Broussard Josiane L, Bergman Richard N, Bediako Isaac Asare, Paszkiewicz Rebecca L, Iyer Malini S, Kolka Cathryn M
Department of Integrated Physiology, University of Colorado Boulder, Boulder, Colorado, USA.
Diabetes and Obesity Research Institute, Department of Biomedical Science, Cedars-Sinai Medical Center, Los Angeles, California, USA.
Obesity (Silver Spring). 2018 Jan;26(1):119-125. doi: 10.1002/oby.22057. Epub 2017 Nov 30.
Diets high in saturated fat induce obesity and insulin resistance and impair insulin access to skeletal muscle, leading to reduced insulin levels at the muscle cell surface available to bind insulin receptors and induce glucose uptake. In contrast, diets supplemented with polyunsaturated fat improve insulin sensitivity (SI) and reduce the risk for type 2 diabetes. It was hypothesized that a diet high in polyunsaturated fat would preserve SI and insulin access to muscle, as compared with a diet high in saturated fat.
After 12 weeks of control, saturated (LARD), or polyunsaturated (salmon oil [SO]) high-fat diet feeding, muscle SI and insulin access to skeletal muscle were measured by using lymph, a surrogate of skeletal muscle interstitial fluid.
Both high-fat diets induced similar weight gain, yet only LARD impaired SI. Hyperinsulinemia in the LARD group did not induce an increase in basal interstitial insulin, suggesting reduced insulin access to muscle after LARD, but not after SO.
A diet high in polyunsaturated fat does not impair insulin access to muscle interstitium or induce insulin resistance as observed with a saturated fat diet, despite similar weight gain. Future studies should determine whether dietary SO supplementation improves impairments in insulin access to skeletal muscle.
高饱和脂肪饮食会导致肥胖和胰岛素抵抗，并损害胰岛素进入骨骼肌的能力，导致肌肉细胞表面可用于结合胰岛素受体并诱导葡萄糖摄取的胰岛素水平降低。相比之下，补充多不饱和脂肪的饮食可提高胰岛素敏感性（SI）并降低2型糖尿病风险。据推测，与高饱和脂肪饮食相比，高多不饱和脂肪饮食可维持SI以及胰岛素进入肌肉的能力。
在进行12周的对照、饱和（猪油[LARD]）或多不饱和（鲑鱼油[SO]）高脂饮食喂养后，通过使用淋巴（骨骼肌间质液的替代物）来测量肌肉SI以及胰岛素进入骨骼肌的情况。
两种高脂饮食均导致相似的体重增加，但只有猪油组损害了SI。猪油组的高胰岛素血症并未导致基础间质胰岛素增加，这表明猪油喂养后胰岛素进入肌肉的能力降低，而鲑鱼油喂养后则未出现这种情况。
尽管体重增加相似，但高多不饱和脂肪饮食不会像饱和脂肪饮食那样损害胰岛素进入肌肉间质或诱导胰岛素抵抗。未来的研究应确定补充膳食鲑鱼油是否能改善胰岛素进入骨骼肌的障碍。
