Temporal optimization of exercise to lower fasting glucose levels.

Exercise stimulates glucose uptake and increases insulin sensitivity acutely. Temporally optimizing exercise timing may minimize the nocturnal rise in glucose levels. This study examined the effect of exercise timing on evening and overnight glucose concentrations in individuals who were non-obese with normal fasting glucose levels (Non-Ob; n = 18) and individuals with obesity (OB) with impaired fasting glucose levels (OB+IFG) and without (n = 16 and n = 18, respectively). Subjects were studied on three occasions (no exercise (NOEX)), morning exercise (AMEX; 0700 h) and evening exercise (PMEX; 2000 h). The evening meal was provided (1800 h) and blood samples were taken from 1740 to 0700 h and morning endogenous glucose production (EGP) was measured. Glucose and insulin concentrations increased with the dinner meal with peak concentrations being higher in OB+IFG than in OB and Non-Ob (P = 0.04). In OB+IFG, evening glucose concentrations rose above baseline levels at about 2300 h, with the glucose concentrations staying somewhat lower with AMEX and PMEX until ∼0500 h than with NOEX. In OB+IFG, insulin concentrations decreased following the dinner meal and waned throughout the night, despite the rising glucose concentrations. In the OB and Non-Ob individuals following the dinner meal, no increase in glucose concentrations occurred in the evening period and insulin levels mirrored this. No difference was observed in the morning fasting glucose levels between study days or between groups. Regardless of time of day, exercise delays the evening rise in glucose concentrations in adults with OB+IFG but does not lower morning fasting glucose levels or improve the synchrony between glucose and insulin concentrations. KEY POINTS: Insulin resistance and type 2 diabetes have been linked to disturbances of the core clock, and glucose tolerance demonstrates a diurnal rhythm in healthy humans with better glucose tolerance in the morning than in the afternoon and evening. Skeletal muscle is a primary site for insulin resistance in people with impaired glucose tolerance. In individuals with obesity and impaired fasting glucose levels (OB+IFG), following a dinner meal, glucose concentrations started to rise and continues throughout the night, resulting in elevated glucose levels, while concomitantly, insulin levels are waning. Exercise, regardless of the time of day, suppressed the rise in glucose levels in OB+IFG for many hours during the night but did not lower morning fasting glucose levels. Morning exercise was not quite as effective as evening exercise.

Change in body composition during a weight loss trial in obese adolescents.

UNLABELLED: What is already known about this subject Adolescence is an important period of physiological growth. Loss of central adiposity with preservation of lean mass during weight loss is optimal. There are discrepancies in the literature concerning changes in lean mass during weight loss in adolescents. What this study adds This study provides information of regional and total body composition change in adolescents during weight loss. This study controls for important factors that impact body composition in growing adolescents such as age, sex, height, baseline weight and race. This study provides correlations of changes in waist circumference and body mass index (BMI) with total and trunk fat mass during weight loss in adolescents. SUMMARY: Background Changes in body composition during weight loss among obese adolescents are poorly understood. This study characterized the composition of weight loss and its association with changes in waist circumference (WC) in obese adolescents. Methods Total (Tot), trunk (Tr) and appendicular (Ap) fat mass (FM) and lean mass (LM) were measured by dual-energy X-ray absorptiometry in 61 obese adolescents (40 girls) who participated in a randomized controlled weight loss trial. Changes in body composition were assessed at 0, 6 and 12 months using mixed-effects regression models. Correlation analysis of change in WC and total and regional compartments of FM and LM were assessed. Results Weight loss for adolescents was 90.3% FM and 15.9% LM at 0-6 months, and 98.2% FM and 7% LM at 0-12 months. At 12 months, girls lost 2.67 kg more TotFM than boys in models adjusted for height, age, race and baseline weight. Boys gained LM in all compartments in all models. At 12 months, girls lost TotLM (2.23 ± 0.74, P < 0.004) and ApLM (0.69 ± 0.31, P = 0.03) and gained TrLM (0.37 ± 0.35, P = 0.29). The percentage LM, increased for boys and girls in all models. TotFM was correlated with body mass index (BMI) change with TotFM (R = 0.70-0.91, P = 0.001) and WC change (R = 0.53-0.55, P < 0.001). Conclusions Weight loss in obese adolescents during a weight loss trial using lifestyle management and sibutramine was primarily from trunk FM. Although absolute LM increased in boys and decreased in girls, the percentage of weight that is LM increased for both boys and girls. Changes in BMI were more reflective of changes in FM than changes in WC.

Resting energy expenditure and adiposity accretion among children with Down syndrome: a 3-year prospective study.

BACKGROUND: Children with Down syndrome (DS) have a higher prevalence of obesity than other children. Whether this increased risk for obesity is due to a lower resting energy expenditure (REE) is controversial. Our study assessed whether (1) the REE of children with DS adjusted for fat-free mass (FFM) was lower than that of sibling controls, and (2) the changes in fat mass (FM) over 3 years were associated with FFM-adjusted baseline REE. METHODS: This study used cross-sectional and prospective cohort designs. Four annual measurement visits were conducted with 28 children with DS and 35 sibling controls aged 3-10 years. REE and serum thyroxine (T4) were measured at baseline. Anthropometry, skinfold thickness measures, and, in a subsample, dual-energy x-ray absorptiometry (DXA) were used at each visit to calculate FM. RESULTS: Children with DS had significantly lower REE adjusted for FFM (-78 kcal/day, 95% CI: -133 to -27, P=0.003). The difference remained significant after adjustment for FM, sex and African ancestry (-49 kcal/day, 95% CI: -94 to -4, P=0.03). In the longitudinal analysis, the baseline REE adjusted for baseline FFM was not predictive of FM accretion over time (P=0.8). CONCLUSION: Children with DS have lower REE than sibling controls, but REE was not associated with changes in FM over time. The results suggest that the lower REE of children with DS does not explain their increased risk for obesity.

Getting the label in: practical research strategies for tracing dietary fat.

The observation that events occurring after consumption of a meal can directly affect metabolic risk has been gaining interest over the past 40 years. As a result, the desire for investigators to conduct postprandial studies has also increased. Study design decisions pertaining to the choice of meal quantity and composition are more difficult than may be readily apparent, and there is now ample evidence available in the literature to suggest that what is fed on the test day significantly affects postprandial metabolism and can therefore influence interpretation of results. In addition, events occurring before the testing day (food intake and activities) can also have an impact on the observed postprandial response. The goal of this review is to present aspects of study design critical to the investigation of postprandial metabolism. These details include subject preparation, meal quantity, form and composition, as well as sampling protocols for measuring metabolites. Key factors and practical examples are provided to minimize the impact of nonresearch variables on subject variability. Finally, aspects related to using stable isotope tracers to measure metabolism of meal fat are discussed, including choice of tracer form, dose and delivery in food. Given that fed-state events contribute significantly to chronic disease risk, improved methods to study the absorption and disposal of food energy will support the development of strategies designed to prevent and treat diseases associated with overconsumption of nutrients.

Population genetic analysis of Tomato spotted wilt virus on peanut in North Carolina and Virginia.

Exploring the genetic diversity and evolutionary history of plant viruses is critical to understanding their ecology and epidemiology. In this study, maximum-likelihood and population genetics-based methods were used to investigate the population structure, genetic diversity, and sources of genetic variation in field isolates of Tomato spotted wilt virus (TSWV) from peanut in North Carolina and Virginia. Selected regions of the nucleocapsid, movement, and RNA-dependent RNA polymerase genes were amplified and sequenced to identify haplotypes and infer genetic relationships between isolates of TSWV with heuristic methods. The haplotype structure of each locus consisted of 1 or 2 predominant haplotypes and >100 haplotypes represented by a single isolate. No specific haplotypes were associated with geographic area, peanut cultivar, or year of isolation. The population was panmictic at the regional level and high levels of genetic diversity were observed among isolates. There was evidence for positive selection on single amino acids in each gene on a background of predominant purifying selection acting upon each locus. The results of compatibility analyses and the persistence of specific gene sequences in isolates collected over three field seasons suggest that recombination was occurring in the population. Estimates of the population mutation rate suggest that mutation has had a significant effect on the shaping of this population and, together with purifying selection, these forces have been the predominant evolutionary forces influencing the TSWV population in peanut in North Carolina and Virginia.

An Assessment of the Genetic Diversity in a Field Population of Phytophthora nicotianae with a Changing Race Structure.

One hundred fifty-three isolates of Phytophthora nicotianae that were collected over a 4-year period from a single field were subjected to amplified fragment length polymorphism (AFLP) analysis to investigate the effect of different types of resistance in tobacco (Nicotiana tabacum) on genetic diversity in the pathogen population. No race 1 isolates were detected in the field prior to initiating the study, but the race was present in multiple plots by the end of the 4-year period. There were 102 race 0 isolates and 51 race 1 isolates characterized. Seventy-six of the 153 isolates had a unique AFLP profile, whereas the remaining 77 isolates were represented by 27 AFLP profiles shared by at least two isolates. Isolates of both races were found in both the unique and shared AFLP profile groups. Twenty-three of the AFLP profiles were detected in multiple years, indicating a clonal component to the pathogen population. Race 1 isolates that were detected over multiple years were always obtained from the same plot. No race 1 profile was found in more than one plot, confirming the hypothesis that the multiple occurrences of the race throughout the field were the result of independent events and not pathogen spread. Three identical race 0 AFLP profiles occurred in noncontiguous plots, and in each case, the plots contained the same partially resistant variety. Cluster analysis provided a high level of bootstrap support for 41 isolates in 19 clusters that grouped primarily by race and rotation treatment. Estimates of genetic diversity ranged from 0.365 to 0.831 and varied depending on tobacco cultivar planted and race. When averaged over all treatments, diversity in race 1 isolates was lower than in race 0 isolates at the end of each season. Deployment of single-gene resistance initially decreased genetic diversity of the population, but the diversity increased each year, indicating the pathogen was adapting to the host genotypes deployed in the field.

Comparison of reliability in anatomical landmark identification using two-dimensional digital cephalometrics and three-dimensional cone beam computed tomography in vivo.

OBJECTIVES: To compare reliability for landmark identification on patient images from three-dimensional (3D) cone beam CT (CBCT) and digital two-dimensional (2D) lateral cephalograms. METHODS: Ten lateral cephalometric digital radiographs and their corresponding CBCT images were randomly selected. 27 observers digitally identified 27 landmarks in both modes. The x- and y-coordinates for each landmark, indicating the horizontal and vertical positions, were analysed for interobserver reliability by comparing each measurement to the best estimate of the true value. Intraobserver reliability was also assessed. Linear models and intraclass correlation coefficients (ICCs) were used for analyses. RESULTS: For interobserver reliability, the following locations were farther from the best estimate for 2D than 3D: x-location in subspinale (A-point), anterior tip of the nasal spine (ANS), L1 lingual gingival border and L1 root; y-location in porion, ramus point and orbitale; x- and y-locations in basion, condylion, midramus, sigmoid notch and U6 occlusal. 3D y-locations were farther in the gonion, L1 tip, sella and U1 tip. For intraobserver reliability, 2D locations were farther in y-locations in orbitale and sigmoid notch, and both x- and y-locations in basion. 3D locations were farther in the x-location in U1 labial gingival border and y-locations in L1 tip, L6 occlusal, menton and sella. For intraobserver ICCs, greater variations in 2D than 3D included: A-point, ANS, midramus, orbitale, ramus point, sigmoid notch and U1 root. CONCLUSIONS: 3D imaging, as in CBCT, allows for overall improved interobserver and intraobserver reliability in certain landmarks in vivo when compared with two-dimensional images.

Density value means in the evaluation of external apical root resorption: an in vitro study for early detection in orthodontic case simulations.

OBJECTIVES: The purpose of this study was to develop an alternative diagnostic tool for the early detection of external apical root resorption (EARR). METHODS: Mandibular incisors (n=36) with and without simulated EARR lesions were used. 18 teeth with facial and proximal windows, each with a range of 2 sizes, were placed in 6 N hydrochloric acid (HCl) baths for 10 min. A sample of the acid solution was analysed for calcium concentration by atomic absorption spectrophotometry. Incisors were imaged at 80 degrees, 90 degrees and 100 degrees under 3 test conditions (bracketed, non-bracketed and with subtraction registration templates (SRTs)). The images were reconstructed and subtracted to determine the accuracy and sensitivity of the method. Quantified histograms for each subtracted image were constructed. RESULTS: At either an angle of 80 degrees or 100 degrees, the bracketed group had the largest mean standard deviation of the subtraction histograms while the SRT group had the smallest. Density values as a function of total calcium removed were plotted indicating a linear relationship between subtraction density units and calcium loss. CONCLUSION: The use of the SRTs was significantly more accurate than the use of the brackets alone for digital subtraction radiography reconstructions. This model shows promise for detecting EARR prior to a noticeable decrease in root length. It may be useful for early detection of resorptive lesions during routine orthodontic treatment.

First Report of Sweet potato chlorotic stunt virus, a Component of Sweetpotato Virus Disease, in North Carolina.

Sweet potato chlorotic stunt virus (SPCSV) is the whitefly-transmitted component of the sweet potato virus disease (SPVD), a devastating disease originally described in Africa (4). Two isolates designated as G-01 and T-03 were obtained in North Carolina in July 2001 and October 2003, respectively, from plants of cv. Beauregard exhibiting symptoms typical of SPVD, including stunting, leaf narrowing and distortion, vein clearing, and chlorotic mosaic. Sap extract from symptomatic plants tested positive for SPCSV by nitrocellulose immuno-dot blot, using monoclonal antibodies specific for SPCSV obtained from the International Potato Center. Total RNA was extracted from 100 mg of symptomatic leaf tissue by using the PureLink Total RNA Purification System Kit from Invitrogen (Carlsbad, CA) with a minor modification (adding 2% PVP-40 and 1% 2-mercaptoethanol to the extraction buffer) (1). Results were confirmed by reverse transcription (RT)-PCR using primers CP1 and CP3 and HSP70-A/HSP70-B (2), corresponding to the capsid protein and 'heat shock' protein genes, respectively. HSP70 amplicons were cloned using the TOPO TA Cloning Kit (Invitrogen) and sequenced. At the nucleotide level, viral sequences from clones from both isolates were an average 99.4% similar to West Africa and 77.9% to East Africa sequences of SPCSV from Genbank (1). Although the isolates were collected from different fields, viral sequences generated from clones for T-03 and G-01 differed by only six nucleotides and were identical at the amino acid level. The neighbor-joining phylogenetic tree constructed using the HSP70 gene fragment (39 nt) delineated two major clusters with two subpopulations each: Cluster 1, "East Africa", consisted of East Africa and Peru subpopulations; Cluster 2, "West Africa", consisted of Argentina-Brazil and USA-West Africa subpopulations (1). In addition, SPCSV isolates from East Africa and West Africa clusters were sufficiently distant phylogenetically to suggest that they may correspond to two different criniviruses, with an average similarity between the populations of 78.14% and an average within the populations above 89%. Hudson's tests confirmed the presence of genetically distinct SPCSV groups with high statistical significance (1). Two groups (Peru and East Africa) were differentiated in the East Africa cluster, and three groups (Argentina-Brazil, USA, and West Africa) were differentiated in the West Africa cluster, suggesting that the USA population is not a recent introduction. Although SPCSV was previously reported in the United States, the source was a single accession of cv. White Bunch from the USDA Sweetpotato Germplasm Repository (3). Sweet potato feathery mottle virus (SPFMV) (family Potyviridae, genus Potyvirus), the other component of SPVD, was also detected in both cultivars. To our knowledge, this is the first report of SPCSV in sweetpotato fields in the United States. References: (1) J. A. Abad et al. Phytopathology (Abstr.) 96(suppl.):S1, 2006. (2) T. Alicai et al. Plant Pathol. 48:718, 1999. (3) G. Pio-Ribeiro et al. Plant Dis. 80:551, 1996. (4) G. A. Schaefer and E. R. Terry. Phytopathology 66:642, 1977.

The utility of panoramic radiography in temporomandibular joint assessment.

OBJECTIVES: Panoramic radiography was used to determine (1) intrarater and inter-rater reliability in assessing temporomandibular joint (TMJ) condylar morphology; (2) alteration in condylar shape in patients with temporomandibular disorders (TMD) and controls when matched by age, gender, and state of dentition; and (3) prevalence of condylar abnormalities in individuals with and without TMD. METHODS: One hundred panoramic radiographs were randomly selected from a hospital clinic (45 TMD and 55 non-TMD patients). The images were cropped to include only the temporomandibular apparatus and were independently evaluated by three examiners without knowledge of the patient's clinical status. Multiple statistical tests were performed to evaluate the accumulated data. RESULTS: Intrarater reliability demonstrated substantial agreement, while inter-rater reliability was fair. There was no difference in condylar morphology between patient groups, but mild condylar change was prevalent in all age groups, regardless of TMD status. CONCLUSIONS: Morphological condylar abnormalities are present on panoramic images in all adult age ranges, regardless of status of the dentition or presence of TMD. Condylar shape alone is not an indicator of TMD, and minor condylar discrepancies may have no significance in TMD.

The impact of image compression on diagnostic quality of digital images for detection of chemically-induced periapical lesions.

OBJECTIVES: To test the hypothesis that there is no significant difference in the detectability of chemically-induced periapical lesions between a non-compressed image and one subjected to a Joint Photographic Experts Group (JPEG) lossy compression technique at a ratio of 23:1 or less. METHOD: Chemically-induced periapical lesions were created by placing a solution of 70% perchloric acid at the apex of extracted teeth in 13 human jaw cadaver specimens. Acid was applied in seven incremental time periods from 0-32 h. Extracted teeth were replaced in the socket and images were made using the Schick CDR digital sensor. Using a JPEG lossy compression algorithm, five compression ratios of 2:1, 14:1, 23:1, 28:1 and 47:1 were applied to the images. Images were viewed three times by three observers who ranked the presence or absence of a lesion at three sites, the mesial area, distal area and apex of the tooth, on a 5-point confidence scale. Intraobserver and interobserver agreement and agreement between the compressed and the original images were assessed with intraclass correlation coefficients (ICCs). RESULTS: Overall ICCs for measuring intraobserver agreement using all images were 0.77, 0.84, and 0.50 for the three observers, respectively. The overall ICC for assessing agreement between observers was 0.57. There was no significant difference (P>0.05) between compressed and original images for any site at compression ratios of 2:1, 23:1 and 28:1. There were significant differences for a compression ratio of 47:1. CONCLUSION: JPEG compression does not impact detectability of artificial periapical lesions at low and moderate compression ratios up to and including 28:1.

Dietary carbohydrate's effects on lipogenesis and the relationship of lipogenesis to blood insulin and glucose concentrations.

The process by which dietary carbohydrate is transformed into fat in the human body is termed de novo lipogenesis. New methods for the measurement of this process in humans are available and have been used to investigate the role of the carbohydrate form (fed as a liquid or solid), the level of processing of carbohydrate in foods, and the role of lipogenesis in the control of liver triacylglycerol secretion. The present paper will discuss how research results are affected by both the physical state of the carbohydrate in the diet and by the metabolic state of individual research subjects. Of interest is the relationship between the glycemic index of a food (or indicators of a food's glycemic index) and that food's ability to stimulate lipogenesis in humans. Given the increasing prevalence of obesity worldwide, future scientific emphasis will expand methods to quantitate the lipogenic potential of specific foods and dietary patterns and investigate how the metabolic state of insulin resistance affects lipogenesis and/or contributes to obesity.

Recent findings in the study of postprandial lipemia.

The study of postprandial metabolism is in the early stages compared with other areas of atherosclerosis research. Recent advances in postprandial research have included improvements in methodology and the investigation of factors that modulate the lipemic response to a meal. Enough studies have now been performed that normal ranges have been identified for blood triacylglycerol (TAG) concentrations that occur after a healthy patient consumes a standardized-mixed meal or a high-fat shake designed to elicit lipemia. Typical postprandial concentrations of other metabolites, such as apolipoproteins B48 and B100 or gastrointestinal hormones (eg, cholecystokinin), have not been studied sufficiently to be able to qualify what represents a standard postprandial response. The method of data analysis is also a key point to consider. Data from children are now becoming available, and the specific effects of ethnicity have just begun to be explored. New areas of study include the effects of different fatty acids (monosaturates or polyunsaturates), the sources of chylomicron lipids (dietary TAG and cholesterol versus that newly synthesized in the body), and the effects of alcoholic beverages consumed with the meal. Variables that can also affect the results of a meal test are under investigation. These include the type of food that is consumed the day before the meal test, the time of day the test is performed, and the palatability of the food. Given solid evidence that delayed postprandial lipemia is an independent risk factor for coronary heart disease, future scientific investigation in the area of postprandial metabolism is likely to yield discoveries that will significantly contribute to advancements in disease treatment.

Effect of dietary carbohydrate on triglyceride metabolism in humans.

When the content of dietary carbohydrate is elevated above the level typically consumed (>55% of energy), blood concentrations of triglycerides rise. This phenomenon, known as carbohydrate-induced hypertriglyceridemia, is paradoxical because the increase in dietary carbohydrate usually comes at the expense of dietary fat. Thus, when the content of the carbohydrate in the diet is increased, fat in the diet is reduced, but the content of fat (triglycerides) in the blood rises. The present article will review studies of carbohydrate-induced hypertriglyceridemia, highlighting data obtained in fasted subjects habituated to high carbohydrate diets, data obtained from subjects in the fed state, and metabolic studies investigating fatty acid and triglyceride synthesis in subjects consuming diets of different carbohydrate content. The available data have been recently expanded by new methodologies, such as the use of stable isotopes, to investigate the metabolism of sugars in humans in vivo. Given the significant increase in body weight observed in the American population over the past decade and the changing availability of carbohydrate in the food supply, future studies of carbohydrate-induced hypertriglyceridemia promise to provide important information of how the macronutrient composition of the diet can influence health.

Predictors of plasma triglyceride elevation in patients participating in a coronary atherosclerosis treatment program.

PURPOSE: Low-fat, high-carbohydrate diets have been used successfully to prevent and treat coronary heart disease, although these diets have been shown to cause elevations in fasting plasma triglyceride concentrations. The present study investigated metabolic factors (glucose, insulin, body weight) associated with changes in plasma triglyceride concentrations in patients participating in a comprehensive, multidisciplinary program, which included the use of a very low-fat diet designed to regress atherosclerotic cardiovascular disease. METHODS: Thirty-six patients were entered into the study and placed on a 10% fat diet. Body mass index and fasting plasma insulin, glucose, lipids, and apolipoproteins were assessed at entrance into and after 3 months of participation in the program. Statistical analysis (discriminant function analysis) was used to identify factors that predicted elevations in plasma triglyceride that occurred during therapy. RESULTS: For the entire group, significant reductions in body weight (-2.4%), fasting glucose (-6%), total cholesterol (-8%), and low-density lipoprotein cholesterol (-11%) were observed, while insulin and triglycerides showed no significant changes. Twenty-one of the patients experienced an increase in fasting triglyceride concentration of 10% or greater. CONCLUSIONS: Three variables (baseline body mass index and fasting triglyceride and insulin concentrations) accurately classified 90% of those who would experience a > or = 10% elevation in triglycerides (P = 0.0002) and 67% of those who experienced no change. The present analysis provides a practical algorithm for clinicians to predict which patients will experience significant elevations in plasma triglyceride concentration when undergoing risk factor reduction that includes the consumption of a very low-fat, high-carbohydrate diet.

Dependence of plasma alpha-tocopherol flux on very low-density triglyceride clearance in humans.

To evaluate the effect of dietary fat-induced alterations in triglyceride (TG) metabolism on plasma and very low-density lipoprotein (VLDL)-alpha-tocopherol, nine healthy males (mean +/- SEM, age: 36 +/- 3 years, BMI: 24.7 +/- 1.1) consumed a 35%-fat diet (control) for one week followed by a 15% low-fat, high-carbohydrate diet for 5 weeks. After each dietary phase, the subjects ingested an evening meal along with a 50 mg capsule of (2)H(6)-RRR-alpha-tocopheryl acetate; blood samples were drawn over a 24 h period while the subjects remained fasted. Low-fat feeding increased fasting plasma TG concentrations by 53% (116 +/- 27 to 178 +/- 32, mg/dl, p < 0.0001) primarily by reducing VLDL-TG clearance. Total plasma alpha-tocopherol concentrations (labeled + unlabeled) were unchanged (25.8 +/- 2.3 vs. 26.4 +/- 3.0 nmol/ml plasma) and no differences between the diets were observed for plasma (2)H(6)-alpha-tocopherol concentration (4.8 +/- 0.6 nmol/ml, for both diets) or enrichments (18.1 +/- 1.8% average for both diets). However, low-fat feeding significantly increased the amount of alpha-tocopherol in the VLDL fraction (43%, p = 0.04) in concert with elevations in VLDL-apoB and TG. The alpha-tocopherol and TG content of VLDL varied in parallel in individual subjects and fractional replacement rates and clearance of alpha-tocopherol and TG in VLDL were closely correlated. Kinetic parameters were decreased by 32-39% from high-fat to low-fat. These data suggest that vitamin E bioavailability is similar between a 15 and 35% fat diet, with a redistribution of alpha-tocopherol in lipoproteins occurring during low-fat feeding (increased in the VLDL fraction, reduced in the other lipoproteins), and transfer of alpha-tocopherol from VLDL depends upon TG removal from the particle, consistent with previous observations in vitro and in animal studies.