By David Dunaief, M.D.
The brain is the most important and complex organ, yet what we know about the brain is inverse to its prominence. In other words, our knowledge only scratches the surface. While other organs can be transplanted readily, it is the one organ that can’t, at least not yet.
The brain also has something called the blood-brain barrier. This is an added layer of small, densely packed cells, or capillaries, that filter what substances from the blood they allow to pass through from the rest of the body (1). This is good, since it protects the brain from foreign substances; however, on the downside, it also makes it harder to treat, because many drugs and procedures have difficulty penetrating the blood-brain barrier.
Unfortunately, there are many things that negatively impact the brain, including certain drugs, head injuries and lifestyle choices. There are also numerous disorders and diseases that affect the brain, including neurological (dementia, Parkinson’s, stroke), infectious (meningitis), rheumatologic (lupus and rheumatoid arthritis), cancer (primary and secondary tumors), psychiatric mood disorders (depression, anxiety, schizophrenia), diabetes and heart disease.
These varied diseases tend to have three signs and symptoms in common: they either cause an alteration in mental status — cognitive decline, weakness or change in mood – or a combination of these.
Probably our greatest fear regarding the brain is cognitive decline. We have to ask ourselves if we are predestined to this decline, either because of the aging process alone or because of a family history, or if there is a third option, a way to alter this course. Dementia, whether mild or full-blown Alzheimer’s, is cruel; it robs us of functioning. We should be concerned about Alzheimer’s because 5.2 million Americans have the disease, and it is on the rise, especially since the population is aging (2).
Fortunately, there are several studies that show we may be able to choose the third option and prevent cognitive decline by altering modifiable risk factors. They involve rather simple lifestyle changes: sleep, exercise and possibly omega-3s. Let’s look at the evidence.
The impact of clutter
The lack of control over our mental capabilities as we age is what frightens us the most since we see friends, colleagues and relatives negatively affected by it. Those who are in their 20s seem to be much sharper and quicker. But are they really?
In a recent study, German researchers found that educated older people tend to have a larger mental database of words and phrases to pull from since they have been around longer and have more experience (3). When this is factored into the equation, the difference in terms of age-related cognitive decline becomes negligible. This study involved data mining and creating simulations. It showed that mental slowing may be at least partially related to the amount of clutter or data that we accumulate over the years. The more you know, the harder it becomes to come up with a simple answer to something. We may need a reboot just like a computer. This may be possible through sleep and exercise and omega-3s.
I have heard people argue that sleep gets in the way of life. Why should we have to dedicate 33 percent of our lives to sleep? There are several good reasons. One involves clearing the mind, and another involves improving our economic outlook.
For the former, a study shows that sleep may help the brain remove waste, such as those all-too-dangerous beta-amyloid plaques (4). When we have excessive plaque buildup in the brain, it may be a sign of Alzheimer’s. This study was done in mice. When mice were sleeping, the interstitial space (the space between brain gyri, or structures) would increase by as much as 60 percent.
This allowed the lymphatic system, with its cerebrospinal fluid, to clear out plaques, toxins and other waste that had developed during waking hours. With the enlargement of the interstitial space during sleep, waste removal was quicker and more thorough because cerebrospinal fluid could reach much further into the spaces. When the mice were anesthetized, a similar effect was seen as with sleeping.
In a published follow-up study, the authors found that sleep position had an impact on glymphatic transport in rodents. Sleeping in a lateral position, or on their sides, was more effective at clearing waste than prone or supine positions. Of course, the authors note that for rodents a prone position is similar to their awake positions. It would be most like a human sleeping while sitting upright (5).
In another study, done in Australia, results showed that sleep deprivation may have been responsible for an almost 1 percent decline in gross domestic product for the country (6). The reason is obvious: People are not as productive at work when they don’t get enough sleep. Their attitude tends to be more irritable, and concentration may be affected. We may be able to turn on and off sleepiness on an acute, or short-term, basis, depending on the environment, but it’s not as if we can do this continually.
According to the Centers for Disease Control and Prevention, an average of 4 percent of Americans report having fallen asleep in the past month behind the wheel of a car (7). I hope this hammers home the importance of sleep.
How can I exercise, when I can’t even get enough sleep? Well there is a study that just may inspire you to exercise.
In the study, which involved rats, those that were not allowed to exercise were found to have rewired neurons in the area of their medulla, the part of the brain involved in breathing and other involuntary activities. There was more sympathetic (excitatory) stimulus that could lead to increased risk of heart disease (8). In those rats that were allowed to exercise regularly, there was no unusual wiring, and sympathetic stimuli remained constant. This may imply that being sedentary has negative effects on both the brain and the heart.
This is intriguing since we used to think that our brain’s plasticity, or ability to grow and connect neurons, was finite and stopped after adolescence. This study’s implication is that a lack of exercise causes unwanted new connections. Of course, these results were done in rats and need to be studied in humans before we can make any definitive suggestions.
Omega-3 fatty acids
In the Women’s Health Initiative Memory Study of Magnetic Resonance Imaging Study, results showed that those postmenopausal women who were in the highest quartile of omega-3 fatty acids had significantly greater brain volume and hippocampal volume than those in the lowest quartile (9). The hippocampus is involved in memory and cognitive function.
Specifically, the researchers looked at the level of omega-3 fatty acids, called eicosapentaenoic acid and docosahexaenoic acid, in red blood cell membranes. The source of the omega-3 fatty acids could either have been from fish or supplementation. This was not delineated. The researchers suggest eating fish high in these substances, such as salmon and sardines, since it may not even be the omega-3s that are playing a role but some other substances in the fish. It’s never too late to improve brain function. You can still be sharp at a ripe old age. Although we have a lot to learn about the functioning of the brain, we know that there are relatively simple ways we can positively influence it.
References: (1) medicinenet.com. (2) alz.org. (3) Top Cogn Sci. 2014 Jan.;6:5-42. (4) Science. 2013 Oct. 18;342:373-377. (5) J Neurosci. 2015 Aug 5;35(31):11034-11044. (6) Sleep. 2006 Mar.;29:299-305. (7) cdc.gov. (8)J Comp Neurol. 2014 Feb. 15;522:499-513. (9) Neurology. 2014;82:435-442. Dr. Dunaief is a speaker, author and local lifestyle medicine physician focusing on the integration of medicine, nutrition, fitness and stress management.