Nancy Van Heel

Nutritional Therapy for High Blood Pressure: Final Report of a Four-Year Randomized Controlled Trial— The Hypertension Control Program

A four-year trial assessed whether less severe hypertensives could discontinue antihypertensive drug therapy, using nutritional means to control blood pressure. Randomization was to three groups: group 1--discontinue drug therapy and reduce overweight, excess salt, and alcohol; group 2--discontinue drug therapy, with no nutritional program; or group 3--continue drug therapy, with no nutritional program. In groups 1 and 2 patients resumed drug therapy if pressure rose to hypertensive levels. Loss of at least 4.5 kg (10 + lb) was maintained by 30% of group 1, with a group mean loss of 1.8 kg (4 lb); sodium intake fell 36% and modest alcohol intake reduction was reported. At four years, 39% in group 1 remained normotensive without drug therapy, compared with 5% in group 2. Study findings demonstrated that nutritional therapy may substitute for drugs in a sizable proportion of hypertensives or, if drugs are still needed, can lessen some unwanted biochemical effects of drug treatment.

Accuracy of Energy Intake Data Estimated by a Multiplepass, 24-hour Dietary Recall Technique

OBJECTIVE This study examined the accuracy of a multiple-pass, 24-hour dietary recall method for estimating energy intakes of men and women by comparing it with energy intake required for weight maintenance. DESIGN Three-day, multiple-pass, 24-hour recalls were obtained on randomly selected days during a self-selected diet period when subjects were preparing their own meals and during a controlled diet period when all meals were provided by the study. During the dietary intervention, weight was maintained; body weight and dietary intake were monitored closely, thereby allowing estimation of the energy intake required for weight maintenance. SUBJECTS/SETTING Seventy-eight men and women (22 to 67 years old) from the Dietary Effects on Lipoprotein and Thrombogenic Activity (DELTA) study participated in this study. All 24-hour recalls were collected using a computer-assisted, interactive, multiple-pass telephone interview technique. Energy requirements for each individual were determined by the energy content of the DELTA study foods provided to maintain weight. STATISTICAL ANALYSIS Paired and independent t tests were conducted to examine differences among study variables. Agreement between recalled energy intake and weight maintenance energy intake was analyzed using the Bland-Altman technique. RESULTS Compared with weight maintenance energy intake, during the self-selected diet period men and women underestimated energy intake by 11% and 13%, respectively. During the controlled diet period, men underestimated energy intake by 13%, whereas women overestimated energy by 1.3%. APPLICATIONS/CONCLUSIONS Men had a tendency to under-estimate energy intake irrespective of the recording period. The accuracy of the recalled energy intake of women may be influenced by recording circumstances. Researchers should examine the factors influencing underreporting and overreporting by individuals and their impact on macronutrient and micronutrient intakes. Also, strategies need to be developed to minimize underreporting and overreporting.

Enhancing data on nutrient composition of foods eaten by participants in the INTERMAP study in China, Japan, the United Kingdom, and the United States

The International Study of Macronutrients and Blood Pressure (INTERMAP) is a four-country study investigating relationships between individual dietary intakes and blood pressure. Dietary intake patterns of individuals were estimated for macronutrients (proteins, lipids, carbohydrates, alcohol) and their components (amino acids, fatty acids, starch), as well as minerals, vitamins, caffeine, and dietary fiber. The dietary assessment phase of the study involved collection of four 24-h recalls and two 24-h urine specimens from each of 4680 adults, ages 40-59, at 16 centers located in the Peoples Republic of China, Japan, the United Kingdom and the United States. For each country, an available database of nutrient composition of locally consumed foods was updated for use in the analysis of dietary data collected within the country. The four original databases differed in number and types of foods and nutrients included, analytic methods used to derive nutrients, and percentage of missing nutrient values. The Nutrition Coordinating Center at the University of Minnesota updated the original databases in several ways to overcome the foregoing limitations and increase comparability in the analyses of nutrient intake of individuals across the four countries: (1) addition of new foods and preparation methods reported by study participants; (2) addition of missing nutrient fields important to the study objectives; (3) imputation of missing nutrient values to provide complete nutrient data for each food reported by participants; and (4) use of adjustment factors to enhance comparability among estimates of nutrient intake obtained through each countrys nutrient-coding methodology. It was possible to expand, enhance, and adjust the nutrient databases from the four countries to produce comparable (60 nutrients) or nearly comparable (ten nutrients) data on composition of all foods reported by INTERMAP participants.

Diet design for a multicenter controlled feeding trial : The DELTA Program

OBJECTIVE To describe the process and results of diet standardization, diet validation, and monitoring of diet composition, which were key components of protocol 1 of Dietary Effects on Lipoproteins and Thrombogenic Activity (DELTA-1), the initial protocol in a program of multicenter human feeding studies designed to evaluate the effects of amount and type of fat on lipoproteins and hemostasis parameters in various demographic groups. DESIGN DELTA-1 was based on a randomized, blinded, crossover experimental design. Three diets were fed for 8 weeks to 103 healthy men and women aged 22 to 67 years at 4 field centers. Diet A, an average American diet, was designed to provide 37% of energy from fat, 16% of energy from saturated fatty acids (SFAs); diet B (step 1 diet) was designed to provide 30% of energy from fat, 9% of energy from SFA; and diet C (low SFA diet) was designed to provide 26% of energy from fat, 5% of energy from SFA. Key features of diet standardization included central procurement of fat-containing foods, inclusion of standard ingredients, precision weighing of foods--especially sources of fat and cholesterol--and use of standardized written procedures. SETTING For menu validation, a set of 12 menus for each diet was prepared in duplicate and chemically assayed. For monitoring of diet composition during the study, an 8-day diet cycle (6 weekday and 2 weekend menus) was sampled by every field center twice during each of 3 feeding periods. STATISTICAL ANALYSES Means (+/- standard error) were calculated and compared with target nutrient specifications. RESULTS DELTA-1 was able to provide a standardized diet that met nutrient specifications across 4 field centers over 24 weeks of participant feeding spanning a total of 8 months. APPLICATIONS Prestudy chemical validation of menus and continuous sampling and assay of diets throughout the study are essential to standardize experimental diets and to ensure that nutrient target goals are met and maintained throughout a controlled multicenter feeding study.

Nonpharmacological control of hypertension

Ability to safely withdraw well-controlled mild hypertensives from drugs is being tested in a three-group randomized trial. Group I (intervention) was removed from drugs after the first 2 months of nutrition counseling. Counseling is continuing through the remaining years of the trial to achieve a minimum weight loss of 10 lb if overweight, reduction of sodium intake to less than 1,800 mg, and reduction of alcohol intake to not more than two drinks per day. Group II (the first control group) was also removed from drugs to see if previous long-term blood pressure control had a carryover effect without dietary change. Blood pressure is monitored frequently in both groups, with return to drug treatment in the event of specified blood pressure rise. Group III (the second control group) has remained on drugs for comparison of blood pressure and biochemical variables. In Group I mean 30-month weight loss was 8 lb, with 35% losing 10+ lb; sodium intake was reduced by 38%. Blood pressure control without drugs was maintained for 47% of Group I patients but only 16% of group II patients (P less than 0.05). These findings indicate it may be possible, after establishing good blood pressure control, to maintain control in a sizable proportion without medication, when reduction of weight, sodium, and alcohol intake is achieved.

Diet Design for a Multicenter Controlled Feeding Trial

OBJECTIVE To describe the process and results of diet standardization, diet validation, and monitoring of diet composition, which were key components of protocol 1 of Dietary Effects on Lipoproteins and Thrombogenic Activity (DELTA-1), the initial protocol in a program of multicenter human feeding studies designed to evaluate the effects of amount and type of fat on lipoproteins and hemostasis parameters in various demographic groups. DESIGN DELTA-1 was based on a randomized, blinded, crossover experimental design. Three diets were fed for 8 weeks to 103 healthy men and women aged 22 to 67 years at 4 field centers. Diet A, an average American diet, was designed to provide 37% of energy from fat, 16% of energy from saturated fatty acids (SFAs); diet B (step 1 diet) was designed to provide 30% of energy from fat, 9% of energy from SFA; and diet C (low SFA diet) was designed to provide 26% of energy from fat, 5% of energy from SFA. Key features of diet standardization included central procurement of fat-containing foods, inclusion of standard ingredients, precision weighing of foods--especially sources of fat and cholesterol--and use of standardized written procedures. SETTING For menu validation, a set of 12 menus for each diet was prepared in duplicate and chemically assayed. For monitoring of diet composition during the study, an 8-day diet cycle (6 weekday and 2 weekend menus) was sampled by every field center twice during each of 3 feeding periods. STATISTICAL ANALYSES Means (+/- standard error) were calculated and compared with target nutrient specifications. RESULTS DELTA-1 was able to provide a standardized diet that met nutrient specifications across 4 field centers over 24 weeks of participant feeding spanning a total of 8 months. APPLICATIONS Prestudy chemical validation of menus and continuous sampling and assay of diets throughout the study are essential to standardize experimental diets and to ensure that nutrient target goals are met and maintained throughout a controlled multicenter feeding study.

Meeting expanding needs for nutrient specificity: the NASA case study

Abstract Food and nutrient databases are populated with data obtained from a variety of sources including USDA Reference Tables, scientific journals, food manufacturers and foreign food tables. The food and nutrient database maintained by the Nutrition Coordinating Center (NCC) at the University of Minnesota is continually updated with current nutrient data that are carefully evaluated for reliability and relevance before incorporation into the database; however, some values are obtained from calculations or from similar foods rather than from direct chemical analysis of specific foods. Precise nutrient values for specific foods are essential to the nutrition program at the National Aeronautics and Space Administration (NASA). Specific foods to be included in the menus of astronauts are chemically analyzed at the Johnson Space Center for selected nutrients. A request from NASA for a method to permit NASA nutritionists to enter chemically analyzed nutrient values for space flight food items into the Nutrition Data System for Research (NDS-R) software resulted in modifications of the database and interview system. The database was expanded by entering the nutrients of interest to NASA as though they were individual foods, thereby allowing entry of a “recipe” of nutrients that exactly match the Johnson Space Center chemical analysis of each specific flight food. Subsequent work by NCC resulted in further modifications to extend the method for related uses by other research studies.