Table 2. The total number of reviewed articles.

CR: caloric restriction; PUFAs: polyunsaturated fatty acids; WSD: Western-style diet; BDGF: brain-derived growth factor; PA: physical activity;

AUTHOR	Year of publication	Purpose of the study	Result/ Conclusion
Philips C et al. [2]	2017	Importance of lifestyle modification for protecting cognitive function and brain health during aging.	Neuroprotective, neuroplastic, neurogenic, inflammatory effects by diets modification especially curcumin, catechins, resveratrol, and omega-3 fatty acids. It showed a straight relation between increased levels of PA and improved cognition, with increased hippocampal volume seen after chronic exercise.
Poulose SM et al. [5]	2017	To study factors affecting neurogenesis.	Folates, vitamin E, Omega-3 fatty acids, and polyphenols found to mitigate aging and age-related behavioral declines.
Rajaram S et al.  [3]	2019	To gain proofs for vegetarian diets prevent the brain aging process	Consumption of 100% fruit juices, berries, cocoa, coffee, green tea, and nuts to improve cognitive function among elderly adults.
Murphy T et al.  [18]	2014	To study the effects in neurogenesis with calorie restriction (CR), intermittent fasting, polyphenols, and poly-unsaturated fatty acids (PUFAs)	A multitude of dietary regimens and components increase the levels of adult hippocampal neurogenesis and neurotrophins as well as acting to enhance the synaptic function.
Abbink MR et al.  [19]	2020	To investigate Nuturis®(Nutricia) could modulate age-induced alterations in later life.	Early-life exposure to a diet containing Nuturis®, better mimicking some of the chemical structure of lipid globules in mammalian milk. It can modulate the hippocampal response to adult Western-style diet (WSD) at a structural level.
Gelfo F et al. [23]	2018	To gain knowledge about experiences can change brain function.	The transformation of brain health and function can be caused by experiences.
Valero J et al. [7]	2009	To study how microglia leads to neurogenesis.	The hippocampal neurogenesis and microglia connection is modulated by lifestyle choices, maintains brain reserve.
Choi SH et al. [24]	2018	To study the effects of exercise and BDGF.	Elevated BDGF can induce neurogenesis.
Paredes JT et al. [28]	2016	To study how hormones and exercise make a difference in neuroplasticity.	The change of hippocampus neurogenesis based on duration, intensity, and frequency of exercise.
Hueston CM et al. [29]	2017	To study the long term effects of the central nervous system disturbances.	Stress can lead to long term detrimental effects.
Raichlen DA et al. [31]	2017	To study how physical activity transforms the brain function and structure.	Exercise can change the structure and function during the aging process.
Raefsky SM et al. [1]	2017	To explore how the adaptive neuronal response can lead to optimal brain function.	Difficult circumstances, physical activity, and fasting can prevent early aging.
Praag HV et al. [8]	2009	To study how physical activity benefits learning, memory, and cognitive function.	Diet and exercise have synergy in between them and activates the same pathway for neurogenesis
Chieffi S et al. [4]	2017	To access how physical activity can delay aging and its associated neurodegenerative disease.	Physical activity stimulates bio mechanisms that lead to delay in the brain aging process.
Mattson M et al. [9]	2010	To study the increased intake of diet and insulin resistance on brain function.	The cellular stress response triggers during caloric restriction and leads to adaptive changes in the brain.
Bayod S et al. [10]	2014	How WNT pathway activation can cause neurogenesis.	Neuroprotection is present in the activated Wnt pathway.
Yaffe K et al. [6]	2009	To know how to maintain the cognitive function of elderly	Healthy lifestyle adherence maintain  the mental health of elderly
Alam MJ et al. [35]	2018	To study how neurogenesis can preserve hippocampus memory capacity.	A new experience can renew hippocampal circuits and maintain hippocampal memory.
Moon HY et al. [36]	2016	To find out running can release cathepsin B and muscle secretory factors that help in cognitive function.	Memory and neurogenesis were not affected by neurogenesis. However, it enhances the process of adult neurogenesis.
Loprinzi PD et al. [37]	2019	To know whether a high-fat diet can be compensated with exercise.	Exercise can counteract the effect of high fatty food.
Nokia MS et al. [38]	2016	How aerobic exercise can cause adult hippocampal neurogenesis.	Adolescents and adulthood exercise affect differently in the hippocampus.
O’Leary JD et al. [39]	2019	To find out how both exercise and diet can affect chronically stressed mice.	Increase in several immature neurons in the hippocampus with diet and exercise in chronically stressed mice.
Hutton CP et al. [40]	2015	To find out the collective effect of diet and exercise on the hippocampal function of mice those who is stress for a long time.	The combination of dietary supplementation and exercise had multiple beneficial effects, as shown in multiple areas of the brain and as well as increased signaling process in the brain.
Gutierrez RMS et al. [41]	2018	How acrobatic exercise can cause neuroplasticity.	Acrobatic exercise can impact neurogenesis depending on intensity, duration, and frequency.