A Systematic Review of the Dietary Choline Impact on Cognition from a Psychobiological Approach: Insights from Animal Studies.

The influence of dietary choline availability on cognition is currently being suggested by animal and human studies which have focused mainly on the early developmental stages. The aim of this review is to systematically search through the available rodent (rats and mice) research published during the last two decades that has assessed the effect of dietary choline interventions on cognition and related attentional and emotional processes for the entire life span. The review has been conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines covering peer-reviewed studies included in PubMed and Scopus databases. After excluding duplicates and applying the inclusion/exclusion criteria we have reviewed a total of 44 articles published in 25 journals with the contribution of 146 authors. The results are analyzed based on the timing and duration of the dietary intervention and the behavioral tests applied, amongst other variables. Overall, the available results provide compelling support for the relevance of dietary choline in cognition. The beneficial effects of choline supplementation is more evident in recognition rather than in spatial memory tasks when assessing nonpathological samples whilst these effects extend to other relational memory tasks in neuropathological models. However, the limited number of studies that have evaluated other cognitive functions suggest a wider range of potential effects. More research is needed to draw conclusions about the critical variables and the nature of the impact on specific cognitive processes. The results are discussed on the terms of the theoretical framework underlying the relationship between the brain systems and cognition.

Dietary choline supplementation in adult rats improves performance on a test of recognition memory.

In two experiments adult rats (aged at least 6 months at the start of the procedure) received a diet enriched with added choline for a period of 10 weeks; control subjects were maintained on a standard diet during this time. All rats then underwent the spontaneous object recognition (SOR) procedure in which they were exposed to a pair of objects and then tested, after a retention interval, to a display with one object changed. Exploration of the changed object indicates retention and use of information acquired during the exposure phase. All subjects showed retention with a 24-h interval (Experiments 1 and 2) and when retested after a further 24 h (Experiment 1). But when tested for the first time after a 48-h interval (Experiment 2), control subjects showed no evidence of retention, exploring both objects equally, whereas those given the dietary supplement continued to show a preference for the changed object. This supports the conclusion that dietary choline supplementation can enhance performance on a task regarded as a test of declarative memory, and will do so even when the supplementations is given in adulthood.

The Psychoexposome: A holistic perspective beyond health and disease / Psicoexposoma: una perspectiva holística más allá de la salud y la enfermedad

Background: The concept of the exposome has emerged as a new strategy for studying all environmental exposures throughout an individual’s life and their impact on human health. Nowadays, electronic devices are available to collect data about an individual’s geolocation, biological function, or exposure biomarkers. The appearance of "omic" sciences and advances in bioinformatics have allowed massive data-gathering and analysis from various scientific fields. Objective: to propose the term Psychoexposome in line with the concept of the exposome from the field of environmental sciences. Method: a literature review of psychological terms associated with the exposome concept was carried out and the rationale and benefits of a psychoexposme approach for psychological sciences is discussed. Results: the terms psychology, psychiatry and neurological diseases are scarce in the exposome approach. A long tradition in psychology of performing epidemiological studies and in the study of multifactorial influences traits places psychologists at an advantageous starting point for conducting psychoexposome studies. Conclusion: psychology may take advantage from both exposome and omic sciences to create an integrated psychoexposome approach that may help in deciphering the etiology of psychological disorders and improving people's mental health (AU)

Antecedentes: el concepto de exposoma surgió como una estrategia para impulsar el estudio exhaustivo de las exposiciones ambientales a lo largo de la vida del individuo y su impacto en la salud. El desarrollo de dispositivos electrónicos para obtener datos de geolocalización, biológicos o biomarcadores de exposición y los avances en las ciencias "ómicas" y en bioinformática permiten la recopilación y el análisis masivo de datos muy diversos. Objetivo: proponer el término psicoexposoma en línea con el concepto de exposoma generado desde las ciencias ambientales. Método: se llevó a cabo una revisión de la literatura para buscar la inclusión de términos psicológicos asociados al concepto de exposoma. Se discute la justificación de un enfoque de psicoexposición para las ciencias psicológicas. Resultados: los términos psicología, psiquiatría o enfermedades neurológicas son escasos en el enfoque del exposoma. La experiencia en el control de variables ambientales sitúa al psicólogo en un punto de partida ventajoso para realizar estudios de psicoexposoma. Conclusión: la psicología puede aprovechar tanto las ciencias de la exposición como las ciencias "ómicas" para crear un enfoque integrado de psicoexposición que pueda ayudar a descifrar la etiología de los trastornos psicológicos y a promover la salud mental del individuo (AU)

The Psychoexposome: A holistic perspective beyond health and disease.

BACKGROUND: The concept of the exposome has emerged as a new strategy for studying all environmental exposures throughout an individual’s life and their impact on human health. Nowadays, electronic devices are available to collect data about an individual’s geolocation, biological function, or exposure biomarkers. The appearance of “omic” sciences and advances in bioinformatics have allowed massive data-gathering and analysis from various scientific fields. OBJECTIVE: to propose the term Psychoexposome in line with the concept of the exposome from the field of environmental sciences. METHOD: a literature review of psychological terms associated with the exposome concept was carried out and the rationale and benefits of a psychoexposme approach for psychological sciences is discussed. RESULTS: the terms psychology, psychiatry and neurological diseases are scarce in the exposome approach. A long tradition in psychology of performing epidemiological studies and in the study of multifactorial influences traits places psychologists at an advantageous starting point for conducting psychoexposome studies. CONCLUSION: psychology may take advantage from both exposome and omic sciences to create an integrated psychoexposome approach that may help in deciphering the etiology of psychological disorders and improving people’s mental health.

Effects of dietary choline availability on latent inhibition of flavor aversion learning.

OBJECTIVE: It has been previously reported that dietary choline supplementation might affect latent inhibition (LI) using a conditioned suppression procedure in rats. We have assessed the effect of dietary choline on LI of flavor aversion learning. METHOD: Adult male Wistar rats received a choline supplemented (5 g/kg), deficient (0 g/kg), or standard (1.1 g/kg) diet for 3 months. After this supplementation period, all rats went through a conditioned taste aversion (CTA) procedure, half of them being pre-exposed to the conditioned stimulus before the conditioning. RESULTS: The results indicated that choline deficiency prevents LI of conditioned flavor aversion to cider vinegar (3%) induced by a LiCl (0.15 M; 2% body weight) intraperitoneal injection, while choline supplementation enhances CTA leading to slower extinction. DISCUSSION: The role of the brain systems modulating attentional processes is discussed.

Long-lasting effects of prenatal dietary choline availability on object recognition memory ability in adult rats.

Choline is an essential nutrient required for early development. Previous studies have shown that prenatal choline availability influences adult memory abilities depending on the medial temporal lobe integrity. The relevance of prenatal choline availability on object recognition memory was assessed in adult Wistar rats. Three groups of pregnant Wistar rats were fed from E12 to E18 with choline-deficient (0 g/kg choline chloride), standard (1.1 g/kg choline chloride), or choline-supplemented (5 g/kg choline chloride) diets. The offspring was cross-fostered to rat dams fed a standard diet during pregnancy and tested at the age of 3 months in an object recognition memory task applying retention tests 24 and 48 hours after acquisition. Although no significant differences have been found in the performance of the three groups during the first retention test, the supplemented group exhibited improved memory compared with both the standard and the deficient group in the second retention test, 48 hours after acquisition. In addition, at the second retention test the deficient group did not differ from chance. Taken together, the results support the notion of a long-lasting beneficial effect of prenatal choline supplementation on object recognition memory which is evident when the rats reach adulthood. The results are discussed in terms of their relevance for improving the understanding of the cholinergic involvement in object recognition memory and the implications of the importance of maternal diet for lifelong cognitive abilities.

Choline dietary supplementation improves LiCl-induced context aversion retention in adult rats.

Previous studies have demonstrated that choline is an essential nutrient during prenatal and early postnatal developmental periods. Thus, the availability of choline during these periods produces some beneficial effects on hippocampal-dependent learning and memory in rats. However, research on the effect of adult choline supplementation on learning and memory abilities is scarce. In the present study, 3-4 month-old male Wistar rats receiving a 7-week choline-supplemented diet (4.5 fold that of a standard diet) and control rats receiving a standard diet were trained in a LiCl-induced contextual aversion task. Short and long-term context aversion retention was assessed by recording the consumption of a flavoured solution in the aversive and safe contexts over two subsequent tests. Statistical analysis showed that the supplemented group exhibited greater intake suppression in the aversive context than in the safe context when two retention tests were applied 3 and 15 days after conditioning. These results suggest that increasing dietary choline availability during adulthood may favour the retention of a context aversion.