title: Diet-Induced Weight Loss Alters Functional Brain Responses during an Episodic Memory Task.
abstract: OBJECTIVE
  It has been suggested that overweight is negatively associated with cognitive functions. The aim of this study was to investigate whether a reduction in body weight by dietary interventions could improve episodic memory performance and alter associated functional brain responses in overweight and obese women.
  
  
  METHODS
  20 overweight postmenopausal women were randomized to either a modified paleolithic diet or a standard diet adhering to the Nordic Nutrition Recommendations for 6 months. We used functional magnetic resonance imaging to examine brain function during an episodic memory task as well as anthropometric and biochemical data before and after the interventions.
  
  
  RESULTS
  Episodic memory performance improved significantly (p = 0.010) after the dietary interventions. Concomitantly, brain activity increased in the anterior part of the right hippocampus during memory encoding, without differences between diets. This was associated with decreased levels of plasma free fatty acids (FFA). Brain activity increased in pre-frontal cortex and superior/middle temporal gyri. The magnitude of increase correlated with waist circumference reduction. During episodic retrieval, brain activity decreased in inferior and middle frontal gyri, and increased in middle/superior temporal gyri.
  
  
  CONCLUSIONS
  Diet-induced weight loss, associated with decreased levels of plasma FFA, improves episodic memory linked to increased hippocampal activity.
authors.affiliation: Center for Demographic and Aging Research, Umex00E5; University, Umex00E5;, Sweden.
authors.forename: Carl-Johan
authors.initials: CJ
authors.lastname: Boraxbekk
authors.forename: Andreas
authors.initials: A
authors.lastname: Stomby
authors.forename: Mats
authors.initials: M
authors.lastname: Ryberg
authors.forename: Bernt
authors.initials: B
authors.lastname: Lindahl
authors.forename: Christel
authors.initials: C
authors.lastname: Larsson
authors.forename: Lars
authors.initials: L
authors.lastname: Nyberg
authors.forename: Tommy
authors.initials: T
authors.lastname: Olsson
mesh_terms: D000368:Aged; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D066046:Diet, Paleolithic; D004038:Diet, Reducing; D005260:Female; D005625:Frontal Lobe / Q000503:physiopathology; D006624:Hippocampus / Q000503:physiopathology; D006801:Humans; D008279:Magnetic Resonance Imaging; D061212:Memory, Episodic; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy* / Q000503:physiopathology* / Q000523:psychology; D050177:Overweight / Q000178:diet therapy* / Q000503:physiopathology* / Q000523:psychology; D013702:Temporal Lobe / Q000503:physiopathology; D015431:Weight Loss / Q000502:physiology*