Metabolically benign obesity

Identification and Characterization of Metabolically Benign Obesity in Humans

Norbert Stefan, MD; Konstantinos Kantartzis, MD; Jürgen Machann, PhD; Fritz Schick, PhD; Claus Thamer, MD; Kilian Rittig, MD; Bernd Balletshofer, MD; Fausto Machicao, PhD; Andreas Fritsche, MD; Hans-Ulrich Häring, MD

Arch Intern Med. 2008;168(15):1609-1616.

Background  Obesity represents a risk factor for insulin resistance, type 2 diabetes mellitus, and atherosclerosis. In addition, for any given amount of total body fat, an excess of visceral fat or fat accumulation in the liver and skeletal muscle augments the risk. Conversely, even in obesity, a metabolically benign fat distribution phenotype may exist.

Methods  In 314 subjects, we measured total body, visceral, and subcutaneous fat with magnetic resonance (MR) tomography and fat in the liver and skeletal muscle with proton MR spectroscopy. Insulin sensitivity was estimated from oral glucose tolerance test results. Subjects were divided into 4 groups: normal weight (body mass index [BMI] [calculated as weight in kilograms divided by height in meters squared], <25.0), overweight (BMI, 25.0-29.9), obese–insulin sensitive (IS) (BMI, 30.0 and placement in the upper quartile of insulin sensitivity), and obese–insulin resistant (IR) (BMI, 30.0 and placement in the lower 3 quartiles of insulin sensitivity).

Results  Total body and visceral fat were higher in the overweight and obese groups compared with the normal-weight group (P < .05); however, no differences were observed between the obese groups. In contrast, ectopic fat in skeletal muscle (P < .001) and particularly the liver (4.3% ± 0.6% vs 9.5% ± 0.8%) and the intima-media thickness of the common carotid artery (0.54 ± 0.02 vs 0.59 ± 0.01 mm) were lower and insulin sensitivity was higher (17.4 ± 0.9 vs 7.3 ± 0.3 arbitrary units) in the obese-IS vs the obese-IR group (P < .05). Unexpectedly, the obese-IS group had almost identical insulin sensitivity and the intima-media thickness was not statistically different compared with the normal-weight group (18.2 ± 0.9 AU and 0.51 ± 0.02 mm, respectively).

Conclusions  A metabolically benign obesity that is not accompanied by insulin resistance and early atherosclerosis exists in humans. Furthermore, ectopic fat in the liver may be more important than visceral fat in the determination of such a beneficial phenotype in obesity.

Manfaat pemberian vitamin B pada penyakit jantung koroner

Suatu studi observasi melaporkan hubungan antara kadar homosistein dan risiko penyakit kardiovaskuler. Pemberian asam folat dan vitamin B12 diketahui dapat menurunkan kadar homosistein. Penelitian ini ingin mengetahui pengaruh asam folat dan vitamin B6 dan B12 untuk pencegahan sekunder pada pasien penyakit jantung koroner (PJK) dan stenosis klep aorta.

 

Penelitian dilakukan terhadap >3000 pasien yang menjalani prosedur angiografi dan berlangsung selama 7 tahun.

 

Setelah 1 tahun terjadi penurunan kadar homosistein kelompok yang mendapat asam folat dan vitamin B12. Tapi penurunan kadar homosistein ini tidak berpengaruh terhadap mortalitas dan cardiovascular events.

 

Kesimpulan penelitian ini tidak mendukung penggunaan vitamin B untuk preventif sekunder pasien dengan PJK.

 

Abstract

 

JAMA. Vol. 300 No. 7, August 20, 2008;300(7):795-804. © 2008 American Medical Association.
Mortality and cardiovascular events in patients treated with homocysteine-lowering B vitamins after coronary angiography.

Marta Ebbing, MD; Øyvind Bleie, MD, PhD; Per Magne Ueland, MD, PhD et al.

 

Context  Observational studies have reported associations between circulating total homocysteine concentration and risk of cardiovascular disease. Oral administration of folic acid and vitamin B₁₂ can lower plasma total homocysteine levels.

Objective  To assess the effect of treatment with folic acid and vitamin B₁₂ and the effect of treatment with vitamin B₆ as secondary prevention in patients with coronary artery disease or aortic valve stenosis.

Design, Setting, and Participants  Randomized, double-blind controlled trial conducted in the 2 university hospitals in western Norway in 1999-2006. A total of 3096 adult participants undergoing coronary angiography (20.5% female; mean age, 61.7 years) were randomized. At baseline, 59.3% had double- or triple-vessel disease, 83.7% had stable angina pectoris, and 14.9% had acute coronary syndromes.

Interventions  Using a 2 x 2 factorial design, participants were randomly assigned to 1 of 4 groups receiving daily oral treatment with folic acid, 0.8 mg, plus vitamin B₁₂, 0.4 mg, plus vitamin B₆, 40 mg (n = 772); folic acid plus vitamin B₁₂ (n = 772); vitamin B₆ alone (n = 772); or placebo (n = 780).

Main Outcome Measures  The primary end point was a composite of all-cause death, nonfatal acute myocardial infarction, acute hospitalization for unstable angina pectoris, and nonfatal thromboembolic stroke.

Results  Mean plasma total homocysteine concentration was reduced by 30% after 1 year of treatment in the groups receiving folic acid and vitamin B₁₂. The trial was terminated early because of concern among participants due to preliminary results from a contemporaneous Norwegian trial suggesting adverse effects from the intervention. During a median 38 months of follow-up, the primary end point was experienced by a total of 422 participants (13.7%): 219 participants (14.2%) receiving folic acid/vitamin B₁₂ vs 203 (13.1%) not receiving such treatment (hazard ratio, 1.09; 95% confidence interval, 0.90-1.32; P = .36) and 200 participants (13.0%) receiving vitamin B₆ vs 222 (14.3%) not receiving vitamin B₆ (hazard ratio, 0.90; 95% confidence interval, 0.74-1.09; P = .28).

Conclusions  This trial did not find an effect of treatment with folic acid/vitamin B₁₂ or vitamin B₆ on total mortality or cardiovascular events. Our findings do not support the use of B vitamins as secondary prevention in patients with coronary artery disease.

Diet untuk menurunkan BB

Penelitian ini membandingkan efektivitas dan keamanan diet untuk menurunkan berat badan (BB).

 

Penelitian dilakukan random random terhadap 322 subyek obese selama 2 tahun. Ada 3 jenis diet yang digunakan yaitu 1) rendah lemak, rendah kalori; 2) Mediterranean, rendah kalori; atau 3) rendah karbohidrat, tanpa pembatasan kalori.

 

Kepatuhan mengikuti diet >95% tahun pertama dan >84% tahun kedua.

 

Penurunan BB terbesar dicapai dengan diet rendah lemak. Penurunan terkecil oleh diet rendah lemak rendah kalori. Penurunan rasio kolesterol total terhadap HDL terbaik dicapai dengan diet rendah karbohidrat. Sedangkan untuk penderita diabetes yang terbaik adalah diet Mediterranean.

Abstract

 

N Engl J Med 359(3):229-241, 17 July 2008 © 2008

Weight Loss with a Low-Carbohydrate, Mediterranean, or Low-Fat Diet

Iris Shai, R.D., Ph.D., Dan Schwarzfuchs, M.D., Yaakov Henkin, M.D., Danit R. Shahar, R.D., Ph.D., Shula Witkow, R.D., M.P.H., Ilana Greenberg, R.D., M.P.H., Rachel Golan, R.D., M.P.H., Drora Fraser, Ph.D., Arkady Bolotin, Ph.D., Hilel Vardi, M.Sc., Osnat Tangi-Rozental, B.A., Rachel Zuk-Ramot, R.N., Benjamin Sarusi, M.Sc., Dov Brickner, M.D., Ziva Schwartz, M.D., Einat Sheiner, M.D., Rachel Marko, M.Sc., Esther Katorza, M.Sc., Joachim Thiery, M.D., Georg Martin Fiedler, M.D., Matthias Blüher, M.D., Michael Stumvoll, M.D., Meir J. Stampfer, M.D., Dr.P.H., for the Dietary Intervention Randomized Controlled Trial (DIRECT) Group

 

Background Trials comparing the effectiveness and safety of weight-loss diets are frequently limited by short follow-up times and high dropout rates.

Methods In this 2-year trial, we randomly assigned 322 moderately obese subjects (mean age, 52 years; mean body-mass index [the weight in kilograms divided by the square of the height in meters], 31; male sex, 86%) to one of three diets: low-fat, restricted-calorie; Mediterranean, restricted-calorie; or low-carbohydrate, non–restricted-calorie.

Results The rate of adherence to a study diet was 95.4% at 1 year and 84.6% at 2 years. The Mediterranean-diet group consumed the largest amounts of dietary fiber and had the highest ratio of monounsaturated to saturated fat (P<0.05 for all comparisons among treatment groups). The low-carbohydrate group consumed the smallest amount of carbohydrates and the largest amounts of fat, protein, and cholesterol and had the highest percentage of participants with detectable urinary ketones (P<0.05 for all comparisons among treatment groups). The mean weight loss was 2.9 kg for the low-fat group, 4.4 kg for the Mediterranean-diet group, and 4.7 kg for the low-carbohydrate group (P<0.001 for the interaction between diet group and time); among the 272 participants who completed the intervention, the mean weight losses were 3.3 kg, 4.6 kg, and 5.5 kg, respectively. The relative reduction in the ratio of total cholesterol to high-density lipoprotein cholesterol was 20% in the low-carbohydrate group and 12% in the low-fat group (P=0.01). Among the 36 subjects with diabetes, changes in fasting plasma glucose and insulin levels were more favorable among those assigned to the Mediterranean diet than among those assigned to the low-fat diet (P<0.001 for the interaction among diabetes and Mediterranean diet and time with respect to fasting glucose levels).

Conclusions Mediterranean and low-carbohydrate diets may be effective alternatives to low-fat diets. The more favorable effects on lipids (with the low-carbohydrate diet) and on glycemic control (with the Mediterranean diet) suggest that personal preferences and metabolic considerations might inform individualized tailoring of dietary interventions.