protein, soy-based diet and 48% of the protein in the low-protein, soy-based diet. Likewise, in the meat-based high- and low-protein diets, animal products contributed 77% and 46% respectively of the total protein. Consistent with previous studies, results showed that subjects consuming the high-protein diets had significantly higher urinary calcium. However, in this study there was not a difference due to the type of protein. Subjects on low-protein diets had substantially higher serum levels of parathyroid hormone (PTH), which can accelerate skeletal resorption. In addition, serum PTH was higher in subjects consuming soy diets compared with meat-based diets. There was a tendency for lower intestinal calcium absorption for subjects on the soy-based diets. In contradiction to the expected outcome, this study showed that the substitution of soy protein for meat protein does not improve calcium economy and may be detrimental to calcium balance. The authors speculate the high phytic acid content of soy foods may be at least partially responsible for impairing intestinal calcium absorption. Thus, the substitution of soy protein for meat proteins in a diet may require an increase in dietary calcium and / or vitamin D to compensate for reduced calcium bioavailability.

Citation:
Meat and Soy Protein Affect Calcium Homeostasis in Healthy Women. Kerstetter JE, Wall DE, O'Brien KO, Caseria, DM, Insogna KL.. Journal of Nutrition 2006 Jul;136(7):1890-5.

To read the abstract, go to Meat and Soy Protein Affect Calcium Homeostasis in Healthy Women.

PROVIDING NUTRITION INFORMATION AT SELECTION SITES INCREASE STUDENT MEAL SATISFACTION

Alarming statistics about childhood obesity and the percentages of youth consuming 30% of daily calories from foods with little or no nutritional value have increased the importance of the school lunch as an opportunity to impact students' food choices. Research shows that healthy eating messages are reaching students but interventions are needed to affect behavior. In addition, research shows that people, when given choices, tend to hold the belief that they are in control of outcomes and, as such, take greater responsibility for the end result. Informed choices inspire even greater feelings of empowerment in the decision-making process. Previous student research demonstrates that the availability of nutrition information is associated with more healthful food choices.

Research reported in The Journal of Child Nutrition & Management assessed the impact of nutrition information at the point of meal selection on students' satisfaction with the foods chosen and the school nutrition program in general. Results showed that, when nutrition information is provided, not only did student satisfaction with the quality of food increase, but also with the service of the food. Nutrition information, as expected, had no effect on student ratings of pricing, dining room ambiance, or perceptions of menu variety. Most importantly, results showed an increase in more healthful food selections as an aggregate number for all ninth- through twelfth-grade students.

Citation:
High School Students Are More Satisfied Customers When Nutrition Information Is Posted. Cranage DA, Conklin MT, Lambert CU. The Journal of Child Nutrition & Management, Issue 1, Spring 2006.

To read the abstract and the study, go to High School Students Are More Satisfied Customers When Nutrition Information Is Posted.

YOUNG ADOLESCENTS CAN LEARN FROM AN EDUCATIONAL PROGRAM ABOUT FOOD LABELS

As children gain increasing control over food choices, easy access to accurate nutrition information becomes an important goal. The Nutrition Facts label is the most readily available tool to facilitate healthful choices. A study reported in the Journal of the American Dietetic Association assessed adolescents' understanding of the Nutrition Facts Label as well as their response to a program teaching about the Nutrition Facts Label.

In this study, 35 adolescents, aged 11 to 14 years, participated in an educational session covering such issues as identifying components of the label, understanding the differences in nutrients consumed when more or less than the recommended serving size is eaten, and how to understand and use the percent Daily Value. Analyses of a pre-test and post-test were used to gauge the educational value of the session. The mean pre-test score was 59% and 52% for girls and boys respectively. The post-test scores improved to 76% and 64% for girls and boys respectively. Girls and boys combined improved their understanding of Daily Value from 38% to 74%. Overall, the subjects' scores improved significantly after the educational session, proving the validity of teaching the Nutrition Facts Label as part of larger programs designed to reduce the incidence of obesity in children.

Citation:

An Educational Program Enhances Food Label Understanding of Young Adolescents. Hawthorne KM, Moreland K, Griffin IJ, Abrams SA. Journal of the American Dietetic Association 2006 Jun;106(6):913-6.

To read the abstract, go to An Educational Program Enhances Food Label Understanding of Young Adolescents.

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