Am J Clin Nutr. 2003 Sep;78(3 Suppl):610S-616S.     Related Articles, Links

Type 2 diabetes and the vegetarian diet.

Jenkins DJ, Kendall CW, Marchie A, Jenkins AL, Augustin LS, Ludwig DS, Barnard ND, Anderson JW.

Clinical Nutrition & Risk Factor Modification Center, St Michael's Hospital, Toronto, Ontario, Canada.

Based on what is known of the components of plant-based diets and their effects from cohort studies, there is reason to believe that vegetarian diets would have advantages in the treatment of type 2 diabetes. At present there are few data on vegetarian diets in diabetes that do not in addition have weight loss or exercise components. Nevertheless, the use of whole-grain or traditionally processed cereals and legumes has been associated with improved glycemic control in both diabetic and insulin-resistant individuals. Long-term cohort studies have indicated that whole-grain consumption reduces the risk of both type 2 diabetes and cardiovascular disease. In addition, nuts (eg, almonds), viscous fibers (eg, fibers from oats and barley), soy proteins, and plant sterols, which may be part of the vegetarian diet, reduce serum lipids. In combination, these plant food components may have a very significant impact on cardiovascular disease, one of the major complications of diabetes. Furthermore, substituting soy or other vegetable proteins for animal protein may also decrease renal hyperfiltration, proteinuria, and renal acid load and in the long term reduce the risk of developing renal disease in type 2 diabetes. The vegetarian diet, therefore, contains a portfolio of natural products and food forms of benefit for both the carbohydrate and lipid abnormalities in diabetes. It is anticipated that their combined use in vegetarian diets will produce very significant metabolic advantages for the prevention and treatment of diabetes and its complications.

Publication Types:

•           Review

•           Review, Tutorial

PMID: 12936955 [PubMed - indexed for MEDLINE]

J Clin Endocrinol Metab. 2003 Aug;88(8):3577-83.     Related Articles, Links

The metabolic response of subjects with type 2 diabetes to a high-protein, weight-maintenance diet.

Nuttall FQ, Gannon MC, Saeed A, Jordan K, Hoover H.

Metabolic Research Laboratory and the Section of Endocrinology, Metabolism, and Nutrition, Department of Veterans Affairs Medical Center and the Department of Medicine, University of Minnesota, Minneapolis, Minnesota 55417, USA.

In a randomized, crossover 5-wk study design, we recently reported that a weight-maintaining diet in which the percentage of total food energy as protein was increased from 15-30% resulted in a decrease in postprandial glucose and glycohemoglobin in people with untreated type 2 diabetes without a significant change in insulin. Protein was substituted for carbohydrate in the diet. The fat content remained unchanged. In this publication, we present data on other hormones and metabolites that were considered to potentially be affected by substitution of protein for carbohydrate in the diet. The mean fasting plasma GH and total IGF-I concentrations were elevated on the 30% protein diet. The urinary free cortisol also was increased. However, the urinary aldosterone was unchanged. Although urinary pH was decreased, calcium excretion was not significantly increased. The plasma postprandial alpha-amino nitrogen concentrations were increased, but the 24-h integrated concentration was unchanged, indicating an accelerated amino acid removal rate. The plasma urea nitrogen was increased as expected. The urea production rate also was increased such that a new steady-state fasting value was present. The calculated urea production rate accounted for 97% of the protein ingested on the 15% protein diet, but only 80% on the 30% protein diet, suggesting net nitrogen retention on the high-protein diet. In conclusion, an increase in dietary protein results in a number of metabolic adaptations in addition to reducing the circulating glucose concentration. Serum TSH, total T(3), free T(4), B(12), folate, homocysteine, uric acid, and creatinine concentrations were unchanged.

Publication Types:

•           Clinical Trial

•           Randomized Controlled Trial

PMID: 12915639 [PubMed - indexed for MEDLINE]

Ann Endocrinol (Paris). 2003 Jun;64(3 Suppl):S37-44.             Related Articles, Links

[Is it possible to prevent type 2 diabetes?]

[Article in French]

Laville M.

Service d'Endocrinologie, Hopital Edouard-Herriot F-69437 LYON Cedex 3. martine.laville@chu-lyon.fr

Four prospective randomised long-term studies have been recently completed and published (Diabetes Prevention Study, Diabetes Prevention Program, STOP-NIDDM trial, XENDOS Study). Both of them clearly demonstrate the possibility to delay and/or prevent the onset of type 2 diabetes in at high-risk subjects with impaired glucose tolerance, through changes in lifestyle (dietary intervention, weight reduction, increased physical activity) or drug treatment (metformin, acarbose, orlistat). These studies are reviewed and practical implications of their results are discussed.

Publication Types:

•           Review

•           Review, Tutorial

PMID: 12910058 [PubMed - indexed for MEDLINE]

Nutr Rev. 2003 May;61(5 Pt 2):S49-55.          Related Articles, Links

Glycemic load and chronic disease.

Brand-Miller JC.

Human Nutrition Unit, School of Molecular and Microbial Biosciences, University of Sydney, NSW, Australia.

The glycemic index (GI) has proven to be a useful nutritional concept, providing new insights into the relationship between foods and chronic disease. Observational studies suggest that diets with a high glycemic load (GI x carbohydrate content) are independently associated with increased risk of type 2 diabetes and cardiovascular disease. Postprandial hyperglycemia plays a direct pathogenic role in the disease process. Lower glucose and insulin levels are associated with improved risk profile, including high-density lipoprotein cholesterol, glycosylated proteins, oxidative status, hemostatic variables, and endothelial function. Limited evidence suggests that a low-GI diet may also protect against obesity, colon cancer, and breast cancer. Diets with a high glycemic load may affect health differently in insulin-resistant and insulin-sensitive individuals. Improvements in postprandial hyperglycemia can be brought about by manipulating either the type (i.e., GI) or amount of dietary carbohydrate, or both; at present, the GI appears to be more effective.

Publication Types:

•           Review

•           Review, Tutorial

PMID: 12828192 [PubMed - indexed for MEDLINE]

Diabetes. 2003 Jul;52(7):1837-42.       Related Articles, Links

Exercise training improves baroreflex sensitivity in type 2 diabetes.

Loimaala A, Huikuri HV, Koobi T, Rinne M, Nenonen A, Vuori I.

South Karelian Central Hospital, Department of Clinical Physiology and Nuclear Medicine, Lappeenranta, Finland. antii.loimaala@ekshp.fi

Type 2 diabetes is a strong risk factor for coronary heart disease and sudden cardiac death. It is associated with reduced baroreflex sensitivity (BRS) and heart rate variability (HRV), which are indicators of increased risk for mortality and morbidity in various patient populations. This study was designed to assess the effects of exercise training on BRS, HRV, and hemodynamics in patients with type 2 diabetes. Subjects (50 men, mean age 53.3 +/- 5.1 years) with type 2 diabetes were randomized into either a control group, in which they received conventional treatment only, or an exercise group, in which they received conventional treatment together with heart rate-controlled endurance training twice a week and supervised muscle strength training twice a week for 12 months. Measurements taken at baseline and follow-up included VO(2max), standard time and frequency domain measures of HRV during 24-h recording, and BRS by the phenylephrine method. Cardiac index, systemic vascular resistance index, stroke index, and pulse wave velocity were measured by whole-body impedance cardiography. Significant improvements in VO(2max) (exercise group: +2.3 ml x kg(-1) x min(-1); P < 0.005 vs. control group), muscle strength, and glycemic control (exercise group: HbA(1c) -0.9%; P < 0.001 vs. control group) were observed in the exercise group. BRS increased in the exercise group, from 6.8 to 8.6 ms/mmHg, and decreased in the control group, from 7.5 to 6.4 ms/mmHg (95% CI for the difference between 0.05 and 4.36 ms/mmHg; P < 0.05). No significant changes in the time or frequency domain measures of HRV or in systemic hemodynamics were observed. We concluded that exercise training improves BRS sensitivity in type 2 diabetes subjects in addition to increasing the exercise capacity and muscle strength and improving glucose control. These beneficial effects in reflectory autonomic regulation and glucose control caused by exercise may be associated with improved prognosis of type 2 diabetes patients.

Publication Types:

•           Clinical Trial

•           Multicenter Study

•           Randomized Controlled Trial

PMID: 12829654 [PubMed - indexed for MEDLINE]

Clin Ther. 2003 May;25(5):1429-39.   Related Articles, Links

The effect of L-carnitine on plasma lipoprotein(a) levels in hypercholesterolemic patients with type 2 diabetes mellitus.

Derosa G, Cicero AF, Gaddi A, Mugellini A, Ciccarelli L, Fogari R.

Department of Internal Medicine and Therapeutics, University of Pavia, Pavia, Italy. giuderosa@tin.it

BACKGROUND: A previous study has demonstrated that L-carnitine reduces plasma lipoprotein(a) (Lp[a]) levels in patients with hypercholesterolemia. OBJECTIVE: To test a tolerable Lp(a)-reducing agent in diabetic patients, we assessed the effect of a dietary supplementation of L-carnitine on plasma lipid levels, particularly Lp(a), of patients with type 2 diabetes mellitus (DM) and hypercholesterolemia. METHODS: In this 6-month, randomized, double-masked, placebo-controlled clinical trial, patients were enrolled, assessed, and followed up at the Diabetic and Metabolic Diseases Center of the Department of Internal Medicine and Therapeutics at the University of Pavia, Pavia, Italy. All study patients had newly diagnosed type 2 DM that was managed through dietary restriction alone throughout the study, as well as hypercholesterolemia. Patients were randomized to 1 of 2 groups. One group received L-carnitine, one 1-g tablet BID. The other group received a corresponding placebo. We assessed body mass index, fasting plasma glucose, postprandial plasma glucose, glycosylated hemoglobin, fasting plasma insulin, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, apolipoprotein (apo) A-I, apo B, and Lp(a) at baseline and at 1, 3, and 6 months of treatment. RESULTS: This study included 94 patients. The treatment group included 24 men and 22 women (mean [SD] age, 52 [6] years). The placebo group included 23 men and 25 women (mean [SD] age, 50 [7] years). The baseline characteristics of the groups did not differ significantly. The mean (SD) body weight, height, and body mass index were 78.2 (5.8) kg, 1.70 (0.04) m, and 27.3 (2.5) kg/m(2), respectively, in the L-carnitine group and 77.6 (6.4) kg, 1.71 (0.05) m, and 26.8 (2.2) kg/m(2), respectively, in the placebo group. In the treatment group, Lp(a) was significantly reduced at 3 and 6 months compared with baseline (P < 0.05) and P < 0.01, respectively). We observed a significant improvement after 6 months (P < 0.05) in the Lp(a) value in patients taking L-carnitine compared with those taking placebo. Between-group differences in other variables did not reach a level of significance at months 3 and 6. No drug-related adverse events were reported or observed. CONCLUSION: In this preliminary study, after 3 and 6 months, L-carnitine significantly lowered the plasma Lp(a) level compared with placebo in selected hypercholesterolemic patients with newly diagnosed type 2 DM.

Publication Types:

•           Clinical Trial

•           Randomized Controlled Trial

PMID: 12867219 [PubMed - indexed for MEDLINE]

Am J Clin Nutr. 2003 Jun;77(6):1434-41.        Related Articles, Links

Dietary intakes and plasma concentrations of carotenoids and tocopherols in relation to glucose metabolism in subjects at high risk of type 2 diabetes: the Botnia Dietary Study.

Ylonen K, Alfthan G, Groop L, Saloranta C, Aro A, Virtanen SM.

Department of Applied Chemistry and Microbiology, Division of Nutrition, University of Helsinki, Finland. ylonen@helsinki.fi

BACKGROUND: The role of antioxidants in the pathogenesis of type 2 diabetes is uncertain. OBJECTIVE: We evaluated cross-sectional relations of dietary intakes and plasma concentrations of antioxidants with glucose metabolism in a high-risk population. DESIGN: The subjects were 81 male and 101 female first- and second-degree, nondiabetic relatives of patients with type 2 diabetes. Antioxidant intake data were based on 3-d food records. Subjects taking supplements containing beta-carotene or alpha-tocopherol were excluded. Plasma antioxidant concentrations were measured by HPLC. By using multiple linear regression analysis and adjusting for demographic, anthropometric, and lifestyle covariates, we studied whether dietary and plasma alpha- and beta-carotene, lycopene, and alpha- and gamma-tocopherol were related to fasting and 2-h concentrations of glucose and nonesterified fatty acids during an oral-glucose-tolerance test, to the homeostasis model assessment index of insulin resistance, and to measures of beta cell function (incremental 30-min serum insulin concentration during an oral-glucose-tolerance test and first-phase insulin secretion during an intravenous-glucose-tolerance test). RESULTS: In men, dietary carotenoids were inversely associated with fasting plasma glucose concentrations (P < 0.05), plasma beta-carotene concentrations were inversely associated with insulin resistance (P = 0.003), and dietary lycopene was directly related to baseline serum concentrations of nonesterified fatty acids (P = 0.034). In women, dietary alpha-tocopherol and plasma beta-carotene concentrations were inversely and directly associated, respectively, with fasting plasma glucose concentrations (P < 0.05). In both sexes, cholesterol-adjusted alpha-tocopherol concentrations were directly associated with 2-h plasma glucose concentrations (P < 0.05). CONCLUSION: The data suggest an advantageous association of carotenoids, which are markers of fruit and vegetable intake, with glucose metabolism in men at high risk of type 2 diabetes.

PMID: 12791620 [PubMed - indexed for MEDLINE]

Eur J Clin Nutr. 2003 May;57(5):713-20.         Related Articles, Links

Influence of fish oil supplementation on in vivo and in vitro oxidation resistance of low-density lipoprotein in type 2 diabetes.

Pedersen H, Petersen M, Major-Pedersen A, Jensen T, Nielsen NS, Lauridsen ST, Marckmann P.

Research Department of Human Nutrition, The Royal Veterinary and Agricultural University, Frederiksberg, Denmark.

OBJECTIVE: Fish oil supplement has been proposed as a non-pharmacological strategy to correct the atherogenic lipid profile associated with type 2 diabetes mellitus. However, fish oil may have deleterious effects on lipid peroxidation and glycemic control. DESIGN: In this study, 44 type 2 diabetic patients were randomized to vitamin E standardized (53.6 mg/day) supplementation (capsules) with 4 g daily of either fish oil (n=23) or corn oil (n=21) for 8 weeks preceded by a 4 week run-in period of corn oil supplementation. LDL was isolated by density gradient ultracentrifugation and oxidized in vitro with Cu(2+). As a marker of in vivo oxidation malondialdehyde concentration in LDL (LDL-MDA) was measured. RESULTS: Fish oil reduced both mean lag time (before, 57.8; after, 48.8 min, P<0.001) and mean propagation rate (before, 0.018 DeltaOD/min; after, 0.015 DeltaOD/min, P<0.001), whereas corn oil had no influence on lag time and propagation rate. The changes in lag time and propagation rate differed significantly between fish oil and corn oil treatment. LDL-MDA changes differed borderline significantly between groups (FO, 110.4 pmol/mg protein; CO, 6.7 pmol/mg protein; P=0.057). Fish oil supplementation had no influence on glycemic control as assessed from HbA(1c) and fasting blood glucose. CONCLUSION: According to our findings, fish oil supplementation leads to increased in vivo oxidation and increased in vitro oxidation susceptibility of LDL particles. More studies are needed to clarify the clinical importance of this finding.

Publication Types:

•           Clinical Trial

•           Randomized Controlled Trial

PMID: 12771973 [PubMed - indexed for MEDLINE]

Metabolism. 2003 Jul;52(7):875-80.     Related Articles, Links

Mode of action of ipomoea batatas (Caiapo) in type 2 diabetic patients.

Ludvik B, Waldhausl W, Prager R, Kautzky-Willer A, Pacini G.

3rd Department of Medicine, Division of Endocrinology and Metabolism, University of Vienna, Austria.

We have previously reported the beneficial effects of Caiapo, the extract of white-skinned sweet potato (ipomoea batatas), on fasting plasma glucose, as well as on total and low-density lipoprotein (LDL) cholesterol in type 2 diabetic patients. The present study aimed to describe the underlying mechanism responsible for the improvement in metabolic control following administration of Caiapo in those type 2 subjects. A total of 18 male patients (age=58+/-8 years, body mass index [BMI]=27.7+/-2.7 kg/m2, mean +/- SEM) treated only by diet were randomized into 3 groups (placebo, low-dose Caiapo, 2 g/d, and high-dose, 4 g/d). Parameters related to glucose tolerance, glucose disappearance, and insulin secretion were obtained by performing both frequently sampled intravenous glucose tolerance test (FSIGT) and oral glucose tolerance test (OGTT) before and after 6 weeks of treatment with Caiapo. Following treatment with high dose Caiapo, insulin sensitivity significantly ameliorated when assessed both with OGTT (from 308+/-13 mg/min/m2 to 334+/-10, P=.048) and FSIGT (from 1.21+/-0.32 10(4) min(-1)/(microU/mL) to 1.73+/-0.40, P=.021). Improvement of insulin sensitivity with the low dose was observed only with the FSIGT (from 2.02+/-0.70 10(4) min(-1)/(microU/mL) to 2.76+/-0.89, P<.05). Glucose effectiveness did not change. While no changes in glucose tolerance were observed in the placebo and low-dose groups, it increased from 0.85+/-0.13 %min(-1) to 1.46+/-0.13 (P<.02) in patients on high dose. No significant changes were seen in any of the parameters related to insulin dynamics: insulin secretion (from C-peptide), distribution, clearance, and hepatic extraction remained virtually the same after the treatment. In conclusion, short-term treatment with 4 g/d of the nutraceutical Caiapo consistently improved metabolic control in type 2 diabetic patients by decreasing insulin resistance without affecting body weight, glucose effectiveness, or insulin dynamics. No side effects related to the treatment were observed. Thus these results indicate that Caiapo could potentially play a role in the treatment of type 2 diabetes.

Publication Types:

•           Clinical Trial

•           Randomized Controlled Trial

PMID: 12870164 [PubMed - indexed for MEDLINE]

J Med Food. 2003 Spring;6(1):43-9.    Related Articles, Links

Effect of Gymnema montanum on blood glucose, plasma insulin, and carbohydrate metabolic enzymes in alloxan-induced diabetic rats.

Ananthan R, Latha M, Pari L, Ramkumar KM, Baskar CG, Bai VN.

Department of Botany, Bharathiar University, Coimbatore-641 046, Tamil Nadu, India.

The effects of Gymnema montanum, an endangered plant used in the ancient period of India, on blood glucose, plasma insulin, and carbohydrate metabolic enzymes were studied in alloxan diabetic rats. Administration of alcoholic extract of G. montanum leaves (50, 100, 200 mg/kg body weight) to alloxan diabetic rats for 3 weeks reduced the blood glucose level. Administration of G. montanum leaf extract (GLEt) at 200 mg/kg body weight significantly decreased the blood glucose levels and significantly increased the plasma insulin levels. This clearly shows the antidiabetic efficacy of GLEt, which was better than that of glibenclamide.

PMID: 12804019 [PubMed - indexed for MEDLINE]

Int J Food Sci Nutr. 2003 May;54(3):241-6.    Related Articles, Links

Hypoglycaemic and antioxidant effects of onion, Allium cepa: dietary onion addition, antioxidant activity and hypoglycaemic effects on diabetic rats.

Campos KE, Diniz YS, Cataneo AC, Faine LA, Alves MJ, Novelli EL.

Department of Chemistry and Biochemistry, Institute of Biological Sciences, University of Sao Paulo State, UNESP, Botucatu, Sao Paulo, Brazil.

The purpose of the present study was to discover the relative potency of onion, Allium cepa, with respect to its hypoglycaemic and hypolipidaemic effects on the diabetic situation, and the association of these effects with the potential against oxidative stress. Male Wistar rats were divided into four groups. A normal control (group A), and a non-diabetic group (group B) were treated daily with 1 ml A. cepa solution (0.4 g A. cepa/rat). Groups C and D were made diabetic by an intraperitoneal injection of streptozotocin (STZ) (60 mg/kg body weight) in citrate buffer (pH 6.3). These animals (groups C and D) were the STZ diabetic control and STZ diabetic rats with onion intake, respectively. Onion increased the fasting serum high-density lipoprotein levels, and demonstrated alleviation of hyperglycaemia in STZ diabetic rats. The hypoglycaemic and hypolipidaemic actions of A. cepa were associated with antioxidant activity, since onion decreased superoxide dismutase activities while no increased lipid hydroperoxide and lipoperoxide concentrations were observed in diabetic rats treated with A. cepa.

PMID: 12775373 [PubMed - indexed for MEDLINE]

Diabetes Care. 2003 Apr;26(4):1277-94.         Related Articles, Links

Systematic review of herbs and dietary supplements for glycemic control in diabetes.

Yeh GY, Eisenberg DM, Kaptchuk TJ, Phillips RS.

Division for Research and Education in Complementary and Integrative Medical Therapies, Harvard Medical School, Boston, Massachusetts, USA. gyeh@caregroup.harvard.edu

OBJECTIVE: To conduct a systematic review of the published literature on the efficacy and safety of herbal therapies and vitamin/mineral supplements for glucose control in patients with diabetes. RESEARCH DESIGN AND METHODS: We conducted an electronic literature search of MEDLINE, OLDMEDLINE, Cochrane Library Database, and HealthSTAR, from database inception to May 2002, in addition to performing hand searches and consulting with experts in the field. Available clinical studies published in the English language that used human participants and examined glycemic control were included. Data were extracted in a standardized manner, and two independent investigators assessed methodological quality of randomized controlled trials using the Jadad scale. RESULTS: A total of 108 trials examining 36 herbs (single or in combination) and 9 vitamin/mineral supplements, involving 4,565 patients with diabetes or impaired glucose tolerance, met the inclusion criteria and were analyzed. There were 58 controlled clinical trials involving individuals with diabetes or impaired glucose tolerance (42 randomized and 16 nonrandomized trials). Most studies involved patients with type 2 diabetes. Heterogeneity and the small number of studies per supplement precluded formal meta-analyses. Of these 58 trials, the direction of the evidence for improved glucose control was positive in 76% (44 of 58). Very few adverse effects were reported. CONCLUSIONS: There is still insufficient evidence to draw definitive conclusions about the efficacy of individual herbs and supplements for diabetes; however, they appear to be generally safe. The available data suggest that several supplements may warrant further study. The best evidence for efficacy from adequately designed randomized controlled trials (RCTs) is available for Coccinia indica and American ginseng. Chromium has been the most widely studied supplement. Other supplements with positive preliminary results include Gymnema sylvestre, Aloe vera, vanadium, Momordica charantia, and nopal.

Publication Types:

•           Review

•           Review, Academic

PMID: 12663610 [PubMed - indexed for MEDLINE]