Evidence of enhanced serum amino acid profile but not appetite suppression by dietary glycomacropeptide (GMP): a comparison of dairy whey proteins

OBJECTIVE

There is evidence that high-protein foods increase satiety and may aid weight loss, yet little is known of differential effects of protein composition. The aim of the study was to compare the acute effects of 4 whey proteins on satiety and food intake and to evaluate possible relationships with postprandial serum amino acid concentrations.

METHODS

Isoenergetic high-protein shakes (∼1 MJ) containing 25 g whey protein were given to 18 lean male participants using a crossover design. Three protein fractions identified as satiating in a rat model, glycomacropeptide (GMP), beta-lactoglobulin (ß-lac), and colostrum whey protein concentrate (WPC), were compared with a WPC control. A standardized 2.5MJ breakfast was given at 0830 hours, followed by the preload beverages at 1130 hours. Participants rated appetite sensations using visual analogue scales (VAS) prior to the beverage (baseline, 0 minutes) and then at 15, 30, 45, 60, 90, 150, and 210 minutes. Energy and macronutrient intake was measured by covert weighing of an ad libitum lunch meal at 90 minutes. Repeat blood samples were collected via venous cannulation.

RESULTS

Serum amino acid (a.a.) concentrations differed between whey fractions (p=0.012) and were higher following GMP compared to ß-lac (p=0.051) and colostrum WPC (p=0.044) but not the WPC control (p=0.20). There was no difference in VAS-rated hunger, satisfaction, or thoughts of food between whey fractions, but fullness did differ (p=0.032) and was highest following the ß-lac beverage. Energy intake was not suppressed relative to control by any of the 3 whey fractions.

CONCLUSIONS

We conclude that total serum a.a. concentration was a poor indicator of satiety, with little evidence of differential satiety between these whey proteins other than a modest enhancement of fullness by ß-lac.

Low-dose whey protein-enriched water beverages alter satiety in a study of overweight women

AIM

To determine the effect of low-dose whey protein-enriched water beverages on postprandial satiety and energy intake (EI).

METHODS

Fifty overweight and mildly obese women were given 500 mL water-based beverages on 4 different occasions in a double blind, cross-over study. The beverages were reasonably matched for colour, flavour, sweetness and contained 0% (water control, 0 g, 8 kJ), 1% (5 g, 93 kJ), 2% (10 g, 178 kJ) and 4% (20 g, 348 kJ) whey protein by weight (ClearProtein8855™). Following a standard evening meal and breakfast, beverages were consumed 120 min before an ad libitum lunch at which EI was measured. Feelings associated with hunger and fullness were also measured using visual analogue scales (VAS).

RESULTS

46 participants completed all 4 beverage conditions. There was a significant effect of beverage preload on hunger (beverage×time; P=0.0074), where each of the 1%, 2% and 4% w/w protein beverages decreased hunger compared to the water control (P<0.05). Suppression of hunger was also maintained for longer following the protein beverages (Friedman test, P=0.013). Fullness (beverage×time; P=0.0020) and satisfaction (beverage×time; P=0.0356) were both increased by the 1% and 4% protein beverages (P<0.05). EI at lunch decreased by up to 8 percent (control vs 4% protein, delta=-247 kJ, Tukey's post hoc, P>0.05) when escalating protein doses were added to the water preload (water control, 3028 kJ; 1%, 3080 kJ; 2%, 2924 kJ; 4%, 2781 kJ), only partial compensation for the added energy.

CONCLUSIONS

These low-dose, whey protein-enriched water beverages significantly altered short term postprandial satiety, however the effect was not sufficient to impact on food intake when assessed 2 h after consumption.

Liking of health-functional foods containing lupin kernel fibre following repeated consumption in a dietary intervention setting

Liking of a particular food after repeated consumption may be reduced, limiting the effectiveness of health-functional foods requiring on-going consumption to deliver their benefits. This study examined the effect of repeated consumption of foods containing the novel ingredient, Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre) on sensory acceptability in the dietary intervention setting. In a single-blind randomised crossover 4-week intervention, participants consumed both control and equivalent LKFibre-containing products daily on separate interventions separated by a 4-week period on habitual diet. Seven products: muesli, bread, muffin, chocolate brownie, chocolate milk drink, pasta and instant mashed potato were assessed twice (days 4 and 18 of intervention), by 38 participants for appearance, texture, flavour and general acceptability using a structured graphic hedonic scale. Overall the results showed there was no reduction (P=0.594) in general acceptability of LKFibre foods after repeated consumption, suggesting potential for long-term consumption. The control food products were however generally preferred (P<0.001) over the LKFibre foods; the mean difference for general acceptability between being <6% (0.82cm) of the 15cm hedonic scale used, suggesting LKF addition did not severely affect product palatability.

Bioinformatic analysis of abundant, gender-enriched transcripts of adult Ascaris suum (Nematoda) using a semi-automated workflow platform

Expressed sequence tag (EST) data representing transcripts with a high level of differential hybridization in suppressive-subtractive hybridization (SSH)-based microarray analysis between adult female and male Ascaris suum were subjected to detailed bioinformatic analysis. A total of 361 ESTs clustered into 209 sequences, of which 52 and 157 represented transcripts that were enriched in female and male A. suum, respectively. Thirty (57.7%) of the 'female' subset of 52 sequences had orthologues/homologues in other parasitic nematodes and/or Caenorhabditis elegans, 13 (25%) exclusively in other parasitic nematodes and nine (17.3%) had no match in any other organism for which sequence data are currently available; the C. elegans orthologues encoded molecules involved in reproduction as well as embryonic and gamete development, such as vitellogenins and chitin-binding proteins. Of the 'male' subset of 157 sequences, 73 (46.5%) had orthologues/homologues in other parasitic nematodes and/or C. elegans, 57 (37.5%) in other parasitic nematodes only, and 22 (14.5%) had no significant similarity match in any other organism; the C. elegans orthologues encoded predominantly major sperm proteins (MSPs), kinases and phosphatases, actins, myosins and an Ancylostoma secreted protein-like molecule. The findings of the present study should support further genomic investigations of A. suum.

Lupin-enriched bread increases satiety and reduces energy intake acutely

BACKGROUND

Protein and fiber may be important determinants of satiety. Lupin kernel flour is a novel food ingredient that is rich in protein and fiber.

OBJECTIVE

The objective was to investigate the effects of lupin kernel flour-enriched bread (LB) on satiety and energy intake in humans.

DESIGN

Two randomized controlled crossover trials were performed to compare the acute effects of LB with those of white bread (WB). In study 1, the subjects (n = 16) completed 4 treatments 1 wk apart: WB breakfast (as toast) and WB lunch (as sandwiches), WB breakfast and LB lunch, LB breakfast and WB lunch, and LB breakfast and LB lunch. Energy intake at all breakfast meals was matched (1655 kJ), and ad libitum energy intake at lunch, 3 h after breakfast, was measured. In study 2, the subjects (n = 17) completed 2 treatments 1 wk apart: WB breakfast and LB breakfast (each 1655 kJ). Blood samples were taken at baseline and at regular intervals for 3 h after breakfast.

RESULTS

In study 1, the LB breakfast resulted in significantly higher self-reported satiety (P < 0.001) and lower energy intake (kJ) at lunch (-488; 95% CI: -798, -178) than did the WB breakfast. The LB lunch resulted in a significantly lower within-meal energy intake (kJ) at lunch (-1028; 95% CI: -1338, -727) than did the WB lunch. In study 2, compared with the WB breakfast, the LB breakfast significantly altered the 3-h postmeal plasma ghrelin response (P = 0.04) and resulted in significantly lower mean 3-h plasma ghrelin concentrations (P = 0.009).

CONCLUSION

A novel food enriched in protein and fiber derived from lupin kernel flour significantly influences energy intake acutely.

Lupin kernel fiber consumption modifies fecal microbiota in healthy men as determined by rRNA gene fluorescent in situ hybridization

BACKGROUND

Changes in the composition of gastrointestinal microbiota by dietary interventions using pro- and prebiotics provide opportunity for improving health and preventing disease. However, the capacity of lupin kernel fiber (LKFibre), a novel legume-derived food ingredient, to act as a prebiotic and modulate the colonic microbiota in humans needed investigation.

AIM OF THE STUDY

The present study aimed to determine the effect of LKFibre on human intestinal microbiota by quantitative fluorescent in situ hybridization (FISH) analysis.

DESIGN

A total of 18 free-living healthy males between the ages of 24 and 64 years consumed a control diet and a LKFibre diet (containing an additional 17-30 g/day fiber beyond that of the control-incorporated into daily food items) for 28 days with a 28-day washout period in a single-blind, randomized, crossover dietary intervention design.

METHODS

Fecal samples were collected for 3 days towards the end of each diet and microbial populations analyzed by FISH analysis using 16S rRNA gene-based oligonucleotide probes targeting total and predominant microbial populations.

RESULTS

Significantly higher levels of Bifidobacterium spp. (P = 0.001) and significantly lower levels of the clostridia group of C. ramosum, C. spiroforme and C. cocleatum (P = 0.039) were observed on the LKFibre diet compared with the control. No significant differences between the LKFibre and the control diet were observed for total bacteria, Lactobacillus spp., the Eubacterium spp., the C. histolyticum/C. lituseburense group and the Bacteroides-Prevotella group.

CONCLUSIONS

Ingestion of LKFibre stimulated colonic bifidobacteria growth, which suggests that this dietary fiber may be considered as a prebiotic and may beneficially contribute to colon health.

Lupin kernel fibre foods improve bowel function and beneficially modify some putative faecal risk factors for colon cancer in men

Consumption of some dietary fibres may benefit bowel health; however, the effect of Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre) is unknown. The present study examined the effect of a high-fibre diet containing LKFibre on bowel function and faecal putative risk factors for colon cancer compared to a control diet without LKFibre. Thirty-eight free-living, healthy men consumed an LKFibre and a control diet for 1 month each in a single-blind, randomized, crossover study. Depending on subject energy intake, the LKFibre diet was designed to provide 17-30 g/d fibre (in experimental foods) above that of the control diet. Bowel function self-perception, frequency of defecation, transit time, faecal output, pH and moisture, faecal levels of SCFA and ammonia, and faecal bacterial beta-glucuronidase activity were assessed. In comparison to the control diet, the LKFibre diet increased frequency of defecation by 0.13 events/d (P=0.047), increased faecal output by 21 % (P=0.020) and increased faecal moisture content by 1.6 % units (P=0.027), whilst decreasing transit time by 17 % (P=0.012) and decreasing faecal pH by 0.26 units (P<0.001). Faecal butyrate concentration was increased by 16 % (P=0.006), butyrate output was increased by 40 % (P=0.002) and beta-glucuronidase activity was lowered by 1.4 micromol/h per g wet faeces compared to the control diet (P<0.001). Addition of LKFibre to the diet incorporated into food products improved some markers of healthy bowel function and colon cancer risk in men.

Lupin kernel fibre-enriched foods beneficially modify serum lipids in men

OBJECTIVE

To examine the effect of a diet containing a novel legume food ingredient, Australian sweet lupin (Lupinus angustifolius) kernel fibre (LKFibre), compared to a control diet without the addition of LKFibre, on serum lipids in men.

DESIGN

Randomized crossover dietary intervention study.

SETTING

Melbourne, Australia--Free-living men.

SUBJECTS

A total of 38 healthy males between the ages of 24 and 64 y completed the intervention.

INTERVENTION

Subjects consumed an LKFibre and a control diet for 1 month each. Both diets had the same background menus with seven additional experimental foods that either contained LKFibre or did not. Depending on energy intake, the LKFibre diet was designed to contain an additional 17 to 30 g/day fibre beyond that of the control diet.

RESULTS

Compared to the control diet, the LKFibre diet reduced total cholesterol (TC) (mean+/-s.e.m.; 4.5+/-1.7%; P=0.001), low-density lipoprotein cholesterol (LDL-C) (5.4+/-2.2%; P=0.001), TC: high-density lipoprotein cholesterol (HDL-C) (3.0+/-2.0%; P=0.006) and LDL-C:HDL-C (3.8+/-2.6%; P=0.003). No effects on HDL-C, triacylglycerols, glucose or insulin were observed.

CONCLUSIONS

Addition of LKFibre to the diet provided favourable changes to some serum lipid measures in men, which, combined with its high palatability, suggest this novel ingredient may be useful in the dietary reduction of coronary heart disease risk.

Palatability and glucose, insulin and satiety responses of chickpea flour and extruded chickpea flour bread eaten as part of a breakfast

OBJECTIVE

To determine the effect of adding chickpea flour or extruded chickpea flour to white bread on palatability and postprandial glycaemia, insulinaemia and satiety.

DESIGN

A randomised, single-blind, cross-over study of four 50 g available carbohydrate breakfasts.

SETTING

School of Exercise and Nutrition Sciences, Deakin University.

SUBJECTS

In all, 12 healthy subjects were recruited through posted notices. Totally, 11 (nine male, two female) completed the study (mean+/-s.e.m.; age 32+/-2 y; body mass index, 24.7+/-0.8 kg/m(2)).

INTERVENTION

After overnight fasting, subjects consumed a control (white) bread (WB) breakfast twice, a chickpea bread (CHB) breakfast once and an extruded chickpea bread (EXB) breakfast once. Palatability and postprandial blood glucose, insulin and satiety responses were determined. Following this, food intakes from an ad libitum buffet and for the remainder of the day were assessed.

RESULTS

A trend towards a lower incremental area under the curve (IAUC) of glucose for the CHB breakfast compared to the WB breakfast was observed (P=0.087). The IAUC of insulin and insulinaemic index (II) of the CHB breakfast were higher (P<0.05) than for the WB breakfast. No differences in glycaemic index (GI), satiety response, food intake or palatability were observed.

CONCLUSIONS

CHB and EXB demonstrated acceptable palatability. CHB demonstrated some hypoglycaemic effect compared to WB, but neither CHB nor EXB demonstrated effects on satiety or food intake. The hyperinsulinaemic effect of CHB observed in this study requires further investigation.

Australian sweet lupin flour addition reduces the glycaemic index of a white bread breakfast without affecting palatability in healthy human volunteers

The addition of some legume ingredients to bread has been associated with effects on glycaemic, insulinaemic and satiety responses that may be beneficial in controlling type 2 diabetes, cardiovascular disease and obesity. However, the effect of Australian sweet lupin (Lupinus angustifolius) flour (ASLF) is unknown. This investigation examined the effect of adding ASLF to standard white bread on post-meal glycaemic, insulinaemic and satiety responses and palatability in healthy subjects. Using a randomised, single-blind, cross-over design, 11 subjects consumed one breakfast of ASLF bread and two of standard white bread > or =7 days apart after fasting overnight. Each breakfast also included margarine, jam, and tea with milk and contained 50 g available carbohydrate. On each test day, blood samples were taken after fasting, then several times over 2 hours post-prandially, and analysed for plasma glucose and serum insulin. Subjects rated breakfast palatability and perception of satiety, in the fasting state and over 3 hours post-prandially, after which food intake from an ad libitum buffet and for the rest of the day was recorded. Incremental areas under the curves for glucose, insulin and satiety, glycaemic index, insulinaemic index and satiety index were calculated. ASLF addition to the breakfast reduced its glycaemic index (mean +/-SEM; ASLF bread breakfast = 74.0 +/-9.6. Standard white bread breakfast = 100, P=0.022), raised its insulinaemic index (ASLF bread breakfast = 127.7 +/-12.0. Standard white bread breakfast = 100, P=0.046), but did not affect palatability, satiety or food intake. ASLF addition resulted in a palatable breakfast; however, the potential benefits of the lowered glycaemic index may be eclipsed by the increased insulinaemic index.

Endoscopic ultrasound localization of a pancreatic insulinoma: case report and review of the localization techniques

A 23-year-old male was referred to our hospital for evaluation of new-onset seizures. Signs and symptoms of neuroglycopenia, including weakness, dizziness, and confusion, appeared during fasting and resolved promptly with intravenous dextrose administration. Insulin, proinsulin, and C-peptide levels were consistent with a diagnosis of insulinoma. Screening tests for multiple endocrine neoplasia type 1 and surreptitious sulfonylurea uses were negative. Preoperative localization of the insulinoma by transabdominal ultrasonography, computed tomography, and indium-111 octreoscanning were unsuccessful. Endoscopic ultrasonography (EUS) identified a 6- to 7-mm tumor at the juncture of the head and body of the pancreas. Surgical exploration confirmed the preoperative localization, and an 8-mm tumor was simply enucleated. The patient has been free of symptoms for 18 months since surgery. This report describes the utility of EUS to localize a solitary pancreatic insulinoma and provides a comparison of EUS and other preoperative localization techniques.

Differences in myosin isoform expression in the subepicardial and subendocardial myocardium during cardiac hypertrophy in the rat

We have investigated myosin isoform expression during progressive cardiac hypertrophy and the development of congestive heart failure in young male rats. Cardiac enlargement was produced by placing a constricting band (0.024-inch diameter) around the ascending aorta of 25-day-old animals, which resulted in progressively increased stenosis as the rat matured. A 57% and 77% cardiac hypertrophy was observed at 2 and 8 weeks, respectively, with signs of congestive failure at the latter time point. Myosin isoform expression was examined in the subendocardial and subepicardial myocardium of the left ventricle and the free wall of the right ventricle by use of native gel electrophoresis. The percentage of the V3 isoform increased dramatically in both ventricles. In the subendocardial myocardium of the left ventricle, expression of the V3 isoform increased (p less than or equal to 0.05) relative to the subepicardial myocardium at 2, 4, and 8 weeks (17.1% vs. 10.2%, 29.4% vs. 18%, and 46.6% vs. 36.2%). In addition to regional differences within a given transmural segment, we also observed a high degree of heterogeneity in myosin isoform expression throughout a given layer (particularly the subendocardial myocardium) when small (less than or equal to 10-15 mg) adjacent samples were examined. This variability illustrated a potential danger in interpretation of gel results obtained from a single small tissue sample. Thus, cardiac hypertrophy produced by pressure overload in 25-day-old rats resulted in significantly increased V3 myosin in both the left and right ventricles. Furthermore, within the hypertrophied left ventricle, the subendocardial myocardium contained a significantly greater percentage of V3 myosin than the subepicardial myocardium.(ABSTRACT TRUNCATED AT 250 WORDS)

The Nominal Group Technique for planning and problem solving

The Nominal Group Technique is a useful planning and problem-solving process that should be part of every biocommunications manager's repertoire of group managerial skills. The NGT process is designed for those situations where individual judgments must be tapped and combined to arrive at decisions which cannot be calculated by one person. It is a problem-solving or idea-generating strategy that involves silent generation of ideas which are then recorded and ranked by the group.