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

Despite growing popularity of carbohydrate restricted diets, consequences of long term use remain unknown. The current study evaluated the effects of low carbohydrate/high fat (LCHF) diets on heart size and cardiac glycogen content in young mice. Young mice (age 21 d, n = 24) and mature mice (age 84 d, n = 18) were placed on either a LCHF, a western (WD) or a control diet for 12 weeks. Upon completion of the dietary intervention, heart wet weights were measured to compute the weight-to-tibia length ratio. Sections of cardiac tissue were stained with periodic acid and Schiff reagent to visualize glycogen. Mice following the LCHF diet displayed 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. 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). This study shows that a LCHF diet reduces heart weight in young and mature mice. Alterations in intercellular cardiac glycogen content may contribute to differences observed in heart weight. LCHF diets should be recommended with caution as long term effects on the heart are unknown.