The rise in blood sugar following a meal is an overlooked facet of health. Slow controlled rises in blood sugar produce lower insulin responses, reduce the stress place upon the liver, and decrease the flux through the de novo lipogenesis pathway. These effects maintain insulin sensitivity and allow normal metabolic regulation to stay within its homeostatic limits. However, when postprandial blood sugar deviates from this controlled state, perhaps because the rise is too sharp, or perhaps because the duration of the rise is excessive, insulin secretion increases beyond its normal physiological limits, nutrients overload the liver with energy, and flux through the de novo lipogenesis pathway increases. The result of these metabolic shifts are a decrease in insulin sensitivity and a shift in energy metabolism that results in detrimental blood lipid changes, weight gain, liver damage and oxidative stress. Controlling blood sugar is therefore pivotal if health is to be maintained, and in this regard food choices are an important consideration.
Much research has focused on the digestion rate of starch as a pivotal factor in controlling blood sugar. It is evidenced for example that those foods that are digested slowly, and therefore produce a slow release of starch, are more able to create more controlled rises in blood sugar postprandially. For example, one group of researchers1 assessed the effects of four types of rice on the blood sugar response in healthy individuals. Subjects consumed either brown rice, white rice, ground brown rice or ground white rice, and then had their blood sugar levels monitored for a number of hours. The maximum increase in blood sugar following a meal was 0.9 mM for brown rice, 1.5 mM for white rice, 3.3 mM for ground brown rice and 3.6 mM for ground white rice (a lower value being more beneficial). When samples of the rice were incubated with pancreatic amylase to simulate digestion, the rate of digestion was found to correlate very closely to the rise in blood sugar seen following consumption of the rice.
Dr Robert Barrington’s Nutritional Recommendation: Controlling blood sugar is pivotal to health. In this regard the more slowly digesting starches are the best foods to incorporate into a high quality diet. Digestion of starch is inhibited by the presence of an intact cell wall, and this is likely the reason why the brown rice was more slowly digested, and produced a less peaky blood sugar responses, in this study. Legumes and oats have been shown to have beneficial glycaemic effects because they maintain their original cells structure and this inhibits the digestion rates of their starch. Refining the fibre from starch is problematic because fibre is a large component of the structure of the cell walls in plant foods and its removal exposes the starch within the grains to digestive enzymes. As a result the rate of digestion increases significantly, and this causes larger increases in blood sugar levels. Consuming supplemental fibre along with foods is often not beneficial because they fibre is not as effective when it is not encapsulating the starch.
RdB
