Calorie Restriction without Restricting Vitamins and Minerals Does Not Deteriorate Bones

Abstract

Calorie restriction has a number of health benefits, however is associated with reduction of bone mineral density (BMD). As calcium and vitamin D are considered to be the most essential nutrients for bone health, this study aimed to determine if restriction of vitamins and minerals is the cause of this bone deterioration in calorie‐restricted diet. We hypothesize that calorie restriction without restricting the vitamins and minerals will not reduce bone mineral density in calorie‐restricted mice. To determine the effect of calorie restriction (CR) on bone mineral density, 6‐month‐old C57BL/6 female mice were fed AIN93 diet ad libitum (AL) or 20% CR for 8 months. Mice were divided into 2 groups: 1) Mice fed AL and 2) Mice fed 20% complete calorie restriction (CCR) where vitamins and minerals are also restricted. Mice were scanned with dual energy x‐ray absorptiometry (DXA) at the age of 6 month (baseline), and 14 month (after 8 months of experimental diet) and analyzed for the bone mass. Calorie restricted mice showed a noticeable reduction in BMD as compared to AL fed mice. To determine if long‐term calorie restriction without restricting vitamins and minerals can attenuate this bone deterioration in CCR mice after 8 months of experimental diet. Six‐month‐old C57BL/6 mice were divided into 2 groups: 1) Mice fed AL and 2) Mice fed 20% CCR for 8 months to induce bone loss. Then 20% CCR diet was replaced with 20% CR diet without restricting vitamins and minerals for another 8 months. Interestingly, reduction of BMD seen in CCR fed mice at the age of 14 month was attenuated at the age of 22 month when this group was fed for 8 months with 20% CR diet without restricting vitamins and minerals. In either case (vitamins and mineral restricted or not restricted), muscle mass, and strength were improved in 20% calorie restricted group as compared to AL group as determined by DXA, and wet weight at sacrifice for muscle mass and by rotarod performance test and endurance stress test for muscle strength. These data indicate that 20% CR without compromising vitamin and minerals could be a natural, cost effective and safe optimal dietary regimen that would improve muscle mass and strength without any deleterious effect on bone.Support or Funding InformationNIH NIA K01 KAG034233A and QNRF UREP23‐097‐1‐026