The role of plant-based foods in brain aging and the role of digital technologies in healthy aging training

This literature review surveys the correlation between the aging of the human brain and the effect of plant-based diets. The search, study and analysis of relevant published research papers revealed that while some cognitive functions remain stable or even improve with advancing age (e.g., crystalline intelligence and judgment abilities), most healthy adults experience age-related declines in a variety of cognitive functions, including spatial orientation, episodic memory, processing speed, language, decision-making abilities, judgment, and abstract thinking. These damaging cognitive changes are amplified and accelerated by common age-related progressive neurodegenerative diseases such as depression and dementia. However, it has become clear that foods and diverse nutrients are biologically interactive, acting in coordination rather than as single physiological agents, hence the true benefit of adherence to the dietary pattern is likely to be due to a complex environment of beneficial effects rather than the contribution of individual components. The current research data suggests that following a healthy dietary programme, such as the Mediterranean diet with the addition of foods rich in fiber, vitamin complexes, minerals and trace elements (strawberries, blueberries, grape juice, etc.) are key factors in increasing the likelihood of healthy brain aging.


Introduction
In recent years, due to a rising concern, multiple studies have been conducted to examine and identify the role of nutrition in the aging of the individual.Meanwhile, the question of whether and to what extent the abundance of certain nutrients can affect both cognitive processes and emotions has been raised.
For thousands of years, nutrition has been deemed essential for the development of the human brain (Gómez-Pinilla, 2008; Puri et al., 2023).During the progress of brain aging, changes in cognitive ability occur, as well as injuries, diseases and mood disorders.While we may not have the ability to intervene in every situation, our lifestyle can play a significant role in preventing some of them (Puri et al., 2023).In recent times, the scientific community has come to recognize that diet and specific nutrients play a significant role in reducing the likelihood of developing neurodegenerative diseases (Gómez-Pinilla, 2008; Puri et al., 2023).A concept that establishes the foundations for new approaches to preventive and therapeutic measures.expression of the brain activity through which thought interacts with external stimuli is also included.All of the above elements are particularly important.In addition, aging affects physical performance involving several activities such as standing, sitting and walking.Consequently, the main criterion of an aging process based on a healthy context is the development of the ability of older people to remain socially active and to perform simple daily activities (Coelho-Junior et al., 2021).

Aging of the brain
Research results highlight the interaction and correlation between the overall functioning of the body and the Central Nervous System (CNS); hence the aging of the brain is not examined separately.For instance, through scientific research it is known that cardiovascular disease affects cognitive decline; thus, reducing the load of the various factors that lead to arteriosclerosis can contribute to maintaining a functional brain in senior years (Bjelland et al., 2003).
Consequently, aging of the human brain is typically characterized by tissue, biochemical and molecular changes (Reuter-Lorenz & Lustig, 2005).Furthermore, Reuter-Lorenz and Lustig (2005) report a study in which cerebellum and cortical DNA-related changes were observed that were highly dependent on the age of the individual.
Oxidative stress has a huge influence on brain function (Bishop et al., 2010 Rink & Khanna, 2011), indicate that the human brain processes about 20% of the main oxygen consumption although it accounts for less than 2% of the total body weight.An important role of the cell is to prevent oxidative damage by developing major defense mechanisms to counteract oxidative stress and oxidative damage (Bishop et al., 2010).However, several diseases associated with cognitive loss, such as Parkinson's disease, have a direct link to the aging of the brain (Goodall et al., 2018).Moreover, age-related motor decline results in a decrease in autonomy (Seidler et al., 2010).
Although the exact causes of brain aging are not yet clarified, it is well known that normal brain aging is related to the premature decline of cognitive functions and more specifically to changes in memory (Murman, 2015).Although the type of dementia most commonly encountered is Alzheimer's disease, accounting for 62% of cases (Prince et al., 2014), the identified indications related to cognitive decline do not fully correspond to the essential criteria for the diagnosis of dementia (Winblad et al., 2004).

Aging of the brain: Depression and dementia
During the progression of brain aging, diseases involving neuronal degeneration as well as depressive disorders are identified (Ali et al., 2016), with depression and dementia being the main brain disorders of concern to the scientific community (National Institute for Health and Care Excellence, 2017).Ali et al. (2016) highlight the role of specific neurological screenings designed to assess daily responses to mainly cognitive activities as well as to identify mental health disorders.The National Institute for Health and Care Excellence, (2017) identifies the main factors associated with the diagnosis of dementia and highlights the need to evaluate attention, concentration, language, orientation, executive function as well as long-term and short-term memory.
According to Luppa et al. (2012), the symptoms of depression reported by older people differ from those experienced by younger adults, with seniors' physical and psychological symptoms being more frequent and accompanied by sleep disturbances, fatigue, loss of appetite and feelings of hopelessness about the future.An additional difference identified within depression in the elderly, as indicated by Polyakova et al. (2014), is that it is more common in women.
Although the scientific community proposes a range of costly pharmacological interventions, they have low response rates in depression (Ilyas & Moncrieff, 2012).Concurrently, research denotes that dementia-related medications do not lead to a cure (Ilyas & Moncrieff, 2012).Consequently, a stronger emphasis tends to be placed on prevention aimed at brain function and general health of the brain rather than on the treatment of related brain disorders (Macready et al., 2010).

Aging and nutrition: A general reference
Diet has an essential role in the prevention of aging-associated diseases, as it contributes to healthy ageing (Kang et al., 2005).Studies suggest that increasing the intake of fruits and vegetables (Kang et al., 2005), such as spinach, strawberries and non-alcoholic red wine (Lampe, 1999), has a beneficial effect on body function (Kang et al, 2005), specifically on biological markers relating to cholesterol levels, blood pressure and immune cell activation (Lampe, 1999), as well as on brain function (Kang et al., 2005) and possibly on brain aging (Lampe, 1999).Lampe (1999) reinforces this insight by pointing out the positive benefits of fruits and vegetables on older people's well-being, highlighting the distinct role they play for women in particular.
Although the role of nutrition in cognitive function and mental health has not been sufficiently examined, particularly in older adults, several studies show a significant association between the two (Goodwin et al., 1983).Research indicates a positive association between increased dietary protein intake with non-verbal learning and reduced incidence of dementia (Roberts et al., 2012) in contrast to reduced protein intake being associated with lower verbal memory in the elderly (Goodwin et al., 1983).Regarding carbohydrates, although the available data is insufficient, it has been found that increasing carbohydrate and sugar consumption results in a decrease in cortical thickness, which is associated with a high risk of mild cognitive impairment and dementia in older individuals (Staubo et al., 2017).

The effects of nutrients on brain function.
The scientific community is interested in investigating the benefits of nutrients and, in particular, vitamins in terms of brain processes (Benzie, 2003;Fekete et al., 2022).Namely, fruits and vegetables compound a wide range of chemicals that are responsible for the basic functions of plant development.Equally, these chemical compounds have a protective effect on human health through their anti-inflammatory and antioxidant actions.Indeed, the intense color of certain fruits and vegetables, for instance, Concord grape juice and blackberry or strawberry extract, indicates these chemicals, which help to reduce age-related motor and cognitive deficits.(Benzie, 2003).

Effect of plant-based food on brain aging
Researchers and scientists concentrate on the treatment and, where possible, the prevention of the decline in cognitive functions that characterize old age.Notably, they are interested in the key role of nutrition and, in particular, plantbased diets (Benzie, 2003).According to Stoll et al. (1996), the consumption of plant food some of which are legumes, fruits (strawberry, raspberry), vegetables (leafy greens like spinach), nuts, spices (such as garlic), as well as extracts like green tea, is associated with a reduction in brain aging-related factors along with the degeneration of cognitive functions (Schindowski et al., 2001).These findings are confirmed by the Nurses' Health Study (Lee et al., 2009), which was conducted among over 15,000 women aged sixty and over.According to this study, the women were divided into two groups.In the first group, the women consumed a small amount of fruits, vegetables and spices as opposed to the women in the second group who had a normal intake.The first group showed negative effects on cognitive brain function (Lee et al., 2001) confirming that overall vegetable consumption, specifically the intake and consumption of green leafy vegetables such as lettuce and cruciferous vegetables such as broccoli and cauliflower, is associated with less cognitive decline (Kang et al., 2005).
In addition, Zeghichi et al. (2003) acknowledge the important role of the Mediterranean diet and, notably, the traditional Cretan diet, which is characterized by an increased intake of greens, in brain health.Another important observation made by Zeghichi et al. (2003) is that, since a large proportion of the vegetables used are semi-cultivated, their high polyphenol content gives them a strong antioxidant effect.

The Mediterranean diet
The Mediterranean diet refers to the eating habits of people living in the periphery of the Mediterranean Basin, which have been passed down through the generations due to the cultural changes that have taken place (Bach-Faig et al., 2011).It is characterized by a high intake of plant foods such as fruits and legumes, a moderate consumption of dairy products, eggs, fish and seafood and a very low consumption of red meat with olive oil being a very good source of fat and a moderate consumption of red wine during main meals being recommended (Bach-Faig et al., 2011).
Bach-Faig et al. ( 2011), conducted a study in which they found that people who followed the Mediterranean diet for long periods observed positive effects on their physical health by reducing the incidence of chronic diseases and cardiovascular diseases.Concurrently, the Mediterranean diet, through its potent antioxidant and anti-inflammatory nutritional components, exerts positive effects on metabolism (Bach-Faig et al., 2011).Moreover, there has been a significant improvement in the physical performance of adults (Valls-Pedret et al., 2015) and a significant decrease in physical dysfunction in older individuals (Bach-Faig et al., 2011).The Mediterranean diet's beneficial effect on brain aging has also been established through the findings of magnetic resonance imaging (MRI), which demonstrated greater thickness of the cerebral cortex associated with a reduced risk of cognitive decline (Staubo et al., 2017).At the same time, the international scientific community highlights the fundamental role of the Mediterranean diet in preventing depression in older people (Psaltopoulou et al., 2013).Psaltopoulou et al. (2013) underline the need for more targeted research on the influence of this diet on the overall health of the human brain.

Concord grapes: Their effects on human memory
As the global human population ages rapidly (Fekete et al., 2022), nutrition is a crucial factor in creating specific strategies to enhance healthy brain aging (Krikorian et al., 2008).An important nutrition component that has been shown to have a positive influence on brain function is the consumption of grape juice, specifically Concord, Niagara or Generic White grape juice (Krikorian et al., 2018).In a study conducted by Krikorian et al. (2008) between two groups, one receiving regular juice and the other receiving placebo juice, they found significant improvement in cognitive ability in those who received Concord and Niagara compared with those who received placebo juice.
Furthermore, these researchers examined the relationship between the consumption of grape juice by older people and their cognitive brain functions.The results showed that these elderly people, who suffered from impaired memory rather than dementia, had significantly benefited in terms of their cognitive function (Krikorian et al., 2008).In this study, two groups participated, one of which received a placebo juice.In the elderly who received Concord grape juice, an improvement in learning processes was observed, which supports the hypothesis that Concord grape juice may have an effective and beneficial effect in maintaining memory function and reversing behavioral deficits (Krikorian et al., 2008).

Blackberries -berries and strawberries: Two powerful allies against brain aging
The high metabolic load of the human brain makes it very vulnerable to oxidative damage (Ganguli et al., 2000).Antioxidants derived from plant foods that have a strong antioxidant effect on brain function (Benzie, 2003) have led to the creation of very popular "antioxidant diets" that are recommended by the international scientific community for their positive effects on neural brain function (Martín-Aragón et al., 1997).
Fruits are a source of anti-inflammatory compounds that have a beneficial effect on the body (Fekete et al., 2022;Galimberti & Scarpini, 2011), reducing the damage caused by oxidative stress, which is considered an important mechanism of cognitive decline (Mecocci, 2004).Plant foods rich in antioxidants, in particular polyphenols and flavonoids, the largest subclass of polyphenols, are found in high concentrations in berries and strawberries (Duffy et al, 2008), both of which were found to significantly reduce inflammation in neurons and work in reverse cognitive decline (Joseph et al., 2009).Moreover, research shows that berry and strawberry extracts, due to their ability to maintain metabolic homeostasis, have a protective effect on lipid peroxidation within membranes, while affecting synaptic plasticity (Andres-Lacueva et al., 2005), exerting a positive effect on learning and memory processes (Duffy et al., 2008).Other micronutrients with antioxidant activity are the anthocyanins in berries (Andres-Lacueva et al.

Other diet-related factors contributing in brain aging
An interesting detail highlighted by Gómez-Pinilla, (2008) is that, besides diet, other aspects of daily living, such as exercise, have had an essential role in determining the process of brain evolution and cognitive capacity.Physical exercise, coupled with the consumption of certain nutrients, such as those included in antioxidant foods, has a profound impact on brain health by affecting molecular systems or cellular processes; vital elements for the maintenance of cognitive function (Vaynman & Gómez-Pinilla, 2006).Moreover, Molteni et al. (2002) place emphasis on the consumption of high fat diets that portray today's lifestyle in industrialized societies.The impact of these diets is detrimental for both the body and the brain (Molteni et al., 2002).Vaynman et al. (2006), using the example of Brain-derived neurotrophic factor (BDNF), illustrate the way in which the energy transferred from foods to neurons is vital to brain function control.By consuming high fat diets, BDNF, which is connected with cognitive and metabolic regulation (Nawa et al., 1995), decreases in the hippocampus resulting in deterioration of learning and memory (Molteni et al., 2002).Fekete et al. (2022) and Gómez-Pinilla (2008) focus their attention on the positive impact a caloric restriction may have on cognitive function.In line with this finding, Logroscino et al. (1996) and Luchsinger et al. (2002) ascertain that a lowcaloric diet is positively associated with lower risk of contracting neurodegenerative diseases, like Alzheimer's and Parkinson's disease.In parallel, special attention should be given to the nutritional load of a low-caloric diet to prevent malnutrition (Gómez-Pinilla, 2008).
An interesting fact emphasized by Gómez-Pinilla ( 2008) is the comparison between Western countries with middleand low-income countries, like India, in relation to the amount of food they consume.As stated previously, a diet based on caloric restriction may have beneficial effects for the overall health.Excessive food consumption in Western countries leads to an increase in obesity rates, which is equally damaging as limited access to food.Middle-and lowincome countries, such as India, although they have limited resources, they present a reduced prevalence of diet-and age-related neurological diseases like Alzheimer's disease (Gómez-Pinilla, 2008).However, a report conducted in the states of India, covering the period from 1990 to 2019 about age-related neurological diseases, indicated a more than double increase in the cases (India State-Level Disease Burden Initiative Neurological Disorders Collaborators, 2021).Although this finding needs further investigation, changes in dietary patterns (processed foods replace fiber-rich foods) and modification of their lifestyle, with a decrease in exercise, might be a leading cause (Nitika et al., 2014).

Conclusion
The purpose of this literature review is to highlight the positive connection between a plant-based diet and the process of healthy brain aging.As brain aging progresses, tissue, biochemical and molecular changes occur resulting in the development of several neurodegenerative diseases, namely, Alzheimer's and Parkinson's disease as well as depression and dementia.The scientific community is emphasizing a healthy lifestyle approach and a plant-based diet as means of prevention given the high cost and low response rates of pharmacological interventions.Adopting a diet model based on the Mediterranean diet, along with the consumption of foods rich in antioxidants, may result in a delayed decline in cognitive function.The prevalence of age-related neurological diseases between the West and middle-and low-income countries was brought to attention at the same time, exploring the potential impact of Western lifestyle adaptation on these countries.In line with these findings, further investigation regarding dietary interventions for brain aging, as well as the influence of the Western culture on the brain and overall health, is proposed.

Compliance with ethical standards
Furthermore, the Mediterranean diet is strongly associated with cognitive function in adults generally (Valls-Pedret et al., 2015) and in older adults in particular (Bach-Faig et al., 2011).This dietary pattern has a direct correlation with the reduction of cognitive impairment and with improved cognitive function in adults (Valls-Pedret et al., 2015) as well as with the deceleration of cognitive decline and hence the development of mild cognitive impairment and dementia in the elderly (Bach-Faig et al., 2011).
, 2005; Fekete et al., 2022), which, through the blood-brain barrier, are located in the hippocampus where memory and learning reside (Andres-Lacueva et al., 2005).Andres-Lacueva et al. (2005) highlight four specific factors whereby these types of foods benefit brain function, namely, free radicals, inhibition of stress signals, activation of protective signals and protein pathways activation.Finally, Devore et al. (2012) found that flavonoids, through increased consumption of strawberries and blueberries, have a direct correlation with delaying cognitive decline in older adults.