Diabetes and Metabolic Syndrome

Page Sections:

Type II Diabetes
Latent Autoimmune Diabetes of Adults
Metabolic Syndrome


Type II Diabetes

Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Abstract:

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.

The effect of a low-carbohydrate, ketogenic diet versus a low-glycemic index diet on glycemic control in type 2 diabetes mellitus
Abstract excerpt:

Objective
Dietary carbohydrate is the major determinant of postprandial glucose levels, and several clinical studies have shown that low-carbohydrate diets improve glycemic control. In this study, we tested the hypothesis that a diet lower in carbohydrate would lead to greater improvement in glycemic control over a 24-week period in patients with obesity and type 2 diabetes mellitus.
Conclusion
Dietary modification led to improvements in glycemic control and medication reduction/elimination in motivated volunteers with type 2 diabetes. 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.

Long-term effects of a diet loosely restricting carbohydrates on HbA1c levels, BMI and tapering of sulfonylureas in type 2 diabetes: A 2-year follow-up study
Abstract excerpt:

The aim was to assess the long-term effect of a loose restriction of carbohydrate intake (carbohydrate-reduced diet: CARD) compared to a conventional diet (CD) in type 2 diabetes. One hundred and thirty-three type 2 diabetic outpatients followed the CD (n=57, 1734±410kcal, carbohydrate:protein:fat ratio=57:16:26) or CARD (n=76, 1773±441kcal, carbohydrate:protein:fat ratio=45:18:33) according to their own will, and were followed up for 2 years. Glycemic control, body mass index (BMI), serum cholesterols and dose of antidiabetic drugs were assessed at baseline and after 1 and 2 years. At baseline, hemoglobin A1c (HbA1c) and BMI levels were 7.1±1.0% and 24.2±2.9, respectively, in the CD group, and 7.4±1.1% and 25.1±3.4 in the CARD group, showing no significant differences. During the 2-year follow-up period, HbA1c levels were significantly improved in the CARD group (CD: 7.5±1.3%, CARD: 6.7±0.6%, P<0.001), and BMI decreased more significantly in the CARD group (CD: 23.8±3.0, CARD: 23.8±3.5, P<0.001). The doses of sulfonylureas clearly tapered, and serum cholesterol profiles improved significantly with the CARD. Our results warrant a long-term and large-scale randomized study of the diet for type 2 diabetes.

Dietary carbohydrate restriction in type 2 diabetes mellitus and metabolic syndrome: time for a critical appraisal (also available as a
380KB PDF document). 24 Doctors and researchers call for more investigation of low carb diets for control of blood glucose levels.

Current nutritional approaches to metabolic syndrome and type 2 diabetes generally rely on reductions in dietary fat. The success of such approaches has been limited and therapy more generally relies on pharmacology. The argument is made that a re-evaluation of the role of carbohydrate restriction, the historical and intuitive approach to the problem, may provide an alternative and possibly superior dietary strategy. The rationale is that carbohydrate restriction improves glycemic control and reduces insulin fluctuations which are primary targets. Experiments are summarized showing that carbohydrate-restricted diets are at least as effective for weight loss as low-fat diets and that substitution of fat for carbohydrate is generally beneficial for risk of cardiovascular disease. These beneficial effects of carbohydrate restriction do not require weight loss. Finally, the point is reiterated that carbohydrate restriction improves all of the features of metabolic syndrome.

Effects of a Mediterranean-Style Diet on the Need for Antihyperglycemic Drug Therapy in Patients With Newly Diagnosed Type 2 Diabetes. Abstract extract:

Conclusion: Compared with a low-fat diet, a low-carbohydrate, Mediterranean-style diet led to more favorable changes in glycemic control and coronary risk factors and delayed the need for antihyperglycemic drug therapy in overweight patients with newly diagnosed type 2 diabetes.

Vitamin D supplementation reduces insulin resistance in South Asian women living in New Zealand who are insulin resistant and vitamin D deficient – a randomised, placebo-controlled trial. von Hurst PR, Stonehouse W, Coad J. Institute of Food, Nutrition and Human Health, Massey University, Private Bag 102 904, North Shore Mail Centre, Auckland, New Zealand. Abstract excerpt:

Significant improvements were seen in insulin sensitivity and IR (P = 0.003 and 0.02, respectively), and fasting insulin decreased (P = 0.02) with supplementation compared with placebo. There was no change in C-peptide with supplementation.

Carbohydrate restriction favorably alters lipoprotein metabolism in Emirati subjects classified with the metabolic syndrome . Abstract conclusion:

These results suggest that weight loss favorably affects lipoprotein metabolism and that the CRD [carbohydrate restricted diet] had a better effect on atherogenic [deposits leading to atherosclerosis contained in] VLDL and HDL than the low fat diet recommended by AHA.

Latent Autoimmune Diabetes of Adults (LADA)

Adults diagnosed with type II diabetes who are unsuccessful at lowering blood sugar levels with low carb diets may want to consider if they are actually suffering from LADA. See Diabetes Update Blog for an introduction.


Latent Autoimmune Diabetes in Adults – Definition, Prevalence, β-Cell Function, and Treatment
. Abstract excerpt:

Latent autoimmune diabetes in adults (LADA) is a disorder in which, despite the presence of islet antibodies at diagnosis of diabetes, the progression of autoimmune β-cell failure is slow. LADA patients are therefore not insulin requiring, at least during the first 6 months after diagnosis of diabetes. Among patients with phenotypic type 2 diabetes, LADA occurs in 10% of individuals older than 35 years and in 25% below that age. Prospective studies of β-cell function show that LADA patients with multiple islet antibodies develop β-cell failure within 5 years, whereas those with only GAD antibodies (GADAs) or only islet cell antibodies (ICAs) mostly develop β-cell failure after 5 years. Even though it may take up to 12 years until β-cell failure occurs in some patients, impairments in the β-cell response to intravenous glucose and glucagon can be detected at diagnosis of diabetes. Consequently, LADA is not a latent disease; therefore, autoimmune diabetes in adults with slowly progressive β-cell failure might be a more adequate concept. In agreement with proved impaired β-cell function at diagnosis of diabetes, insulin is the treatment of choice.

Is Latent Autoimmune Diabetes in Adults Distinct From Type 1 Diabetes or Just Type 1 Diabetes at an Older Age?. Abstract excerpt:

Diabetes is classified clinically into two types: type 1 and type 2 diabetes. Type 1 diabetes is an autoimmune diabetes, whereas, in contrast, type 2 diabetes is nonautoimmune. However, there is a group of phenotypic adult type 2 diabetic patients (∼10%) who have islet autoantibodies similar to type 1 diabetes. These patients are said to have latent autoimmune diabetes in adults (LADA) or type 1.5 diabetes. T-cells reacting with islet proteins have been demonstrated in type 1 and type 1.5 diabetic patients. In contrast, classic autoantibody-negative type 2 diabetic patients are also negative for T-cell responses to islet proteins. Therefore, we questioned whether type 1 and type 1.5 diabetes are similar or different autoimmune diseases. We have investigated the immunological and metabolic differences between type 1, type 1.5, and classic type 2 diabetic patients. We have identified autoantibody differences, differences in islet proteins recognized by T-cells, and differences in insulin resistance. We have also identified a small group of patients who have T-cells responsive to islet proteins but who are autoantibody negative. These patients appear to be similar to type 1.5 patients in having decreased stimulated C-peptide values. These immunological differences between type 1 and type 1.5 diabetes suggest at least partially distinct disease processes.

Metabolic Syndrome


Moderate vs Low Fat Diet Effects on Lipids and Inflammation in Metabolic Syndrome
, abstract:

Background: The optimal diet for people with metabolic syndrome (MetS) is not known. We assessed the impact of a 40en% fat & 45en% carbohydrate diet (Moderate Fat Diet= MF) vs. a 20en% fat & 65en% carbohydrate diet (Low Fat Diet= LF) on lipids and inflammation. Both diets had 8% saturated fat.

Methods: We enrolled 71 men and women with MetS in a double-blinded, randomized, cross-over feeding trial to evaluate MF vs. LF diet at constant body weight. Primary outcomes included non-HDL cholesterol (non-HDL-C) and high sensitivity C reactive protein (hs-CRP) change from baseline. Participants underwent each study diet for 4 weeks. They also underwent an 8 week NCEP Step 1 diet prior to randomization and for 4 weeks between MF and LF diets. 64 participants completed both diets. Other outcomes included LDL-C, HDL-C, and triglycerides. Linear mixed models which accounts for repeated measures were fitted to evaluate the effect of each diet on outcomes.

Results: The mean age was 54±8 yrs. 52% were women. Mean waist circumference was 109 cm±11 cm. Mean lipids (mg/dL) were: non-HDL-C 164±29, triglycerides 220± 81, LDL-C 120±29, and HDL-C 42±8. The mean hs-CRP was 3.3±3.0 mg/L.

Conclusions: This is the first study to examine the effects of low fat vs. moderate fat diet in MetS. MF compared to LF diet improves the atherogenic dyslipidemia of MetS. MF diet is a preferable dietary intervention in people with MetS to improve CVD risk.


Carbohydrate restriction has a more favorable impact on the metabolic syndrome than a low fat diet. Abstract:

We recently proposed that the biological markers improved by carbohydrate restriction were precisely those that define the metabolic syndrome (MetS), and that the common thread was regulation of insulin as a control element. We specifically tested the idea with a 12-week study comparing two hypocaloric diets (approximately 1,500 kcal): a carbohydrate-restricted diet (CRD) (%carbohydrate:fat:protein = 12:59:28) and a low-fat diet (LFD) (56:24:20) in 40 subjects with atherogenic dyslipidemia. Both interventions led to improvements in several metabolic markers, but subjects following the CRD had consistently reduced glucose (-12%) and insulin (-50%) concentrations, insulin sensitivity (-55%), weight loss (-10%), decreased adiposity (-14%), and more favorable triacylglycerol (TAG) (-51%), HDL-C (13%) and total cholesterol/HDL-C ratio (-14%) responses. In addition to these markers for MetS, the CRD subjects showed more favorable responses to alternative indicators of cardiovascular risk: postprandial lipemia (-47%), the Apo B/Apo A-1 ratio (-16%), and LDL particle distribution. Despite a threefold higher intake of dietary saturated fat during the CRD, saturated fatty acids in TAG and cholesteryl ester were significantly decreased, as was palmitoleic acid (16:1n-7), an endogenous marker of lipogenesis, compared to subjects consuming the LFD. Serum retinol binding protein 4 has been linked to insulin-resistant states, and only the CRD decreased this marker (-20%). The findings provide support for unifying the disparate markers of MetS and for the proposed intimate connection with dietary carbohydrate. The results support the use of dietary carbohydrate restriction as an effective approach to improve features of MetS and cardiovascular risk.


Carbohydrate restriction improves the features of Metabolic Syndrome. Metabolic Syndrome may be defined by the response to carbohydrate restriction. Abstract excerpts:

Metabolic Syndrome (MetS) represents a constellation of markers that indicates a predisposition to diabetes, cardiovascular disease and other pathologic states. The definition and treatment are a matter of current debate and there is not general agreement on a precise definition or, to some extent, whether the designation provides more information than the individual components. We consider here five indicators that are central to most definitions and we provide evidence from the literature that these are precisely the symptoms that respond to reduction in dietary carbohydrate (CHO).

Chronicling the End of the Low Fat Craze