A look at a single mitochondrion through a microscope
An interesting tidbit on the mitochondriaThe mitochondria are interesting little organelles found within our cells. Organelles are little structures within our cells that carry out tasks. Each cell within in an organ has organelles that perform the function of that organ. For example, one of the functions of your liver is detoxification and many of the cells within the liver contain organelles that do just that. The mitochondria, which along with energy generation have many functions critical to survival, can be found in just about any cell within a multicellular organism. The predominant theory on how mitochondria came to be in our cells is referred to as endosymbiosis.
Endosymbiosis is the theory that many of the organelles within our cells came to be there due to a mutually beneficial relationship with the host cell. In the case of the mitochondria, the theory goes that the mitochondria were bacteria that were engulfed by a separate single celled organism. There is plenty of evidence for this, and the fact that mitochondria contain their own DNA in the shape of a circle, something primarily found in viruses and bacteria, lends support to this theory. Over time, the mitochondria became organelles within the cell and lost some of their DNA to the nucleus. However, to this day, the mitochondria still contain some DNA that cannot be found in the nucleus of the cell. This DNA primarily codes for proteins found in the electron transport chain, something we will discuss a little later.
What do the mitochondria do?While the mitochondria within your cells do quite a few things, the role they are most famous for is generating most of the ATP. ATP, or adenosine triphosphate, is the form of energy your cells use to accomplish the many tasks they perform. Some cells create hormones, some cells create movement, some cells transmit nerve impulses, and some cells relay information within the body. Any cell that requires energy to power it's processes uses ATP to do so. Most cells have many mitochondria, and the number of mitochondria within the cell is in proportion to the energy needs of the cell. In addition to generating energy for cells, mitochondria also have a prominent role in apoptosis, or cell suicide.
While the concept of cell suicide may sound bleak, apoptosis is a critical process that begins when you are developing as a fetus. The formation of fingers and toes is accomplished by apoptosis of the cells between the fingers and the toes. In people with webbed feet or hands, this process did not operate efficiently when they were in the womb. Apoptosis helps remove unwanted or unhealthy cells before they become a problem. When apoptosis doesn't occur, bad things happen. Cancerous cells somehow override apoptosis which is how they proliferate and become tumors. As long as apoptosis is working properly, irregular cells are terminated. In fact, thousands of cancer cells develop and go through apoptosis ever day. It's when apoptosis doesn't work smoothly that cancerous cells proliferate and become tumorous.
As you can see, healthy mitochondria are important for health. By eating the proper foods and getting regular physical activity, you can keep your mitochondria working smoothly. Let's take a look at the foods you should be eating and things you should be doing to maintain healthy mitochondria.
Foods for healthy mitochondriaMany foods are beneficial to healthy mitochondria, chief among them are vegetables high in sulforaphane. Sulforaphane is a molecule found in cruciferous vegetables that helps to increase intracellular glutathione levels. Glutathione is your body's master antioxidant. One of the ways your mitochondria makes ATP is the electron transport chain(ETC). The ETC generates energy by passing electrons between molecules in the mitochondria which creates an electrochemical gradient. It's not important to understand the specifics of this energy generating process, but it is important to understand that this process generates free radicals as a natural byproduct of making ATP.
Free radicals are unstable substances with an unpaired electron in their outer shell that react with healthy components of your cells. It is important to limit free radicals because they can interfere with proper functioning of the cell. Antioxidants donate electrons to free radicals but become weaker free radicals in the process. Glutathione, being the master antioxidant, donates electrons to free radicals as well as antioxidants that have become free radicals. Having high glutathione levels, then, can allow you to limit free radical production and limit the amount of damage free radicals can do to your mitochondria. This is important because most of the antioxidants you eat cannot enter the mitochondria and since the mitochondria has DNA that codes for the proteins in the ETC, damage to that DNA can accelerate free radical production.
Eating cruciferous vegetables such as broccoli, cauliflower, cabbage, asparagus, and kale is important to help keep your glutathione levels high. Studies have shown the sulforaphane found in these vegetables helps induce cell apoptosis in cancer cells(1). However, since these vegetables are also goitrogenic meaning they can interfere with thyroid function, you want to limit consumption of these foods to five or six servings a week. Cruciferous vegetables are not the only foods found to increase glutathione levels, whey protein(2) and blueberries(3) both contain compounds that increase glutathione levels as well.
Supplements for healthy mitochondriaWhile keeping glutathione levels high should be one of your goals, supplemental glutathione won't work because it is destroyed by stomach acid. N-Acetylcysteine does appear to work very well at keeping glutathione levels high(4). However, when looking at maintaining good mitochondrial health and a healthy number of mitochondria in your cells, there is more to it than just increasing glutathione levels.
Magnesium deficiency has been shown to lead to fewer mitochondria in cells(5), so getting sufficient levels of magnesium is important to generating many mitochondria. Iodine is another important nutrient to make sure you are getting enough of to support healthy mitochondria. In addition to it's role as a component of thyroid hormone which regulates metabolism throughout the body, iodine also has an important role to play in cell apoptosis(6) which it apparently mediates through mitochondrial mechanisms(7, 8). In one study, iodine was shown to induce apoptosis in human breast cancer cells but not in healthy cells that surround the cancerous cells(7). In another, iodine helped induce apoptosis in 4 out of 5 breast cancer cell lines. For the most part, people tend to be deficient in iodine unless they consume large amounts of fish or low to moderate amounts of seaweed. Table salt is iodized but few people use iodized salt and the iodine tends to evaporate out of the salt over time.
Lifestyle factors for healthy mitochondriaGiven what we've discussed thus far about mitochondria, you may be able to figure out the things you should be doing to have many, healthy mitochondria. Calorie restriction has been shown to boost the health of mitochondria which makes sense. Fewer calories going through the mitochondria means fewer free radicals that can potentially react with healthy parts of the cell. Ketogneic diets tend to lead to healthy mitochondria, potentially via an increase in glutathione levels(9). It is important to note that one should not randomly undertake a long term ketogenic diet as these types of diets require modulating the intake of other nutrients for safe implementation.
Another thing people can do to maintain healthy mitochondria is exercise. Daily physical activity is important to signal cells to keep many mitochondria on hand. There is probably a sweet spot you should shoot for as excessive exercise should, in theory, lead to greater free radicals via increased mitochondrial free radical production. If I were to ballpark it I would say running for 3-5 miles per day is probably ok but anything above that would provide no added benefit with potential negative consequences, but there are no studies to back up this assertion. As far as strength training, a normal strength training program is probably fine but bootcamp or circuit style training could potentially cause problems in excess. Regardless, any situation where you are calling on your body to produce lots of energy will create lots of free radicals that you should attempt to keep in check by keeping glutathione levels high and eating foods high in antioxidants(fruits and veggies).