Printable View
If you were to take 100% natural oatmeal and grind it up in a blender and save it to put in your shakes, would that raise the GI level of the oatmeal?
It shouldn't right? Because blending or grinding shouldn't change the chemical structure of the carb right?
Let me know what you guys think.
I dont think so...as long as you dont add anything like a processed chemical then the nutritional value should stay the same.
Actually, it probably would raise the GI some. The finer you grind it, the less fiber benefit your body gets. The less fiber, the quicker your body converts it to glucose. Probably would be better to just mix it into your shakes unaltered, although that is harder to drink. Kind of like drinking cereal at that point.
I found this study that shows blending oatmeal does not affect the GI.
There are several factors that affect the GI of foods. So the answer can vary depending on the type of food in question. For oatmeal, however, blending does not seem to be an issue since the presence of fats and protein probably help to retard absorption rates. However, foods that are primarily composed of carbohydrate may be affected more so by blending. This is likely due to the increased dissolution and bioavailabilty of finer particles. (This concept is used in medicines designed for rapid release). Here's some evidence showing that blending oats has no affect on its GI.
Am J Clin Nutr. 1988 Apr;47(4):675-82.
Particle size of wheat, maize, and oat test meals: effects on plasma glucose and insulin responses and on the rate of starch digestion in vitro.
Heaton KW, Marcus SN, Emmett PM, Bolton CH.
University Department of Medicine, Bristol Royal Infirmary, UK.
When normal volunteers ate isocaloric wheat-based meals, their plasma insulin responses (peak concentration and area under curve) increased stepwise: whole grains less than cracked grains less than coarse flour less than fine flour. Insulin responses were also greater with fine maizemeal than with whole or cracked maize grains but were similar with whole groats, rolled oats, and fine oatmeal. The peak-to-nadir swing of plasma glucose was greater with wheat flour than with cracked or whole grains. In vitro starch hydrolysis by pancreatic amylase was faster with decreasing particle size with all three cereals. Correlation with the in vivo data was imperfect. Oat-based meals evoked smaller glucose and insulin responses than wheat- or maize-based meals. Particle size influences the digestion rate and consequent metabolic effects of wheat and maize but not oats. The increased insulin response to finely ground flour may be relevant to the etiology of diseases associated with hyperinsulinemia and to the management of diabetes.
Here's another one pertaining to lentils:
Am J Clin Nutr. 1982 Dec;36(6):1093-101.
Effect of processing on digestibility and the blood glucose response: a study of lentils.
Jenkins DJ, Thorne MJ, Camelon K, Jenkins A, Rao AV, Taylor RH, Thompson LU, Kalmusky J, Reichert R, Francis T.
To test the effect of processing on digestibility and the glycemic response to a leguminous seed, a group of eight healthy volunteers took a series of breakfast test meals containing either lentils which had been processed in four different ways or the same amount of carbohydrate as white bread. Lentils, boiled for 20 min, resulted in a flattened blood glucose response by comparison with bread. This was unaltered by blending the lentils to a paste or boiling them for an additional 40 minutes. However the blood glucose response was significantly enhanced by drying the boiled blended lentils for 12 h at 250 degrees F. In vitro digestion with human saliva showed the rate of sugars released from the food related positively to the blood glucose rise. Breath hydrogen studies indicated that carbohydrate malabsorption was too small to account for differences in the blood glucose response. These results emphasize the importance of processing in determining digestibility and hence the glycemic response to a food.