Why We Need Glucose (A Biological History)
Diabetes Still Isn't Easy
Diabetes Still Isn't Easy

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Why We Need Glucose (A Biological History)

Diabetes Mellitus appears to affect close to 50 percent of the population of the U.S. in one form or another (the subject of a separate blog to follow). This series of blogs will be an attempt to simplify the understanding of diabetes and hopefully simplify prevention and treatment.

Recently there was an article on the new cleanliness of the waters in the Gulf of Mexico. This happened many years earlier than expected because bacteria that were put into the gulf after the BP spill ate the oil. They thrive on petroleum products. On the other hand, we (and other animals) thrive on glucose. This is likely the result of hundreds of thousands of years of evolution starting with one-celled animals and with continuous change arriving at “us.” Very early species, some of which still exist, had an insulin receptor on their cells—so it is clear that glucose control goes back millions of years.

Here’s an easy way to understand our relationship to glucose: In high school, you probably learned about photosynthesis. But to recap, this is a process where a plant takes carbon dioxide and water and turns them into glucose, using the energy from sunlight. Afterwards, organisms in the plant and vegetable world store this self-made glucose by sewing glucose molecules together to make carbohydrates. The carbohydrates make the storing of glucose easier. As a result, as long as plants grow there was and is an abundance of glucose in the environment.

This was generally the case for millions of years, until organisms like animals began to obtain glucose from outside themselves. Instead of making their own glucose, animals got it from the plants that they ate.

Glucose is the source of energy for all of our body functions, especially the brain. The only energy the brain can use is from glucose. Glucose is also the primary source of energy for muscles, backed up by other sources if it runs out. Proteins, for example, are for building the tissues that use glucose. Fat is a storage depot as backup for when glucose runs out—however, in the case of excess glucose, fat storage remains high. 

However, when the outer conditions of the world are not kind, and glucose is hard to obtain, the body has a system where it will produce glucose in the liver if needed and literally use itself up. We also have “stress” hormones that drive the liver to increase production under stress. Too much or too little glucose is dangerous. So, in order to keep glucose levels in the blood in a healthy range, a hormone called “insulin” is produced in a cell called the “Beta Cell” in special areas of the pancreas.  

The relationship of glucose and insulin is very sensitive, like a really good thermostat. Thus, when glucose levels rise, it leads to the production of more insulin, minute-by-minute, keeping glucose levels in the blood in a vey narrow range. When there is not enough insulin or the insulin is defective, blood glucose rises—this is diabetes. This may occur because the Beta cells are destroyed (as in Type 1 diabetes) or because there is resistance to the action of insulin and/or the Beta cells can’t keep up with an increasing demand for more insulin (as in Type 2 diabetes).

In a nutshell, the human body requires glucose for normal functioning of the brain and other tissues. If the system for obtaining, creating, and using glucose is disrupted, diabetes occurs and a lot of bad things can follow like heart attacks, blindness, and loss of limbs. But, it can all be prevented. More in the next blogs.

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About the Author


Dr. Bernstein is director of the diabetes management program at the Friedman Diabetes Institute.