Energetic efficiency and mitochondrial function in rats fed trans fatty acids.

Area of Science:

• Nutrition Science
• Biochemistry
• Mitochondrial Physiology

Background:

• Dietary fats significantly influence metabolic processes.
• Trans fatty acids (TFAs) are known to have adverse health effects, but their specific impact on energy metabolism and mitochondrial function requires further elucidation.
• Safflower oil is rich in linoleate, an essential omega-6 fatty acid.

Purpose of the Study:

• To investigate the effects of specific dietary trans fatty acids, elaidic acid (t18:1) and trans,trans-18:2 (t,t18:2), on the energetic efficiency and liver mitochondrial oxidative phosphorylation in growing rats.
• To determine if the presence of linoleate influences the impact of TFAs.
• To establish a dose-response relationship for t,t18:2 on energy utilization.

Main Methods:

• Growing male rats were fed diets supplemented with 10% fat, including safflower oil (SAF) alone or in mixtures with partially hydrogenated soybean oil (PHSO) or a trans fatty acid concentrate (TRANS).
• Diets varied in their content of linoleate and specific TFAs (t18:1 and t,t18:2).
• Energetic efficiency was assessed through energy balance experiments, and oxidative phosphorylation was measured using isolated liver mitochondria.

Main Results:

• Dietary treatments did not affect basal metabolic rate or metabolizable energy values.
• Partially hydrogenated soybean oil (PHSO) did not alter energy utilization or mitochondrial function compared to safflower oil.
• Increasing levels of trans,trans-18:2 (t,t18:2) significantly reduced the efficiency of metabolizable energy utilization and depressed mitochondrial ATP synthesis, with effects observed at 2% and 5% dietary TRANS.
• A direct correlation was found between t,t18:2 incorporation into liver mitochondria, reduced mitochondrial function, and decreased energetic efficiency.

Conclusions:

• Trans,trans-18:2 (t,t18:2) exerts a significant negative effect on energy utilization and mitochondrial oxidative function in rats.
• These detrimental effects occur even at relatively low dietary levels (1.0% and 2.5%) and in the presence of high concentrations of linoleate.
• Dietary elaidic acid (t18:1) from PHSO did not show significant adverse effects on energy metabolism or mitochondrial function in this study.