Alterations of attention and impulsivity in the rat following a transgenerational decrease in dietary omega-3 fatty acids

Polyunsaturated fatty acids(PUFAs),particularly the omega-3 PUFAs,are thought to be involved in neuronal processes,to play a role in neurodevelopmental disorders and to be important for the integrity of central nervous system functioning.The present study investigated the effects of nutritional omega-3 PUFAs on attentional functions and impulsive behavior in Wistar rats.For this purpose,female Wistar rats were fed an omega-3 deficient diet over several generations,and the dams of the seventh generation were randomly assigned to two diet groups and fed an omega-3 deficient or an omega-3 sufficient diet.In addition,a group of previously untreated dams was fed an omega-3 sufficient diet.The male offspring of these three diet groups were tested using an established paradigm for the assessment of attention and impulsive behavior,i.e.a modified version of the five-choice-serial-reaction-time task(5CSRTT).The present data show that the deficiency of omega-3 PUFAs over generations led to substantial changes in attentional processes and impulsive behaviors.The impairments associated with an omega-3 deficiency were partly corrected by treatment with the omega-3 sufficient diet in the last generation of the omega-3 deficient group which showed substantial improvements in attention parameters.While there were no significant effects of dietary modifications on psychomotor activity levels,there was some evidence for changes in impulsive behavior.In conclusion,transgenerational dietary changes in the availability of omega-3 PUFAs led to changes in attentional processes and impulsive behavior in rats,supporting the hypothesis that omega-3 PUFAs play a role in cognitive and behavioral processes.The present findings offer a promising approach in the investigation of the role of omega-3 PUFAs in a variety of cognitive and behavioral domains.

Dietary seaweeds and obesity

Potential therapeutic benefits of seaweed consumption have been reported in the management of body weight and obesity.In vitro and in vivo animal studies provide the majority of data available at present.The majority of studies assessing the short-term effects of alginate consumption indicate that alginate may increase satiety,reduce energy intake and support weight reduction.Mechanisms suggested for these effects include delayed gastric clearance,stimulation of gastric stretch receptors and attenuated nutrient absorption.Long-term studies in humans are required in order to allow firm conclusions.Animal studies have investigated potential anti-obesity effects of seaweeds on adipogenesis and the inhibition of major lipid hydrolyzing and metabolizing enzymes.The results of these studies suggest beneficial effects of seaweed components such as fucoxanthin on body weight and the percentage of abdominal white adipose tissue.It is premature to extrapolate these findings to humans since consistent findings are still lacking.There is at present no solid evidence indicating that seaweeds are effective in long-term weight management.However,available findings suggest potential benefits of seaweed components on obesity.Future investigations are required to establish the therapeutic efficacy in the management of overweight and obesity in humans and elucidate the underlying mechanisms of actions.

Behavioral assessment of hippocampal function following dietary intervention

Pattern separation keeps items distinct in memory and is mediated by the hippocampus.A relationship between hippocampal function and diet quality has been suggested by findings in both humans and animals.In the present study,rats were fed over seven generations a diet containing increased amounts of sugar and saturated fatty acids,reduced levels of polyunsaturated fatty acids and an increased ratio of omega-6/omega-3 fatty acids(“Western”diet).Spatial pattern separation(or local discrimination)performance of these animals was compared with that of rats fed a standard diet.A separation-dependent difference between the standard and Western diet groups was found in the number of discriminations performed in the pattern separation task,with rats of the“Western”group performing fewer discriminations.The present results suggest that behavioral assessment of spatial pattern separation can detect effects of dietary interventions in rats and that pattern separation can be impaired by transgenerational administration of a“Western”diet.Future studies should determine which components of this diet induce the memory impairments related to the hippocampus.The translational relevance of these findings in regard to mental disorders such as dementia and depression needs to be investigated.

Ketogenic diets and Alzheimer’s disease

Alzheimer’s disease(AD)is a progressive neurodegenerative disorder characterized by decline in cognitive functions and associated with the neuropathological hallmarks of amyloid-peptide plaques and neurofibrillary tangles.Cerebral glucose uptake and metabolism deteriorate in AD and this hypometabolism precedes the onset of clinical signs in AD.The early decline in brain glucose metabolism in AD has become a potential target for therapeutic intervention.This has led to investigations assessing the supplementation of the normal glucose supply with ketone bodies which are produced by the body during glucose deprivation and can be metabolized by the brain when glucose utilization is impaired.The present review provides a synopsis of preclinical studies and clinical trials assessing the efficacy of ketogenic diets in the treatment of AD.Both the direct administration of ketone bodies and the use of high-fat,low-carbohydrate ketogenic diets have been shown to be efficacious in animal models of AD and clinical trials with AD patients.The mechanism underlying the efficacy of ketogenic diets remains unclear,but some evidence points to the normalization of aberrant energy metabolism.At present there is only limited evidence of the usefulness of ketogenic diets in AD.However,this dietary approach seems to be promising and deserves further clinical investigations.