The following guest editorial by by Samy I. McFarlane, MD, MPH (who I just discovered thanks to Dr. Katharine Morrison) is a great read--in addition, the sources cited at the end of the article are immensely valuable.
Recommendations should take account of current evidence for carbohydrate restriction.by Samy I. McFarlane, MD, MPH
Special to ENDOCRINE TODAY
The current dietary guidelines for people with diabetes are based on a traditional low-fat/high-carbohydrate strategy with carbohydrate intake ranging between 55% to 70%. These diets have largely failed for people with diabetes as well as for the general population.
In fact, the epidemic of obesity and diabetes in our society over the past three decades has been accompanied by a steady decline in fat consumption and an apparent attempt to adopt the recommended low-fat diet.
According to the USDA Continuing Survey of Food Intakes by Individuals (CSFII), the absolute amount of fat as well as saturated fat consumed has significantly decreased during the obesity epidemic.
From a public health perspective, this represents a failure of low-fat/high-carbohydrate strategies to curb the obesity epidemic or at least to negate the other contributing factors such as sedentary lifestyle.
In people with diabetes, where traditional low-fat diets are recommended, reports by our group and others including national data indicate that only a minority of patients achieve the recommended treatment goals.
For example, in a national survey by our group across several health care delivery systems, 3,678 records of diabetic patients were examined with only one-third of the patients achieving HbA1c of <7% and less than half with LDL-cholesterol of <100 mg/dL. In this cohort of diabetic patients, 85% were either overweight or obese, with only 15% having a BMI <25.
These data, from 2002, are consistent with data from the Third National Health and Nutrition Examination Survey (NHANES III, conducted 1988-1994) and NHANES 1999-2000. Collectively, these data show a consistent pattern of overwhelming obesity and poor control of glycemia and dyslipidemia in the diabetic population despite decades of low-fat recommendations.
These observations point to the need for alternative dietary approaches. Among these approaches, lowering the carbohydrate content of the diabetic patients needs to be strongly considered given the current evidence for its effectiveness.
In another study, reductions in medications also included insulin, metformin, thiazolidinedione and sulfonylurea.
This dramatic effect should be a wake-up call for diabetologists, although because it is so dramatic, very low-carbohydrate regimens in patients on insulin or oral hypoglycemic agents should be done with close clinical supervision and we are reluctant to recommend them.
Because of the somewhat contentious atmosphere surrounding this subject, I feel obligated to point out that I am not supported or affiliated in any way with any individual or entity that promotes a particular diet.
This editorial is intended to stimulate a scientific and scholarly debate that will lead to more effective dietary recommendations that take account of the current evidence for carbohydrate restriction. This will thereby provide more options to our patients and our society at large in the current struggle with the epidemic of obesity and diabetes, which is claiming thousands of lives daily and leaving many people disabled.
I do not recommend the extreme reduction of carbohydrate, and I believe that the need of the hour is to accept the benefits of carbohydrate restriction with care.
It is also important to establish guidelines for carbohydrate restriction, especially emphasizing the use of mono- and polyunsaturated fats as a way to achieve caloric balance, since these have been inversely linked with CVD risk.
I also believe that clinical trials need to be conducted using graded levels of carbohydrate restriction and fat intake, with special emphasis on unsaturated fats, to examine their effects on weight loss, glycemic control, insulin resistance and CVD.
An open-minded analysis of such experiments is needed to resolve the present controversy about optimal dietary recommendations for patients with diabetes.
For more information:
- Samy I. McFarlane, MD, MPH, FACP, is an Associate Professor of Medicine and Interim Chief of Division of Endocrinology, Diabetes and Metabolism at SUNY Downstate Medical Center and Associate Medical Editor of Endocrine Today.
- Franz MJ, Bantle JP, Beebe CA, et al. Nutrition principles and recommendations in diabetes. Diabetes Care. Jan 2004;27 Suppl 1:S36-46.
- The American Association of Clinical Endocrinologists Medical Guidelines for the Management of Diabetes Mellitus: the AACE system of intensive diabetes self-management—2000 update. Endocr Pract. Jan-Feb 2000;6(1):43-84.
- Krauss RM, Eckel RH, Howard B, et al. AHA Dietary Guidelines: revision 2000: A statement for healthcare professionals from the Nutrition Committee of the American Heart Association. Circulation. Oct 31 2000;102(18):2284-2299.
- Mokdad AH, Bowman BA, Ford ES, Vinicor F, Marks JS, Koplan JP. The continuing epidemics of obesity and diabetes in the United States. Jama. Sep 12 2001;286(10):1195-1200.
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- McFarlane SI, Castro J, Kaur J, et al. Control of blood pressure and other cardiovascular risk factors at different practice settings: outcomes of care provided to diabetic women compared to men. J Clin Hypertens (Greenwich). Feb 2005;7(2):73-80.
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- Arora SK, McFarlane SI. The case for low carbohydrate diets in diabetes management. Nutr Metab (Lond). Jul 14 2005;2:16.
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- Hu FB, Manson JE, Willett WC. Types of dietary fat and risk of coronary heart disease: a critical review. J Am Coll Nutr. Feb 2001;20(1):5-19.
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- Intensive blood-glucose control with sulphonylureas or insulin compared with conventional treatment and risk of complications in patients with type 2 diabetes (UKPDS 33). UK Prospective Diabetes Study (UKPDS) Group. Lancet. Sep 12 1998;352(9131):837-853.
- McFarlane SI, Shin JJ, Rundek T, Bigger JT. Prevention of type 2 diabetes. Curr Diab Rep. Jun 2003;3(3):235-241.
- Garg A, Bantle JP, Henry RR, et al. Effects of varying carbohydrate content of diet in patients with non-insulin-dependent diabetes mellitus. Jama. May 11 1994;271(18):1421-1428.
- Seshadri P, Iqbal N, Stern L, et al. A randomized study comparing the effects of a low-carbohydrate diet and a conventional diet on lipoprotein subfractions and C-reactive protein levels in patients with severe obesity. Am J Med. Sep 15 2004;117(6):398-405.
- Samaha FF, Iqbal N, Seshadri P, et al. A low-carbohydrate as compared with a low-fat diet in severe obesity. N Engl J Med. May 22 2003;348(21):2074-2081.
- Yancy WS, Jr., Vernon MC, Westman EC. A Pilot trial of a Low-Carbohydrate, Ketogenic Diet in Patients with Type 2 Diabetes. Metabolic Syndrome and Related Disorders. 2003;1(3):239-243.
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