Can lowering blood sugar in diabetics save lives? (Part 2)
Last week’s article was about the ACCORD study, Action to Control Cardiovascular Risk in Diabetes. This study tested the hypothesis that aggressive glucose lowering prevented cardiovascular events such as heart attack and stroke in patients with type 2 diabetes. The study was discontinued after 3.5 years because of the finding of higher mortality in the intensive-therapy group where blood sugar was lowered to the normal range. In order to get blood sugar into the normal range, participants took multiple drugs and injected themselves with insulin. Many were taking four or five shots of insulin a day. Besides the drugs they took to lower their blood sugar, they took pills for other medical conditions and to lower their blood pressure and cholesterol.
Does the way blood sugar is lowered make a difference?
In an artcle in the June 12, 2008, issue of The New England Journal of Medicine commenting on the discontinuation of the ACCORD study, the authors, Harlan M. Krumholz, M.D. and Thomas H. Lee, M. D., wrote “Clearly, the way in which risk factors are modified really does matter. Lifestyle interventions may have few risks, but we cannot assume the same for drugs – and drug-related risks are not always known or appreciated.” Oral anti-diabetic drugs have side effects, and then there is the effect of drug interaction.
Another commentary on the ACCORD study was published in the April 9, 2008, issue of Nutriton & Metabolism: “Has carbohydrate-restriction been forgotten as a treatment for diabetes mellitus?” The authors, Eric C. Westman and Mary C. Vernon, wrote, “We believe that it is unlikely that the increased mortality [in the ACCORD study] was due to the tight glucose control, but rather due to the particular method of trying to achieve it.”
They go on to say that there are other ways to improve blood glucose levels without the risk of hypoglycemic reactions and the other side effects of drugs; one of these is carbohydrate-restriction. They argued that carbohydrate-restriction makes patho- physiological sense because type 2 diabetes is, in essence, a case of carbohydrate intolerance. Carbohydrates in the diet raise blood glucose. Since diabetes is defined by high blood glucose, it makes sense to lower the carbohydrate in the diet. In the early 20th century, before any medications were available for the treatment of diabetes mellitus, experts recommended dietary carbohydrate-restriction, and it worked well for type-2 diabetes.
Studies on the efficacy of a low-carbohydrate diet
The authors then cited studies in which the efficacy of a low-carbohydrate diet in lowering blood glucose levels was demonstrated. In one of these published in the journal Metabolic Syndrome & Related Disorders in December 2003, the authors, D. F. O’Neill, E. C. Westman, and R. K. Bernstein, found that a carbohydrate-restricted regimen improved glycemic control and cholesterol levels in both type 1 and type 2 diabetics. Additionally, they asserted, the reduction of insulin afforded by this diet could theoretically lead to a reduction in hypoglycemic events.
A study done on the effect of a low-carbohydrate diet on diabetes appeared in the December 19, 2008, issue of Nutrition & Metabolism. The researchers, E. C. Westman, W. S. Yancy Jr., J. C. Mavropoulos, M. Marquart, and J. R. McDuffie, compared the effect of a low-carbohydrate diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus for a period of 24 weeks. Foods with a low glycemic index don’t cause a rapid rise in blood sugar. The low-carbohydrate diet restricted intake of dietary carbohydrate to fewer than 20 grams per day, without explicitly restricting caloric intake. The low glycemic index diet was a reduced-calorie diet with approximately 55 percent of daily caloric intake from carbohydrate So the low glycemic diet was also a high-carbohydrate diet.
The participants on the low-carbohydrate diet had greater improvement in A1C, a measure of long-term blood glucose control, than those in the low-glycemic reduced-calorie diet group. Those in the low-carbohydrate diet group also lost more weight and had an increase in “good” cholesterol compared to those in the low-glycemic diet group. It was possible for 95.2 percent of those in the low-carbohydrate diet group and 62.1 percent in the low-glycemic reduced-calorie diet group to eliminate or reduce their diabetes medications.
The authors concluded that “The diet lower in carbohydrate led to greater improvements in glycemic control, and more frequent medication reduction/elimination than the low-glycemic index diet. Lifestyle modification using low carbohydrate interventions is effective for improving and reversing type 2 diabetes.”
Mary Lou Williams, M. Ed., is a lecturer and writer in the field of nutrition. She welcomes inquiries. She can be reached at 267-6480.