Dietary carbohydrates and insulin action in humans
Open Access
- 1 June 2000
- journal article
- review article
- Published by Cambridge University Press (CUP) in British Journal of Nutrition
- Vol. 83 (S1) , S97-S102
- https://doi.org/10.1017/s0007114500001021
Abstract
The metabolic syndrome represents a vicious cycle whereby insulin resistance leads to compensatory hyperinsulinaemia, which maintains normal plasma glucose but may exacerbate insulin resistance. Excess insulin secretion may eventually reduce β-cell function due to amyloid deposition, leading to raised blood glucose and further deterioration of β-cell function and insulin sensitivity via glucose toxicity. Reducing postprandial glucose and insulin responses may be a way to interrupt this process, but there is disagreement about the dietary approach to achieve this. Glucose and insulin responses are determined primarily by the amount of carbohydrate consumed and its rate of absorption. Slowly absorbed, low glycaemic-index (GI) foods are associated with increased HDL cholesterol and reduced risk of type 2 diabetes. There is some evidence that low-GI foods improve insulin sensitivity in humans, although studies using established techniques (glucose clamp or frequently sampled intravenous glucose tolerance test) have not been done. Low carbohydrate diets have been suggested to be beneficial in the treatment of the metabolic syndrome because of reduced postprandial insulin. However, they may increase fasting glucose and impair oral glucose tolerance — effects which define carbohydrate intolerance. The effects of low carbohydrate diets on insulin sensitivity depend on what is used to replace the dietary carbohydrate, and the nature of the subjects studied. Dietary carbohydrates may affect insulin action, at least in part, via alterations in plasma free fatty acids. In normal subjects a high-carbohydrate/low-GI breakfast meal reduced free fatty acids by reducing the undershoot of plasma glucose, whereas low-carbohydrate breakfasts increased postprandial free fatty acids. It is unknown if these effects occur in insulin-resistant or diabetic subjects. Thus further work needs to be done before a firm conclusion can be drawn as to the optimal amount and type of dietary carbohydrate for the treatment of the metabolic syndrome.Keywords
This publication has 45 references indexed in Scilit:
- Diets with a Low Glycemic IndexNutrition Today, 1999
- Diets with a Low Glycemic IndexNutrition Today, 1999
- The central role of dietary fat, not carbohydrate, in the insulin resistance syndromeCurrent Opinion in Lipidology, 1997
- The Effect of Acarbose on Insulin Sensitivity in Subjects With Impaired Glucose ToleranceDiabetes Care, 1996
- Mechanisms of fatty acid-induced inhibition of glucose uptake.Journal of Clinical Investigation, 1994
- Long-term exposure of rat pancreatic islets to fatty acids inhibits glucose-induced insulin secretion and biosynthesis through a glucose fatty acid cycle.Journal of Clinical Investigation, 1994
- Comparison of effects of high and low carbohydrate diets on plasma lipoproteins and insulin sensitivity in patients with mild NIDDMDiabetes, 1992
- Banting lecture 1990. Beta-cells in type II diabetes mellitusDiabetes, 1991
- Nibbling versus Gorging: Metabolic Advantages of Increased Meal FrequencyNew England Journal of Medicine, 1989
- THE GLUCOSE FATTY-ACID CYCLE ITS ROLE IN INSULIN SENSITIVITY AND THE METABOLIC DISTURBANCES OF DIABETES MELLITUSPublished by Elsevier ,1963