Carbohydrate and protein metabolism : influences on cognition and Alzheimer’s disease

Research into understanding the pathogenesis of Alzheimer’s disease (AD) has been ongoing for over a century, yet there is no cure, and current treatments are only effective temporarily. In the last two decades, the influence of diet and lifestyle on AD risk have been studied, and research into the effect of individual dietary components (such as macronutrients) on AD risk is gaining momentum. A number of cross*sectional and epidemiological research studies indicate that nutritional parameters influence cognitive performance in humans. Furthermore, chronic diseases and conditions such as type 2 diabetes, insulin resistance, obesity, cardiovascular disease, and hypertension, which are all risk factors for dementia, have dietary risk factors which are also proving to be risk factors for cognitive impairment and AD. Evidence from mechanistic studies and animal models suggests that certain dietary nutrients are essential for maintaining brain function and cognition. The consumption of a good balance of macronutrients enhances cognitive performance, whereas too high an intake of certain foods has sometimes been shown to lead to metabolic disruptions and chronic diseases. In this chapter we discuss the metabolism of carbohydrates and proteins in relation to cognition and AD. Other topics include the effects of glucose on cognition and memory, and the requirements for specific amino acids in brain function.