What you’ll learn:
- The essential roles mitochondria play in energy production, cell function, and overall health
- How lifestyle, diet, and aging impact mitochondrial efficiency and oxidative stress
- Practical strategies including exercise, nutrition and targeted supplements to optimize mitochondrial health
What are mitochondria?
Mitochondria are tiny double membrane-bound organelles found in almost every cell type of all organisms except bacteria. Known as the “powerhouse of the cell” they are primarily responsible for converting the air we breathe and the food we eat into energy that our cells can use to grow, divide and function.
Given this, it is no surprise that cells that require the most energy, such as those in the brain, heart, liver and muscle, have the highest number of mitochondria in them (liver cells can have over 2,000). The only cells in humans which do not contain mitochondria are our red blood cells.
In addition to producing energy, mitochondria are responsible for many other tasks including producing cell signalling molecules, regulating vital calcium levels, producing body heat and killing off cells that have become unviable.
Mitochondrial DNA
The most popular theory about the origin of mitochondria is that they were once bacteria that were engulfed by more advanced single-cell organisms. These bacteria survived that process and formed a symbiotic relationship with the organisms. This provided an energy production advantage that has persisted through the evolution of more complex organisms, right to this very day.
Some of the strongest evidence for this theory is that mitochondria contain their very own tiny DNA sequence which is completely separate from that of the cell they are located in.
Mitochondria and ATP synthesis
Mitochondria produce energy by turning glucose and oxygen into a chemical called ATP. ATP carries energy in its chemical bonds that the cellular machinery can use to function and grow. Once these bonds are broken and the energy is released, ATP is recycled by the mitochondria back to its active form to be used again. It is estimated that there are only around 250 grams of ATP in the average adult body, but due to this constant recycling, that same adult will go through their bodyweight in ATP every day.
Researchers have even calculated that elite marathon runners can burn through their bodyweight in ATP in a single 2-hour race!
When mitochondria produce ATP, they produce by-products known as free radicals. These free radicals are mostly highly-reactive oxygen compounds which, if not kept in check, can react with (oxidise) and damage other parts of the cell such as the mitochondrial membranes and the cell’s DNA. When this happens, mitochondria can become inefficient at producing energy, DNA can become corrupted, and the cell cannot perform its various tasks as it should. This “cell stress” can cause a person to suffer from low energy levels. It is also thought to be a major contributor to the aging process itself.
When mitochondria produce ATP, they produce by-products known as free radicals. These free radicals are mostly highly-reactive oxygen compounds which, if not kept in check, can react with (oxidise) and damage other parts of the cell such as the mitochondrial membranes and the cell's DNA.
Thankfully there are several different types of natural antioxidant molecules inside mitochondria (and the rest of the cell) which neutralize these harmful free radicals and protect the cellular machinery from damage. When we are young and healthy, our mitochondria produce lots of energy and we have plenty of natural antioxidants to fight free radical damage. However, as we age our mitochondria begin to decline in function and they produce less antioxidants to fight oxidative stress. We don’t have the energy we once had, the visible signs of aging start to appear which significantly impact our quality of life.
Why are mitochondria important?
First, to grasp the sheer scale of mitochondria’s impact on our overall health, consider this: Each of us has quadrillions (that’s thousands of trillions) of these energy factories in our bodies.
Each mitochondrion is filled with some 17,000 biochemical assembly lines, all designed to produce a molecule called adenosine triphosphate, or ATP — our bodies’ major, most elemental fuel.
The more energy a tissue or organ demands for proper function, the more mitochondria its cells contain. Mitochondria are especially abundant in the cells that make up our hearts, brains, and muscles.
In fact, the heart is so energy-intensive that up to 40 percent of the space in its cells is taken up with mitochondrial power plants.
The density and health of the mitochondria in your organs and muscles are, to a large extent, a reflection of your current level of health and fitness (lean muscle tissue, for example, contains far more mitochondria than fat does, and a strong heart is likely to be denser with mitochondria than a weak one.)
The more healthy mitochondria your body contains, the better you’ll feel, and the more robust your metabolism will be. A mighty mitochondrial force translates to better energy and focus, and greater ability to sustain high levels of activity without fatiguing.
Mitochondria produce energy by breaking down food, then they release that energy in the form of ATP, along with some byproducts, like carbon dioxide, water and free radicals.