Indeks glikemiczny - przełom ?

Jedynym dotychczasowym sposobem wyznaczania wpływu węglowodanów na organizm (indeksu glikemicznego) była metoda pomiarów stężenia glukozy po posiłkach zawierających dane węglowodany. Nauka nie przyjmowała do wiadomości metody obliczania indeksu glikemicznego, jako średniej indeksów wchodzących w skład mieszaniny produktów - potrawy.

Powodem tego był przypuszczalny wpływ białek i tłuszczów zawartych w tych produktach, które mogły spowalniać wchłanianie węglowodanów, a co za tym idzie obniżać indeks glikemiczny takiej mieszaniny.

Naukowcy z Kanady (University of Toronto) i Australii (University of Sydney) postanowili sprawdzić, czy rzeczywiście do wyznaczenie indeksu gliemicznego potrawy, składającej się z produktów o znanych IG, należy robić badania stężenia glukozy we krwi.
Ich metoda polegała na sprawdzeniu, jak na wypadkowy IG wpływa różna zawartość białka i tłuszczu w testowych potrawach.

Okazało się, że rzeczywisty wpływ tych składników pokarmowych na indeks glikemiczny mieszaniny produktów był pomijalny. Wzrost glikemii po posiłkach, w około 90%, zależał tylko i wyłącznie od węglowodanów (ich ilości i jakości).

Choć oznaczenia te były prowadzone jedynie na 24 osobach i testowały tylko 14 potraw, to mogą zachęcić do prowadzenia dalszych badań nad tym zagadnieniem. Potwierdzenie tej teorii mogłoby oszczędzić wielu długotrwałych i kosztownych badań nad indeksami glikemicznymi potraw złożonych, skoro wyliczenie może dać nam 90% dokładność.


American Journal of Clinical Nutrition


bibliografia: www.jedzdobrze.pl 

Szkoda ze takie badania. Mogli byc cos wiecej na ten temat zrobic.

Za***iste badanie, w którym podano tylko liczbę posiłków i ich średnią kaloryczność. Badano wpływ kompozycji posiłku (której nie podano) na glikemię.

Nadmiar informacji mnie przytłacza.

off topic
fajny ten program na tej stronce

To badanie w którym był odwrotny wynik było wcześniej:

The use of glycaemic index tables to predict glycaemic index of composite breakfast meals.

Flint A, Moller BK, Raben A, Pedersen D, Tetens I, Holst JJ, Astrup A.

Department of Human Nutrition, Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, DK-1958 Frederiksberg C, Denmark. [email protected]

The applicability of the glycaemic index (GI) in the context of mixed meals and diets is still debatable. The objective of the present study was to investigate the predictability of measured GI in composite breakfast meals when calculated from table values, and to develop prediction equations using meal components. Furthermore, we aimed to study the relationship between GI and insulinaemic index (II). The study was a randomised cross-over meal test including twenty-eight healthy young men. Thirteen breakfast meals and a reference meal were tested. All meals contained 50 g available carbohydrate, but differed considerably in energy and macronutrient composition. Venous blood was sampled for 2 h and analysed for glucose and insulin. Prediction equations were made by regression analysis. No association was found between predicted and measured GI. The meal content of energy and fat was inversely associated with GI (R(2) 0.93 and 0.88, respectively; P<0.001). Carbohydrate content (expressed as percentage of energy) was positively related to GI (R(2) 0.80; P<0.001). Using multivariate analysis the GI of meals was best predicted by fat and protein contents (R(2) 0.93; P<0.001). There was no association between GI and II. In conclusion, the present results show that the GI of mixed meals calculated by table values does not predict the measured GI and furthermore that carbohydrates do not play the most important role for GI in mixed breakfast meals. Our prediction models show that the GI of mixed meals is more strongly correlated either with fat and protein content, or with energy content, than with carbohydrate content alone. Furthermore, GI was not correlated with II.

Zmieniony przez - ellis w dniu 2006-07-07 23:32:47

Ja dzisiaj przeglądałem takie oto "badanie" a raczej meta analizę, treść dotyczy czego innego, ale wnioski pasują do tematu.



The Argument against Glycemic Index: What Are the Other Options?

Franz MJ.

Nutrition Concepts by Franz, Inc., Minneapolis, MN, USA.

There is debate among professionals regarding the use of the glycemic index (GI) for meal planning. In type-1 diabetes, there are 4 studies (average duration &sim;4 weeks) comparing high versus low GI diets; none reported improvements in HbA1c, and although 2 reported improvements in fructosamine, 2 reported no differences. In type-2 diabetes, there are 12 studies (average duration &sim;5 weeks); 3 reported improvements in HbA1c and fructosamine, 5 reported no differences in HBA1c, and 3 reported no differences in fructosamine. In adults, there is limited evidence that a low GI diet is beneficial for weight loss or satiety. Three epidemiologic studies reported that a low GI/glycemic load (GL) is associated with a reduced risk of developing diabetes or prevalence of insulin resistance; however, 5 studies report no association between GI/GL and the risk of developing diabetes, fasting insulin or insulin resistance, or adiposity. In general, the total amount of carbohydrate in a meal is the primary meal-planning strategy for people with diabetes. The GI can be used as an adjunct for the fine tuning of postprandial blood glucose responses. Other food/meal-planning interventions have been shown to be more effective than the use of the GI.

To jest chyba to:

Food glycemic index, as given in glycemic index tables, is a significant determinant of glycemic responses elicited by composite breakfast meals.

Wolever TM, Yang M, Zeng XY, Atkinson F, Brand-Miller JC.

Department of Nutritional Sciences, Faculty of Medicine, University of Toronto, Toronto, Canada. [email protected]

BACKGROUND: Recent studies have concluded that the carbohydrate content and glycemic index (GI) of individual foods do not predict the glycemic and insulinemic effects of mixed meals. We hypothesized that these conclusions may be unwarranted because of methodologic considerations. OBJECTIVE: The aim was to ascertain whether the GI and carbohydrate content of individual foods influence glucose and insulin responses elicited by realistic mixed meals in normal subjects. DESIGN: With the use of a crossover design, we determined the glucose and insulin responses of 6 test meals in 16 subjects in Sydney and the glucose responses of 8 test meals in 10 subjects in Toronto and then the results were pooled. The 14 different test meals varied in energy (220-450 kcal), protein (0-18 g), fat (0-18 g), and available carbohydrate (16-79 g) content and in GI (35-100; values were rounded). RESULTS: The glucose and insulin responses of the Sydney test meals varied over a 3-fold range (P < 0.001), and the glucose responses of the Toronto test meals varied over a 2.4-fold range (P < 0.001). The glucose responses were not related to the fat or protein content of the test meal. Carbohydrate content (P = 0.002) and GI (P = 0.022) alone were related to glucose responses; together they accounted for 88% of the variation in the glycemic response (P < 0.0001). The insulin response was significantly related to the glucose response (r = 0.94, P = 0.005). CONCLUSIONS: When properly applied in realistic settings, GI is a significant determinant of the glycemic effect of mixed meals in normal subjects. For mixed meals within the broad range of nutrient composition that we tested, carbohydrate content and GI together explained approximately 90% of the variation in the mean glycemic response, with protein and fat having negligible effects.

Tak, to to.

To są też dosyć przełomowe podsumowania

Should obese patients be counselled to follow a low-glycaemic index diet? No.

Raben A.

Research Department of Human Nutrition, Centre for Advanced Food Studies, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark. [email protected]

In diabetes research the glycaemic index (GI) of carbohydrates has long been recognized and a low GI is recommended. The same is now often the case in lipid research. Recently, a new debate has arisen around whether a low-GI diet should also be advocated for appetite- and long-term body weight control. A systematic review was performed of published human intervention studies comparing the effects of high- and low-GI foods or diets on appetite, food intake, energy expenditure and body weight. In a total of 31 short-term studies (< 1 d), low-GI foods were associated with greater satiety or reduced hunger in 15 studies, whereas reduced satiety or no differences were seen in 16 other studies. Low-GI foods reduced ad libitum food intake in seven studies, but not in eight other studies. In 20 longer-term studies (< 6 months), a weight loss on a low-GI diet was seen in four and on a high-GI diet in two, with no difference recorded in 14. The average weight loss was 1.5 kg on a low-GI diet and 1.6 kg on a high-GI diet. To conclude, there is no evidence at present that low-GI foods are superior to high-GI foods in regard to long-term body weight control. However, the ideal long-term study where ad libitum intake and fluctuations in body weight are permitted, and the diets are similar in all aspects except GI, has not yet been performed

Glycaemic index effects on fuel partitioning in humans.

Diaz EO, Galgani JE, Aguirre CA.

Laboratory of Energy Metabolism and Stable Isotopes, Institute of Nutrition and Food Technology (INTA), University of Chile, Macul, Santiago, Chile.

The purpose of this review was to examine the role of glycaemic index in fuel partitioning and body composition with emphasis on fat oxidation/storage in humans. This relationship is based on the hypothesis postulating that a higher serum glucose and insulin response induced by high-glycaemic carbohydrates promotes lower fat oxidation and higher fat storage in comparison with low-glycaemic carbohydrates. Thus, high-glycaemic index meals could contribute to the maintenance of excess weight in obese individuals and/or predispose obesity-prone subjects to weight gain. Several studies comparing the effects of meals with contrasting glycaemic carbohydrates for hours, days or weeks have failed to demonstrate any differential effect on fuel partitioning when either substrate oxidation or body composition measurements were performed. Apparently, the glycaemic index-induced serum insulin differences are not sufficient in magnitude and/or duration to modify fuel oxidation.

świetny temat się zrobił może warto zrobić post na o tematyce nowych badań , wtedy byśmy tutaj je zamieszczali i dyskutowali , naprawde było by to ciekawe