scholarly journals Effect of blood sampling schedule and method of calculating the area under the curve on validity and precision of glycaemic index values

2004 ◽  
Vol 91 (2) ◽  
pp. 295-300 ◽  
Author(s):  
Thomas M. S. Wolever

To evaluate the suitability for glycaemic index (GI) calculations of using blood sampling schedules and methods of calculating area under the curve (AUC) different from those recommended, the GI values of five foods were determined by recommended methods (capillary blood glucose measured seven times over 2·0 h) in forty-seven normal subjects and different calculations performed on the same data set. The AUC was calculated in four ways: incremental AUC (iAUC; recommended method), iAUC above the minimum blood glucose value (AUCmin), net AUC (netAUC) and iAUC including area only before the glycaemic response curve cuts the baseline (AUCcut). In addition, iAUC was calculated using four different sets of less than seven blood samples. GI values were derived using each AUC calculation. The mean GI values of the foods varied significantly according to the method of calculating GI. The standard deviation of GI values calculating using iAUC (20·4), was lower than six of the seven other methods, and significantly less (P<0·05) than that using netAUC (24·0). To be a valid index of food glycaemic response independent of subject characteristics, GI values in subjects should not be related to their AUC after oral glucose. However, calculating GI using AUCmin or less than seven blood samples resulted in significant (P<0·05) relationships between GI and mean AUC. It is concluded that, in subjects without diabetes, the recommended blood sampling schedule and method of AUC calculation yields more valid and/or more precise GI values than the seven other methods tested here. The only method whose results agreed reasonably well with the recommended method (ie. within ±5 %) was AUCcut.

Food Research ◽  
2019 ◽  
Vol 4 (2) ◽  
pp. 421-430
Author(s):  
Norsyahera Elena Natasha Amiruddin ◽  
Mohd Nizam Zahary ◽  
Bhaskar Raj Naresh ◽  
Abbe Maleyki Mhd Jalil

β-Glucan (βG) and whey protein (WP) are two functional ingredients widely used to maintain desirable blood glucose and weight management. However, the effect of combining βG and WP is still not thoroughly explored. This study was aimed to determine the effects of combining βG and WP in energy drinks on glycaemic index (GI), palatability and acceptability. Ten females (22.0±0.64 years old, 20.6±0.24 kg/m²) randomly completed four trials (control drink, βG drink, WP drink and βG+WP drink) in a cross-over manner. Palatability and acceptability were measured using visual analogue scale (VAS). Capillary blood was collected at 0 min (fasting state, baseline) and 15, 30, 60 and 120 min after the test drinks and assayed for glucose. There were no significant differences in palatability and acceptability of test drinks compared with control (p>0.005). The incremental area under the curve (iAUC) for blood glucose responses showed no significant differences between all test drinks. Time x treatment showed a significant increased from 0 to 30 mins (peak) (p<0.005) for all test drinks. Blood glucose response significantly (p<0.005) decreased from 30 to 120 mins for all test drinks except control. There were no significant differences in GI of βG, WP, and βG+WP drinks compared with control (117%, 124% and 114%, respectively). This study suggested that drinks prepared with βG and WP were palatable and acceptable either per se or in combination but did not significantly reduce the GI compared with control drink. In addition, the drink prepared with βG and whey protein reduced short-term glucose but does not affect overall glycaemic response.


2006 ◽  
Vol 96 (5) ◽  
pp. 799-802 ◽  
Author(s):  
Thomas M. S. Wolever ◽  
Blanche Ip ◽  
Elham Moghaddam

The precision with which glycaemic responses, expressed as incremental area under the curve (AUC), can be measured may be improved by using the average of several measures of fasting blood glucose (FBG). To see if taking two fasting blood samples would increase the precision of AUC, the glycaemic responses elicited by four test meals (50 g glucose; 50 g glucose plus 10 g fat and 10 g protein; 100 g white bread; 100 g white bread plus 10 g fat and 10 g protein) were determined in thirteen overnight-fasted healthy subjects. Two fasting blood samples were taken 5 min apart (−5 min and 0 min before starting to eat) with glucose measured three times in each sample. AUC was calculated using different estimates of FBG derived from the three measures of glucose in the two fasting blood samples and each set of AUC values subjected to ANOVA. Unexpectedly, the results were more precise when AUC was calculated from mean glucose in the 0 min blood sample (FBG0) than from mean glucose in the two different fasting blood samples. The 95 % CI of the AUC calculated using FBG0 in thirteen subjects was ±29·8; to obtain the same CI using the mean of the two fasting blood samples would require fourteen subjects. These results suggest that taking two fasting blood samples does not necessarily improve, and may even reduce, the precision of AUC as a measure of glycaemic response. Further studies are needed before requiring that two fasting blood samples be taken for determining glycaemic index.


2021 ◽  
pp. 105477382110247
Author(s):  
Eda Ergin ◽  
Ayten Zaybak

The purpose of this study is to compare whether or not there is a difference between venous and capillary blood samples in blood glucose measurements and investigate the effects of different aseptic methods used in skin cleaning before collecting blood samples on measurement results. This quasi-experimental study was conducted with 109 patients. The capillary first and second blood drop values taken from the patients after fasting and at 2 hours following 75 g oral glucose tolerance test (OGTT) and capillary and venous blood glucose values were compared. There was no significant difference between the median venous blood glucose value and the capillary second blood drop value taken after wiping the finger with alcohol. There was no significant difference between the first and second blood drop values of capillary blood glucose 2 hours after OGTT.


2005 ◽  
Vol 94 (6) ◽  
pp. 917-921 ◽  
Author(s):  
C. Jeya K. Henry ◽  
Helen J. Lightowler ◽  
Caroline M. Strik ◽  
Michael Storey

The glycaemic response to eight potato varieties commercially available in Great Britain was compared against a glucose standard in a non-blind, randomised, repeated measure, crossover design trial. Seventeen healthy subjects (three males, fouteen females), mean age 32 (sd 13) years and mean BMI 22·3 (sd 3·6) kg/m2, were recruited to the study. Subjects were served portions of eight potato varieties and a standard food (glucose), on separate occasions, each containing 50 g carbohydrate. Capillary blood glucose was measured from finger-prick samples in fasted subjects (0 min) and at 15, 30, 45, 60, 90 and 120 min after the consumption of each test food. For each potato variety, the glycaemic index (GI) value was calculated geometrically by expressing the incremental area under the blood glucose curve (IAUC) as a percentage of each subject's average IAUC for the standard food. The eight potato varieties exhibited a wide range in GI values from 56 to 94. A trend was seen whereby potatoes with waxy textures produced medium GI values, whilst floury potatoes had high GI values. Considering the widespread consumption of potatoes in Great Britain (933–1086 g per person per week), this information could be used to help lower the overall GI and glycaemic load of the diets of the British population.


2021 ◽  
pp. 1-27
Author(s):  
Akila SRV ◽  
Suman Mishra ◽  
Allan Hardacre ◽  
Lara Matia-Merino ◽  
Kelvin Goh ◽  
...  

Abstract The hypothesis that coarse grain particles in breads reduce glycaemic response only if the particles remain intact during ingestion was tested. Three breads were formulated: (1) White bread (WB - reference), (2) 75% of kibbled purple wheat in 25% white bread matrix (PB), (3) a 1:1 mixture of 37.5% kibbled soy beans and 37.5% of kibble purple wheat in 25% white bread matrix (SPB). Each bread was ingested in three forms: unchewed (U), as customarily consumed (C), and homogenized (H). Twelve participants ingested 40 g available carbohydrate portions of each bread in each form, with post prandial blood glucose measured over 120 min. Glycaemic responses to WB were the same regardless of its form when ingested. Unchewed PB had significantly less glycaemic effect than WB, whereas the C and H forms were similar to WB. Based on a glycaemic index (GI) of 70 for WB the GI values for the C, U and H breads respectively were WB: 70.0, 70, 70, PB: 75, 42, 61, SPB: 57, 48, 55 (%) (Least significant difference = 17.43, p <0.05, bold numbers significantly different from WB). The similar glycaemic response to the H and C forms of the breads, and their difference from the U form, showed that the glycaemia-moderating effect of grain structure on starch digestion was lost during customary ingestion of bread. We conclude that kibbled grain structure may not effectively retard starch digestion in breads as normally consumed because it is largely eliminated by ingestive processes including chewing.


2018 ◽  
Vol 43 (12) ◽  
pp. 1298-1306 ◽  
Author(s):  
Aaron Raman ◽  
Jeremiah J. Peiffer ◽  
Gerard F. Hoyne ◽  
Nathan G. Lawler ◽  
Andrew J. Currie ◽  
...  

This study examined the effect of 2 forms of exercise on glucose tolerance and the concurrent changes in markers associated with the interleukin (IL)-6 pathways. Fifteen sedentary, overweight males (29.0 ± 3.1 kg/m2) completed 2 separate, 3-day trials in randomised and counterbalanced order. An oral glucose tolerance test (OGTT; 75 g) was performed at the same time on each day of the trial. Day 2 of each trial consisted of a single 30-min workload-matched bout of either high-intensity intermittent exercise (HIIE; alternating 100% and 50% of peak oxygen uptake) or continuous moderate-intensity exercise (CME; 60 % of peak oxygen uptake) completed 1 h prior to the OGTT. Venous blood samples were collected before, immediately after, 1 h after, and 25 h after exercise for measurement of insulin, C-peptide, IL-6, and the soluble IL-6 receptors (sIL-6R; soluble glycoprotein 130 (sgp130)). Glucose area under the curve (AUC) was calculated from capillary blood samples collected throughout the OGTT. Exercise resulted in a modest (4.4%; p = 0.003) decrease in the glucose AUC when compared with the pre-exercise AUC; however, no differences were observed between exercise conditions (p = 0.65). IL-6 was elevated immediately after and 1 h after exercise, whilst sgp130 and sIL-6R concentrations were reduced immediately after exercise. In summary, exercise was effective in reducing glucose AUC, which was attributed to improvements that took place between 60 and 120 min into the OGTT, and was in parallel with an increased ratio of IL-6 to sIL-6R, which accords with an increased activation via the “classical” IL-6 signalling pathway. Our findings suggest that acute HIIE did not improve glycaemic response when compared with CME.


2017 ◽  
Vol 117 (8) ◽  
pp. 1110-1117 ◽  
Author(s):  
Ayesha S. Al Dhaheri ◽  
C. Jeyakumar K. Henry ◽  
Maysm N. Mohamad ◽  
Eric O. Ohuma ◽  
Leila Cheikh Ismail ◽  
...  

AbstractGlycaemic index (GI) and glycaemic load (GL) values of some commonly consumed foods in the United Arab Emirates were determined with an aim of adding these values to the existing international table of GI and GL values. In all, eighteen test foods categorised into breads (n5), entrée dishes (n3), main dishes (n5) and sweet dishes (n5) were tested. For each test food, at least fifteen healthy participants consumed 25 or 50 g available carbohydrate portions of a reference food (glucose), which was tested three times, and a test food after an overnight fast, was tested once, on separate occasions. Capillary blood samples were obtained by finger-prick and blood glucose was measured using clinical chemistry analyser. A fasting blood sample was obtained at baseline and before consumption of test foods. Additional blood samples were obtained at 15, 30, 45, 60, 90 and 120 min after the consumption of each test food. The GI value of each test food was calculated as the percentage of the incremental area under the blood glucose curve (IAUC) for the test food of each participant divided by the average IAUC for the reference food of the same participant. The GI values of tested foods ranged from low (55 or less) to high (70 or more). The GI values of various breads and rice-containing dishes were comparable with previously published values. This study provides GI and GL values of previously untested traditional Emirati foods which could provide a useful guide on dietary recommendations for the Emirati population.


2021 ◽  
Author(s):  
Yun Hu ◽  
Peng Zhang ◽  
Bo Ding ◽  
Xin Cao ◽  
Yi Zhong ◽  
...  

Abstract Food temperature may be important in diabetes. Newly diagnosed treatment-naïve type 2 diabetes patients (T2DM, 22) and normal controls (19) were randomly assigned to either hot (50°C) or cold (8˚C) oral glucose tolerance test (OGTT) on day 1, and OGTT at the other temperature on the next day. Measurements were made on venous blood obtained at 0, 5, 10, 30, 60, and 120 min. Compared to cold OGTT, blood glucose was significantly higher with hot OGTT in both groups. However, insulin and glucagon-like peptide-1 (GLP-1) levels were significantly higher in hot OGTT in normal subjects only. The glucose-dependent insulinotropic peptide (GIP) and cortisol responses did not differ with temperature in both groups. After the OGTT, subjects took corresponding, either hot (> 42˚C) or cool (room temperature) meals and water, that entire day, followed by identical food at the other temperature the next day. Continuous glucose monitoring showed that normal subjects had significantly higher 24-hour mean glucose (MBG), and standard deviation of MBG with hot meals, T2DM patients had higher MBG only. Our study showed that blood glucose, insulin, and GLP-1 responses to different food temperatures may be deficient in newly diagnosed T2DM.


2009 ◽  
Vol 34 (6) ◽  
pp. 1040-1047 ◽  
Author(s):  
Ying-Ju Chen ◽  
Hsuan-Ying Chen ◽  
Ming-Fu Wang ◽  
Mei-Hsiang Hsu ◽  
Woei-Ming Liang ◽  
...  

Repeated blood sampling in rodents is often necessary and difficult. Magnesium has been touted as an agent for enhancing physical activity. An auto-blood-sampling device coupled with a microdialysis analyzer was developed to determine blood glucose and lactate concentrations in rats subjected to treadmill exercise. The effects of magnesium on exercise performance and blood energy metabolism were also evaluated. Sprague–Dawley rats fed a magnesium-adequate diet were randomly assigned to 2 experimental groups. Exercise performance was evaluated at 3 treadmill speeds (10, 15, and 20 m·min–1) with or without magnesium administration (90 mg·kg–1, intraperitoneal) in the first experiment. In the other experiment, each rat was fitted with a catheter in the jugular vein for collection of blood samples during the treadmill exercise at a speed of 20 m·min–1. Exercise performance was significantly higher at the lower speed of 10 m·min–1 in the control group. In addition, exercise performance was significantly enhanced only at 20 m·min–1 in the magnesium-sulfate-treated group when compared with the control group. Blood samples were collected every 15 min. Glucose concentrations increased significantly and then declined immediately after completion of the exercise task at 20 m·min–1 in both groups. However, glucose concentrations increased immediately after administration of magnesium and increased further during exercise when compared with those of the control group. Findings from a repeated blood-sampling assay suggest that increased blood glucose contributes to enhanced exercise performance by rats injected intraperitoneally with magnesium.


2011 ◽  
Vol 106 (3) ◽  
pp. 335-338 ◽  
Author(s):  
Miriam E. Clegg ◽  
Megan Pratt ◽  
Ciara M. Meade ◽  
C. Jeya K. Henry

It is now known that health benefits associated with diets rich in fruit and vegetables may be partly derived from intake of polyphenols. Berry polyphenols may influence carbohydrate metabolism and absorption and hence postprandial glycaemia. To date, studies related to polyphenol effects on the glycaemic response have been completed only in liquids using either monosaccharides or disaccharides. It remains to be determined whether berries known to be rich in polyphenols can reduce the glycaemic response (GR) to a solid polysaccharide meal. The aim of the present study was to investigate whether berries alter postprandial hyperglycaemia and consequently the GR to a starchy food. Blood glucose was tested on seven occasions, on three occasions using a reference food and on four occasions using pancakes supplemented with either raspberries or blueberries or control pancakes containing similar amounts of fructose and glucose. Results showed that there were no differences in GR (blueberry 51·3 (sem5·7); raspberry 54·7 (sem5·6); blueberry control 43·9 (sem4·2); raspberry control 41·8 (sem6·4)), GR area under the curve or satiety index between any of the tests. The present study indicates that the ability of berries to reduce blood glucose from starch-based foods is unsubstantiated.


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