What determines where we fall in this spectrum? From a global perspective the best way to understand what occurs is to consider several overlapping processes. We start out as a single cell in the womb. The brain and other organs develop and enlarge as pregnancy progresses. Our genes and the availability of the proper nutritional building blocks underlie the construction of the brain much like a blueprint and the necessary amounts of concrete, stone, steel and glass enable tall buildings to be erected.
After birth new nerve cells (called neurons) are constantly being produced throughout the brain. They form connections with adjacent neurons. Each neuron has the capacity to form up to 100,000 connections with surrounding neurons. The key is not necessarily which connections or how many are formed, but which survive. It is akin to the survival of the fittest. In this case the “fittest” connections are the ones that are used most frequently. A term used by neuroscientists to describe this process of changing connectivity is plasticity. Just remember the rhyme, “neurons that fire together, wire together.” When one neuron is triggered and “talks” to its neighbor, that physical interaction strengthens the point of contact between the two (called a synapse). As this happens repeatedly, connections develop and become stronger. Simultaneously, connections with neighboring neurons that are not being used as routinely wither and may even disappear. That is how nerves form networks with one another. The process is driven by brain activity in response to both the external world and internal thoughts. The greater the depth and breadth of experiential interactions processed by the brain, the more dense the networks of contacts are and the better the function. These processes determine how good a brain you are building.
After a great brain has been sculpted keeping it functioning optimally and making it as resistant as possible to the dents and dings associated with the aging process is important. A combination of continued mental stimulation, a proper diet, stress avoidance, adequate sleep, social interaction and all types of physical exercise will help assure a healthy brain well into later life.
We have all heard that “the brain burns glucose.” Glucose is the sugar that is measured in the blood stream when blood tests are performed. It is what becomes elevated when diabetics lose blood sugar control. They inject the hormone insulin to keep blood glucose levels properly regulated. Glucose differs from table sugar, which is also called sucrose (one molecule of glucose combined with one molecule of another sugar called fructose). Fructose is also called fruit sugar and occurs naturally in grapes, for example. When a molecule of table sugar is digested, it produces one molecule of glucose and one of fructose.
Starch (a carbohydrate that is found in rice and potatoes, for example) consists of long branched chains of glucose molecules hooked together end to end. It is digested by enzymes in the intestine that break these connections, thus producing millions of individual glucose molecules – a process that allows them to be quickly absorbed into the blood. When digested, a potato produces half a cup of sugar (glucose). Even though a potato is a naturally occurring vegetable, it is digested rapidly, flooding the blood with glucose at a rate much faster than can be used. Hence, blood sugar rises, and sensing this change, the body releases high amounts of insulin to help control the blood sugar level.
Although the brain requires sufficient glucose to function normally, too much at one time causes spikes of blood glucose and insulin. The frequent repetition of this process, as happens regularly on our modern “Western type diet,” is detrimental to brain health. This is easily seen by noting that people with diabetes (too much glucose in their blood) have a fourfold risk of developing memory problems and Alzheimer’s disease. Pre-diabetes is associated with triple the incidence of these problems. A disorder called insulin-resistance (a condition wherein your blood sugar level is normal, but to keep it there your body needs to use much higher amounts of insulin than it would produce under healthy circumstances) is linked to a doubling of Alzheimer’s disease.
Observations like these reveal how dietary alterations can adversely impact brain function and brain aging. Therefore, some preliminary recommendations can be made regarding a brain-healthy diet. Any rapidly digested carbohydrates (such as bread, cakes, cookies, soda, candy and starchy fruits and vegetables) and sweeteners containing sucrose (table sugar) or HFCS (high fructose corn syrup) should be avoided. Lean protein, especially cold-water fish, is to be encouraged. Non-starchy veggies and fruits (such as berries of all types), nuts, seeds, and eggs are all good brain foods. One other caveat is that controlling your weight is also very important because new research is showing that weight gain is linked to loss of brain function.
The science behind sticky fat cells, the Brain-Belly connection, explanations of common dietary paradoxes, how to make the right food choices and why the dietary recommendations I discuss produce weight loss are all presented.
Mentally challenging thought patterns are engaged during stimulating occupational pursuits or school projects, by leisure activities that require solving complex mental problems (such as playing the card game bridge), learning a new language, mastering a musical instrument, reading or writing, discussing your response to a recent op-ed piece…really anything that forces you to become actively mentally engaged and that encourages you to look at and evaluate things from many perspectives. A physical exercise analogy may be appropriate here. Flexing and contracting your pinkie finger repeatedly isn’t considered very good exercise. However, swimming, getting on an elliptical machine at the gym or playing tennis are all great forms of exercise because they activate many muscle groups. The same applies for brain activities. You want to choose mentally challenging, novel activities for maximal stimulation.
That having been said, aerobic exercise (meaning exercise that elevates your heart rate for an extended period of time) carries more blood throughout the body, including the brain. This supplies additional oxygen and other necessary nutrients. It also acts directly on the neurons by elevating specific chemicals called neurotrophins. They go by many different names such as BDNF (Brain-Derived Neurotrophic Factor) and NGF (Nerve Growth Factor). These compounds facilitate the production of increased connections between neurons and make them more resistant to the myriad insults to which they are routinely exposed. Resistance exercise, meaning weight training, that we all know is good for bone health, is also good for the brain due to its impact on the same neurotrophins. Other types of exercise that engage many brain regions are activities that involve balance, coordination and agility such as ping-pong, trampoline, juggling, balance beam, standing on one foot, jumping rope and sports like skiing or skating. My recommendation is to cross-train the brain by including a mix of exercises from each category on a regular basis. If you can work up to 30 minutes on most days, I guarantee that you will see a difference in several weeks. Go safely so you won’t get injured. And enjoy!
These are all important distinctions because bad stress is not good for the brain. It is usually associated with a persistent elevation of the hormone cortisol – the “stress” hormone. The excessive amount of cortisol produced under stressful circumstances causes the neurons in the delicate memory centers of the brain – the hippocampus – to wither and die. So, bad stress is a brain killer and should be avoided at all costs. Depression and lack of sleep produce similar brain changes. You should know that exercise can help ameliorate the effects of stress, improve sleep disorders and even has anti-depressant properties. So try to include a bit of it every day and consider embarking on a stress reduction program.
