Super Agers And Aging Brains
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Longevity and anti-aging are evergreen topics in the health and wellness realm. Mechanisms and factors that decrease the rate of cellular aging have been studied extensively in animal models over several decades. More recently, progress has been made in better understanding the aging process of one of our most important organs: the brain. Cognitive decline is a phenomenon observed in a large proportion of aging individuals, and discovering ways to delay its onset and slow its progression has been an ongoing effort. What distinguishes people whose brains age well from their forgetful friends? What can we do to assist in keeping our memory sharp, even into old age? This article will discuss brain aging and physiological differences that have been observed in the brains of people who have maintained supreme cognition into old age, as well as evidence-based lifestyle interventions that are associated with improved cognition and brain health well into old age.
A gradual reduction in total brain volume and the thinning of specific brain areas important for cognitive and motor function are typically observed in normally aging individuals. In particular, volume reductions in the main brain regions associated with cognitive function, the frontal lobe and the hippocampus, have been observed in many different studies. The hippocampus which is responsible for memory formation and retrieval has been shown to decrease in volume at about 60 or 70 years of age. Similar volume reduction have been observed in the cerebellum, a brain area important for motor function and autonomic function and the thalamus, as a major relay center for many different brain areas. Age-related loss of white matter, the brain component made up by connections between cortical areas may further contribute to a slowing in cognitive function and sharpness.
“Both the larger neuronal size, as well as the resistance to abnormal tau protein formation compose the biological signature helping SuperAgers keep a sharp memory into old age.”
In a recently study published in the Journal of Neuroscience, the investigators analyzed post mortem brains of so-called “SuperAgers” and observed a significant difference in the size of specific neurons found in the entorhinal cortex. The SuperAgers in this study averaged 91 years of age and scored similarly to a control group that was 20 – 30 years younger in memory tests. The significantly larger neurons of the SuperAgers were located in a specific part (layer II) of the entorhinal cortex, a brain region exhibiting early signs of Alzheimer’s disease. The entorhinal cortices of individuals showing greater cognitive impairment with age were observed to have twice the amount of neurofibrillary tangles, also known as tau proteins, in that brain area than SuperAgers did. Tau proteins are found in brains from both healthy individuals and those with Alzheimer’s disease, but are misfolded and abnormally shaped in the patients only. The normal tau protein forms part of a structure called a microtubule. One of the functions of the microtubule is to help transport nutrients and other important substances from one part of the nerve cell to another. Based on their findings, the authors hypothesized that both the larger neuronal size, which may correspond to greater intra- and interneuronal information processing, as well as the resistance to abnormal tau protein formation compose the biological signature helping SuperAgers keep a sharp memory into old age.
“The MIND diet is characterized by a high intake in whole grains, fresh vegetables and fruit (berries in particular), legumes, nuts, occasional fish and poultry, extra virgin olive oil for added fat, as well as a limited consumption of red wine.”
Several large scale epidemiological studies have shown that lifestyle factors including exercise, eating a healthy diet, sleeping well, managing stress, and supportive social connections are associated with improved brain health and a slower age-related rate of cognitive decline. Exercise has been associated with decreased risk for developing Alzheimer’s disease by reducing systemic inflammation, causing an increase in cerebral blood flow, and affecting the levels of certain brain chemicals such as neurotrophin and amyloid beta. In order to produce brain health enhancing effects, it has been recommended that individuals do a combination of resistance training and aerobic exercise of about 45 minutes as many days a week as possible. Adhering to a Mediterranean type diet has also been associated with a decreased rate of cognitive decline in a variety of large-scale observational studies. One of such diets is the MIND (Mediterranean-DASH Diet Intervention for Neurodegenerative Delay) diet, which has been associated with reduced risk for developing Alzheimer’s disease. The MIND diet is characterized by a high intake in whole grains, fresh vegetables and fruit (berries in particular), legumes, nuts, occasional fish and poultry, extra virgin olive oil for added fat, as well as a limited consumption of red wine. Furthermore, sleeping well and managing stress which both contribute to maintaining a healthy circadian rhythm have also been associated with better brain health and cognition into old age. Finally, social support has been associated with a stress-buffering effect and decreases in amygdala volume (a deep brain structure playing a key role in fear and stress responses) in older individuals.
“Paying attention to key lifestyle factors, including a healthy diet, regular exercise, normal sleep, stress management, and social connections is critical in supporting optimal brain health into old age.”
When viewed together, taking care of a healthy brain requires similar interventions as caring for a healthy gut. The gut-brain connection in fact may be of critical importance to healthy brain aging, as low grade chronic inflammation in the gut and metabolic endotoxemia are important risk factors for neuroinflammation and neurodegeneration at the brain level. Importantly, paying attention to key lifestyle factors, including a healthy diet, regular exercise, normal sleep, stress management, and social connections is critical in supporting optimal brain health into old age.