Why a lack of exercise and poor diet may be leading to memory loss, mental decline, and dementia

According to studies, regular exercise has been shown to help prevent normal cognitive decline due to aging and dementia.

If you were under the impression that you couldn’t grow new brain cells (and that you could kill them by excessive alcohol consumption), you aren’t alone.

Research, however, suggests that there indeed is one area of the brain that does grow new brain cells, and it is involved with the formation of new memories (and therefore linked to cognition, commonly known as “thinking”).  This area is called the dentate gyrus, which is found in the hippocampus, which has been shown to grow when people are learning new information, such as when a taxi driver is learning the “maps” of the streets they will be navigating as part of their job.

In her book titled Pictures of the Mind, author Miriam Boleyn-Fitzgerald discusses studies of the dentate gyrus which revealed a link between exercise and dementia.  According to studies, regular exercise has been shown to help prevent normal cognitive decline due to aging and dementia.  The reason this appears to be so is not so much about exercise as it is about elevated levels of glucose in the blood, and how it affects the growth and development of cells in the dentate gyrus (GC).

Glucose (sugar) is needed by the brain to create the energy we need to fuel our bodies.  Our cells “suck” up the glucose (okay, it’s not really “sucked” in, but just go along with me here) and convert it into an energy form called “ATP.”

So, you may be wondering why too much glucose would even be an issue — if a little glucose was good, wouldn’t more glucose be better?  Not really…It has to do with sensitivity to sugar…

When blood sugar levels increase, our pancreas is told to release insulin, which is like the “key” that fits in the “locks” of our cells, telling our cells to let glucose in.  If our cells are continually “bathed” in insulin due to high blood glucose levels, the cell becomes lazy and complacent, assuming that there will always be insulin around, so it starts to break down some of the locks that would normally allow glucose to get in.

The more the locks are broken down, the less glucose is able to enter the cell.  The less glucose enters the cell, the more glucose is left behind in the blood.  The more glucose remaining in the blood, the more the pancreas releases insulin.  The  more insulin that is released, the more the cell is bathed in insulin.  The more the cell is bathed in insulin, the more locks are broken down.  It’s a vicious cycle, and you may have heard of it — it’s called Type 2 diabetes.

Glucose is a good thing, but too much is not.  It contributes to our blood becoming thicker and more ‘sticky.”  The blood doesn’t flow well, and the glucose starts causing damage to the walls of blood vessels, as well as contributing to a host of issues.  One of those issues is a relatively decreased blood flow, especially to areas that need it to create new growth.  Without blood, there is no oxygen or nutrients — both are needed to create new cells of any kind.

If you decrease the blood flow to the dentate gyrus, then it is less capable of producing new nerve cells, or “neurons” (in a process called “neurogenesis”), and it is believed that these nerve cells created in the dentate gyrus when we are forming new memories or learning new information are key to maintaining a certain “mental sharpness” as we age.  As brain cells degenerate with age, why wouldn’t we want to add more new ones?

Getting back to the brain — now here’s how exercise affects blood glucose levels…The more one exercises, the more the cells are using up energy.  This increased demand for energy creates an increased demand for glucose.  By exercising, you make your cells more “thirsty” for glucose, thereby prompting the cell to create more locks that can interact with insulin, so that it can “soak” up the glucose as soon as it’s available.  If you remove more glucose from the blood, the blood is now able to flow more freely and effectively, thereby allowing for better cell growth (and neurogenesis).

More exercise, more glucose “soak,” and more new cell growth.  It’s that easy!  It doesn’t hurt to eat a bit healthier too — less refined or simple sugars and more complex carbohydrates.  Reach for the fruits and vegetables instead of the chocolate bars and sodas.

It’s for the good of your brain!

-Victor

Here’s an article from the New York Times on a study regarding this very concept, in case you are interested.

Photo source: freedigitalphotos.net