Johns I, Frost G, Dornhorst A
Nutrition and Dietetic Research Group, Imperial College London, London, UK.
J Nutr Sci. 2019 Nov 29;9:e6. doi: 10.1017/jns.2019.29.
The effect of modifying dietary fatty acid (FA) composition on insulin sensitivity remains unclear. We aimed to investigate whether changes in plasma phospholipid (PL) FA composition, as a result of dietary intervention, correspond with changes in insulin sensitivity. The RISCK study was a 6-month randomised controlled dietary intervention study, which assessed the effect of modifying dietary fat and the glycaemic index (GI) of carbohydrates on insulin sensitivity. Total NEFA levels, fasting plasma PL FA profiles and an insulin sensitivity index (Si), derived from intravenous glucose tolerance minimal-model analysis, were available from 533 participants, all at elevated risk of type 2 diabetes. Bivariate correlations between changes in saturated PL FA (SFA), MUFA (as a percentage of total plasma NEFA) and changes in Si were assessed according to treatment group. Age, sex, ethnicity, percentage change in body mass and change in dietary GI were controlled for. Increasing total NEFA concentration was associated with worsening Si (0·152; = 0·001). In the high-MUFA/low-GI diet group, change in PL-MUFA was positively and independently associated with change in Si ( 0·297; = 0·002). Among MUFA, change in oleic acid (18 : 1) was most strongly correlated with change in Si ( 0·266 = 0·005), as was change in minor FA 24 : 1 ( 0·244; = 0·011) and 17 : 1 ( 0·196; = 0·042). In the high-SFA/high-GI group, change in SFA concentration was not significantly associated with change in Si. In conclusion, increases in the proportion of plasma PL-MUFA following a high-MUFA dietary intervention were associated with improvements in insulin sensitivity.
改变膳食脂肪酸（FA）组成对胰岛素敏感性的影响尚不清楚。我们旨在研究饮食干预导致的血浆磷脂（PL）FA组成变化是否与胰岛素敏感性变化相对应。RISCK研究是一项为期6个月的随机对照饮食干预研究，评估了改变膳食脂肪和碳水化合物血糖指数（GI）对胰岛素敏感性的影响。共有533名2型糖尿病风险均升高的参与者提供了总非酯化脂肪酸（NEFA）水平、空腹血浆PL FA谱以及通过静脉葡萄糖耐量最小模型分析得出的胰岛素敏感性指数（Si）。根据治疗组评估饱和PL FA（SFA）、单不饱和脂肪酸（MUFA，占总血浆NEFA的百分比）变化与Si变化之间的双变量相关性。对年龄、性别、种族、体重百分比变化和饮食GI变化进行了控制。总NEFA浓度升高与Si恶化相关（0·152；P = 0·001）。在高MUFA/低GI饮食组中，PL-MUFA的变化与Si的变化呈正相关且独立相关（β = 0·297；P = 0·002）。在MUFA中，油酸（18 : 1）的变化与Si的变化相关性最强（β = 0·266；P = 0·005），次要脂肪酸24 : 1的变化（β = 0·244；P = 0·011）和17 : 1的变化（β = 0·196；P = 0·042）也是如此。在高SFA/高GI组中，SFA浓度变化与Si变化无显著相关性。总之，高MUFA饮食干预后血浆PL-MUFA比例的增加与胰岛素敏感性的改善相关。
