A High-Fructose-High-Coconut Oil Diet Induces Dysregulating Expressions of Hippocampal Leptin and Stearoyl-CoA Desaturase, and Spatial Memory Deficits in Rats

Abstract

We investigated the effects of high-fructose-high-fat diets with different fat compositions on metabolic parameters, hippocampal-dependent cognitive function, and brain leptin (as well as stearoyl-CoA desaturase (SCD1) mRNA expressions). Thirty-two male Wistar rats were divided into 3 groups, a control group (n = 8), a high-fructose soybean oil group (37.5% of fat calories, n = 12), and a high-fructose coconut oil group (37.5% of fat calories, n = 12) for 20 weeks. By the end of the study, the coconut oil group exhibited significantly higher serum fasting glucose, fructosamine, insulin, leptin, and triglyceride levels compared to those of the control and soybean oil groups. However, hippocampal leptin expression and leptin receptor mRNA levels were significantly lower, while SCD1 mRNA was significantly higher in rats fed the high-fructose-high-coconut oil diet than in rats fed the other experimental diets. In addition, the coconut oil group spent significantly less time in the target quadrant on the probe test in the Morris water maze (MWM) task. Rats fed the high-fructose-high-coconut oil diet for 20 weeks were prone to develop hyperglycemia, hyperinsulinemia, hyperleptinemia, and hypertriglyceridemia. These metabolic consequences may contribute to hippocampal-dependent memory impairment, accompanied by a lower central leptin level, and a higher SCD1 gene expression in the brain.

Anti-diabetic effects of pomegranate extracts in long-term high fructose-fat fed rats

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The nutraceutical potential ofLepidium sativum L.seed flavonoid-rich extract in managing metabolic syndrome components

“…Concerning glucose dysregulation, several studies concur with our findings and support the direct correlation between high consumption of coconut fat and glucose intolerance (Lin, Shen, Hsu, & Lin, ). Motshakeri, Goh, and Ebrahimi () found that hyperglycemia induced by a high‐saturated fat diet was associated with a loss of insulin sensitivity.…”

Cerebral Fructose Metabolism as a Potential Mechanism Driving Alzheimer’s Disease

“…The effect on memory-driven by the fructose component of sugar is amplified by diets low in omega-3 fatty acids (Agrawal and Gomez-Pinilla, 2012 ). Combining fructose with saturated fats (coconut oil) causes worse memory defects than when combined with fats rich in omega-6 polyunsaturated fats (such as soybean oil; Lin et al, 2017 ). Furthermore, supplementation of omega-3 fatty acids can improve both fructose-induced metabolic syndrome and fructose-induced cognitive defects (Meng et al, 2016 ).…”