Last time I introduced the thyroid gland. I said that thyroid is a small organ, about 1 oz. It is located at the base of the neck, and it produces hormones, T3 and T4, that regulate the metabolism of the whole body. They are important for growth and development, repairs and maintenance, normal cell functions, basically all the activities in the body that require energy.
All cells need energy to do their job. The cells run on energy; sort of like cars run on gasoline. But unlike gasoline, energy doesn’t come from outside, it is made inside each cell and that’s where thyroid hormones come in.
The thyroid hormones do not actually provide the energy. What they do is make the cells of the body burn fuel to produce energy and heat.
Our cells have little “power houses” that make energy by burning fuel. These power houses are called mitochondria, which is pleural for “mitochondrion.” No cell has just one mitochondrion. The number usually ranges from a dozen to a few thousand, depending on how active the cell is.
For example, a skin cell doesn’t really need a lot of energy to do its job. That’s why it has about a dozen mitochondria. On the other hand, a heart cell needs a tremendous amount of energy, so it has 4-5 thousand mitochondria.
Imagine a fireplace, filled with wood, just waiting to be fired. All you need is a lighted match to start the fire. This is what thyroid hormone T3 does – it turns on the fire in the mitochondria, it starts and supports this process of burning the fuel to produce energy and heat.
The fuel comes from the food we eat. It is usually the carbohydrates and fats that are used for fuel. Under some extreme conditions protein can be used as fuel also, but normally it’s just carbohydrates and fats.
The easiest thing to turn into energy is a substance called glucose, or blood sugar. We make glucose from carbohydrates. Burning glucose is the preferred way to make energy. There is always a certain amount of glucose in the blood, plus some glucose is stored in the liver, in the form called “glycogen”, so there is usually enough for normal daily activities. I
If the activities are higher than normal, say you are doing a lot of physical work, or running a marathon, or you are not eating enough carbohydrates, then the body starts burning the stored glucose. After that is gone, the body starts burning fats. Many of us have extra fat that is stored just for this eventuality, when we are getting fewer calories from food than we need for our daily activities. In other words, when we don’t eat enough. Stored fat is our protection against starvation.
After the body burns the glucose and fat it begins burning proteins. Proteins are the last to go into the oven, because while carbs and fats are mostly used for energy, proteins are used for many other things. We can turn proteins into fat and carbohydrates, if necessary, but it’s a one-way street. We cannot make proteins from fats or carbohydrates, which is why we hold on to proteins as long as we can.
All the enzymes, used by the cells to perform thousands of different processes, are made from proteins. Many hormones are made from proteins, for example insulin, growth hormone, thyroid hormones and many others, Proteins are used for building and repairing the cells of the body. The muscles and the heart are made from protein. That’s why the body holds on to protein to the very last.
How do thyroid hormones get inside the cells? Practically every cell in the body has thyroid receptors. A receptor is like a door with a lock that only a particular key can open.
You see, each of our cells is like a house. When all the windows and doors are closed, you can’t get into a house, unless you are invited, or you have the key.
And this is what receptors are for. They create an entrance for a particular substance. It could be a hormone, a neurotransmitter, a nutrient, a vitamin, whatever a cell wants to invite.
Thyroid hormone has a door through which it enters the cell and lights up the mitochondria. When I say “lights us” I don’t mean that it literally starts the fire. A better description would be that it turns on the mitochondria, which then start burning the fuel. And it keeps this process going.
For technically inclined, this process is called oxidative phosphorylation. It requires oxygen, just like the actual fire. And it produces a waste product called CO2 (carbon dioxide). That’s why we inhale oxygen and exhale CO2.
So now you know why thyroid hormones are essential for energy production. In the next lecture we’ll talk in detail about thyroid hormones, how they are made, how they become active. In the future lectures I’ll talk about how thyroid hormones are regulated and how they are distributed by the blood to all the cells of the body.
My website LowThyroidDoctor.com has even more information about low thyroid. There are many reports that explain things in more details, and they can be downloaded for free any time.
If you know someone who might be interested in low thyroid, please direct them to the site. Also, if you have questions or comments, please email to DrTeplisky@gmail.com.
Finally, you can get a free, no obligation 30 min phone consultation with me to see if I can help you figure out if you have hypothyroidism. Just book it online or call my office at 718-769-0997.