Brain health paves the way to healthy aging and longevity

‍Highlights:

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• The World Health Organization describes brain health is an emerging concept that emphasizes brain functionality as a key to complete life
• Aging affects the functionality of the brain in multiple ways on multiple levels – morphological, vascular, cellular, and biochemical 
• Brain aging increases the risk of many dangerous neurological conditions and significantly worsens the quality of life by disrupting the cognitive performance
• Aging changes can be counteracted by lifestyle changes, helping to sustain brain health for longer

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Introduction

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The brain emerges as an incredibly complex organ whose functionality influences every aspect of human life. How we perceive the world, process information, and form our personality – all that work belongs to the brain. And that is not to mention the control of multiple unconscious processes, including mood, temperature, motor control, and many others. As we age, the brain functionality gradually deteriorates leading to suppressed cognitive function, neurodegenerative diseases, and lower quality of life. This leads us to the importance of preserving and nurturing brain health. In this article, we will discuss what comprises brain health and how it is connected with longevity and aging.

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What is a healthy brain?

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Brain health as a concept envelops neural development, plasticity, functionality, and ability to recover during the life course. There is no single robust definition of brain health. WHO (World Health Organization) describes good brain health as a state in which an individual is aware of their abilities and can adjust or optimize cognitive, emotional, behavioral, and psychological functioning according to a situation (1). The US Centers for Disease Control and Prevention defines brain health through the performance of the mental processes of cognition, such as the ability to remember, learn, judge, and use language (2). Another definition by the American Heart Association focuses on the absence of known brain or other organ system diseases as a criterion of brain health (3). However different the existing definitions might be, they all underline the importance of brain health as a prerequisite to freely performing any activities and enjoying the desired quality of life. 

Three levels of brain functionality are crucial for all aspects of our daily lives (4):

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• Interpretation of senses and control of movement,
• Maintenance of cognitive, mental, and emotional processes,
• Maintenance of behavior and social cognition.

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Brain and aging

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Through the course of life, the brain gradually accumulates multiple aging effects on molecular, cellular, vascular, and morphological levels. The brain shrinks in volume with age, particularly in the frontal cortex. It has been found that brain volume starts decreasing after 40 at a rate of around 5% per decade, and this decline rate increases after 70 (5). The 90+ longitudinal study (6) demonstrated that a typical brain of a 90-year-old person is 100 or more grams lighter than the typical 40-year-old brain.

The shrinking of brain tissues is accompanied by the aging of vasculature and an increased tendency for hypertonia (high blood pressure), leading to a growing risk of stroke and ischemia (7). Reduced vascular function leads to impaired glucose metabolism and reduced input of oxygen. Multiple evidence suggests that vascular factors contribute to the development of several types of dementia. 

On a biochemical level, aging leads to the disruption of two vital groups of signaling molecules – hormones and neurotransmitters. The neurotransmitters most connected to the aging brain are dopamine and serotonin. Dopamine levels decline by around 10% per decade since the beginning of adulthood, which leads to a gradual disruption of motor and cognitive function (8). Similarly, serotonin levels fall with age leading to a decreased brain plasticity. Other factors linked to brain aging include increased monoamine oxidase levels (an enzyme that participates in neurotransmitter degradation), calcium dysregulation, neuroinflammation, dysfunction of blood-brain barrier, mitochondrial dysfunction, and heightened production of reactive oxygen species. Hormone levels also decrease in the aging brain, which was shown to affect cognitive processes, particularly in women in menopause. Research demonstrates significant gender differences in human brain diseases (9). For example, women have a significantly higher incidence of Alzheimer’s disease even when accounting for longer life expectancy. Growth hormone levels also tend to decline, subsequently leading to worsened cognitive performance and stress regulation (10).

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Brain health impacts longevity and well-being

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The processes mentioned above lead to a brain health decline, which may manifest itself as multiple neurological and neurodegenerative conditions. These conditions include various types of dementia, cerebrovascular disease, multiple sclerosis, Parkinson’s disease, brain tumors, and neuroinfections. The global burden of these conditions is high as they are the leading cause of disability-adjusted years and the second leading cause of death globally (1). Nine million deaths per year as of 2016 were caused by neurological disorders (11). The three main contributors are stroke, migraine, and dementias. Due to an increasingly large aging population, Parkinson’s disease is becoming the fastest growing neurological disorder. 

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Even in cases when a person does not develop a neurological condition, brain health decline can significantly lower the quality of life. The most affected cognitive process is memory, particularly episodic memory. Episodic memory stores information about events and tends to decline from middle age. Main effects of “normal aging” are the decline in recall and recognition speed (12). Besides, brain aging affects all other aspects of brain health, leading to emotional dysregulation, decreased motor control, and communication and social skills disruption.

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Defying brain aging

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Even though brain health decline is considered a part of aging, it does not necessarily have to be. Several longitudinal studies (13,14) identified a particular subgroup of elderly adults the researchers called cognitive super-agers. At the age of 80-90+, their cognitive abilities were comparable to those “normal” for 20-30 years old, especially episodic memory. Several explanations were suggested for this remarkable finding, including genetic predisposition and environmental factors. Investigations (15,16) showed that super-agers indeed have distinct genetic and anatomic markers. Specifically, people in this group showed none of the common age-related brain atrophy patterns, had a lower frequency of the e4 variant of APOE (apolipoprotein E, e4 variant strongly elevates the risk of developing Alzheimer’s disease), and their brain showed fewer markers of dementia. The studies to estimate the influence of lifestyle factors on cognitive super-aging are still ahead. Still, this research shows that what is perceived as “unavoidable” with the brain aging is not necessarily so.

Though not everyone might be a cognitive super-ager, the already mentioned 90+ study (6) managed to identify a range of factors common to people with low risks of developing dementia. Activities including mental, social, and physical components have been linked with a reduced risk of dementia. Interestingly, consumers of 200+ mg of caffeine per day had a 40% reduced risk of dementia. Long-term supplementation with the antioxidants also correlated with a reduced risk of cognitive decline. Generally, adherence to a healthy lifestyle (even in the presence of chronic diseases) has been associated with better brain health and lower mortality (6).

Key strategies for brain health

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As the first signs of brain aging start to show from middle age, it is crucial to intervene as early as possible. There are multiple things you can advise your patient or client that can help preserve their brain health, including:

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• Mental stimulation (such as puzzles, new games, and lifelong learning in general). This will help them to increase neuroplasticity and build a protective functional reserve of the brain (17)
• Exercises, especially aerobic ones that can improve their vascular health (18)
• Improving their diet. The research shows that the Mediterranean-DASH diet, in particular, protects from cognitive impairment and dementia (19).
• Monitor blood pressure, low-density cholesterol, and blood sugar levels – all these factors are strongly associated with brain health decline (20). 
• Avoiding tobacco and alcohol. Tobacco usage is harmful in all its forms, and excessive use of alcohol is considered a major risk for dementia.
• Advice your clients to be conscious of their mental health and emotional well-being.
• Explain to them that strong social networks are highly beneficial for lowering risks of cognitive decline and increasing life expectancy.

Conclusions

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The brain is one of the main “tools” with which our body can perceive the world, interact with it, and form the notion of self. Brain health is, thus, crucially important for every aspect of our life. Being aware of the importance of brain health and employing strategies to maintain it will help your patients or clients increase their chances for healthy longevity.

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References

1.         WHO: Brain Health [Internet]. [cited 2022 Apr 20]. Available from: https://www.who.int/health-topics/brain-health#tab=tab_1

2.         Centers for Disease Control and Prevention. What is a healthy brain? New research explores perceptions of cognitive health among diverse older adults [Internet]. [cited 2022 Apr 20]. Available from: https://www.cdc.gov/aging/pdf/perceptions_of_cog_hlth_factsheet.pdf

3.         Gorelick PB, Furie KL, Iadecola C, Smith EE, Waddy SP, Lloyd-Jones DM, et al. Defining Optimal Brain Health in Adults: A Presidential Advisory From the American Heart Association/American Stroke Association. Stroke [Internet]. 2017 Oct [cited 2022 Apr 20];48(10). Available from: https://www.ahajournals.org/doi/10.1161/STR.0000000000000148

4.         Wang Y, Pan Y, Li H. What is brain health and why is it important? BMJ. 2020 Oct 9;m3683.

5.         Scahill RI, Frost C, Jenkins R, Whitwell JL, Rossor MN, Fox NC. A Longitudinal Study of Brain Volume Changes in Normal Aging Using Serial Registered Magnetic Resonance Imaging. Arch Neurol. 2003 Jul 1;60(7):989.

6.         Paganini-Hill A, Kawas CH, Corrada MM. Lifestyle Factors and Dementia in the Oldest-old: The 90+ Study. Alzheimer Dis Assoc Disord. 2016 Jan;30(1):21–6.

7.         Peters R. Ageing and the brain. Postgrad Med J. 2006 Feb 1;82(964):84–8.

8.         Mukherjee J, Christian BT, Dunigan KA, Shi B, Narayanan TK, Satter M, et al. Brain imaging of18F-fallypride in normal volunteers: Blood analysis, distribution, test-retest studies, and preliminary assessment of sensitivity to aging effects on dopamine D-2/D-3 receptors. Synapse. 2002 Dec 1;46(3):170–88.

9.         Compton J, Van Amelsvoort T, Murphy D. HRT and its effect on normal ageing of the brain and dementia: HRT, ageing of the brain and dementia. Br J Clin Pharmacol. 2001 Dec;52(6):647–53.

10.       Ashpole NM, Sanders JE, Hodges EL, Yan H, Sonntag WE. Growth hormone, insulin-like growth factor-1 and the aging brain. Exp Gerontol. 2015 Aug;68:76–81.

11.       Feigin VL, Nichols E, Alam T, Bannick MS, Beghi E, Blake N, et al. Global, regional, and national burden of neurological disorders, 1990–2016: a systematic analysis for the Global Burden of Disease Study 2016. Lancet Neurol. 2019 May;18(5):459–80.

12.       Nyberg L, Lövdén M, Riklund K, Lindenberger U, Bäckman L. Memory aging and brain maintenance. Trends Cogn Sci. 2012 May;16(5):292–305.

13.       Gefen T, Shaw E, Whitney K, Martersteck A, Stratton J, Rademaker A, et al. Longitudinal Neuropsychological Performance of Cognitive SuperAgers. J Am Geriatr Soc. 2014 Aug;62(8):1598–600.

14.       Sohrabi HR, Gardener SL, Weinborn M, Shen K, Rainey‐Smith SR, Brown BM, et al. [O5–05–01]: COGNITIVE SUPER‐AGING VERSUS TYPICAL AGING IN COMMUNITY‐DWELLING OLDER ADULTS: LONGITUDINAL TRAJECTORIES IN GLOBAL CORTICAL THICKNESS OVER SIX YEARS. Alzheimers Dement [Internet]. 2017 Jul [cited 2022 Apr 22];13(7S_Part_30). Available from: https://onlinelibrary.wiley.com/doi/10.1016/j.jalz.2017.07.531

15.       Rogalski EJ, Gefen T, Shi J, Samimi M, Bigio E, Weintraub S, et al. Youthful Memory Capacity in Old Brains: Anatomic and Genetic Clues from the Northwestern SuperAging Project. J Cogn Neurosci. 2013 Jan 1;25(1):29–36.

16.       Harrison TM, Weintraub S, Mesulam MM, Rogalski E. Superior Memory and Higher Cortical Volumes in Unusually Successful Cognitive Aging. J Int Neuropsychol Soc. 2012 Nov;18(6):1081–5.

17.       Kawashima R, Okita K, Yamazaki R, Tajima N, Yoshida H, Taira M, et al. Reading Aloud and Arithmetic Calculation Improve Frontal Function of People With Dementia. J Gerontol A Biol Sci Med Sci. 2005 Mar 1;60(3):380–4.

18.       Cotman C. Exercise: a behavioral intervention to enhance brain health and plasticity. Trends Neurosci. 2002 Jun 1;25(6):295–301.

19.       Elsayed MM, Rabiee A, El Refaye GE, Elsisi HF. Aerobic Exercise with Mediterranean-DASH Intervention for Neurodegenerative Delay Diet Promotes Brain Cells’ Longevity despite Sex Hormone Deficiency in Postmenopausal Women: A Randomized Controlled Trial. Corbi G, editor. Oxid Med Cell Longev. 2022 Apr 4;2022:1–8.

20.       Solfrizzi V, D’Introno A, Colacicco AM, Capurso C, Todarello O, Pellicani V, et al. Circulating biomarkers of cognitive decline and dementia. Clin Chim Acta. 2006 Feb;364(1–2):91–112.

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