Identifying sources of reporting error using measured food intake.

OBJECTIVE: To investigate the magnitude and relative contribution of different sources of measurement errors present in the estimation of food intake via the 24-h recall technique. DESIGN: We applied variance decomposition methods to the difference between data obtained from the USDA's Automated Multiple Pass Method (AMPM) 24-h recall technique and measured food intake (MFI) from a 16-week cafeteria-style feeding study. The average and the variance of biases, defined as the difference between AMPM and MFI, were analyzed by macronutrient content, subject and nine categories of foods. SUBJECTS: Twelve healthy, lean men (age, 39+/-9 year; weight, 79.9+/-8.3 kg; and BMI, 24.1+/-1.4 kg/m2). RESULTS: Mean food intakes for AMPM and MFI were not significantly different (no overall bias), but within-subject differences for energy (EI), protein, fat and carbohydrate intakes were 14, 18, 23 and 15% of daily intake, respectively. Mass (incorrect portion size) and deletion (subject did not report foods eaten) errors were each responsible for about one-third of the total error. Vegetables constituted 8% of EI but represented >25% of the error across macronutrients, whereas grains that contributed 32% of EI contributed only 12% of the error across macronutrients. CONCLUSIONS: Although the major sources of reporting error were mass and deletion errors, individual subjects differed widely in the magnitude and types of errors they made.

Dietary intake of whole grains.

OBJECTIVE: The objective of this study was to provide national estimates of whole-grain intake in the United States, identify major dietary sources of whole grains and compare food and nutrient intakes of whole-grain consumers and nonconsumers. METHODS: Data were collected from 9,323 individuals age 20 years and older in USDA's 1994-96 Continuing Survey of Food Intakes by Individuals through in-person interviews on two non-consecutive days using a multiple-pass 24-hour recall method. Foods reported by respondents were quantified in servings as defined by the Food Guide Pyramid using a new database developed by the USDA. Whole-grain and nonwhole-grain servings were determined based on the proportion, by weight, of the grain ingredients in each food that were whole grain and nonwhole grain. Sampling weights were applied to provide national probability estimates adjusted for differential rates of selection and nonresponse. Then, t tests were used to assess statistically significant differences in intakes of nutrients and food groups by whole-grain consumers and nonconsumers. RESULTS: According to the 1994-96 survey, U.S. adults consumed an average of 6.7 servings of grain products per day; 1.0 serving was whole grain. Thirty-six percent averaged less than one whole-grain serving per day based on two days of intake data, and only eight percent met the recommendation to eat at least three servings per day. Yeast breads and breakfast cereals each provided almost one-third of the whole-grain servings, grain-based snacks provided about one-fifth, and less than one-tenth came from quick breads, pasta, rice, cakes, cookies, pies, pastries and miscellaneous grains. Whole-grain consumers had significantly better nutrient profiles than nonconsumers, including higher intakes of vitamins and minerals as percentages of 1989 Recommended Dietary Allowances and as nutrients per 1,000 kilocalories, and lower intakes of total fat, saturated fat and added sugars as percentages of food energy. Consumers were significantly more likely than nonconsumers to meet Pyramid recommendations for the grain, fruit and dairy food groups. CONCLUSION: Consumption of whole-grain foods by U.S. adults falls well below the recommended level. A large proportion of the population could benefit from eating more whole grain, and efforts are needed to encourage consumption.

Presence of inulin and oligofructose in the diets of Americans.

The U.S. Department of Agriculture 1994-1996 Continuing Survey of Food Intakes by Individuals was used to estimate the intake of naturally occurring inulin and oligofructose by the U.S. population. Two nonconsecutive 24-h dietary recalls from >15,000 Americans of all ages were conducted, and a special database of inulin and oligofructose was developed specifically for the analyses. American diets provided on average 2.6 g of inulin and 2.5 g of oligofructose. Intakes varied by gender and age, ranging from 1.3 g for young children to 3.5 g for teenage boys and adult males. When standardized for amount of food consumed, the intakes showed little difference across gender and age. Significant differences in intake of these components were seen between categories within region of the country, season, income, and race and origin; however, the actual differences were relatively small. Major food sources of naturally occurring inulin and oligofructose in American diets were wheat, which provided about 70% of these components, and onions, which provided about 25% of these components. The estimation of the presence of inulin and oligofructose in the diets of Americans has not been published to date.

The National Nutrition Monitoring and Related Research Program: progress and activities.

The National Nutrition Monitoring and Related Research Act of 1990 outlined a number of requirements for nutrition monitoring and research relevant to nutrition monitoring needs of today and tomorrow. The Department of Agriculture (USDA) along with the Department of Health and Human Services (HHS) are charged with carrying out the requirements. The Act legally established the National Nutrition Monitoring and Related Research Program and numerous activities including development and implementation of a Ten-Year Comprehensive Plan and formation of the Interagency Board for Nutrition Monitoring and Related Research. Both requirements serve as the basis for planning and coordinating the activities of 22 Federal agencies that either conduct nutrition monitoring surveys and surveillance activities or are major users of nutrition monitoring data. As an advisory mechanism to both USDA and HHS, the law required establishment of a 9-member National Nutrition Monitoring Advisory Council. Progress and future activity plans for the Nutrition Monitoring Program are discussed.