"To get my youth back, I would do anything in the world except exercise, get up early or be decent" (Oscar Wilde)
Diet and exercise for prevention

Unfortunately, this calculation doesn't quite add up - Mr. Wilde! Because physical activity is probably the most effective way to maintain a healthy body and mind! Exercise is associated with a reduction in a number of physical and mental disorders. In fact, there is ample scientific evidence that physical activity reduces the incidence of cardiovascular disease, colon and breast cancer and obesity, as well as diseases such as Alzheimer's, depression and anxiety.[1] [2]
A healthy diet plays just as important a role as physical activity. For a long time, food intake was only seen as a means of providing energy and building materials for the body. However, the ability of a healthy diet to prevent and protect against disease is receiving more and more attention in the scientific community. Nutrition and health are therefore an effective means of counteracting any negative health effects. [3]
Influencing brain development

Recent scientific data now even indicates that not only general health, but also brain development, brain performance and cognition are influenced by exercise and diet. If only Oscar Wilde had known this - perhaps he could have graced us with another literary classic before his untimely demise?
Nutrition provides building blocks for the brain to make and maintain connections, which is crucial for improved cognition and academic performance. In particular, individual dietary components have a positive effect on neural function and brain plasticity. Findings from cross-sectional studies have shown that cognitive functions such as processing speed, short-term memory, working memory and long-term memory decline linearly with age.
Structural brain changes

The findings are also reflected in structural changes to the brain. For example, one study shows that the volume of the hippocampus - an area responsible for learning and memory - is larger in fit children compared to physically unfit children of the same age. [8] Another study shows that obesity and type 2 diabetes are associated with a decrease in brain volume, which could lead to deficits in cognitive and academic performance. [9]
Fewer calories in old age

A study with monkeys, for example, shows that the volume of gray brain matter decreases in aging monkeys - while it is preserved in monkeys that are in a calorie deficit. [14]
Limitation
A large number of natural products now promise to have benefits for cognition. However, there is still a fundamental need for controlled, randomized trials with a strong design, sufficient statistical power and well-defined outcome measures before claims can be made about their positive effects on brain function. Future studies could focus on identifying the single factor(s) in natural substances that have a cognitive enhancing effect and selecting the most potent ones for further investigation.
Sources
[1] Meeusen R. (2014). Exercise, nutrition and the brain. Sports medicine (Auckland, N.Z.), 44 Suppl 1(Suppl 1), S47-S56.
[2] van Praag H. (2009). Exercise and the brain: something to chew on. Trends in neurosciences, 32(5), 283-290.
[3] Meeusen R. (2014). Exercise, nutrition and the brain. Sports medicine (Auckland, N.Z.), 44 Suppl 1(Suppl 1), S47-S56.
[8] Chaddock L, Erickson KI, Prakash RS. A neuroimaging investigation of the association between aerobic fitness, hippocampal volume, and memory performance in preadolescent children. Brain Res. 2010;1358:172-183.
[9] Raji CA, Ho AJ, Parikshak NN, et al. Brain structure and obesity. Hum Brain Mapp. 2010;31:353-364.
[10] Shukitt-Hale B, Lau FC, Carey AN, et al. Blueberry polyphenols attenuate kainic acid-induced decrements in cognition and alter inflammatory gene expression in rat hippocampus. Nutr Neurosci. 2008;11(4):172-182.
[11] Meeusen R. (2014). Exercise, nutrition and the brain. Sports medicine (Auckland, N.Z.), 44 Suppl 1(Suppl 1), S47-S56.
[12] Spencer J. Food for thought: the role of dietary flavonoids in enhancing human memory, learning and neuro-cognitive performance. Proc Nutr Soc. 2008;67:238-252.
[13] Meeusen, R., & Decroix, L. (2018). Nutritional Supplements and the Brain, International Journal of Sport Nutrition and Exercise Metabolism, 28(2), 200-211. Retrieved Apr 1, 2021, from http://journals.humankinetics.com/view/journals/ijsnem/28/2/article-p200.xml
[14] Colman RJ, Anderson RM, Johnson SC, et al Caloric restriction delays disease onset and mortality in rhesus monkeys. Science. 2009;325:201-204.
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