Implications of a Low-Carbohydrate, High-Fat Diet on Heart Size in a Murine Model

Abstract

Objective: The incidence of childhood obesity in North America and around the world has risen significantly over the past decade leaving clinicians constantly searching for effective weight loss strategies. Despite the growing popularity or carbohydrate restricted diets, consequences of long term use remain widely unknown. The objective of the current investigation is to evaluate the effects of LCHF diets on heart size and cardiac glycogen content in young mice. Methods: Young mice (age 21 d, n = 24) and mature mice (age 84 d, n = 18) were placed on either a LCHF diet, a WD diet or a control diet for 12 weeks. Activity levels, body weight, and glucose values were measured during the investigation. At the competition of the dietary intervention, wet heart weights were measured to compute the heart weight-to-tibia length ratio, cross sectional area was calculated and sections of cardiac tissue were stained with periodic acid and Schiff reagent to visualize glycogen. Results: No differences in activity levels or glucose measures were noted between groups. Mice following the LCHF diet displayed a smaller heart weight-to-tibia length ratio when compared to controls. The trend was observed in both young (p = 0.012) and mature (p = 0.024) mice. No differences in cross sectional area were detected. Cardiac tissue from mice consuming the LCHF diet had a reduced percentage of total area stained positive for glycogen when compared to mice following the WD diet (p = 0.016). Conclusions: A LCHF diet can lead to the development of a smaller heart in young and mature mice. Alterations in intercellular cardiac glycogen content may contribute to differences observed in heart weight. Cardiac restricted diets should be recommended with caution as long term cardiac developmental impairments are unknown.