Jogging their memory: developmental effects of fitness, body composition, and nutrition on relational memory

memory;relational memory;nutrition;fitness;development;hippocampus;obesity;body mass index;cognition

Baym, Carol

关键词: memory;    relational memory;    nutrition;    fitness;    development;    hippocampus;    obesity;    body mass index;    cognition;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/45636/Carol_Baym.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Increasingly prevalent in the media and public awareness, the growing problem of obesity, particularly childhood obesity, has become a significant concern in the United States and many developed countries around the world. Current longevity estimates predict that if trends continue, children born today may die younger than their parents’ generation for the first time in history. Many factors have contributed to the rising incidence of childhood obesity including increasingly sedentary and unfit lifestyle, as well as poor diet resulting from an ethos that taste and convenience are the paramount concerns in deciding what to consume. Sedentary lifestyle, poor diet, and the weight gain that accompanies those choices have been repeatedly shown to cause adverse consequences for physical health, including markedly increasing the risk for stroke, type 2 diabetes, and cardiovascular disease. More recently these unhealthy lifestyle choices are beginning to be linked to negative outcomes in brain health as well, including increasing risk of premature cognitive aging and Alzheimer’s disease. How these health and fitness factors affect the developing brain is even more sparsely studied in the literature to date. It may be the case that health factors do not affect the brain and its functionality until their effects have accumulated for many decades, but it is equally possible that early adoption of healthy or unhealthy habits may set the developmental trajectory for the long-term early in life and also manifest in the short-term. Although aspects of the whole brain may be vulnerable to these health habits, one region of the brain, the hippocampus, has been shown to be particularly susceptible to these factors due in part to its high metabolic demand and extraordinary capabilities of plasticity including neurogenesis. The hippocampus is necessary for a type of memory, relational memory, which is critical for many types of learning, and thus for successful scholastic achievement. Thus, it may be expected that changes to the functionality of the hippocampus may strongly impact learning capabilities. Another type of memory, item memory, relies not on the hippocampus, but on surrounding medial temporal lobe cortices. These cortical structures are neither as plastic nor metabolically demanding as the hippocampus and thus may be expected to be less functionally or structurally susceptible to changes in physical health, although they may still potentially be vulnerable to broad effects such as global inflammation.The current investigation thus sought to extend our understanding of the ways in which various lifestyle factors including physical fitness and nutrition, along with health factors that may result from lifestyle choices including body mass and body composition, interact with the developmental time courses of relational and item memory as they unfold over the first several decades of life. Using a mixed-approach combining cross-sectional and longitudinal studies, the current investigation sampled across three age groups: prepubertal children (ages 7-9), young adolescents (ages 11-13), and young adults (ages 18-34). In sampling across these three time points in development, we aimed to begin to shed light on how these various lifestyle factors relate to these various types of memory across development, and also to probe how early in time these effects can be seen to emerge. In measuring this, we combined behavioral and eye movement measures of memory to allow for a rich representation of how these health and fitness factors may interact with memory function across the age groups. Aerobic fitness was found to relate positively to relational memory function across all time points sampled, with the relationship becoming stronger in the young adults than either of the younger groups. The relationship between aerobic fitness and item memory showed a different pattern, with fitness predicting behavioral memory performance in the children but not in the young adults. Potential mechanisms for these relationships within age group are discussed in the appropriate chapter discussions and how they relate across development is discussed in the General Discussion. Body mass index was also assessed across all three developmental time points and showed a negative relationship with memory performance in the prepubertal children but not the adolescents or young adults, suggesting that body size may be more important to the developing brain than the more mature brain. Interestingly, body composition was shown to be a stronger predictor of relational memory performance than body size alone, in children, such that children who stored a greater amount of fat in the central abdominal region showed poorer relational memory performance than those who preferentially stored fat peripherally. Finally, nutritional intake, particularly of dietary fats, was found to correlate with memory performance in prepubertal children. Specifically, higher intake of saturated fats was found to negatively correlate with both types of memory performance and higher intake of omega-3 fatty acids was found to positively correlate with relational memory performance, even after adjusting for body mass. Taken together the results of the current investigation demonstrate that health and fitness factors are related to memory function in differing ways across the first several decades of life and begins to suggest a developmental trajectory by which these effects unfold. Furthermore, the current investigation suggests that these effects emerge early in development, after less than one decade of life. The public health implications of these findings and the findings that will follow stand to be potentially enormous as compromised brain health may interfere with learning and achievement during the school years and beyond, and set children on a lower developmental trajectory from which it is difficult or impossible to recover. As such, the current findings underscore the importance of early adoption and continued maintenance of a healthy, active lifestyle.