Hidden Factors that Affect Cognition

by CP Staff

According to New York University Medical Center’s Alzheimer’s Disease Center,¹ a significant number of elderly individuals live with common age-related memory impairment (ARMI), which can be described as mild memory problems that are part of the normal aging process. The inability to promptly recall short-term memories is increasingly common among people of the baby-boomer generation (or people born between 1946 and 1964), a group that now represents the largest segment of the U.S. population.² Although many of these problems only mildly interfere with daily life, they may be troublesome to the person experiencing them.

As we age, this issue of memory and cognitive function becomes increasingly important, and even vital to our quality of life.

Clearly, it is advisable to take any steps possible to promote healthy cognitive function while aging. Some of these steps may not be readily apparent since there are health-related factors that don’t at first glance seem related to cognition. This article will identify five of those hidden factors, including 1) air pollution 2) blood sugar 3) stress 4) homocysteine and 5) sleep.

Air Pollution

Air pollution is well-known for its deleterious effects on human health, especially respiratory health. Animal research also suggests that it may have a similar deleterious effect on cognitive function. This was seen in a study where researchers concentrated particulate matter to emulate levels of air pollution similar to those seen in regions with high levels of pollution.³ A group of mice was then exposed to the polluted air for six hours per day, five days per week for 10 months. Concurrently, another group of mice were exposed to filtered air. The mice then underwent a battery of tests assessing learning and memory, and mood. The results were that the mice that breathed the polluted air were slower to learn, and gave up more quickly, a sign of low mood.

An analysis of the mice hippocampi revealed that those exposed to polluted air had fewer connections between neurons, as well as high levels of cytokines and TNF-alpha, molecules known to promote the inflammatory process. The researchers suggest that mild, chronic, low-grade inflammation may have occurred in the mice exposed to particulate matter, reducing the neuronal connections and in turn lowering the rats’ cognitive abilities. Although the study was conducted on mice, exposure to air pollution may turn out to have a similar effect on humans.

When it is not possible or practical to avoid living or working in regions with high levels of air pollution, the use of air filtering devices to improve air quality and reduce particulate matter is advisable.

Blood Sugar

Blood sugar is another little recognized factor that affects cognitive health. Americans as a whole tend to consume an excess of refined carbohydrates, resulting in elevated blood sugar levels. Aside from the obvious nutritional imbalance associated with this situation, this ongoing increase in blood sugar levels provides an opportunity for the production of glycated proteins. This term simply means that glucose has attached itself to a protein. For example, glucose can attach itself to the protein in red blood cells’ hemoglobin and form glycated hemoglobin, also called hemoglobin A1C, HbA1C or just A1C for short. If this process continues to excess, it eventually forms compounds called Advanced Glycation End Products (AGEs). These AGEs become permanent fixtures in cells. AGEs-impregnated cells are very reactive and react with one another, and other proteins. In the case of blood capillaries, their presence can result in the walls of the capillaries thickening, eventually causing the vessels to be blocked off.⁴

In addition, an ongoing increase in blood sugar levels is associated with declines in cognition, including learning and memory, mental flexibility, and mental speed. The degree of decrement tends to be modest and evolves slowly as a person ages. AGEs may also contribute to the process of cognitive decline since they damage organs, including the brain, by increasing oxidative stress and inflammation.⁵

Healthy lifestyle choices may do much to help maintain healthy blood glucose levels and avoid the production of AGEs. Such choices may include the consumption of a Mediterranean diet and exercise. The Mediterranean diet is based upon the diets of at least 16 countries that border the Mediterranean Sea. Although there are many differences in culture, ethnic background, religion, economy and agricultural production which result in variations in food intake among the population groups, there is still a common Mediterranean dietary pattern which includes: 1) high consumption of fruits, vegetables, bread and other whole grain cereals, potatoes, beans, nuts and seeds, 2) olive oil is an important monounsaturated fat source, 3) dairy products, fish and poultry are consumed in low to moderate amounts, and little red meat is eaten, 4) eggs are consumed zero to four times a week, and 5) wine is consumed in low to moderate amounts. Consequently, this diet plan tends to be lower on the glycemic index (i.e., a numerical system of measuring how fast a carbohydrate triggers a rise in circulating blood sugar), with a good balance of dietary fats.⁴ Research has shown that the Mediterranean diet promotes healthy cardiovascular function,^6-7 while helping provide good control over blood sugar levels.⁸

Data from 20 studies⁹ present a consistent picture indicating that regular physical activity substantially promotes healthy blood sugar levels. In fact, a high level of physical activity is associated with a 20-30 percent reduction in risk of high blood glucose levels.⁹ Several studies also have demonstrated that exercise helps to reduce or prevent cognitive deterioration among older adults.¹⁰

Supplementing with GluControl™, which contains nutrients and botanicals used to support and promote healthy blood sugar balance, can enhance the blood-sugar-supporting effects of the lifestyle strategies mentioned above. The rationale for the inclusion of the specific nutraceuticals in GluControl is as follows:

• Vitamin C – High blood sugar levels increase urinary losses of vitamin C.^11-12 Vitamin C may help promote a healthy balance of glycation.¹³
• Vitamin E – Some research¹² has shown that plasma vitamin E levels are significantly lower in subjects with high blood sugar levels. Research also suggests that daily supplementation with vitamin E promotes healthy levels of hemoglobin A1c¹⁴ already within normal ranges.^15-16
• Vitamin B6 – Many individuals with high blood glucose levels have low blood levels of vitamin B6.¹⁷ Research has shown that vitamin B6 can reduce the oxidative stress-induced structural and functional protein damage associated with glycation and AGEs.^18-21
• Quercetin – Quercetin may help reduce oxidation associated with high blood sugar levels.²²
• Bitter Melon – Bitter melon may help significantly support healthy blood sugar levels within a normal range.²³
• N-Acetyl Cysteine – NAC may help reduce intracellular oxidative stress and the oxidation of blood sugar.²⁴
• Goat’s Rue – Goat’s rue (Galega officinalis) is a plant traditionally used for promoting healthy blood sugar levels within a normal range.^25-26
• Cinnamon – Cinnamon may significantly support healthy blood sugar levels within a normal range.²⁷
• Vanadium – Vanadium supports the effects of insulin,²⁸ and promotes healthy blood sugar levels within a normal range.²⁹

Stress

Stress affects cognition in a number of ways, producing long-term changes in dendritic structure (i.e., neurons) that last for weeks. Prolonged exposure to stress leads to loss of neurons, particularly in the hippocampus. Evidence suggests that stress-related cognitive impairments included declarative memory and emotionally laden memories.³⁰ Research has also demonstrated older men with high levels of the stress hormone epinephrine are more likely to suffer from mild cognitive impairment than are older men with normal levels.³¹ Likewise, common, everyday stress in combination with major stressful events may exert a cumulative effect over a lifetime that exacerbates cognitive decline.³²

The ill effects of stress on cognitive performance were recently elucidated in a symposium on stress modulation of cognitive and affective processes, which was held during the 2010 workshop on the neurobiology of stress (Boulder, CO, USA).³³ The four presenters addressed a number of specific cognitive and affective factors that are modulated by exposure to acute or repeated stress. These included the adverse effects of various repeated stress situations on cognitive flexibility, responses to repeated audiogenic (i.e., loud sounds) stress exposures, the modulation and extinction of fear memories, and human decision-making processes in response to exogenous glucocorticoid hormone administration.

Avoidance of stress or stressful situations is not always possible. Developing effective strategies for dealing with stress, however, may help to mitigate some of its ill effects. These may include the use of relaxation training and biofeedback techniques. Such techniques have been shown to increase self-management abilities, improve sense of well-being, increase coping skills, lower incidence of depression, and lessen perceived stress.³⁴

In addition, relaxation training and biofeedback techniques may help to lower blood sugar levels,^35-36 the value of which was discussed previously.

According to the Association for Applied Psychophysiology and Biofeedback, the Certification Institution of America (BCIA), and the International Society for Neurofeedback and Research (ISNR), Biofeedback is defined as “a process that enables an individual to learn how to change physiological activity for the purposes of improving health and performance. Precise instruments measure physiological activity such as brainwaves, heart function, breathing, muscle activity, and skin temperature. These instruments rapidly and accurately ‘feed back’ information to the user. The presentation of this information—often in conjunction with changes in thinking, emotions, and behavior—supports desired physiological changes. Over time, these changes can endure without continued use of an instrument.”³⁷

Homocysteine

Homocysteine, a by-product of normal protein metabolism, also plays a role in cognitive health. It is formed from the conversion of the amino acid methionine. Since high levels of homocysteine are not beneficial for the cardiovascular system, the body has a built-in mechanism to partially convert it back into methionine and other beneficial, non-toxic amino acids. If, however, this process is imbalanced, homocysteine builds up in bodily fluids and tissues. This may have a negative impact on healthy cardiovascular function as well as cognition.^38-39

In 2002, a study published in the American Journal of Psychiatry⁴⁰ examined 3,884 elderly people for symptoms relating to mood and cognitive function, folate, vitamin B12 and homocysteine blood levels. The results were that high homocysteine levels, vitamin B12 deficiency and, to a lesser extent, folate deficiency all corresponded to symptoms relating to moodiness and a lesser degree of cognitive function. Other research has found similar results.⁴¹ The mechanism of action seems to be related to homocysteine’s alteration of neurotransmitters.^42-43

The good news is that a substantial body of scientific evidence suggests that generous intakes of folate, vitamin B6 and B12 can help promote healthy homocysteine levels.^44-45

Sleep

Sleep is necessary for the nervous system to function properly. Too little sleep results in drowsiness and an inability to concentrate the following day. It also leads to impaired memory and physical performance and reduced ability to carry out math calculations. Continued sleep deprivation may result in hallucinations and mood swings. In sleep deprivation, neurons may become excessively depleted of energy or polluted with byproducts of normal cellular activities so that they begin to malfunction.⁴⁶ It should be noted that compromised circulation to the brain either due to carotid narrowing or sleep apnea should always be examined. Often in clinical practice, patients with sleep apnea often present with impaired cognitive capacity.

Sleep deprivation can adversely affect cognitive function. This was demonstrated when MRI was used to monitor the brains of sleep-deprived subjects performing simple verbal learning tasks.⁴⁷ Depending on the task, the brain would sometimes attempt to compensate for the adverse effects caused by lack of sleep. The temporal lobe was activated during verbal learning in rested subjects, but not in sleep deprived subjects. The parietal lobe was not activated in rested subjects during the verbal exercise, but was more active when the subjects were deprived of sleep. Overall, memory performance was less efficient with sleep deprivation.

A recent study also has shown that during sleep, the brain is processing information and this ability may contribute to memory in a waking state.⁴⁸

The only solution to sleep deprivation is to obtain adequate sleep. The National Institute of Neurological Disorders and Stroke offers the following tips for getting a good night’s sleep:⁴⁶

• Go to bed at a set time each night and get up at the same time each morning. Disrupting this schedule may lead to insomnia.
• Try to exercise 20 to 30 minutes per day. Daily exercise often helps people sleep, although a workout soon before bedtime may interfere with sleep.
• Avoid drinks that contain caffeine, which acts as a stimulant and keeps people awake.
• A warm bath, reading, or another relaxing routine can make it easier to fall asleep.
• If possible, wake up with the sun, or use very bright lights in the morning. Sunlight helps the body’s internal biological clock reset itself each day.
• If you can’t get to sleep, don’t just lie in bed. Do something else, like reading, watching television, or listening to music, until you feel tired.
• Maintain a comfortable temperature in the bedroom. Extreme temperatures may disrupt sleep or prevent you from falling asleep.

Other important things to note:

• It is vitally important to sleep in a totally dark room, not even using a night light, unless needed for safety, or any light with a blue hue that could throw off one’s circadian rhythm. If your alarm clock is light, covering it up is a good consideration.
• If your bed partner snores or you have pets that disturb your sleep, address the disturbance. If your partner snores, a dental appliance may help after having him or her evaluated for sleep apnea.
• Also do not drink liquids or eat food 2 hours prior to bed. Not only will this lessen the need to break up restful sleep with bathroom visits, it will lessen intra-abdominal pressure that can increase the risk of overt or silent acid reflux while one sleeps.
• It’s also essential for individuals to work with a doctor to ensure there are no sleep apnea issues. Researchers have linked sleep apnea to less than optimal cognitive function.⁴⁹

Conclusion

There are a variety of issues that may have an adverse effect on cognitive function. Taking steps to address these issues by making simple lifestyle changes may do much to help promote healthy cognitive function with aging.

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