Effects of a Saturated Fat and High Cholesterol Diet on Memory and Hippocampal Morphology in the Middle-Aged Rat

• Published in: Journal of Alzheimer's disease Vol. 14; no. 2; pp. 133 - 145
• Main Authors: Granholm, Ann-Charlotte, Bimonte-Nelson, Heather A., Moore, Alfred B., Nelson, Matthew E., Freeman, Linnea R., Sambamurti, Kumar
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.06.2008
• Subjects: Age Factors; Animals; Cerebral Cortex - pathology; Cholesterol - blood; Cholesterol, Dietary - adverse effects; Cholesterol, HDL - blood; Coconut Oil; Cues; Dietary Fats - adverse effects; Fatty Acids - adverse effects; Hippocampus - pathology; Humans; Image Processing, Computer-Assisted; Male; Maze Learning - physiology; Memory, Short-Term - physiology; Microscopy, Video; Orientation - physiology; Plant Oils - adverse effects; Rats; Rats, Inbred F344; Retention (Psychology) - physiology; Triglycerides - blood; Aging; cognitive impairment; saturated fatty acids; memory; dietary effects
• ISSN: 1387-2877; 1875-8908
• DOI: 10.3233/JAD-2008-14202

Diets rich in cholesterol and/or saturated fats have been shown to be detrimental to cognitive performance. Therefore, we fed a cholesterol (2%) and saturated fat (hydrogenated coconut oil, Sat Fat 10%) diet to 16-month old rats for 8 weeks to explore the effects on the working memory performance of middle-aged rats. Lipid profiles revealed elevated plasma triglycerides, total cholesterol, HDL, and LDL for the Sat-Fat group as compared to an iso-caloric control diet (12% soybean oil). Weight gain and food consumption were similar in both groups. Sat-Fat treated rats committed more working memory errors in the water radial arm maze, especially at higher memory loads. Cholesterol, amyloid-β peptide of 40 (Aβ40) or 42 (Aβ42) residues, and nerve growth factor in cortical regions was unaffected, but hippocampal Map-2 staining was reduced in rats fed a Sat-Fat diet, indicating a loss of dendritic integrity. Map-2 reduction correlated with memory errors. Microglial activation, indicating inflammation and/or gliosis, was also observed in the hippocampus of Sat-Fat fed rats. These data suggest that saturated fat, hydrogenated fat and cholesterol can profoundly impair memory and hippocampal morphology.