Checking for completeness of 24-h urine collection using para-amino benzoic acid not necessary in the Observing Protein and Energy Nutrition study

BACKGROUND/OBJECTIVES

The orally administered para-amino benzoic acid (PABA) is known to have near 100% excretion in urine and is used as a measure of 24-h urine collection completeness (referred to as PABAcheck). The purpose was to examine the effect of including urine collections deemed incomplete based on PABAcheck in a dietary measurement error study.

SUBJECTS/METHODS

The Observing Protein and Energy Nutrition (OPEN) study was conducted in 1999-2000 and included 484 men and women aged 40-69 years. A food frequency questionnaire and 24-h dietary recalls were evaluated using recovery biomarkers that included urinary nitrogen and potassium from two 24-h urine collections. Statistical modeling determined the measurement error properties of dietary assessment instruments. In the original analyses, PABAcheck was used as a measure of complete urine collection; incomplete collections were either excluded or adjusted to acceptable levels. The OPEN data were reanalyzed including all urine collections and by using criteria based on self-reported missing voids to assess the differences.

RESULTS

Means and coefficients of variation for biomarker-based protein and potassium intakes, and measurement error model-based correlations and attenuation factors were similar regardless of whether PABAcheck or missed voids were considered.

CONCLUSION

PABAcheck may not be required in large population-based biomarker studies. However, until there are more analyses evaluating the necessity of a PABAcheck, it is recommended that PABA be given to all participants, but not necessarily analyzed. Then, PABAcheck could be used selectively as a marker of completeness among the collections in which low levels of biomarker are detected or for which noncompliance is suspected.

Flavonoid intake and risk of pancreatic cancer in the National Institutes of Health-AARP Diet and Health Study Cohort

Background:

Limited epidemiological studies show inverse associations between dietary flavonoid intake and pancreatic cancer risk, but results are inconsistent and are based on few cases. We examined the association between intake of flavonoids and pancreatic cancer risk in the large, prospective National Institutes of Health-AARP Diet and Health Study Cohort.

Methods:

During follow-up through 2006 (median follow-up 10.6 years), 2379 pancreatic cancer cases were identified. We used Cox proportional hazards modelling to estimate hazard ratios (HRs) and 95% confidence intervals (CIs).

Results:

We found no association between total flavonoid intake (Q5 vs Q1 HR=1.09, 95% CI: 0.96–1.24) or any flavonoid subtypes and pancreatic cancer risk. Significant interactions were not observed by age, sex, smoking status, BMI or diabetes.

Conclusion:

Our results do not support the hypothesis that flavonoids have a protective role in pancreatic cancer carcinogenesis.

Food Intake Recording Software System, version 4 (FIRSSt4): a self-completed 24-h dietary recall for children

The Food Intake Recording Software System, version 4 (firsst4), is a web-based 24-h dietary recall (24 hdr) self-administered by children based on the Automated Self-Administered 24-h recall (ASA24) (a self-administered 24 hdr for adults). The food choices in firsst4 are abbreviated to include only those reported by children in US national surveys; and detailed food probe questions are simplified to exclude those that children could not be expected to answer (e.g. questions regarding food preparation and added fats). ASA24 and firsst4 incorporate 10 000+ food images, with up to eight images per food, to assist in portion size estimation. We review the formative research conducted during the development of firsst4. When completed, firsst4 will be hosted and maintained for investigator use on the National Cancer Institute's ASA24 website.

The accuracy of the Goldberg method for classifying misreporters of energy intake on a food frequency questionnaire and 24-h recalls: comparison with doubly labeled water

BACKGROUND/OBJECTIVES

Adults often misreport dietary intake; the magnitude varies by the methods used to assess diet and classify participants. The objective was to quantify the accuracy of the Goldberg method for categorizing misreporters on a food frequency questionnaire (FFQ) and two 24-h recalls (24HRs).

SUBJECTS/METHODS

We compared the Goldberg method, which uses an equation to predict total energy expenditure (TEE), with a criterion method that uses doubly labeled water (DLW), in a study of 451 men and women. Underreporting was classified using recommended cut points and calculated values. Sensitivity and specificity, positive predictive value (PPV) and negative predictive value and the area under the receiver operating characteristic curve (AUC) were calculated. Predictive models of underreporting were contrasted for the Goldberg and DLW methods.

RESULTS

AUCs were 0.974 and 0.972 on the FFQ, and 0.961 and 0.938 on the 24HR for men and women, respectively. The sensitivity of the Goldberg method was higher for the FFQ (92%) than the 24HR (50%); specificity was higher for the 24HR (99%) than the FFQ (88%); PPV was high for the 24HR (92%) and FFQ (88%). Simulation studies indicate attenuation in odds ratio estimates and reduction of power in predictive models.

CONCLUSIONS

Although use of the Goldberg method may lead to bias and reduction in power in predictive models of underreporting, the method has high predictive value for both the FFQ and the 24HR. Thus, in the absence of objective measures of TEE or physical activity, the Goldberg method is a reasonable approach to characterize underreporting.

Associations between food patterns defined by cluster analysis and colorectal cancer incidence in the NIH-AARP diet and health study

BACKGROUND/OBJECTIVES

To examine associations between food patterns, constructed with cluster analysis, and colorectal cancer incidence within the National Institutes of Health-AARP Diet and Health Study.

SUBJECTS/METHODS

A prospective cohort, aged 50-71 years at baseline in 1995-1996, followed until the end of 2000. Food patterns were constructed, separately in men (n=293,576) and women (n=198,730), with 181 food variables (daily intake frequency per 1000 kcal) from a food frequency questionnaire. Four large clusters were identified in men and three in women. Cox proportional hazards regression examined associations between patterns and cancer incidence.

RESULTS

In men, a vegetable and fruit pattern was associated with reduced colorectal cancer incidence (multivariate hazard ratio, HR: 0.85; 95% confidence interval, CI: 0.76, 0.94), when compared to less salutary food choices. Both the vegetable and fruit pattern and a fat-reduced foods pattern were associated with reduced rectal cancer incidence in men. In women, a similar vegetable and fruit pattern was associated with colorectal cancer protection (age-adjusted HR: 0.82; 95% CI: 0.70, 0.95), but the association was not statistically significant in multivariate analysis.

CONCLUSIONS

These results, together with findings from previous studies support the hypothesis that micronutrient dense, low-fat, high-fiber food patterns protect against colorectal cancer.

Index-based dietary patterns and risk of colorectal cancer: the NIH-AARP Diet and Health Study

The authors compared how four indexes-the Healthy Eating Index-2005, Alternate Healthy Eating Index, Mediterranean Diet Score, and Recommended Food Score-are associated with colorectal cancer in the National Institutes of Health-AARP Diet and Health Study (n = 492,382). To calculate each score, they merged data from a 124-item food frequency questionnaire completed at study entry (1995-1996) with the MyPyramid Equivalents Database (version 1.0). Other variables included energy, nutrients, multivitamins, and alcohol. Models were stratified by sex and adjusted for age, ethnicity, education, body mass index, smoking, physical activity, and menopausal hormone therapy (in women). During 5 years of follow-up, 3,110 incident colorectal cancer cases were ascertained. Although the indexes differ in design, a similarly decreased risk of colorectal cancer was observed across all indexes for men when comparing the highest scores with the lowest: Healthy Eating Index-2005 (relative risk (RR) = 0.72, 95% confidence interval (CI): 0.62, 0.83); Alternate Healthy Eating Index (RR = 0.70, 95% CI: 0.61, 0.81); Mediterranean Diet Score (RR = 0.72, 95% CI: 0.63, 0.83); and Recommended Food Score (RR = 0.75, 95% CI: 0.65, 0.87). For women, a significantly decreased risk was found with the Healthy Eating Index-2005, although Alternate Healthy Eating Index results were similar. Index-based dietary patterns that are consistent with given dietary guidelines are associated with reduced risk.

The EPIC nutrient database project (ENDB): a first attempt to standardize nutrient databases across the 10 European countries participating in the EPIC study

OBJECTIVE

This paper describes the ad hoc methodological concepts and procedures developed to improve the comparability of Nutrient databases (NDBs) across the 10 European countries participating in the European Prospective Investigation into Cancer and Nutrition (EPIC). This was required because there is currently no European reference NDB available.

DESIGN

A large network involving national compilers, nutritionists and experts on food chemistry and computer science was set up for the 'EPIC Nutrient DataBase' (ENDB) project. A total of 550-1500 foods derived from about 37,000 standardized EPIC 24-h dietary recalls (24-HDRS) were matched as closely as possible to foods available in the 10 national NDBs. The resulting national data sets (NDS) were then successively documented, standardized and evaluated according to common guidelines and using a DataBase Management System specifically designed for this project. The nutrient values of foods unavailable or not readily available in NDSs were approximated by recipe calculation, weighted averaging or adjustment for weight changes and vitamin/mineral losses, using common algorithms.

RESULTS

The final ENDB contains about 550-1500 foods depending on the country and 26 common components. Each component value was documented and standardized for unit, mode of expression, definition and chemical method of analysis, as far as possible. Furthermore, the overall completeness of NDSs was improved (>or=99%), particularly for beta-carotene and vitamin E.

CONCLUSION

The ENDB constitutes a first real attempt to improve the comparability of NDBs across European countries. This methodological work will provide a useful tool for nutritional research as well as end-user recommendations to improve NDBs in the future.

OPEN about obesity: recovery biomarkers, dietary reporting errors and BMI

OBJECTIVE

Obesity-related under-reporting of usual dietary intake is one of the most persistent sources of bias in nutrition research. The aim of this paper is to characterize obese and non-obese individuals with respect to reporting errors observed with two common dietary instruments, using energy and protein recovery biomarkers as reference measures.

POPULATION AND METHODS

This report employs data from the Observing Protein and Energy Nutrition (OPEN) study. Analyses are based on stratified samples of 211 (57 obese) men and 179 (50 obese) women who completed 24-h recalls (24HR), food frequency questionnaires (FFQ), doubly labelled water (DLW) and urinary nitrogen (UN) assessments.

RESULTS

In obese and non-obese subgroups, FFQ yielded lower energy and protein intake estimates than 24HR, although biomarker-based information indicated under-reporting with both dietary instruments. Gender differences in obesity-related bias were noted. Among women, the DLW-based energy requirement was 378 kcal greater in obese than in non-obese groups; the FFQ was able to detect a statistically significant portion of this extra energy, while the 24HR was not. Among men, the DLW-based energy requirement was 485 kcal greater in the obese group; however, neither FFQ nor 24HR detected this difference in energy requirement. Combining protein and energy estimates, obese men significantly over-reported the proportion of energy from protein using the 24HR, but not with the FFQ. In obese women, no significant reporting error for energy percent protein was observed by either method. At the individual level, correlations between energy expenditure and reported energy intake tended to be weaker in obese than non-obese groups, particularly with the 24HR. Correlations between true and reported protein density were consistently higher than for protein or energy alone, and did not vary significantly with obesity.

CONCLUSION

This work adds to existing evidence that neither of these commonly used dietary reporting methods adequately measures energy or protein intake in obese groups. The 24HR, while capturing more realistic energy distributions for usual intake, may be particularly problematic in the obese.

Precision of the doubly labeled water method in a large-scale application: evaluation of a streamlined-dosing protocol in the Observing Protein and Energy Nutrition (OPEN) study

OBJECTIVE

To evaluate whether the doubly labeled water (DLW) method is precise under conditions required for a large-scale evaluation of dietary intake instruments.

DESIGN

Energy expenditure was measured in 484 subjects (main study). Subjects received one of five different weight DLW dose bottles prepared in advance of the study. A repeat energy expenditure measure was obtained in a subset of 24 subjects (substudy). DLW measures of energy expenditure were performed over a 2-week interval with urine collection at the beginning and end.

SETTING

Free-living environment with three clinic visits in the Maryland suburban area of Washington, DC.

SUBJECTS

A total of 484 subjects (261 men and 223 women) aged 40-69 y, 24 of whom (13 men and 11 women) participated in a substudy in which DLW was administered a second time.

RESULTS

The coefficient of variation of the DLW energy expenditure measurement was 5.1%. This included a 2.9% analytical and a 4.2% physiologic variation. Based on observed initial isotopic enrichment, the preweighed dosages were optimal in 70% of the main study subjects, and 9% received a dose that was less than optimal. Only six subjects (1%) were excluded because the final isotopic enrichment was too low to conduct precise measurement.

CONCLUSIONS

Use of preweighed DLW dosages did not compromise the precision of the DLW method. The DLW method is a reliable measure of energy expenditure for large-scale evaluations of dietary intake instruments.

Design and serendipity in establishing a large cohort with wide dietary intake distributions : the National Institutes of Health-American Association of Retired Persons Diet and Health Study

In 1995-1996, the authors mailed a food frequency questionnaire to 3.5 million American Association of Retired Persons members who were aged 50-69 years and who resided in one of six states or two metropolitan areas with high-quality cancer registries. In establishing a cohort of 567,169 persons (340,148 men and 227,021 women), the authors were fortunate in that a less-than-anticipated baseline response rate (threatening inadequate numbers of respondents in the intake extremes) was offset by both a shifting and a widening of the intake distributions among those who provided satisfactory data. Reported median intakes for the first and fifth intake quintiles, respectively, were 20.4 and 40.1 (men) and 20.1 and 40.0 (women) percent calories from fat, 10.3 and 32.0 (men) and 8.7 and 28.7 (women) g per day of dietary fiber, 3.1 and 11.6 (men) and 2.8 and 11.3 (women) servings per day of fruits and vegetables, and 20.7 and 156.8 (men) and 10.5 and 97.0 (women) g per day of red meat. After 5 years of follow-up, the cohort is expected to yield nearly 4,000 breast cancers, more than 10,000 prostate cancers, more than 4,000 colorectal cancers, and more than 900 pancreatic cancers. The large size and wide intake range of the cohort will provide ample power for examining a number of important diet and cancer hypotheses.

Comparative validation of the Block, Willett, and National Cancer Institute food frequency questionnaires : the Eating at America's Table Study

Researchers at the National Cancer Institute developed a new cognitively based food frequency questionnaire (FFQ), the Diet History Questionnaire (DHQ). The Eating at America's Table Study sought to validate and compare the DHQ with the Block and Willett FFQs. Of 1,640 men and women recruited to participate from a nationally representative sample in 1997, 1,301 completed four telephone 24-hour recalls, one in each season. Participants were randomized to receive either a DHQ and Block FFQ or a DHQ and Willett FFQ. With a standard measurement error model, correlations for energy between estimated truth and the DHQ, Block FFQ, and Willett FFQ, respectively, were 0.48, 0.45, and 0.18 for women and 0.49, 0.45, and 0.21 for men. For 26 nutrients, correlations and attenuation coefficients were somewhat higher for the DHQ versus the Block FFQ, and both were better than the Willett FFQ in models unadjusted for energy. Energy adjustment increased correlations and attenuation coefficients for the Willett FFQ dramatically and for the DHQ and Block FFQ instruments modestly. The DHQ performed best overall. These data show that the DHQ and the Block FFQ are better at estimating absolute intakes than is the Willett FFQ but that, after energy adjustment, all three are more comparable for purposes of assessing diet-disease risk.

Association of awareness, intrapersonal and interpersonal factors, and stage of dietary change with fruit and vegetable consumption: a national survey

PURPOSE

To examine associations of awareness, intrapersonal and interpersonal factors, and stage of change with consumption of fruits and vegetables.

DESIGN

Nationally representative, random digit dial survey conducted in 1997 with a response rate of 44.5%. Psychosocial correlates of fruit and vegetable consumption were assessed using regression analyses.

SETTING

United States.

SUBJECTS

A total of 2605 adults who were 18 years and older.

MEASURES

Awareness of the "5 A Day for Better Health" program and its message, along with stage of change; taste preferences; self-efficacy; and perceived benefits, barriers, threats, social support, and norms related to fruit and vegetable consumption.

RESULTS

Awareness and intrapersonal and interpersonal factors explained 24% of the variance in fruit and vegetable consumption beyond the 9% explained by demographic characteristics. Knowledge of the 5 A Day message was associated with a 22% increase in fruit and vegetable consumption. Self-efficacy for eating fruits and vegetables and taste preferences (affect) were the factors most consistently and strongly associated with both higher consumption and higher likelihood of being in action or maintenance stages of change. Affect and perceived barriers were more strongly associated with increased vegetables and salad than fruit.

CONCLUSIONS

Dietary intervention programs to increase fruit and vegetable consumption should emphasize the 5 A Day message, increased self-efficacy, and ways to make vegetables more palatable and easily accessible. Understanding the factors that influence dietary choices should be used when designing dietary interventions.

Is shorter always better? Relative importance of questionnaire length and cognitive ease on response rates and data quality for two dietary questionnaires

In this study, the authors sought to determine the effects of length and clarity on response rates and data quality for two food frequency questionnaires (FFQs): the newly developed 36-page Diet History Questionnaire (DHQ), designed to be cognitively easier for respondents, and a 16-page FFQ developed earlier for the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial. The PLCO Trial is a 23-year randomized controlled clinical trial begun in 1992. The sample for this substudy, which was conducted from January to April of 1998, consisted of 900 control and 450 screened PLCO participants aged 55-74 years. Controls received either the DHQ or the PLCO FFQ by mail. Screenees, who had previously completed the PLCO FFQ at baseline, were administered the DHQ. Among controls, the response rate for both FFQs was 82%. Average amounts of time needed by controls to complete the DHQ and the PLCO FFQ were 68 minutes and 39 minutes, respectively. Percentages of missing or uninterpretable responses were similar between instruments for questions on frequency of intake but were approximately 3 and 9 percentage points lower (p < or = 0.001) in the DHQ for questions on portion size and use of vitamin/mineral supplements, respectively. Among screenees, response rates for the DHQ and the PLCO FFQ were 84% and 89%, respectively, and analyses of questions on portion size and supplement use showed few differences. These data indicated that the shorter FFQ was not better from the perspective of response rate and data quality, and that clarity and ease of administration may compensate for questionnaire length.

Etiologic and early marker studies in the prostate, lung, colorectal and ovarian (PLCO) cancer screening trial

The Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, which is randomizing 74,000 screening arm participants (37,000 men, 37,000 women; ages 55-74) and an equal number of nonscreened controls, is a unique setting for the investigation of the etiology of cancer and other diseases and for the evaluation of potential molecular markers of early disease. At entry, baseline information is collected by questionnaire on dietary intake, tobacco and alcohol use, reproductive history (for women), family history of cancer, use of selected drugs, and other selected risk factors. Blood samples collected at the baseline screening exam are aliquoted to serum, plasma, red blood cell, and buffy coat fractions. At the next two annual screening visits, serum samples are collected. At the third annual reexamination, cryopreserved whole blood is obtained, in addition to serum, plasma, red blood cell, and buffy coat fractions. At the fourth and fifth years, serum, plasma, and buffy coat are collected. All blood samples are shipped to a central repository for long-term storage at -70 degrees C. Dietary questionnaires and buccal cells for DNA analysis are obtained from nonscreened controls. Cancer cases are identified through annual follow-up questionnaires, and all deaths are identified through vital status tracing mechanisms. Procedures are being developed to obtain archival pathologic material for selected cases of cancer and related diseases. Initial investigations are focusing on the etiology of colorectal cancer and on the operative characteristics of tests for the early detection of colorectal and prostate cancer.

Evaluation of alternative approaches to assign nutrient values to food groups in food frequency questionnaires

Although every food frequency questionnaire (FFQ) requires a nutrient database to produce nutrient intake estimates, it is often unclear how a particular database has been generated. Moreover, alternative methods for constructing a database have not been rigorously evaluated. Using 24-hour recalls from the 1994-1996 Continuing Survey of Food Intake by Individuals, the authors categorized 5,261 individual foods reported by 10,019 adults into 170 food groups consistent with line items on an FFQ. These food groups were used to generate 10 potential nutrient databases for a FFQ that varied by whether the authors 1) used means or medians, 2) did or did not consider age, 3) incorporated collapsing strategies for small age-gender-portion size cells, 4) excluded outliers in a regression, and 5) used weighted median nutrient density x age-gender-portion size-specific median gram weights (Block method). Mean error, mean squared error, and mean absolute error were calculated and compared across methods, with error being the difference in total observed (from recalls for each individual) and total estimated intake (from each of the 10 methods) for seven nutrients. Mean methods for assigning nutrients to food groups were superior to median approaches for all measurements. Among the mean methods, no single variation was consistently better.

Evaluation of 2 brief instruments and a food-frequency questionnaire to estimate daily number of servings of fruit and vegetables

BACKGROUND

Measurement of fruit and vegetable intake is important in the surveillance of populations and in epidemiologic studies that examine the relations between diet and disease. Some situations require the use of brief dietary assessment tools.

OBJECTIVE

Our objective was to evaluate the performance of 2 brief dietary assessment instruments, a 7-item standard screener and a new 16-item screener, and a complete food-frequency questionnaire (FFQ) in measuring total fruit and vegetable consumption.

DESIGN

About 800 men and women from the National Institutes of Health-AARP Diet and Health Study completed an FFQ, 1 of the 2 screeners, and two 24-h dietary recalls. Fruit and vegetable intakes as measured by each screener and the FFQ were compared with estimated true usual intake by using a measurement-error model.

RESULTS

Median daily servings of fruit and vegetables were underestimated by both screeners. The estimated agreement between true intake and the screener was higher for the new screener than for the standard screener and was higher for women than for men. The estimated agreement between true intake and the FFQ was higher than that for both screeners. Attenuation coefficients for the FFQ and screeners were comparable.

CONCLUSIONS

For estimating median intakes of fruit and vegetables and the prevalence of recommended intakes being met, the use of screeners without appropriate adjustment is suboptimal. For estimating relative risks in the relations between fruit and vegetable intake and disease, screeners and this FFQ are similar in performance.

Diet and lung cancer mortality: a 1987 National Health Interview Survey cohort study

OBJECTIVES

To study the association between diet and lung cancer mortality in the United States.

METHODS

Records from 20,195 participants with usable dietary data in the 1987 National Health Interview Survey were linked to the National Death Index. Baseline diet was assessed with a 59-item food-frequency questionnaire. Food groups (fruits, vegetables, total meat/poultry/fish, red meats, processed meats, dairy products, breakfast cereals, other starches, added fats, and alcohol) were analyzed in cause-specific Cox proportional hazard regression models adjusted for age, gender and smoking.

RESULTS

There were 158 deaths from lung cancer (median follow-up 8.5 years). Frequencies of meat/poultry/fish intake (relative risk [RR] (highest compared to lowest quartile) = 2.0; 95% confidence interval [CI] 1.2-3.5, p for trend [p] < 0.027), and red meat intake (RR = 1.6; CI 1.0-2.6, p < 0.014), were positively and significantly associated with lung cancer mortality. Specifically, the red meats, including pork (RR = 1.6; CI 1.0-2.7, p < 0.028), and ground beef (RR = 2.0; CI 1.1-3.5, p < 0.096) were associated with increased risk, although for ground beef the trend was not significant. Dairy products (RR = 0.5; CI 0.3-0.8, p < 0.009) were inversely associated with lung cancer mortality. There was no statistically significant association between intake of fruits and vegetables and lung cancer mortality.

CONCLUSIONS

In this nationally representative study, intake of red meats was positively associated with lung cancer mortality while intake of dairy products was inversely associated. While smoking is the major risk for lung cancer mortality, diet may have a contributory role.

Nonvitamin, nonmineral dietary supplements: issues and findings from NHANES III

The Commission on Dietary Supplement Labels encourages nutrition professionals to become knowledgeable about all dietary supplements. The Dietary Supplement Health and Education Act of 1995 (DSHEA) expanded the definition of dietary supplements beyond essential nutrients while distinguishing them from drugs or food additives. In order to give practical advice to consumers and policymakers, dietetics professionals need to understand the implications resulting from this less-restrictive regulatory environment for supplements. Dietetics professionals must also become familiar with claims made by manufacturers, retailers, and others regarding popular nonvitamin, nonmineral (NVNM) supplements, as well as usage prevalence and trends. However, NVNM supplements currently are classified inconsistently, and information on the prevalence of use is limited. Sales data suggest that total intake is increasing, and garlic and ginseng are consistently among the most popular supplements. Reported use of NVNM supplements in the third National Health and Nutrition Examination Survey was highest for garlic and lecithin. The data suggest associations of NVNM supplement use with age and more healthful lifestyles; however, there is also a reported link with higher alcohol consumption and obesity. Associations with education, income, region, and urbanization are not evident from the sales data. Standardized survey procedures regarding question phraseology, referent time period, and supplement categorization--along with use of representative samples--will improve our ability to assess supplement use, prevalence, and trends.

Low energy reporters vs others: a comparison of reported food intakes

OBJECTIVE

To partition the food reports of low energy reporters (LERs) and non-LERs into four aspects-tendency to report a given food, frequency of reports per user, portion sizes per mention, and the qualitative (low-fat, low-sugar, low-energy) differences of the reports-in order to determine what differentiates them from one another. ASSESSMENT METHOD: Two non-consecutive 24h dietary recalls. Low energy reporting was defined as energy intake lower than 80% of estimated basal metabolic rate.

SETTING

In-home personal interviews.

SUBJECTS

8334 adults from a stratified, multi-stage area probability sample designed to be representative of noninstitutionlized persons residing in households in the United States.

RESULTS

Across all different types of foods, there are those food groups which LERs are less likely to report (28 of 44 food groups), those which they report less frequently when they do report them (15 of 44 groups), and those for which they report smaller quantities per mention (26 of 44). Qualitative differences in the food choices-that is, differences in fat, sugar, and/or energy content-were not so widespread (4 of 24 food groups).

CONCLUSIONS

The practical application of analyses such as these is to improve the methods of gathering dietary data so that this kind of bias can be reduced. Further methodological research is needed to reduce the likelihood of respondents neglecting to mention foods and underestimating portion sizes.

Dietary sources of nutrients among US children, 1989-1991

OBJECTIVE

To identify major food sources of nutrients and dietary constituents for US children.

METHODS

Twenty-four-hour dietary recalls were collected from a nationally representative sample of children age 2 to 18 years (n = 4008) from the US Department of Agriculture's 1989-1991 Continuing Survey of Food Intakes by Individuals. For each of 16 dietary constituents, the contribution of each of 113 food groups was obtained by summing the amount provided by the food group for all individuals and dividing by total intake from all food groups for all individuals.

RESULTS

Milk, yeast bread, cakes/cookies/quick breads/donuts, beef, and cheese are among the top 10 sources of energy, fat, and protein. Many of the top 10 sources of carbohydrate (yeast bread, soft drinks/sodas, milk, ready-to-eat cereal, cakes/cookies/quick breads/donuts, sugars/syrups/jams, fruit drinks, pasta, white potatoes); protein (poultry, ready-to-eat cereal, pasta); and fat (potato chips/corn chips/popcorn) also contributed >2% each to energy intakes. Ready-to-eat cereal is among the top contributors to folate, vitamin A, vitamin C, iron, and zinc intakes. Fruit drinks, containing little juice, contribute approximately 14% of total vitamin C intakes.

CONCLUSIONS

Fortified foods are influential contributors to many vitamins and minerals. Low nutrient-dense foods are major contributors to energy, fats, and carbohydrate. This compromises intakes of more nutritious foods and may impede compliance with current dietary guidance.

Dietary sources of nutrients among US adults, 1989 to 1991

OBJECTIVE

To identify major food sources of 27 nutrients and dietary constituents for US adults.

DESIGN

Single 24-hour dietary recalls were used to assess intakes. From 3,970 individual foods reported, 112 groups were created on the basis of similarities in nutrient content or use. Food mixtures were disaggregated using the US Department of Agriculture (USDA) food grouping system.

SUBJECTS/SETTING

A nationally representative sample of adults aged 19 years or older (n = 10,638) from USDA's 1989-91 Continuing Survey of Food Intakes by Individuals. ANALYSES PERFORMED: For each of 27 dietary components, the contribution of each food group to intake was obtained by summing the amount provided by the food group for all respondents and dividing by total intake from all food groups for all respondents.

RESULTS

This article updates previous work and is, to the authors' knowledge the first to provide such data for carotenes, vitamin B-12, magnesium, and copper. Beef, yeast bread, poultry, cheese, and milk were among the top 10 sources of energy, fat, and protein. The following other major sources also contributed more than 2% to energy intakes: carbohydrate: yeast bread, soft drinks/soda, cakes/cookies/ quick breads/doughnuts, sugars/syrups/jams, potatoes (white), ready-to-eat cereal, and pasta; protein: pasta; and fat: margarine, salad dressings/mayonnaise, and cakes/ cookies/quick breads/doughnuts. Ready-to-eat cereals, primarily because of fortification, were among the top 10 food sources for 18 of 27 nutrients.

APPLICATIONS/CONCLUSIONS

These analyses are the most current regarding food sources of nutrients and, because of disaggregation of mixtures, provide a truer picture of contributions of each food group.

Trends in food intake: the 1987 and 1992 National Health Interview Surveys

To examine food intake trends in the US population, cross-sectional nationally representative food intake data were obtained from the 1987 and 1992 National Health Interview Survey Cancer Control Supplements. In each of these years, approximately 10,000 respondents completed methodologically consistent food frequency questionnaires containing the same 57 food items. Between 1987 and 1992, the proportion of Americans consuming high-fat foods, including fried fish, fried chicken, bacon, eggs, whole milk, and butter, decreased. The proportion of Americans drinking alcoholic beverages also decreased: fewer drank wine and hard liquor in 1992. The proportion of fruit and vegetable consumers remained stable over time. These results are similar to those obtained from more detailed national surveys. National guidelines urge Americans to avoid intake of high-fat foods, increase consumption of fruits and vegetables, and practice moderation when drinking alcoholic beverages to prevent cancer and other chronic diseases. The direction of Americans' apparent changes in food usage between 1987 and 1992, evaluated using limited data from food frequency questionnaires, suggests greater behavioral changes in the direction of guidelines recommending avoidance of foods that may increase the risk of cancer than in the direction of guidelines recommending increased consumption of foods that may confer protection.

Dietary intake of fat, fiber and other nutrients is related to the use of vitamin and mineral supplements in the United States: the 1992 National Health Interview Survey

Supplement intake is hypothesized to increase the risk of some diseases while decreasing the risk of others. Both diet and lifestyle behaviors, however, may be associated with supplement use and confound observed associations. Nutrient intake from a food frequency questionnaire, demographic characteristics and lifestyle among supplement users and nonusers were examined in 11,643 adults who participated in the 1992 National Health Interview Survey Epidemiology Supplement. Forty-six percent reported taking a supplement in the past year; 24% reported daily use. Daily use was highest among women, whites, those 75 y of age or older, those at or above the poverty level, those with more than 12 y of education, former smokers, and light drinkers consuming less than one alcoholic beverage per week. When controlled for sociodemographic factors, smoking status and drinking habits, there were no significant (P < 0.01) differences in dietary nutrient intake between daily and occasional supplement users. Compared with those of nonusers, diets of vitamin supplement users were lower (P < 0.001) in fat and higher in fiber and vitamins A and C for both men and women and higher in vitamin E and calcium for women only. In general, diet, demographic and lifestyle characteristics of supplement users are typical of patterns associated with low risk of chronic disease.

Fruit and vegetable intakes of children and adolescents in the United States

OBJECTIVES

To identify the ways in which fruits and vegetables are consumed by children, to provide estimates of their intakes compared with recommendations, and to estimate the percentage of children meeting those recommendations.

DESIGN

We examined 3 days of dietary data from respondents in the US Department of Agriculture's 1989-1991 Continuing Survey of Food Intakes by Individuals. All foods reported in the survey were disaggregated into their component ingredients; all fruit and vegetable ingredients were assigned specific weights to correspond with a serving as defined by current dietary guidance materials; and the number of servings of each fruit and vegetable was tallied.

PARTICIPANTS

A total of 3148 children and adolescents aged 2 to 18 years in the 48 conterminous United States.

MAIN OUTCOME MEASURES

Percentages of fruit and vegetable servings consumed in various forms, mean number of servings consumed per day, and percentage of persons meeting various recommendations by sex/age, race/ethnicity, and household income.

RESULTS

Nearly one quarter of all vegetables consumed by children and adolescents were french fries. Their intakes of all fruits and of dark green and/or deep yellow vegetables were very low compared with recommendations. Only one in five children consumed five or more servings of fruits and vegetables per day.

CONCLUSION

Pediatricians should encourage the consumption of fruits and vegetables, especially dark green and deep yellow vegetables, by children.

US adults' fruit and vegetable intakes, 1989 to 1991: a revised baseline for the Healthy People 2000 objective

OBJECTIVES

This study provides revised baseline data for the Healthy People 2000 objective related to fruit and vegetable intakes, accounting for fruits and vegetable intakes, accounting for fruits and vegetables from all sources and measuring servings in a manner consistent with current dietary guidance.

METHODS

Dietary data from 8181 adults in the US Department of Agriculture's 1989-1991 Continuing Surveys of Food Intakes by Individuals were examined. All foods were disaggregated into their component ingredients; all fruit and vegetable ingredients were assigned specific weights to correspond to a serving as defined by current dietary guidance materials; and the number of servings was tallied.

RESULTS

While mean intakes of fruits and vegetables--4.3 servings per day--were not far from the Year 2000 objective, only 32% of American adults' intakes met the objective. When more stringent standards were set either to compensate for higher calorie levels or to achieve the balance between fruits and vegetables suggested in current guidance, only 24% and 12%, respectively, met the recommendations.

CONCLUSIONS

These results suggest a need to develop strategies for overcoming barriers to eating fruits and vegetables.

Psychosocial factors associated with fruit and vegetable consumption

PURPOSE

This study examined the relationship between various psychosocial factors and fruit and vegetable consumption.

DESIGN

The 5 A Day Baseline Survey, conducted in August 1991, just before the initiation of the 5 A Day for Better Health Program, obtained data on adults' intakes of, and their knowledge, perceptions, and attitudes regarding, fruits and vegetables.

SETTING

The survey was conducted by telephone.

SUBJECTS

Subjects were 2811 adults (response rate, 43%) aged 18 years and older in the 48 coterminous United States.

MEASURES

Fruit and vegetable intake was measured as self-reported frequency of use; most of the psychosocial variables were measured using Likert scales.

RESULTS

This study estimates that only 8% of American adults thought that five or more servings of fruits and vegetables were needed for good health. Of the factors studied, the most important in determining someone's fruit and vegetable intake were the number of servings they thought they should have in a day, whether they liked the taste, and whether they had been in the habit of eating many fruits and vegetables since childhood. These few factors accounted for 15% more of the variation in fruit and vegetable consumption than did demographic variables alone (8%).

CONCLUSIONS

Nutrition education should stress the need to eat five or more servings of fruits and vegetables per day because few adults are aware of this recommendation and such knowledge is strongly associated with increased intake. Furthermore, efforts to increase the palatability of fruits and vegetables, especially among children, should be promoted.

Zinc intake and sources in the US adult population: 1976-1980

OBJECTIVE

To determine levels of intake and food sources of zinc in 1976-80 in US adults between the ages of 19 and 74.

METHODS

Dietary data from 24-hour recalls collected in the Second National Health and Nutrition Examination Survey were analyzed. Levels of zinc intake were compared between demographic subgroups using analysis of variance. The contribution of individual foods to overall zinc consumed was also estimated.

RESULTS

Mean daily intakes (+/- SEM) were 15.5 mg +/- 0.4 and 9.8 mg +/- 0.2 in white men and women, respectively. Mean daily intake estimates in black men and women (12.3 mg +/- 0.8 and 7.8 mg +/- 0.3, respectively) were significantly lower. Lower intakes were observed in women versus men, in older (65 to 74 years) versus younger (19 to 34 years) age groups, and among people with lower versus higher education and income levels. Lower zinc intakes in women and older persons could be mainly attributed to lower overall energy intake compared with gender and age counterparts. However, lower intakes in blacks and persons with lower education or income levels were not explained by differences in energy intake and may be attributed to differences in food selections. Meat and milk products contributed the majority of zinc in recalled diets, accounting for 56 and 60% of total zinc intake in blacks and whites, respectively.

CONCLUSIONS

Levels and sources of zinc intake in 1976-80 were higher than in more recent national surveys, suggesting that zinc intakes may be declining. Population groups more likely to have lower intakes were women, older adults, blacks, and those with lower levels of education and higher poverty levels.

Improving food frequency questionnaires: a qualitative approach using cognitive interviewing

In an attempt to improve data quality and ease of administration of standard self-administered food frequency questionnaires, various alternative approaches were tried for inquiring about frequency of consumption, portion size, seasonal intake, and food preparation. Evaluation consisted of a cognitive interviewing method in which respondents verbalize their thought process while completing several variations of a questionnaire. Interviewers observed and asked follow-up probe questions to evaluate problems or inconsistencies verbalized by respondents. Consensus and judgment by interviewers and observers suggested several problematic features of food frequency questionnaires: formatting of questions about frequency and portion size; computing average frequencies for aggregated food items or for foods eaten seasonally; comprehension of many items; and ordering of foods. These findings led to cognitive refinement and innovations, which included detailed questions regarding preparation or use of low-fat varieties or other alternatives to help better describe specifics of intake for some foods; questions on seasonal intake for several foods; inclusion of portion size ranges; and additional response categories for frequency of intake. Cognitive interviewing is an important step in pinpointing cognitive problems in dietary questionnaires.

Fruit and vegetable intake in the United States: the baseline survey of the Five A Day for Better Health Program

PURPOSE

The purpose of the Five A Day Baseline Survey was to assess fruit and vegetable intake and associated factors among US adults.

DESIGN

Questionnaires querying frequency of intake of 33 fruits and vegetables, as well as demographics, attitudes, and knowledge related to fruits and vegetables were administered by telephone.

SETTING

The study was a nationally representative random digit dial survey conducted by telephone in the summer of 1991; response rate was 42.8%.

SUBJECTS

Respondents were 2811 US adults (including an oversample of African-Americans and Hispanics).

MEASURES

Mean and median self-reported intakes of fruits and vegetables were calculated. Estimated servings per week were adjusted on the basis of responses to summary questions regarding overall fruit and vegetable intakes.

RESULTS

Median intake of fruits and vegetables was 3.4 servings per day. Linear regressions (accounting for no more than 10% of the variation) showed that education, income, and smoking status were predictors of fruit and vegetable intake and that intake increased with education, income, and nonsmoking status. Women had higher intakes than men at all ages; these differences between men and women increased with age. Fruit and vegetable intakes increased with age for whites and Hispanics, but not for African-Americans.

CONCLUSIONS

Fruit and vegetable intake among adults in the United States is lower than the recommended minimum of five daily servings. These data will be useful in targeting campaign efforts and in assessing progress of the Five A Day for Better Health Program.

Fruit and vegetable intake among adults in 16 states: results of a brief telephone survey

A brief food frequency questionnaire was used to assess daily fruit and vegetable consumption among 23,699 adults in 16 US states sampled in a random-digit dialing telephone survey. Men consumed fewer servings per day (3.3) than did women (3.7). Only 20% of the population consumed the recommended 5 or more daily servings. Intakes varied somewhat by state and were lower among the young and the less educated. Efforts are needed to improve fruit and vegetable consumption among all Americans, especially younger adults and those with lower levels of education.

Differences in reported food frequency by season of questionnaire administration: the 1987 National Health Interview Survey

We assessed seasonal reporting bias in a 59-item food frequency questionnaire (FFQ) administered throughout 1 year using data from the 1987 National Health Interview Survey (N = 20,143 adults). Few meaningful differences were found in the proportion of individuals reporting rarely or never consuming a food by season of questionnaire administration. Seasonal reporting bias is evident in FFQs, however, and appears to be due to reporting most recent consumption. Using gender-specific median servings per week, an analysis using logistic regression showed that the estimated proportion of individuals reporting food intake at greater than the yearly median differed between any two seasons by at least 5% of the population for 22 foods. We compared gender-specific quintiles of selected nutrients/food groups for the whole year and each season; these showed that quintile assignment never varied by more than one adjacent quintile. The most frequent shift in quintile assignment, involving as many as 18.5% of women in the summer, occurred for citrus fruits. The intake biases are small and do not greatly affect population estimates if the FFQ is administered in all seasons, but they may somewhat affect classification of individuals into quantiles for some foods/nutrients.

US dietary patterns associated with fat intake: the 1987 National Health Interview Survey

OBJECTIVES

This research used food frequency data to investigate dietary patterns associated with fat intake.

METHODS

Data from the 1987 National Health Interview Survey of 20,143 adults were used to determine correlations between fat (adjusted for kilocalories) and both nutrient and food group intakes. Median food and nutrient intakes were determined within quartiles of percentage of kilocalories from fat.

RESULTS

Intakes of vegetables, fruits, cereals, fish/chicken, low-fat milk, alcoholic beverages, vitamin C, percentage of kilocalories from carbohydrates, carotenoids, folate, dietary fiber, carbohydrates, and vitamin A decreased as percentage of kilocalories from fat increased. Intakes of salty snacks, peanuts, processed and red meats, whole milk and cheese, desserts, eggs, fried potatoes, table fats, cholesterol, vitamin E, sodium, protein, and energy increased with percentage of kilocalories from fat. Results by demographic subgroups showed few differences from those found in the total population.

CONCLUSIONS

Fat intake is consistently associated with specific dietary patterns. Such patterns need to be evaluated concurrently in studies of diet and chronic disease.

Dietary patterns associated with a low-fat diet in the national health examination follow-up study: identification of potential confounders for epidemiologic analyses

To identify systematically the nutrient and food group intakes associated with a low-fat diet, the authors used the detailed dietary information collected from 10,306 individuals aged 32-86 years in the 1982-1984 National Health Epidemiologic Follow-up Study. Intakes of vitamin C and percentages of calories from carbohydrates, dietary fiber, poultry, low-fat dairy products, fruits, vegetables, cereals, and whole grains were markedly higher, while intakes of protein, total fat, saturated fat, oleic and linoleic acids, cholesterol, sodium, all red meats, high-fat dairy products, eggs, nuts, white bread, fried potatoes, desserts, fats, and oils were much lower in the quartile with the lowest percentage of calories from fat. These dietary patterns associated with a low-fat diet were essentially constant across strata of age, sex, race, and socioeconomic status. This study suggests that individuals on a low-fat diet substitute certain carbohydrate-rich foods such as fruits and vegetables for fat. Given these associations between low-fat diets and other dietary factors independently associated with certain cancers, these dietary factors should be considered potential confounders in studies of dietary fat and these cancers.

Estimates of nutrient intake from a food frequency questionnaire: the 1987 National Health Interview Survey

Nutrient intake data are reported from a 60-item food frequency questionnaire administered in the 1987 National Health Interview Survey to a representative sample of US adults 18 to 99 years of age (n = 22,080). These data provide for the first time an estimate of the distribution of usual nutrient intakes in a national probability sample. For several nutrients, 10% to 25% of respondents may habitually consume substantially less than the Recommended Dietary Allowance, despite apparently adequate group means. Hispanics reported higher energy and carbohydrate intakes and a lower percentage of energy from fat than blacks or whites (35.6%, 38.4%, and 38.7% of energy from fat for Hispanics, blacks, and whites, respectively.) Whites had lower cholesterol intake than the other two groups, and blacks had a higher intake of sweets. Alcohol intake was lower among women and persons older than 65 years, but no other differences in alcohol intake emerged. Use of adjustment factors improved nutrient intake estimates from this shortened questionnaire to levels similar to those obtained from other national dietary surveys. The nutrient intake data from this research can be used to compare demographic subgroups and to describe the mean and distribution of nutrient intake. Furthermore, this research provides national reference data to investigators who use this or related questionnaires in nutrition research.

Does beta-carotene explain why reduced cancer risk is associated with vegetable and fruit intake?

Increased intake of vegetables, fruits, and carotenoids and elevated blood levels of beta-carotene are consistently associated with reduced risk of lung cancer in epidemiologic studies. Epidemiologic research also suggests that carotenoids may reduce the risk of other cancers, although the evidence is less extensive and consistent. The simplest explanation is that beta-carotene is protective. However, the possible roles of other carotenoids, other constituents of vegetables and fruits, and associated dietary patterns have not been adequately explored. To evaluate these alternative hypotheses, we are undertaking three lines of research. (a) With dietary data from the 1987 National Health Interview Survey and the 1982-1984 Epidemiologic Follow-up of the first National Health and Nutrition Examination Study, we have determined which food groups and nutrients are highly correlated with vegetable and fruit intake. (b) We have developed and characterized a liquid chromatography method for optimal recovery and resolution of the common carotenoids in blood, specifically lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha-carotene, and beta-carotene. (c) In a population-based case-control study of lung cancer in white men in New Jersey, we are assessing whether estimates of the intake of the individual carotenoids might produce stronger inverse associations than estimates of provitamin A carotenoids based on current food composition tables.

Use of vitamin and mineral supplements: demographics and amounts of nutrients consumed. The 1987 Health Interview Survey

Data from the 1987 National Health Interview Survey show that 51.1% of the adults aged 18-99 years in the United States consumed a vitamin/mineral supplement in the past year, but that only 23.1% did so daily. Whites, women, and older individuals were more likely than blacks, men, and younger individuals to consume supplements regularly. Multivitamins were the most commonly consumed supplement, followed by vitamin C, calcium, vitamin E, and vitamin A. Results suggest that supplementation practices have changed little since the 1970s. Results regarding the amounts of nutrients obtained from supplements show that a food frequency type of methodology collects reasonably accurate data reflecting intake of supplements over the past year. Few, if any, individuals were consuming nutrients in amounts considered toxic. Although vitamin and mineral supplementation is a common health habit, it appears not to pose a significant health risk for most of the population.

Food and nutrient intake differences between smokers and non-smokers in the US

Data from the Second National Health and Nutrition Examination Survey were analyzed to determine food and nutrient intake differences between current smokers (also categorized as light, moderate, and heavy smokers) and non-smokers. Smokers in several age-race-sex categories have lower intakes of vitamin C, folate, fiber, and vitamin A than non-smokers, and intake tended to decrease as cigarette consumption increased, particularly for vitamin C, fiber, and folate. Smokers were less likely to have consumed vegetables, fruits (particularly fruits and vegetables high in vitamins C and A), high fiber grains, low fat milk, and vitamin and mineral supplements than non-smokers. A negative linear trend was found between smoking intensity and intake of several categories of fruits and vegetables. These data suggest that the high cancer risk associated with smoking is compounded by somewhat lower intake of nutrients and foods which are thought to be cancer protective.

Vitamin E intakes and sources in the United States

Twenty-four-hour-recall data from 11,658 adults interviewed in the Second National Health and Nutrition Examination Survey (NHANES II) were used to estimate intakes of vitamin E and polyunsaturated fatty acids (PUFAs) in the United States. Although mean intakes of vitamin E were close to the recommended dietary allowance for both men and women (9.6 and 7.0 mg/d, respectively), median intakes were considerably lower (7.3 and 5.4 mg/d). If a ratio of vitamin E to PUFAs of greater than or equal to 0.4 is considered desirable, 23% of men and 15% of women had diets with low ratios. Ratios tended to decrease as PUFAs in the diet increased. The fruits-and-vegetables group and the fats-and-oils group each provided 20% of the vitamin E in the US diet. Increasing food choices from the fruits-and-vegetables group would provide low-fat sources of vitamin E for individuals whose intakes are likely to be inadequate.

Folate intake and food sources in the US population

Dietary data from 24-h recalls collected in the Second National Health and Nutrition Examination Survey (NHANES II) were analyzed to determine intake and food sources of folate in US adults between ages 19 and 74 y. Mean daily folate intake was 242 +/- 2.8 micrograms (means +/- SEM) for all adults, 281 +/- 3.6 micrograms for males, and 207 +/- 2.9 micrograms for females. Daily intake per 1000 kcal was 130 +/- 1.3 micrograms for all adults 122 +/- 1.3 micrograms for males, and 137 +/- 1.7 micrograms for females. Based on the Recommended Dietary Allowance of 400 micrograms/d, our results suggest that folate intake in the United States is low, particularly among women and blacks. Intake by age, education, and poverty index is discussed. Orange juice, white breads, dried beans, green salad, and ready-to-eat breakfast cereals are the major food sources of folate on a given day, contributing 37% of total folate intake.

The contribution of enrichment and fortification to nutrient intake of women

A volunteer group of 162 women aged 25 to 49 years was recruited from three suburban supermarkets in central New York state. The women completed 3-day food records, which were analyzed for total nutrient intake and contribution of eight nutrients from three sources: (a) nutrients naturally present in food, (b) enriched/fortified foods with a standard of identity (FF + SI), and (c) fortified foods without standards of identity (FF-SI). Subjects were placed into study groups of high-, moderate-, and low-fortifiers on the basis of frequency of intake of highly fortified foods (FF-SI) which, unlike FF + SI, are not staple foods and may represent selective dietary nutrient addition by the consumer. For all groups, mean intakes of riboflavin, niacin, and vitamins A and C were greater than 100% of the RDAs without nutrient addition. Mean thiamin intake met the RDA only when the nutrient addition from FF + SI was included. Mean intakes of iron, calcium, and vitamin D were all below the RDA even when all sources of intake were included. No significant differences between study groups were found for total nutrient intake. With the exceptions of vitamin C, vitamin D, and calcium, high- and moderate-fortifiers had significantly greater (p less than .01) nutrient intake from fortification. Low-fortifiers had significantly greater (p less than .05) intake from naturally occurring vitamins A and C than high-fortifiers.