Given the large number of persons reaching the age of 65 in the United States, there is a need for a multidisciplinary study on variables impacting the trajectory of cognition and brain aging in older adults. Researchers explore the aggregate effect of food and exercise treatments on age-related cognitive and brain health changes in a recent study published in Nutrients.
Cognitive deterioration as we age
Along with poorer semantic and episodic memory, one of the primary cognitive deficiencies identified in older persons is slower processing speed. Working memory, which actively retains knowledge in the near term to facilitate goal-directed decision-making, likewise diminishes with age.
In senior age, decreased working memory leads to decreased executive functioning. Aging impacts both crystallized and fluid intelligence because of anatomical and functional changes in the brain.
Reduced gray matter volume and cortical thickness are two structural changes in the brain related to aging. Gray matter volume, a measure of neuronal and glial cell bodies, decreases in volume throughout numerous brain areas, including the hippocampus’s medial temporal lobe and entorhinal cortex, as people age. Age-related reductions in hippocampus volume, caused by neuronal cell death and a decrease in neurogenesis, are linked to poor cognitive performance on memory, spatial learning, and emotional regulation tasks.
Diet and exercise have an impact on aging.
Understanding the link between nutritional consumption and neuronal function, neurometabolic processes, and cognitive decline is critical.
There is mounting evidence that nutrients from different dietary categories have synergistic effects that go beyond the effects of individual nutrients. Green salad, for example, absorbs more vitamins when served with olive oil and vinegar rather than fat-free ranch dressing.
So far, the most commonly cited diets in the literature are the Mediterranean diet (MeDi), Dietary Approaches to Stop Hypertension (DASH), and Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND). Each of these diets appears to enhance neurological aging indicators such as cell membrane and vascular integrity, inflammation, resolution, and oxidation, as well as lipid and glucose metabolism.
There is substantial evidence that the MeDi and MIND diets are connected with both general and domain-specific aspects of cognitive performance. Several studies, for example, have linked the MeDi diet to improved attention and long-term memory. Adherence to the MIND diet is also connected with improved visuospatial ability, perceptual quickness, and executive function.
The effect of the ketogenic diet (KD) and intermittent fasting (IF) on cognition and brain function has also been extensively researched, as weight loss diets appear to increase cognitive performance. Similarly, weight loss through bariatric surgery improves attention, memory, and executive function.
Exercise, in addition to food, has been shown to improve cognition in a prior study in which overweight and obese people participated in a one-year behavioral weight reduction intervention. These patients were on a low-energy diet, a low-energy diet with 150 minutes of moderate-intensity activity per week, or a low-energy diet with 250 minutes of exercise per week.
Both groups lost weight significantly after the intervention. More precisely, the high-exercise group outperformed the other two research groups on the Iowa Gambling Task (IGT) reward. Even if there were no weight reduction advantages, increased exercise with behavioral weight loss regimens provided an extra effect on executive functioning.
Walking is the most common type of endurance exercise among older persons, followed by jogging, running, swimming, and cycling. Higher levels of endurance fitness are linked to decreased age-related brain volume loss.
Randomized controlled experiments on the effects of endurance exercise on cognition have yielded conflicting results. However, all data demonstrates that endurance exercise improves cognitive ability, visual attention, and memory in older individuals, promotes brain plasticity, and reduces hippocampal atrophy.
Similarly, a recent comprehensive study discovered that resistance training improved executive and global cognitive skills in older persons. This type of exercise also improved memory, albeit only a little, but did not significantly increase attention. Furthermore, tri-weekly resistance training improved general cognitive capacities more than biweekly resistance training.
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There has been no indication of an interfering impact between aerobic and weight exercise. However, there is a scarcity of research comparing resistance or combination exercise to a non-exercise control. As a result, it is unclear which activities should be given to older persons in order to maintain and improve cognition and brain health.
Yoga and other behavioral therapies tend to slow age-related and neurodegenerative deterioration. Yoga favorably improved the structure and function of the hippocampus, prefrontal and cingulate cortex, amygdala, and neural networks in one assessment of the benefits of practicing yoga on brain architecture, function, and cerebral blood flow.
A recent review of the literature on the effects of tai chi, a traditional Chinese martial art, on brain structure and neurobehavioral changes discovered that this type of exercise increased cortical grey matter volume, improved neural activity and homogeneity, and increased neural connectivity in the frontal, temporal, and occipital lobes, cerebellum, and thalamus.
All of the diets examined in this research addressed issues linked to aging and neurodegenerative disorders such as Alzheimer’s disease and related dementias (ADRD). Exercise, depending on the type and intensity, was found to improve brain vascularization, neurotransmitter modulation, growth factors, and neurogenesis.