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Biomedical subjects

S I Barr

Publications and source records attributed to S I Barr.

At least 55 records · Page 3Linked to original sources
PubMed1994

Vegetarian vs nonvegetarian diets, dietary restraint, and subclinical ovulatory disturbances: prospective 6-mo study.

Ovulatory function was prospectively assessed over 6 mo in 23 vegetarians and 22 nonvegetarians with clinically normal menstrual cycles. Subjects were 20-40 y of age, of stable weight (body mass index, in kg/m2, of 18-25), on current diets for > or = 2 y, and not using oral contraceptives. Quantitative analysis of basal body temperature records classified cycles as normally ovulatory, short luteal phase (< 10 d), or anovulatory. Subjects completed the Three-Factor Eating Questionnaire (subjects completed the Three-Factor Eating Questionnaire (subscales for restraint, hunger, and disinhibition) and kept three 3-d food records. Vegetarians had lower BMIs (21.1 +/- 2.3 vs 22.7 +/- 1.9, P < 0.05), percentage body fat (24.0 +/- 5.5% vs 27.4 +/- 5.1%, P < 0.05), and restraint scores (6.4 +/- 4.4 vs 9.5 +/- 3.7, P < 0.05). Mean cycle lengths were similar, but vegetarians had longer luteal phase lengths (11.2 +/- 2.6 vs 9.1 +/- 3.8 d, P < 0.05). Cycle types also differed (chi 2 = 9.64, P < 0.01): vegetarians had fewer anovulatory cycles (4.6% vs 15.1% of cycles). Compared with those with restraint scores below the median, highly restrained women had fewer ovulatory cycles (3.6 +/- 2.3 vs 5.0 +/- 1.4, P < 0.05) and shorter mean luteal phase lengths (7.4 +/- 4.1 vs 10.7 +/- 3.1 d, P < 0.05). We conclude that ovulatory disturbances and restrained eating are less common among vegetarians, and that restraint influences ovulatory function.

Adult↗
PubMed1993

Body composition analysis of female adolescent athletes: comparing six regression equations.

This study investigated whether meaningful differences occurred when percentage body fat (%BF) values were estimated for female adolescent athletes using six different regression equations found in the two of which were age-adjusted. Skinfold thickness (SF) and bioelectrical impedance analysis (BIA) measurements were taken prior to training and > or = 2 h postprandial on 29 gymnasts and 25 speed skaters who competed at a minimum of a provincial level. Mean ages were similar (14.3 +/- 1.6 yr, mean +/- SD, vs 14.3 +/- 1.5 yr); however, the speed skaters were taller (162.2 +/- 8.2 cm vs 154.0 +/- 5.0 cm, P < 0.001) and heavier (58.5 +/- 9.5 kg vs 46.0 +/- 7.9 kg, P < 0.001). Analysis of variance of %BF revealed a significant effect of sport (F(1,52) = 39.3, P < 0.001), with gymnasts having lower values. There was also a significant effect of regression equation (F(5,260) = 147.8, P < 0.001), and post-hoc comparisons revealed significant differences between almost all equations. Calculated %BF values ranged from 21.0 +/- 7.7% to 28.1 +/- 3.9% for speed skaters and from 10.3 +/- 5.3% to 22.8 +/- 3.7% for gymnasts. For both sports, the age-adjusted equations for SF and BIA produced the lowest and the highest %BF values, respectively. Our results indicate the need for caution when using field techniques to estimate %BF of female adolescent athletes. We suggest that an appropriate technique and regression equation for use with this group is the Jackson and Pollock quadratic equation for skinfolds, using Lohman's age-adjusted specific constants to correct for lower density of fat-free mass in youths.

Adipose Tissue↗
PubMed1992

Effect of increased training volume on nutrient intake of male collegiate swimmers.

To assess the effect of a period of increasing training on dietary quantity and quality, a men's collegiate swim team (n = 24) was divided into two groups of equal skill at the start of a 25-week season of training and competition. After a 4-week conditioning period, the "Long" group underwent a 6-week period during which they swam up to 44,000 m.wk-1, while the "Short" group maintained their swimming at 22,000 m.wk-1. For the remainder of the season, the two groups swam together, performing the same volume and intensity of training. Two-day food intake records were obtained during the early season, during the period of increased training, and during the late season. Swimmers' diets during the early season averaged 15.3 MJ, with 55% from carbohydrate (500 g), and exceeded RDAs for all nutrients assessed. During the increased training period, energy and carbohydrate intakes of the Long group increased significantly (p less than 0.05) to 17.7 MJ and 600 g respectively, but the percentage of energy derived from carbohydrate, protein and fat was stable. Intakes of the Short group did not change over the season. Energy intake did not fully compensate for expenditure, as both groups maintained weight but lost subcutaneous fat. An increase in training volume appears to result in an increased consumption of the athletes' usual diets.

Adult↗
PubMed1992

Effect of daytime protein restriction on nutrient intakes of free-living Parkinson's disease patients.

Studies have shown that severe daytime restriction of dietary protein improves the efficacy of L-dopa and reduces response fluctuations in some Parkinson's disease (PD) patients. This study investigated the nutritional adequacy of the daytime restricted-protein diet. Eleven free-living PD patients suffering from unpredictable response fluctuations to L-dopa were counseled to limit protein intake to approximately 10 g before 1700. Three sets of 6-d food records obtained during the 8-wk study showed that while on the test diet, mean intakes of most nutrients remained above the recommended nutrient intakes, although significant decreases occurred in protein, calcium, iron, phosphorus, riboflavin, and niacin intakes. The impact of the test diet on nutritional status as evaluated by changes in body weight and serum prealbumin was small. We conclude that healthy and highly motivated patients can maintain adequate intakes of most nutrients while restricting daytime protein intake. However, nutrient intakes might be compromised in patients whose regular diets are marginally adequate.

Aged↗
PubMed1992

Satisfaction of recent University of British Columbia dietetics graduates with undergraduate education and current job.

This study was designed to investigate the career status of recent University of British Columbia (UBC) dietetics graduates and their satisfaction with undergraduate education and current job. All graduates from the UBC Dietetics Program between 1978-1987, inclusive (n = 238), were mailed questionnaires. Information was sought regarding success in obtaining a dietetic internship, current employment status, job satisfaction, and satisfaction with undergraduate education. Questionnaires were returned by 67% (n = 130) of those who received them. Approximately 83% were eventually successful in obtaining an internship. Most respondents (68.5%) were employed as dietitian/nutritionists, and 69% of those who were employed worked full-time. Those who interned had significantly higher salaries than those who did not. A measure of overall job satisfaction revealed that 89.6% were satisfied to very satisfied with their present job, and scores on the Brayfield-Rothe Index of Job Satisfaction revealed no differences between those who did and did not intern. With regard to undergraduate education, respondents were most satisfied with library resources, class size and quality of teaching, and least satisfied with internship opportunities. Those who had interned were significantly more satisfied with their undergraduate education than were those who had not. We conclude that success in obtaining a dietetic internship affects salary and satisfaction with undergraduate education, but does not affect job satisfaction.

Attitude of Health Personnel↗
PubMed1992

Effects of folate and zinc supplementation on patients undergoing chronic hemodialysis.

Twelve men and nine women undergoing chronic hemodialysis were studied to evaluate folate intake and status in relation to use of folate supplements. Because of possible folate-zinc interactions, zinc status was also evaluated. The patients were classified into four groups based on daily supplementation: no folate or zinc, 22.5 mg zinc, 5 mg folate, and 5 mg folate and 22.5 mg zinc. A food frequency questionnaire was developed to estimate average daily intakes of folate and zinc. Patients' mean dietary folate intake was 30% or more above the Recommended Dietary Allowance (RDA), whereas their mean dietary zinc intake was close to the RDA. No significant differences in dietary folate or zinc intakes existed among groups. Red blood cell (RBC) folate levels of folate-supplemented patients were approximately 10 times higher than those of patients who did not receive folate and who had normal RBC folate levels. Serum zinc levels in all four groups of patients were close to the lower limit of the normal range and were unaffected by supplementation; however, hair zinc levels of six zinc-supplemented patients were significantly higher than those of healthy unsupplemented control patients. Generalization of this study's findings are limited by its descriptive nature; nevertheless, for these patients and presumably for similar patients who also have adequate dietary folate intakes, high-dose folate supplementation does not appear to be necessary to maintain normal folate status. No evidence of a folate-zinc interaction was obtained; however, serum zinc may not be a valid index of zinc status in these patients.

Adult↗
PubMed1991

Effect of increased training volume on blood lipids and lipoproteins in male collegiate swimmers.

This study was conducted to assess whether a previously described dose-response relationship between the amount of exercise and the magnitude of change in blood lipid and lipoprotein levels is observed with large volumes of exercise in young, healthy individuals. Blood lipid and lipoprotein levels were monitored during a 25-wk season of training and competition in experienced male collegiate swimmers, who were divided into two groups matched for swimming skill. After an initial 4-wk conditioning period for both groups, one group (N = 11) underwent a 6-wk period during which their training volume was increased from 22,000 m.wk-1 to 44,000 m.wk-1. The other group (N = 13) maintained their swimming distance at 22,000 m.wk-1 during this period. During the remaining 15 wk of the season, both groups swam approximately 22,000 m.wk-1. Swimmers' body weights did not change over the season, but body fat decreased significantly (P less than 0.01). No changes in HDL cholesterol were observed during the season in either the increased training or the regular training groups. Total and LDL cholesterol levels were lower at 20 wk than at the start of the study, but final levels did not differ from initial levels. Thus, the volume of swimming exercise may not be related to the degree of change in blood lipid and lipoprotein levels in healthy subjects with high activity levels.

Adult↗
PubMed1991

Fluid replacement during prolonged exercise: effects of water, saline, or no fluid.

This study assessed the need to replace sodium in endurance exercise less than or equal to 6 h in duration by comparing responses to fluid replacement with water, saline (25 mmol.l-1), or no fluid. Eight subjects (five male, three female) participated in three 6-h exercise trials on an electrically braked cycle ergometer at 55% VO2max, at 30 degrees C and 50% r.h. In the water (W) and saline (S) trials, sufficient fluid was ingested to balance sweat and urinary fluid losses, while in the third trial, no fluid (NF) was ingested. Plasma sodium less than or equal to 130 mmol.l-1 was a criterion for trial termination. In the NF trial, heart rate, rectal temperature, plasma sodium, plasma aldosterone, and rating of perceived exertion were all significantly higher (P less than 0.001) than during W and S, whereas plasma volume was lower (P less than 0.001). On average, subjects terminated this trial 1.5 h prior to its scheduled completion, having lost 6.4% body weight. In contrast, no significant differences between fluid replacement with W or S were detected, although the effect of time on all aforementioned variables was highly significant (P less than 0.001). Saline intake was not associated with significantly higher plasma sodium during exercise than was water intake: plasma sodium decreased significantly during both W (to 135.5 +/- 0.5 mmol.l-1) and S (to 137.3 +/- 0.7 mmol.l-1). No subject had to terminate a trial based on plasma sodium less than or equal to 130 mmol.l-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Exercise during rat pregnancy and lactation: maternal effects and offspring growth.

Eighty Sprague-Dawley rats were divided into exercised (E) and sedentary (S) groups. E rats were trained to run on a treadmill (30 m/min, 2 hr/day). Within each group, two subgroups were mated and three served as virgin time controls. Of the mated subgroups, one was terminated within 24 hours of delivery and the other on day 14 of lactation. Subgroups of virgin S and E controls were terminated at times corresponding to the mating, delivery and lactation day 14 of mated rats. MANOVA revealed that exercise significantly affected food intake, body weight and body composition in both virgin and mated animals: generally, E rats ate more, gained more weight, and had less carcass fat than S controls. E rats did not store fat during pregnancy. At parturition, they were 7.0% fat, similar to both E (6.6%) and S (7.6%) controls prior to mating, and less than S rats at parturition (11.9%). Despite diminished fat stores at parturition in E rats, litter size and pup birthweight were similar in E and S rats, as was offspring growth during lactation (mean weights on day 14 of 28.9 g and 29.3 g, respectively). Remaining body fat and increased food intake were adequate to support normal pup growth.

Animals↗
PubMed1990

Impaired muscle glycogen resynthesis after eccentric exercise.

Eight men performed 10 sets of 10 eccentric contractions of the knee extensor muscles with one leg [eccentrically exercised leg (EL)]. The weight used for this exercise was 120% of the maximal extension strength. After 30 min of rest the subjects performed two-legged cycling [concentrically exercised leg (CL)] at 74% of maximal O2 uptake for 1 h. In the 3 days after this exercise four subjects consumed diets containing 4.25 g CHO/kg body wt, and the remainder were fed 8.5 g CHO/kg. All subjects experienced severe muscle soreness and edema in the quadriceps muscles of the eccentrically exercised leg. Mean (+/- SE) resting serum creatine kinase increased from a preexercise level of 57 +/- 3 to 6,988 +/- 1,913 U/l on the 3rd day of recovery. The glycogen content (mmol/kg dry wt) in the vastus lateralis of CL muscles averaged 90, 395, and 592 mmol/kg dry wt at 0, 24, and 72 h of recovery. The EL muscle, on the other hand, averaged 168, 329, and 435 mmol/kg dry wt at these same intervals. Subjects receiving 8.5 g CHO/kg stored significantly more glycogen than those who were fed 4.3 g CHO/kg. In both groups, however, significantly less glycogen was stored in the EL than in the CL.

Adult↗
PubMed1989

Evaluating the literature.

The ability to read critically and evaluate research literature will increase in importance as the dietetic profession builds a research base to support practice. In this article, the "who, why, what, where, and when" of critiquing the literature are presented. An overview of "how" to critique the literature is outlined in a 10-step process that emphasizes effective time use. At each step, a decision is made to continue reading the article or to go to the next article or journal. The process includes examination of: 1) the journal and the title of the article; 2) the authors' names; 3) the abstract; 4) the introduction; 5) the objective of the study; 6) the methods; 7) the results; 8) the discussion; and 9) the conclusions. The 10th step, reached only if the article satisfactorily addresses the previous nine, is to attempt to use the information in practice.

British Columbia↗
PubMed1989

Water: can the endurance athlete get too much of a good thing?

Several cases of hyponatremia, with symptoms including altered mentation, seizures, and pulmonary edema, have been reported in endurance athletes over the last few years. This condition has been observed most frequently in individuals participating in ultra-distance events but has also been reported in a marathon runner. Excessive water intake has been identified as a common etiological factor. Given that this is a serious condition but that the risks of impaired performance and heat injury from inadequate water ingestion are substantial, how likely is it that hyponatremia will develop in events of marathon duration or shorter? A review of fluid and electrolyte balance--and an example of expected sodium and fluid losses in a marathon runner--suggest that normal regulatory mechanisms should prevent its occurrence in the absence of other contributing factors. Accordingly, ingestion of adequate fluid should remain a priority for individuals engaged in endurance activity.

Drinking↗
PubMed1988

Influence of increasing concentrations of ethanol on food and water intake, body weight, and wheel-running of male Sprague-Dawley rats.

Male Sprague-Dawley rats were used to study the influence of increasing concentrations of ethanol on wheel-running, food and water intake and body weight. Animals were housed individually in screen-bottom cages (n = 12) or in activity wheel cages (n = 12). Half the animals in each activity condition received an ethanol-free liquid diet, and the remainder received liquid diet in which the concentration of ethanol was increased by 5% of energy intake per week to a maximum of 35%, at the expense of dextrin. Ethanol did not significantly affect total wheel-running, but was associated with decreased total food intake when it represented greater than or equal to 20% of energy (p less than 0.001). The decreased intake was restricted to the dark cycle, while light cycle intake was unaffected. Neither water intake nor body weight (with food intake as a covariate) were affected by ethanol. In contrast, wheel-running was associated with increased water intake and decreased body weight, but did not affect food intake. No interactions between activity and ethanol were detected. It is concluded that ethanol in the concentrations tested does not affect wheel-running in male rats, but does reduce food intake and may disrupt circadian food intake patterns.

Animals↗
PubMed1987

Women, nutrition and exercise: a review of athletes' intakes and a discussion of energy balance in active women.

Given the heightened interest in nutritional aspects of exercise, and an increase in athletic participation by women, it appeared timely to review the nutritional implications of exercise in women. The initial part of this paper contains a compilation of published studies on the nutrient intakes of female athletes. These reveal that most groups of athletes have adequate nutrient intakes, and that their vitamin and mineral intakes appear to be superior to those of nonathletic women. The average energy intake of athletes in studies summarized in this paper was 2069 kcal, and for certain groups of athletes, energy intakes were even lower. How these women manage to train intensely while consuming energy intakes similar to those of sedentary women is not readily apparent, and for this reason, the remainder of the paper discusses energy balance as affected by activity. Methodological considerations related to assessment of the components of the energy balance equation (food intake, energy expenditure, and body energy stores) are presented, with a focus on considerations in women. The effects of activity on each of these components are then discussed in an attempt to determine whether some form of energy conservation may occur. Finally, effects of activity on the menstrual cycle are reviewed. The observed changes are discussed in relation to nutrition 1) in terms of how nutrition may play a role in their causation; and 2) in terms of their nutritional implications for the amenorrheic athlete, specifically as regards energy balance and bone density.

Amenorrhea↗
PubMed1987

Nutrition knowledge of female varsity athletes and university students.

The objectives of this study were to compare the nutrition knowledge, including knowledge about nutrition in relation to physical activity, of female university students and members of varsity athletic teams and to document selected nutrition practices of those groups. Instruments developed for the study were completed by varsity athletes (no. = 70) and students not on teams (no. = 129). The two groups were similar in education, but the athletes were younger, taller, and heavier than the students and were considerably more active. The athletes used more nutritional supplements (especially iron) and were less likely to exclude red meat from their diet than were students. Scores on the knowledge test (which had a possible range of - 100% to 100%) averaged 34% for both team members and students. Both groups scored higher on general nutrition questions than on questions about nutrition in relation to activity. Among students, age, education, dietary pattern, total number of nutrition information sources, and length of time an activity program had been maintained were positively associated with nutrition knowledge. Those relationships were not detected among varsity athletes. It was concluded that female varsity athletes had levels of both general and sports-related nutrition knowledge that were similar to those of female students not participating on varsity teams.

Adult↗