The Effect of Macronutrient Composition on Endogenous Long-Chain Polyunsaturated Fatty Acid Status during Weight Loss
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- The influence on tissue fatty acid composition of three different isocaloric diets containing carbohydrates with a low glycemic index, carbohydrates with a high glycemic index, or a reduced fat content, respectively, was assessed in overweight-obese adults on a 500 kcal/d-energy restriction in a randomized controlled intervention trial.
- The study had been designed to avoid previous limitations in addressing the effect of macronutrients on weight loss, and revealed improvements in insulin control in participants on the low-glycemic index diet. However, potential adverse effects on polyunsaturated fatty acid (PUFA) status had not been previously investigated.
- After six months, no changes in red blood cell membrane fatty acid composition were observed in participants on the low-glycemic index diet, eicosapentaenoic acid (EPA) level decreased in the high-glycemic index group, and decreases in several omega-3 LCPUFAs and increases in omega-6 LCPUFAs were observed in the low-fat diet group.
- This study suggests that during energy-restricted weight loss PUFA levels are sensitive to changes in total dietary fat content, but are not perturbed, or much less affected, by diets with varying carbohydrate profile.