Left Ventricular Mass and Function With Reduced-Fat or Reduced-Carbohydrate Hypocaloric Diets in Overweight and Obese Subjects

Abstract

Abstract-In animals, carbohydrate and fat composition during dietary interventions influenced cardiac metabolism, structure, and function. Because reduced-carbohydrate and reduced-fat hypocaloric diets are commonly used in the treatment of obesity, we investigated whether these interventions differentially affect left ventricular mass, cardiac function, and blood pressure. We randomized 170 overweight and obese subjects (body mass index, 32.9Ϯ4.4; range, 26.5-45.4 kg/m 2 ) to 6-month hypocaloric diets with either reduced carbohydrate intake or reduced fat intake. We obtained cardiac MRI and ambulatory blood pressure recordings over 24 hours before and after 6 months. Ninety subjects completing the intervention period had a full cardiac MRI data set. Subjects lost 7.3Ϯ4.0 kg (7.9Ϯ3.8%) with reduced-carbohydrate diet and 6.2Ϯ4.2 kg (6.7Ϯ4.4%) with reduced-fat diet (PϽ0.001 within each group; Pϭnot significant between interventions). Caloric restriction led to similar significant decreases in left ventricular mass with low-carbohydrate diets (5.4Ϯ5.4 g) or low-fat diets (5.2Ϯ4.8 g; PϽ0.001 within each group; Pϭnot significant between interventions). Systolic and diastolic left ventricular function did not change with either diet. The 24-hour systolic blood pressure decreased similarly with both interventions. Body weight change (␤ϭ0.33; Pϭ0.02) and percentage of ingested n-3 polyunsaturated fatty acids (␤ϭϪ0.27; Pϭ0.03) predicted changes in left ventricular mass. In conclusion, weight loss induced by reduced-fat diets or reduced-carbohydrate diets similarly improved left ventricular mass in overweight and obese subjects over a 6-month period. However, n-3 polyunsaturated fatty acid ingestion may have an independent beneficial effect on left ventricular mass. O besity is associated with increased left ventricular (LV) mass, 1,2 a potential contributor to heart failure, cardiovascular events, and mortality. 3,4 Energy-restricted diets decrease LV mass in conjunction with body weight loss. [5][6][7] In addition to caloric intake, dietary macronutrient composition appears to influence cardiac metabolism, structure, and function, 8 as well as vascular compliance. 9 In animals, high-fat feeding attenuated cardiac hypertrophy and remodeling, 10,11 whereas high-carbohydrate feeding accelerated the process. 12 Excessive simple sugars and saturated fatty acid ingestion worsened cardiac structure and function. 13,14 In contrast, n-3 polyunsaturated fatty acid supplementation attenuated cardiac hypertrophy and fibrosis in rats. 15,16 Therefore, in addition to caloric intake, macronutrient content and composition could affect LV mass and ventricular function during energy restricted diets. Carbohydrate-restricted and fat-restricted diets are commonly prescribed. 17 Whether macronutrient content, without changing physical activity, affects hypocaloric diet-induced changes in LV mass and function has not been investigated in humans. The issue is important given the independent prognostic role of LV mass on cardiovascular events. ...

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Independent Influence of Overweight and Obesity on the Regression of Left Ventricular Hypertrophy in Hypertensive Patients

“… 4 Undergoing substantial weight loss through bariatric surgery and diet restriction reduced LVH in overweight and obese subjects independent of changes in blood pressure (BP). 5 , 6 However, there are different viewpoints. Hsuan et al 7 considered that BP reduction was the major determinant for the regression of LVH in the early stage of surgical weight reduction.…”

Reduced Difference in Left Ventricular Mass at End Diastole and Peak Systole Is a Predictor of Major Stenosis of the Left Coronary Artery Territory

“…Currently, magnetic resonance imaging remains the reference standard for evaluation of LV mass, [8][9][10] but it is not always readily available. Echocardiography is convenient and flexible and can be performed at the bedside.…”