Use of fat-modified food products to change dietary fat intake of young people.

Food purchasing and preparation practices were modified in two boarding high schools to increase the polyunsaturated-to-saturated fat ratio (P/S) of the diet of students by changing food products rather than attempting to change eating behaviors. During years when fat-modified products were served, the P/S of males increased by 75 percent, versus a decrease of 6 percent during control years. For females, P/S increased by 53 percent during intervention years, versus an increase of 6 percent during control years.

Effects on blood pressure of a decrease in sodium use in institutional food preparation: the Exeter-Andover Project.

To judge the effect on blood pressure, sodium intake of students at two boarding high schools was reduced by 15-20% through changes in food purchasing and in preparation practices in the schools' kitchens. Students were not asked to change their usual eating habits. Each school served alternately as the control or intervention school for one school year. Blood pressure was monitored among 341 subjects during control years and 309 subjects during intervention years. Analysis of blood pressure differences between early in the school year and near the end of the school year, with adjustment for sex and initial blood pressure, showed the effect of the dietary intervention to be -1.7 mmHg for systolic (95% CI = -0.6, -2.9, p = 0.003) and -1.5 mmHg for diastolic pressure (95% CI = -0.6, -2.5, p = 0.002). Such modest and easily attainable changes in sodium intake, if maintained, could have a significant effect on the future risk of essential hypertension among young people.

The environmental component: changing school food service to promote cardiovascular health.

An environmental program directed at the food service departments of two boarding high schools has been tested in a concurrently controlled longitudinal investigation in which the intervention was applied to each school in alternate years. It has been demonstrated that changes in food purchasing and preparation practices can markedly decrease sodium and modify the fat composition of foods, and that such practices result in significant changes in the nutrient intake of students. Even without an educational component for students, who maintained their usual dietary practices, the changes by food service workers led to 15-20% less sodium intake, 20% less saturated fat intake, and an increase in the P/S ratio from 0.46 to 0.84 among students. The change in sodium intake over a school year resulted in lower blood pressure among students receiving the intervention. Adjusting for sex and baseline blood pressure, the estimated effect of the intervention on systolic pressure was -1.7 mmHg (95% C.I. -0.6, -2.9; p = 0.003); for diastolic pressure, it was -1.5 mmHg (95% C.I. -0.6, -2.5; p = 0.002). Such modifications by school food service workers are well accepted and produce very palatable foods. The widespread dissemination of such practices could favorably affect cardiovascular risk factors of students everywhere.

Sources of sodium, potassium, and energy in the diets of adolescents.

Analysis of food diaries of 200 students in two boarding high schools indicated that 30% of their average daily sodium intake was contributed by bakery foods and ready-to-eat cereals. The next most important source of sodium (24%) was a category made up of food adjuncts, snack-type foods, soups, and beverages. The largest proportion of sodium in most foods had been added during food manufacture or preparation. Salt added at the table contributed less than 1% of the sodium in the diets of the teenagers. All students did not eat foods from all categories on their day of recording; 70% or more ate bakery products, dairy foods, food adjuncts, and meat, fish, poultry, and eggs. Changes in recipe formulations can decrease sodium content for a variety of bakery products, cereals, mixed dishes, snack-type foods, soups, and processed meats. It is therefore possible to make large reductions in dietary sodium without disturbing other nutrient values.

Dietary sodium reduction among students: feasibility and acceptance.

Modifications in the preparation of food served in a boarding high school during a 5-week period were successful in decreasing the sodium content of a variety of food products by an average of 51%. Such food was, in general, well accepted. The ratings of specific reduced-sodium food products equaled those of similar products containing "usual" amounts of sodium. Food diaries kept by students gave estimates of total sodium intake comparable with those measured by laboratory analysis of 24-hour food collections. Food diaries collected from an average of 70 volunteers per week indicated that during the reduced-sodium period, the total sodium intake of students, including that from dining hall food, snack food, and food consumed outside the school, decreased from 136 mEq (3 gm sodium, 8 gm salt) to 88 mEq (2 gm sodium, 5 gm salt), a reduction of 35% (p less than .0001). The impact of salt added at the table was very small; the choice and the quantity of foods consumed were the main determinants of sodium intake. The results indicate that foods can be prepared with appreciably less sodium and still be highly acceptable to young people.

Family cooperation and effectiveness in a cholesterol-lowering diet.

An average reduction in serum cholesterol approximating 10 per cent was achieved in a short-term, family-centered study in which intakes of cholesterol and saturated fats were decreased and sunflower oil and margarine were added as the major sources of polyunsaturated fats. Dietary Achievement Scores demonstrated shifts in food consumption between baseline and diet periods. Changes were evident in all fat-containing food groups; meat was the least altered. A high degree of cooperation was evident in participating families, implying the possibilities for complete family cooperation in preventive or therapeutic dietary programs. Approximately three months after the end of the test period, cholesterol levels had returned to pre-diet levels, indicating the need for continuation of the changed regimen if cholesterol-lowering is to be maintained.