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Effect of added fat on the plasma glucose and insulin response to ingested potato given in various combinations as two meals in normal individuals.

OBJECTIVE: In normal subjects, ingestion of fat with potato in a morning meal resulted in a decrease in the glucose response. Therefore, we wished to determine whether a fat-induced decrease in blood glucose also would be observed after a second identical meal. In addition, we were interested in determining if fat ingestion with a morning meal would have an effect on the blood glucose and insulin responses to a second meal not containing fat. RESEARCH DESIGN AND METHODS: Nine healthy male subjects ingested two meals consisting of an amount of potato containing 50 g carbohydrate, either alone or with 50 g fat as butter. The meals were served in four combinations as follows: 1) potato for the first meal, potato for the second meal; 2) potato for the first meal, potato with fat for the second meal; 3) potato with fat for the first meal, potato for the second meal; and 4) potato with fat for the first meal, potato with fat for the second meal. Meals were ingested at 8:00 A.M. and noon. Plasma glucose and C-peptide, serum insulin, triglyceride, and free fatty acid (FFA) concentrations were determined over an 8-h period. The integrated area responses to the meals were quantified over the subsequent 4-h period using the fasting value or the noon value as baseline for the first and second meals, respectively. RESULTS: When the first meal contained potato only, the glucose area response to the second meal was significantly less when the second meal contained fat. However, fat ingestion had no effect on the glucose area response to the second meal when fat was present in the first meal. The insulin area responses to the first and second meals were similar after ingestion of potato or potato with fat. However, the insulin response to the second meal always was less than that to the first meal. The C-peptide area responses after ingestion of the second meal also were all higher than those after the first meal. The triglyceride area responses were slightly negative after ingestion of potato alone in the first meal. When fat was ingested, they were positive. When the first meal contained fat but the second meal did not, there was a rise in triglyceride concentration after the second meal as well as after the first meal. That is, a rise occurred without ingestion of fat with the second meal. If fat was present in the second meal the rise was even greater. The FFA area responses were similar to the triglyceride area responses. CONCLUSIONS: When fat was ingested with carbohydrate in either the first or second meal, the glucose area response was decreased. However, when both meals contained fat, a decrease in the glucose area response did not occur with the second meal. The glucose area responses all were greater after the second meal compared with those after the first meal, i.e., the opposite of a Staub-Traugott effect was observed. The insulin area responses to the first and second meals were similar whether fat was ingested or not.

Adult↗

Changes in toxicity and bioavailability of lead in contaminated soils to the earthworm Eisenia fetida (Savigny 1826) after bone meal amendments to the soil.

The effect of bone meal (Ca5(PO4)3OH) amendments on lead (Pb) bioavailability to Eisenia fetida (Savigny 1826) was investigated. A standard uncontaminated soil was amended with Pb(NO3)2 solution to give Pb concentrations of 7,000 microg/g of soil. After one week, bone meal was added to one half of the soil in the ratio 1:20 bone meal:soil. Immediately after addition of the bone meal, survival times of E. fetida were 23 and 41 h in the bone meal-free and bone meal-amended soil, respectively. Twenty-eight days after addition of the bone meal, survival times of Eisenia fetida were 67 h in the bone meal-free soil and more than 168 h in the bone meal-amended soil. In a second experiment, a standard Organisation for Economic Co-operation and Development reproduction toxicity test was carried out, but in addition to Pb(NO3)2 solution, bone meal was added to the soil in the ratio 1:20 bone meal:soil. The bone meal-free soil was left for five weeks before addition of E. fetida. In the bone meal-amended soil, bone meal was added to the soil one week after addition of the Pb. The soil was left for a further four weeks before addition of Eisenia fetida. Calculated toxicities were significantly lower for the bone meal-amended soil than those calculated for the bone meal-free soil. Twenty-eight-day median lethal concentrations (LC50s; concentration that is statistically likely to kill 50% of the exposed test organism within a given time period +/- 95% confidence intervals) of Pb were 4,379 +/- 356 microg/g of soil for bone meal-free soil and 5,203 +/- 401 microg/g of soil for bone meal-amended soil. Twenty-eight-day median effect concentrations (EC50s; concentration causing a reduction by 50% of a stated parameter) of Pb for weight change were 1,408 +/- 198 microg/g of soil for bone meal-free soil and 3,334 +/- 731 microg/g of soil for bone meal-amended soil and EC50s for cocoon production were 971 +/- 633 microg/g of soil for bone meal-free soil and 1,814 +/- 613 microg/g of soil for bone meal-amended soil. Significant mortalities occurred at Pb concentrations of 2,000 microg/g of soil in the bone meal-free soil and 5,000 microg/g of soil in the bone meal-amended soil. Earthworm Pb body load was lower in the bone meal-treated soil than in the bone meal-free soil up to a Pb concentration of 5,000 microg/g of soil. Earthworm Pb body load was approximately 100 microg/g of worm in surviving earthworms in both experiments when significant mortality occurred. Water and diethylenetriamine pentaacetic acid-extractable soil Pb showed good correlations with earthworm Pb body load. These extractions could be used as estimates for Pb bioavailability.

Animals↗

The value of crude protein content and in vitro pepsin digestibility of abattoir by-product meals in the prediction of their available protein content.

Amino acid composition of meat-and-bone meals, poultry by-product meals, blood meals, bone meals and feather meals showed characteristic differences. Meat-and-bone meals and blood meals had surplus in lysine, whereas poultry by-product meals and feather meals were relatively rich in cystine. Blood meals had high levels of branched-chain amino acids as compared to isoleucine. In vitro pepsin digestibility of meat-and-bone meals (79.9 +/- 17.7%; n = 24) and blood meals (95.8 +/- 4.2%; n = 11) was found to be higher than that of poultry by-product meals (65.3 +/- 7.7%; n = 14) or feather meals (44.7 +/- 9.2%; n = 16). Pepsin digestibility of poultry by-product meals showed a significant negative correlation with crude protein content (r = -0.73; P less than 0.05; n = 14). However, in vitro pepsin digestibility of poultry by-product meals as well as meat-and-bone meals, blood meals and feather meals, showed insignificant correlations with NPU indices as well as with available crude protein contents of the meals. The NPU values of meat-and-bone meals for rats (29.9 +/- 11.7; n = 100) were lower than those of poultry by-product meals (52.1 +/- 7.1; n = 14). The NPU values of blood meals (6.4 +/- 5.6; n = 11) and feather meals (23.5 +/- 10.0; n = 16), determined as sole sources of protein, were low and they did not elicit weight gain in rats. The available crude protein content of poultry by-product meals (34.3 g/100 g +/- 3.6; n = 14) was higher than that of meat-and-bone meals (17.0 g/100 g +/- 7.3; n = 100).(ABSTRACT TRUNCATED AT 250 WORDS)

Abattoirs↗

Effects of raw material source, ash content, and assay length on protein efficiency ratio and net protein ratio values for animal protein meals.

Experiments were conducted to determine the protein efficiency ratio (PER) and net protein ratio (NPR) of meat and bone meals containing 24 or 34% ash, poultry by-product meals containing 7 or 16% ash, lamb meals containing 15 or 24% ash, a lamb meal analog containing 19% ash (mixture of lamb meal and turkey meal), and two meat and bone meals processed at either a low or a high temperature. The PER values (weight gain per unit of protein intake) and NPR values (PER corrected for maintenance) were determined using a chick growth assay in which chicks were fed a N-free diet or 10% CP diets containing one of the animal meals as the only source of dietary protein for 6, 9, or 13 d. The PER of the lamb meal analog was greater (P < 0.05) than that of the other meals, and the PER values of the poultry by-product meals were generally greater than those for the lamb and meat and bone meals. The PER values for the lamb meals were higher than those for most of the meat and bone meals. The PER of the 34% ash meat and bone meal was lower (P < 0.05) than the PER of the 24% ash meat and bone meal (1.03 vs 1.63, respectively, at 9 d). Further experiments showed that the lower PER of the high ash meat and bone meal was not due to its high Ca and P content. Ash content had no significant effect on PER of the poultry by-product and lamb meals. The PER of the low-temperature meat and bone meal was higher (P < 0.05) than the PER of the high-temperature meat and bone meal. The relative differences in NPR values among the animal meals were similar to those observed for PER values. Decreasing the length of the assay from 13 to 6 d increased the PER and NPR of all meals but had little or no effect on the ranking of values among meals. The results of this study indicated that PER and NPR values of animal meals were influenced by raw material source, and that ash content and processing temperature affected the PER and NPR of meat and bone meal. The results also indicated that PER and NPR assays could be reduced to 6 d without reducing sensitivity.

Analysis of Variance↗

Effect of increasing the dietary level of rapeseed meal on intake by growing beef steers.

Three experiments were conducted to determine the effects of rapeseed meal on intake by cattle. In the first experiment, the effect of increasing rapeseed meal level on intake, growth, and performance of growing beef steers was evaluated. In the second experiment, the effect of extrusion (glucosinolate reduction) on supplement intake by steers was evaluated. In the third experiment, the effect of increasing dietary rapeseed meal level on supplement intake was evaluated. In the first experiment, rapeseed meal replaced soybean meal at 0, 33, 67, or 100% of the supplemental protein. Dry matter intake, crude protein intake, and serum thyroxine levels were decreased linearly (P < .01) with increasing level of rapeseed meal in the supplement. Protein sources used in Exp. 2 were soybean meal, rapeseed meal, extruded rapeseed meal, and soybean meal containing rapeseed oil at the same level as the rapeseed meal. In Exp. 3, the protein sources were composed of different combinations of rapeseed meal and soybean meal (100% rapeseed meal; 67% rapeseed meal and 33% soybean meal; 33% rapeseed meal and 67% soybean meal; and 100% soybean meal). Supplement intake was measured at .5, 4, and 24 h after feeding in both experiments. Extrusion treatment, which reduced glucosinolate content in rapeseed meal 75%, did not improve (P > .10) supplement intake. Rapeseed meal resulted in lower supplement intakes at .5 and 4 h than the soybean meal and soybean meal+rapeseed oil supplements (P = .003).(ABSTRACT TRUNCATED AT 250 WORDS)

Animal Feed↗

Effects of blood meal pH and irradiation on nursery pig performance.

A total of 720 nursery pigs in three experiments were used to evaluate the effects of blood meal with different pH (a result of predrying storage time) and irradiation of spray-dried blood meal in nursery pig diets. In Exp. 1, 240 barrows and gilts (17 +/- 2 d of age at weaning) were used to determine the effects of blood meal pH (7.4 to 5.9) in diets fed from d 10 to 31 postweaning (7.0 to 16.3 kg of BW). Different lots of dried blood meal were sampled to provide a range in pH. Overall (d 0 to 21), pigs fed diets containing blood meal had greater ADG (P < 0.05) and ADFI (P < 0.05) than pigs fed diets without blood meal. Ammonia concentrations in blood meal rose as pH decreased. However, blood meal pH did not influence (P > 0.16) ADG, ADFI, or gain:feed (G:F). In Exp. 2, 180 barrows (17 +/- 2 d of age at weaning) were used to determine the effects of post drying pH (7.6 to 5.9) and irradiation (gamma ray, 9.5 kGy) of blood meal on growth performance of nursery pigs from d 5 to 19 postweaning (6.8 to 10.1 kg of BW). One lot of whole blood was isolated with 25% of the total lot dried on d 0, 3, 8, and 12 after collection to create a range in pH. Overall, pigs fed blood meal had improved G:F (P < 0.01) compared to pigs fed the control diet. Similar to Exp. 1, the ammonia concentration of blood meal increased with decreasing pH. Blood meal pH did not influence ADG, ADFI, or G:F (P > 0.21), but pigs fed irradiated blood meal (pH 5.9) had greater ADG and G:F (P < 0.05) than pigs fed nonirradiated blood meal (pH 5.9). In Exp. 3, 300 barrows (17 +/- 6 d of age at weaning) were used to determine the effects of blood meal irradiation source (gamma ray vs. electron beam) and dosage (2.5 to 20.0 kGy) on growth performance of nursery pigs from d 4 to 18 postweaning (8.7 to 13.2 kg of BW). Overall, the mean of all pigs fed blood meal did not differ in ADG, ADFI, or G:F (P > 0.26) compared to pigs fed the control diet without blood meal. Pigs fed irradiated blood meal had a tendency (P < 0.10) for increased G:F compared with pigs fed nonirradiated blood meal. No differences in growth performance were detected between pigs fed blood meal irradiated by either gamma ray or electron beam sources (P > 0.26) or dosage levels (P > 0.11). These studies suggest that pH alone as an indicator of blood meal quality is not effective and irradiation of blood meal improved growth performance in nursery pigs.

Animal Feed↗

The effects of poultry meal source and ash level on nursery pig performance.

Weanling pigs (total of 560) were used in two experiments to determine the effects of poultry meal in nursery diets on pig performance. In Exp. 1,210 barrows and gilts (initially 7.4 kg and 21 +/- 2 d of age) were fed one of five diets, which included a control diet with no specialty protein products or (as-fed basis) the control with 2.5 or 5.0% fish meal, or 2.9 or 5.9% poultry meal (11.8% ash). Poultry meal replaced fish meal on an equal lysine basis. Overall (d 0 to 28), pigs fed diets containing fish meal had greater (P < 0.01) ADG than pigs fed poultry meal. Increasing fish meal tended to have increased (quadratic, P < 0.07) ADG, with the greatest improvement observed in pigs fed the diet containing 2.5% fish meal. Pigs fed diets containing fish meal had improved (P < 0.01) G:F compared with pigs fed diets containing poultry meal. In Exp. 2, a total of 350 barrows and gilts (initially 8.9 kg and 22 +/- 2 d of age) were fed one of seven experimental diets, which included a control diet with no specialty protein products, or the control with 2.5 or 5.0% fish meal, 2.9 or 5.8% low-ash (10.9%) poultry meal, and 3.1 or 6.2% high-ash (13.5%) poultry meal. Poultry meal replaced fish meal on an equal lysine basis. Overall (d 0 to 15), there were no differences in ADG and ADFI (P = 0.14); however, pigs fed diets containing fish meal or poultry meal had improved (linear, P < 0.01) G:F compared with pigs fed the control diet. Pigs fed diets containing low-ash poultry meal had greater (P < 0.01) G:F compared with pigs fed diets containing high-ash poultry meal. Based on these data, quality control specifications, such as ash content, need to be considered when using poultry meal as an animal protein replacement in diets for nursery pigs.

Animal Feed↗

Effects of red pepper added to high-fat and high-carbohydrate meals on energy metabolism and substrate utilization in Japanese women.

The effects of dietary red pepper added to high-fat (HF) and high-carbohydrate (HC) meals on energy metabolism were examined in thirteen Japanese female subjects. After ingesting a standardized dinner on the previous evening, the subjects took an experimental breakfast (1883 kJ) under the following four conditions: HF meal, HF and red-pepper (10 g) meal, HC meal, or HC and red-pepper meal. Palatability of the experimental meals was measured immediately after the meals. Expired air was collected before and for 210 min after the meal to determine energy expenditure and macronutrient oxidation. Diet-induced thermogenesis was significantly higher after the HC meals than after the HF meals. Lipid oxidation was significantly lower and carbohydrate oxidation was significantly higher after the HC meals than after the HF meals. Addition of red pepper to the experimental meals significantly increased diet-induced thermogenesis and lipid oxidation, particularly after the HF meal. On the other hand, carbohydrate oxidation was significantly decreased by the addition of red pepper to the experimental meals. Addition of red pepper to the HC meal increased the perceived oiliness of the meal to the same level as that of the HF meals. These results indicate that red pepper increases diet-induced thermogenesis and lipid oxidation. This increase in lipid oxidation is mainly observed when foods have a HF content whereas the increase in the perceived oiliness of the meal was found under the HC meal conditions.

Adult↗

Small bowel motor activity in response to physiological meals of different chemical composition in man.

Meals disrupt the interdigestive pattern of small bowel motor activity and convert it into the more irregular postprandial pattern. Previous animal studies suggest that the duration of and contractile activity within the postprandial period depend on the chemical composition of a meal. It is not clear whether this is also true for man. In 8 healthy volunteers I investigated how physiological and isocaloric meals of different chemical composition affect small bowel motor activity. Volunteers underwent two separate, ambulatory 24-hour small bowel manometry studies. Volunteers had a total of four meals on the two study days. They ingested two identical fish meals rich in protein, a pasta meal rich in carbohydrates, and a meat meal rich in fat. Records were analyzed visually for the reappearance of phase III of the migrating motor complex, and a validated computer program calculated the incidence of contractions during the postprandial period, as well as the amplitude and propagation of contractions. The durations of the postprandial periods were similar after the two protein meals (238 +/- 35 and 227 +/- 25 min), the carbohydrate (220 +/- 23 min) and the fat meal (242 +/- 43 min). The incidence of contractions was not significantly different after the protein meals (1.6 +/- 0.3 and 1.0 +/- 0.2 contractions per min), the carbohydrate meal (1.0 +/- 0.2 contractions per min) and the fat meal (1.5 +/- 0.2 contractions per min). The amplitude of contractions was similar after the protein meals (14 +/- 0.1 and 13 +/- 0.1 mmHg), the carbohydrate meal (14 +/- 0.1 mmHg) and the fat meal (14 +/- 0.1 mmHg). Propagation of contractions was similar after the protein meals (13 +/- 3 and 18 +/- 3 %), after the carbohydrate meal (15 +/- 2 %) and after the fat meal (13 +/- 2 %). Contractile activity within consecutive 30-min periods of the postprandial period was also not different between the meals. I conclude that physiological, isocaloric meals of different chemical composition elicit a similar postprandial motor response in the human small bowel.

Adult↗

Lactational performance of high producing dairy cows fed diets containing salmon meal and urea.

Thirty Holstein cows were used in a 12-wk trial to study the effects of salmon meal and urea on lactational performance. Two experimental diets, one containing 5.6% salmon meal and the other 5.2% salmon meal plus .42% urea, were compared with a soybean meal control diet. Salmon meal and urea replaced a portion of the soybean meal. Dietary undegraded intake protein levels (expressed as percentage of CP) were 28.8, 35.6, and 32.4% for soybean meal, salmon meal, and salmon meal plus urea. Total mixed diets (average 17.3% CP, 17.6% ADF) consisting of 60% concentrate mixture and 40% bromegrass silage (DM basis) were fed twice daily. Total DMI was lower with salmon meal compared with soybean meal (20.2 versus 22.2 kg/d); salmon meal plus urea (21.2 kg/d) was intermediate. Actual milk production was similar for all diets (average 41.1 kg/d). Percentage milk fat and 4% FCM yield were lower with salmon meal (2.56%, 31.6 kg/d) and salmon meal plus urea (2.50%, 31.4 kg/d) than with soybean meal (3.03%, 35.9 kg/d). Gross efficiency (weight FCM/weight DMI) was higher for soybean meal than for salmon meal and salmon meal plus urea. Acetate: propionate tended to be higher with the soybean meal diet. The use of a high oil fish meal to provide a source of rumen undegraded intake protein, alone or in combination with urea, resulted in a decrease in milk fat percentage and yield without any beneficial effects on milk production or lactational efficiency.

Ammonia↗

Decreased thermic effect of food after an irregular compared with a regular meal pattern in healthy lean women.

OBJECTIVES: To investigate the impact of irregular meal frequency on body weight, energy intake, appetite and resting energy expenditure in healthy lean women. DESIGN: Nine healthy lean women aged 18-42 y participated in a randomised crossover trial consisting of three phases over a total of 43 days. Subjects attended the laboratory at the start and end of phases 1 and 3. In Phase 1 (14 days), subjects were asked to consume similar things as normal, but either on 6 occasions per day (regular meal pattern) or follow a variable predetermined meal frequency (between 3 and 9 meals/day) with the same total number of meals over the week. In Phase 2 (14 days), subjects continued their normal diet as a wash-out period. In Phase 3 (14 days), subjects followed the alternative meal pattern to that followed in Phase 1. Subjects recorded their food intake for three predetermined days during the irregular period when they were eating 9, 3 and 6 meals/day. They also recorded their food intake on the corresponding days during the regular meal pattern period. Subjects fasted overnight prior to each laboratory visit, at which fasting resting metabolic rate (RMR) was measured by open-circuit indirect calorimetry. Postprandial metabolic rate was then measured for 3 h after the consumption of a milkshake test meal (50% CHO, 15% protein and 35% fat of energy content). Subjects rated appetite before and after the test meal. RESULTS: There were no significant differences in body weight and 3-day mean energy intake between the regular and irregular meal pattern. In the irregular period, the mean energy intake on the day when 9 meals were eaten was significantly greater than when 6 or 3 meals were consumed (P=0.0001). There was no significant difference between the 3 days of the regular meal pattern. Subjective appetite measurement showed no significant differences before and after the test meal in all visits. Fasting RMR showed no significant differences over the experiment. The overall thermic effect of food (TEF) over the 3 h after the test meal was significantly lower after the irregular meal pattern (P=0.003). CONCLUSION: Irregular meal frequency led to a lower postprandial energy expenditure compared with the regular meal frequency, while the mean energy intake was not significantly different between the two. The reduced TEF with the irregular meal frequency may lead to weight gain in the long term.

Adolescent↗

Nutritional value of lupin (Lupinus albus)-seed meal for growing pigs: availability of lysine, effect of autoclaving and net energy content.

1. Two experiments were conducted to assess the nutritional value of lupin (Lupinus albus)-seed meal for growing pigs. In the first, the availability of lysine was assessed using slope-ratio analysis. In the second, the effects of autoclaving lupin seeds and formulating the diets on the basis of estimated digestible or net energy were assessed. 2. In the first experiment, the availability of lysine in three samples of lupin-seed meal was compared with that in meat-and-bone meal and soya-bean meal. Availability of lysine in the five protein concentrates, using food conversion efficiency on a carcass basis as the criterion of response, was (proportion of total): lupin-seed meal no. 1 0.44, no. 2 0.57, no. 3 0.53, meat-and-bone meal 0.42, soya-bean meal 0.80. 3. Availability estimates, based on protein deposited:food intake, were: lupin-seed meal no. 1 0.82, no. 2 0.73, no. 3 0.70, meat-and-bone meal 0.27, soya-bean meal 0.77. These estimates had higher standard deviations than those based on carcass response. 4. Regressing the measures of response v. lysine intake resulted in estimates of availability similar to, or higher than, the slope-ratio analysis but was associated with greater statistical invalidity and higher standard deviations. 5. The proportion of energy retained in the carcasses was unaffected by the inclusion levels of lysine or soya-bean meal. Energy retention was depressed (P less than 0.05) with the three lupin-seed meals and the meat-and-bone meal. 6. In the second experiment, the response of pigs given a diet containing lupin-seed meal was inferior, on a carcass basis (P less than 0.05), to that of pigs given a diet containing soya-bean meal formulated to similar total lysine and digestible energy contents. 7. The addition of soya-bean oil to the diet containing lupin-seed meal, to equalize the estimated net energy of the diet to that of the diet containing soya-bean meal, depressed protein deposition (P less than 0.05) and increased fat deposition (P less than 0.05), indicating that energy was not limiting the growth of pigs given the lupin-seed-meal diet. 8. Autoclaving the lupin-seed at 121 degrees for 5 min had no effect on the growth of pigs, indicating that the low availability of lysine was not due to the presence of heat-labile anti-nutritional factors.

Animal Feed↗

Small bowel transit of a bran meal residue in humans: sieving of solids from liquids and response to feeding.

BACKGROUND: Ileal motor patterns are adapted to the propulsion of viscous meal residue, such as bran, which accumulates in the distal ileum postprandially. AIMS: To examine the effects of a second liquid/solid meal on ileal emptying. SUBJECTS AND METHODS: Eleven healthy fasting subjects consumed a 1.47 MJ pancake containing 15 g bran and 5 MBq Technetium-99m labelled amberlite resin (meal A). Gastric emptying and transit through the left upper quadrant (proximal) and right lower quadrant (distal) small bowel regions and colon were assessed scintigraphically. Transit was compared with and without a second Indium-111 liquid/solid DTPA labelled 2.28 MJ meal (B) given three hours after the first meal. RESULTS: Gastric emptying of meal A was slower than meal B (the time for 50% of the activity to leave the stomach (T50) being 113 (11) minutes versus 48 (3) minutes respectively, p < 0.01, n = 11). Both meals passed rapidly through the proximal small bowel (T50 meal A = 57 (14) minutes versus T50 meal B = 42 (11) minutes). Transit of meal A through the distal small bowel was much slower (T50 more than 390 minutes versus 176 (29) minutes for meal B, p < 0.01), resulting in meal B overtaking meal A and entering the colon earlier. Ingestion of the second meal (B) resulted in significantly less meal A marker entering the colon (5 (3)%) at 11 hours than when meal A was taken alone (18 (4)%) (p < 0.05, n = 8). CONCLUSIONS: The distal small bowel selectively retains bran, allowing liquid phase markers through to the colon. Consuming a second liquid/solid meal does not stimulate ileal transit of bran which seems to be propelled quicker by fasting motor patterns.

Adult↗

Acute effect of meal glycemic index and glycemic load on blood glucose and insulin responses in humans.

OBJECTIVE: Foods with contrasting glycemic index when incorporated into a meal, are able to differentially modify glycemia and insulinemia. However, little is known about whether this is dependent on the size of the meal. The purposes of this study were: i) to determine if the differential impact on blood glucose and insulin responses induced by contrasting GI foods is similar when provided in meals of different sizes, and; ii) to determine the relationship between the total meal glycemic load and the observed serum glucose and insulin responses. METHODS: Twelve obese women (BMI 33.7 +/- 2.4 kg/m2) were recruited. Subjects received 4 different meals in random order. Two meals had a low glycemic index (40-43%) and two had a high-glycemic index (86-91%). Both meal types were given as two meal sizes with energy supply corresponding to 23% and 49% of predicted basal metabolic rate. Thus, meals with three different glycemic loads (95, 45-48 and 22 g) were administered. Blood samples were taken before and after each meal to determine glucose, free-fatty acids, insulin and glucagon concentrations over a 5-h period. RESULTS: An almost 2-fold higher serum glucose and insulin incremental area under the curve (AUC) over 2 h for the high- versus low-glycemic index same sized meals was observed (p < 0.05), however, for the serum glucose response in small meals this was not significant (p = 0.38). Calculated meal glycemic load was associated with 2 and 5 h serum glucose (r = 0.58, p < 0.01) and insulin (r = 0.54, p < 0.01) incremental and total AUC. In fact, when comparing the two meals with similar glycemic load but differing carbohydrate amount and type, very similar serum glucose and insulin responses were found. No differences were observed for serum free-fatty acids and glucagon profile in response to meal glycemic index. CONCLUSION: This study showed that foods of contrasting glycemic index induced a proportionally comparable difference in serum insulin response when provided in both small and large meals. The same was true for the serum glucose response but only in large meals. Glycemic load was useful in predicting the acute impact on blood glucose and insulin responses within the context of mixed meals.

Adult↗

Comment: response of the hypothalamic-pituitary-adrenocortical axis to high-protein/fat and high-carbohydrate meals in women with different obesity phenotypes.

Subjects with abdominal obesity are characterized by hyperactivation of the hypothalamic-pituitary-adrenal (HPA) axis. Food intake, particularly at noon, is a well-known inducer of HPA axis activation. Whether obese subjects present an abnormal response to meals containing different macronutrient proportions is at present unknown. Therefore, this study was carried out to investigate the effect of a high-lipid/protein meal (HLP-meal) and a high-carbohydrate meal (HCHO-meal) on the HPA axis activity in women with different obesity phenotypes. Nondepressed, noncomplicated obese (body mass index greater than 28 kg/m(2)) women with abdominal (A-BFD) (n = 10) and peripheral body fat distribution (P-BFD) (n = 9) and a group of 11 normal-weight controls were investigated in the follicular phase of the menstrual cycle. They were randomly given an 800-kcal HCHO-meal (containing 89% carbohydrates, 11% proteins, 0% lipids), and an 800-kcal HLP-meal (containing 53% lipids, 43% proteins, 4% carbohydrates), which were eaten within 15 min at noon, with an interval of 2 d between each meal. Blood samples for ACTH, cortisol, glucose, and insulin were obtained at 15-min intervals before and after each meal. Baseline hormone and glucose concentrations in the three groups were similar. After the HLP-meal, ACTH tended to similarly but insignificantly increase in all groups, whereas cortisol increased significantly (P < 0.05) in the P-BFD group and insignificantly in the other groups. Conversely, both ACTH and cortisol significantly (P < 0.05) increased only in the A-BFD group, without any significant changes in both controls and P-BFD women. The analysis of the interaction between meals and groups clearly indicated that the cortisol response to the HLP-meal and the HCHO-meal was significantly different (P < 0.025) between the two obese groups, the A-BFD group being characterized by a significantly lower response to the HLP-meal and a significantly higher response to the HCHO-meal, compared with the P-BFD group. Considering all groups together and after adjusting for body mass index, a highly significant relationship was found between cortisol-area under the curve and ACTH-area under the curve after each meal test. However, no relationships were found between changes in ACTH and cortisol and those of glucose, insulin, and the glucose:insulin ratio after each meal. Therefore, our data demonstrate that the response of the HPA axis to meals containing different macronutrient proportions may depend on the pattern of body fat distribution. We also suggest that the activation of the HPA axis following the ingestion of large amounts of carbohydrates may have some pathophysiological relevance, specifically in women with the abdominal obesity phenotype.

Adrenocorticotropic Hormone↗

Effects of carbohydrate meals of varying consistency on gastric myoelectrical activity.

BACKGROUND: There is at present no agreement on the type of test meal to be used when performing EGG. To our knowledge the response of the stomach to high carbohydrate isocaloric meals of different consistencies has not been formally assessed. AIM: To study 1) the effects of high carbohydrate meals of varying consistency on EGG activity; and 2) the effects of increasing the calorie content of a meal without changing its consistency and composition on the postprandial EGG. SUBJECTS: Eighteen healthy volunteers, six males (age: 21-35 year, weight: 45-60 kg) and 12 females in the follicular phase of the menstrual cycle (age: 24-30 years, weight: 45-55 kg). METHODS: Following an overnight fast subjects were given three high carbohydrate, low fat, isocaloric meals (165-170 kcal) of different consistencies (solid, semisolid, liquid), on three separate days in a random order. The liquid and semisolid meals were equal in volume (200 ml) while the volume of the solid meal was smaller. One hour EGG recordings were done in the fasting and fed states in each subject. As a second step, ten of the above volunteers (taken randomly) were given the solid test meal on a separate day after increasing the calorie content of the meal to 350 kcal. RESULTS: The power of the EGG at the dominant frequency significantly increased after solid (175 kcal meal: fasting 49 +/- 12 dB vs. fed 57 +/- 13 dB; p < 0.05, 375 kcal meal: fasting 48.5 +/- 12.9 dB vs fed 58.1 +/- 11.7 dB) and semisolid (fasting 50 +/- 12 dB vs. fed 55 +/- 13; P < 0.05). The increase in power was not significantly different when fed with solids and semisolids. There was no statistically significant change in EGG power during the first 15 or 60 minutes after the liquid meal. Feeding showed no significant effect on the dominant frequency and the percentage of 2-4 cpm waves of the EGG with any of the three types of test meals. CONCLUSIONS: Solid and semisolid meals high in carbohydrate and low in fat are capable of inducing a significant increase in the EGG power in normal subjects. Isocaloric solid and semisolid meals have similar effects on gastric slow wave activity. EGG appears unaffected by the liquid meal. Therefore only an increase in the power of the EGG can be regarded as normal if a high carbohydrate solid or a semisolid meal is given as the test meal when performing an EGG.

Adult↗