Validation of a new computerized technique for quantitating individual dietary intake: the Nutrition Evaluation Scale System (NESSy) vs the weighed food record.

A validation study was conducted in which food intake recorded by research volunteers using a new computerized technique, the Nutrition Evaluation Scale System (NESSy), was compared with food intake obtained from a weighed food record concurrently measured and recorded by metabolic unit dietary staff. Nine women between ages 23 and 35 y resided in the metabolic research unit and recorded their food intake with NESSy for 16 consecutive days. The mean of the differences between NESSy and the manual technique was not significant on a group basis (p less than 0.05) for food energy or any other nutrient. All mean differences were less than 5% and Pearson correlation coefficients ranged from 0.81 to 0.98 (p less than 0.0001), with all but iron, potassium, sodium, and preformed niacin having correlations greater than 0.92. For the majority of the individuals, accuracy within 10% of their actual dietary intake was found for energy and selected nutrients. NESSy is a new computerized approach to dietary intake assessment that yields accurate data on both a group and individual basis.

Protein and energy utilization in men given a rural Guatemalan diet and egg formulas with and without added oat bran.

Healthy men were fed a fiber-free formula diet providing the FAO/WHO Safe Level of egg protein (0.57 g/kg) and a rural Guatemalan diet giving 0.0875 g of protein per kilogram, the recommended dietary allowance for Central America and Panama. For comparison an egg formula diet was fed at the higher protein level, with and without oat bran (0.6 g/kg). All diets maintained nitrogen balance over the 15-day test periods, and balance was distinctly positive at the higher intake of egg protein. Addition of bran doubled the fecal excretion of dry matter and energy; digestibility of energy and protein was reduced 3 to 4%. With the Guatemalan diet, fecal dry matter, nitrogen and energy excretions were nearly four times as high as with egg formula. Relative to egg ( = 100%), protein digestibility of the Guatemalan diet was 78% and total digestible energy was 92%. Present recommended dietary allowances of protein maintain nitrogen equilibrium at an energy intake of 40 kcal/kg in spite of the large fecal losses.

Changes in dietary intake, urinary nitrogen, and urinary volume across the menstrual cycle.

The effect of four menstrual cycle phases on changes in dietary intake, urinary nitrogen excretion, and urinary volume was examined in nine women confined to a metabolic unit, maintained at a constant activity level, and fed an ad libitum, rotating, staff-weighed diet. No significant changes in intakes of energy, protein, and fat occurred throughout the menstrual cycle although significant changes were found for intakes of ascorbic acid and water in food. A significant increase in consumption of carbonated, sugar-containing beverages was found in the luteal phase as was a significant increase in urine volume. Results suggest food choices and urine volume may be responsive to physiological regulators associated with hormonal changes in the menstrual cycle. Findings also suggest that energy intake is not altered across the menstrual cycle when physical activity is controlled and an accurate dietary assessment method is employed.

Some aspects of bile acid and urobilinogen excretion and fecal elimination in men given a rural Guatemalan diet and egg formulas with and without added oat bran.

Six healthy men were fed a formula diet with and without oat bran and a natural food diet typical of rural Guatemala. No significant difference in dye transit time was found between diets but the Guatemalan diet significantly decreased dye retention time and increased stool frequency. Serum cholesterol and triglyceride levels showed no significant differences among dietary treatments. Excretion of fecal bile acids significantly increased on the Guatemalan and oat bran diets, but fecal bile acid concentration was significantly lower only on the Guatemalan diet. Urinary urobilinogen excretion and fecal urobilinogen concentration were significantly lower with the Guatemalan diet.

Electroencephalographic changes and periodontal status during short-term vitamin B-6 depletion of young, nonpregnant women.

As part of a larger investigation to determine the effect of animal vs. plant proteins on the vitamin B-6 requirement of young women, clinical changes during vitamin B-6 depletion were documented. Eight healthy young women were confined to a metabolic unit and fed a defined formula diet nearly devoid of vitamin B-6 (less than 0.05 mg/d). Serial electroencephalographic (EEG) tracings, peripheral nervous system tests, periodontal evaluations, and biochemical measures of vitamin B-6 status were conducted. Within 12 d on the depletion diet, two of the eight women exhibited abnormal EEG tracings. These changes were readily reversed by repletion of vitamin B-6 at the 0.5-mg/d level. Biochemical measures reflected lowered vitamin B-6 status but were not predictive of the onset of EEG changes. No detectable alterations in oral or periodontal status were found, nor did plaque flora change markedly. This study is the first report of EEG changes occurring in women undergoing vitamin B-6 depletion and the first report to document EEG changes in adults within 12 d on a vitamin B-6-depletion regimen.

Folate requirement and metabolism in nonpregnant women.

Folate metabolism and requirements were studied in 10 adult nonpregnant women maintained for 92 d in a metabolic unit. After a folate depletion period of 28 d, the subjects received increasing supplements of folate from food items or as pteroylmonoglutamic acid (PGA). Plasma folate levels fell 60% during the depletion period and continued to fall until 200 micrograms/d of naturally occurring food folates were provided. Supplements of 300 micrograms/d of naturally occurring folates produced a small rise in plasma folate levels although erythrocyte folate levels continued to fall. Lymphocyte deoxyuridine suppression, neutrophil hypersegmentation, and other measurements related to folate metabolism were performed. When compared with PGA, dietary folates appeared to be no more than 50% available. A daily intake of 200-250 micrograms of dietary folates appears to meet the folate requirements of nonpregnant adult women whereas an intake of 300 micrograms/d provides an allowance for storage.

Milk's effect on the bioavailability of iron from cereal-based diets in young women by use of in vitro and in vivo methods.

A study was conducted in healthy young women to measure and compare the availability of iron from cereal-based diets with and without milk by use of in vivo and in vitro methods. In vitro iron-bioavailability tests demonstrated that the amounts of soluble and ionizable iron in cereal-based diets were increased two- and three-fold, respectively, when milk was added. 54Fe, a stable isotope of iron, and fecal monitoring were used to determine iron absorption in eight young women. Iron absorption was higher with milk than without milk in seven of the eight subjects but did not differ significantly between the two treatments. The results suggest that in vivo and in vitro effects differ and that the absorption of iron from cereal-based diets is neither enhanced nor inhibited by the addition of milk.

Protein utilization by young women consuming animal or plant protein diets at various levels of vitamin B-6 intake.

Eight young women consumed a vitamin B-6 depletion diet (egg albumen formula, less than 0.05 mg vitamin B-6/d) for 11-28 d. Subjects (n = 4) then consumed either animal protein (AP, mainly dairy and poultry products) or plant protein (PP, mainly various types of beans) diets with increasing vitamin B-6 intake (0.5, 1.0, 1.5, and 2.0 mg/d) for periods of 14-21 d. All diets provided 1.55 g protein/kg body wt. Apparent protein digestibility of AP (94.6%) was significantly higher than that of PP (88.4%) diets (p less than 0.001). Protein digestibility was not significantly affected by vitamin B-6 intake. Apparent nitrogen balance of subjects consuming AP diets was slightly, though not significantly, higher than that of subjects fed PP diets. N balance was not influenced by vitamin B-6 intake. Data suggest that short-term low vitamin B-6 intake does not affect protein utilization in humans as determined by digestibility and N balance.

Ascorbic acid and erythorbic acid metabolism in nonpregnant women.

Ascorbic acid (AA) metabolism and requirements were studied in 11 adult nonpregnant women maintained in a metabolic unit and fed a formula diet devoid of AA for 54 d. After depletion for 24 d, the subjects received increasing supplements of AA in the presence or absence of 600 mg/d of erythorbic acid (EA). Various analytical procedures were used to measure AA concentrations in blood components. The depletion period resulted in a marked decrease in AA in all blood indices. During the study scorbutic signs developed in some of the subjects. AA supplements of 30 mg/d for 10 d failed to increase plasma ascorbate concentrations; 60 mg/d for 10 d produced a small increase; 90 mg/d resulted in a mean AA concentration of 29 mumol/L. EA did not present any adverse effects, but rather had a small sparing effect. Vitamin C requirements for adult nonsmoking, nonpregnant women would be marginally met by an intake of 60 mg/d of AA whereas 90 mg/d would provide an allowance for body storage.

Vitamin B-6 depletion followed by repletion with animal- or plant-source diets and calcium and magnesium metabolism in young women.

An 84-98-d study was conducted in young women to determine the effect of vitamin B-6-deficient diets on calcium and magnesium metabolism. A vitamin B-6-deficient formula diet fed initially was followed by either animal- or plant-source protein food diets containing four increasing amounts of vitamin B-6. Calcium balance was negative during vitamin B-6 depletion. Serum calcium was higher and calcium balance negative with the plant protein diets. Magnesium balance was negative during vitamin B-6 depletion due to increased urinary magnesium excretion. Urinary calcium decreased during vitamin B-6 depletion and increased as dietary vitamin B-6 increased. Urinary oxalate was significantly higher at the end than at the beginning of vitamin B-6 depletion and was higher with plant than animal protein diets. The results suggest that vitamin B-6 depletion may alter calcium and magnesium metabolism and that dietary components associated with the protein source may influence calcium retention.

Vitamin B-6 requirement and status assessment: young women fed a depletion diet followed by a plant- or animal-protein diet with graded amounts of vitamin B-6.

The vitamin B-6 requirement of young women consuming a high-protein diet (1.55 g/kg body wt) and the effect of protein quality on this requirement was studied. In addition, the response of clinical, functional, and biochemical measures of vitamin B-6 nutriture to short-term depletion and step-wise repletion of vitamin B-6 were evaluated. Eight healthy young women resided in a metabolic unit and were fed a formula depletion diet (< 0.05 mg vitamin B-6/d) for 11-28 d followed by either an animal-protein (AP) or plant-protein (PP) diet with successively increasing vitamin B-6 intakes (0.5, 1.0, 1.5, and 2.0 mg/d) for periods of 14-21 d. Animal proteins were primarily from dairy and poultry sources and plant proteins were primarily from legumes. Vitamin B-6 status measures were assessed at weekly intervals. Results showed that a PP diet does not elevate the vitamin B-6 requirement over that required for an AP diet given the high amount of dietary protein used in this study. It was also found that 0.015 mg vitamin B-6/g protein intake normalized most biochemical indexes of vitamin B-6 status (including those indicative of functional status), and that 0.020 mg/g protein normalized all biochemical measures except total urinary vitamin B-6. Adding a margin of safety to either the 0.015 or 0.020 mg/g protein intake would raise the vitamin B-6 requirement for young women above the currently recommended dietary allowance of 0.016 mg/g protein.

A stable-isotope study of zinc, copper, and iron absorption and retention by young women fed vitamin B-6-deficient diets.

A 98-d study was conducted in young women to determine the effect of vitamin B-6-deficient diets on zinc, copper, and iron metabolism. Young women were fed vitamin B-6-deficient formula initially, followed by food diets containing four increasing amounts of vitamin B-6. Zinc, copper, and iron absorption, retention, and status were determined at intervals throughout the study. Zinc absorption and retention were greater during vitamin B-6 depletion but serum zinc declined, suggesting that absorbed zinc was not available for utilization. Copper absorption was lower during vitamin B-6 depletion but serum copper was not affected and balance was positive. Iron absorption was not impaired significantly by vitamin B-6-deficient diets but status may have declined. The results suggest that vitamin B-6 depletion of young women may alter zinc metabolism, inhibit copper absorption, and affect iron status. The effects of vitamin B-6 depletion differ markedly among these elements.

Nutrition Evaluation Scale System reduces time and labor in recording quantitative dietary intake.

A time and labor cost study was conducted to evaluate two quantitative techniques for recording dietary intake of individuals: the Nutrition Evaluation Scale System (NESSy) and the weighed food record. NESSy, a new computerized method, uses interactive software to prompt and guide participants through the recording of food weights and descriptions. Twelve men and nine women (aged 23 to 36 years, with 11 to 16 years of education) utilized NESSy for 16 consecutive days while residing in a metabolic research unit. Concurrently, food intake was weighed and manually recorded by trained dietary staff. Analysis of variance on data gathered from NESSy showed no statistically significant differences among sex, age, and educational groupings in the time spent using NESSy. NESSy required 1.73 +/- 0.3 minutes (mean +/- SD) to weigh in, weigh out, and record each food item consumed, whereas the manual technique required 8.4 minutes. The reason for the magnitude of time difference between the two methods is that NESSy provides the flexibility of weighing and recording only foods eaten whereas the manual method requires complete entry of all foods served whether eaten or not. Using the Nutrition Evaluation Scale System to record food intake provides savings in time and labor of about 80%.

Behavioral and body size correlates of energy intake underreporting by obese and normal-weight women.

OBJECTIVE: To examine behavioral and body size influences on the underreporting of energy intake by obese and normal-weight women. DESIGN: Seven-day estimated food records were kept by subjects before they participated in a 49-day residential study. Self-reported energy intake was compared with energy intake required to maintain a stable body weight during the residential study (reference standard). Energy intake bias and its relationship to various body size and behavioral measures were examined. SUBJECTS: Twenty-two, healthy, normal-weight (mean body mass index [BMI] = 21.3) and obese (mean BMI = 34.2) women aged 22 to 42 years were studied. STATISTICAL ANALYSES: Analysis of variance, paired t test, simple linear regression, and Pearson correlation analyses were conducted. RESULTS: Mean energy intake from self-reported food records was underreported by normal-weight (-9.7%) and obese (-19.4%) women. BMI correlated inversely with the energy intake difference for normal-weight women (r = -.67, P = .02), whereas the Beck Depression Inventory correlated positively with the energy intake difference for obese women (r = .73, P < .01). CONCLUSION/APPLICATIONS: Results suggest that body size and behavioral traits play a role in the ability of women to accurately self-report energy intake. BMI appears to be predictive of underreporting of energy intake by normal-weight women, whereas emotional factors related to depression appear to be more determinant of underreporting for obese women. Understanding causative factors of the underreporting phenomenon will help practicing dietitians to devise appropriate and realistic diet intervention plans that clients can follow to achieve meaningful change.

Cognitive function, iron status, and hemoglobin concentration in obese dieting women.

OBJECTIVE: To determine the relationships between cognitive function and iron status in dieting obese women. DESIGN: Longitudinal weight loss study (repeated measures within-subject design) with 3 weeks of baseline, 15 weeks of 50% caloric restriction, and 3 weeks of weight stabilization. Dietary iron was fed at twice the US Recommended Dietary Allowance with half of the iron from food sources and half from an oral supplement. SETTING: This was a free-living study with the exception that subjects came to the research center for one meal per day and were provided all other meals and snacks to take home. SUBJECTS: Healthy, premenopausal, obese women (mean BMI=31.5) were recruited through local newspaper, poster and radio advertising. Twenty-four women volunteers were recruited and 14 completed the study. MEASUREMENTS: Cognitive function, iron and hematological status, height, body weights and body composition were measured at baseline; at weeks 5, 10, and 15 of the energy restriction period; and at the end of weight stabilization. Computerized cognitive tests included: Bakan vigilance task, two finger tapping, simple reaction time, immediate word recall, and a focused attention task. Iron status and hematological measures included: serum iron, total iron binding capacity (TIBC), transferrin saturation, serum ferritin, hemoglobin (Hb), hematocrit, red cell count, MCV, MCH, MCHC, and RDW. RESULTS: A significant reduction in Hb, hematocrit, and red blood cell count occurred across the study. Hb at the end of the study was positively correlated (r=0.72, P < 0.01) with mean performance on a measure of sustained attention. Transferrin saturation also correlated positively to sustained attention task performance for those subjects whose Hb declined across the study (r=0.86, P < 0.01). CONCLUSIONS: These findings suggest that dieting diminishes iron status in obese women, even when sufficient dietary iron is available, and that the inability to sustain attention may be an early sign of developing iron deficiency in dieting women.

Cognitive effects of a long-term weight reducing diet.

OBJECTIVE: To investigate if long-term caloric restriction under controlled conditions adversely affects cognitive function in obese women. SUBJECTS: Healthy, premenopausal women between 23-42 y. Dieting group: n = 14. CONTROL GROUP: n = 11. DESIGN: Longitudinal weight loss study (repeated measures within-subject design) with 3 weeks of baseline, 15 weeks of 50% caloric restriction, and 3 weeks of weight stabilization. MEASUREMENTS: Computerized cognitive function tests (sustained attention, short-term memory, simple reaction time, motor performance and attentional focus), height, body weight, body composition (TOBEC) and behavioral questionnaires (Dutch Eating Behaviour Questionnaire, Eating Attitudes Test, and State-Trait Anxiety Inventory). RESULTS: Dieting women lost 12.3 +/- 5.5 kg (mean +/- s.d.) of body weight. Controlled long-term caloric restriction significantly slowed simple reaction time but did not diminish sustained attention, motor performance or immediate memory. Word recall performance significantly improved by 24% at the end of caloric restriction. CONCLUSIONS: The slowing of simple reaction time is a short-term and long-term consequence of caloric restriction. In contrast to previous short-term dieting studies, sustained attention and immediate memory were not impaired with long-term caloric restriction.

Comparison of hemoglobin values in black and white male U.S. military personnel.

Black and white male military personnel were studied to determine if hemoglobin (Hb) differences existed between the two groups, and if so, whether they were due to dissimilar nutrient intakes or to different patterns of vitamin and mineral self-therapy. Data analyses showed that black males (n = 331) had a 0.27 g/dl lower mean Hb than white males (n = 2268, P = 0.006). However, when only black (n = 60) and white (n = 371) subjects with known iron intakes at or above the recommended level were compared, the differences in the Hb of the two groups became smaller. The serum ferritin values of both of the latter groups appeared adequate for unimpaired Hb synthesis. The use of vitamin and mineral supplements did not differ significantly between the two groups. Adequate intakes of the hemopoietic nutrients resulted in higher Hb levels for both black and white males; at these levels of nutrient intakes the differences in the Hb values of black and white subjects were smaller than those previously reported. Studies comparing the Hb levels of black and white personnel should consider the level of iron intake of the two groups before drawing conclusions about the magnitude and implications of observed differences in Hb concentrations.