Mitochondria: Energy & Aging

Mitochondria are membranous, slightly elongated structures contained within the Eurkaryotic part of the cell (which means 'real' nucleus), often referred to as the 'power-houses' of the cell. Using aerobic respiration, they take oxygen and the compounds in our food to make energy (in the form adenosine triphosphate, known as 'ATP'). This gives them major street cred in the body as a whole as without them, nothing would be able to work. It might be hard to believe but gram for gram humans are literally the most powerful energy producers in the world. It could be argued that we produce 10,000 times more energy per gram than the sun every second. Think about that next time you're feeling a bit tired. Interestingly, mitochondria have their own DNA, known as mtDNA which is normally passed on to our children in the mother's egg (this doesn't include the father's sperm). This gives them a certain degree of autonomy within the cell and freedom to initiate certain actions like cell death (apoptosis). Subsequently, it also makes mtDNA great in forensics for identifying people.

Mitochondria act like little digestive systems taking nutrients and breaking them down for energy production. Each cell contains the appropriate amount of mitochondria relative to its energy use so naturally there are lots found in the heart as pumping that everyday is massively energy intensive. When we lose mitochondria or they begin to malfunction in these key organs, we get problems like heart disease. This is what makes mitochondria research in the field of medicine extremely interesting. Mitochondria were originally independent bacterial entities which at some point over a billion years ago (through much trial and error) entered other bacterial cells and decided to partner up. This moment was monumentous, cells all around the world through a giant party, you could argue this was the beginning of complex life as we know it.

Given mitochondria's role in the body, the mitochondria theory of aging is probably the best theory we currently have. It essentially argues that diseases (including dying) are the result of mitochondria degeneration. This degeneration happens through free radical build up as mitochondria process cellular respiration. This process gets more and more 'faulty' and after a certain threshold passes, the oxidative stress becomes overbearing and the cell dies.

Application

The two most important cycles that occur in the mitochondria for energy are the tricarboxylic acid cycle (TCA) and the electron transport chain (ETC). All you need to know here is that these cycles and their enzymes must flow freely, when they get backed up, this is where free radical leakage occurs. During normal oxidation phosphorylation (whereby ATP is formed by electron transfer) about 2 percent of all the oxygen consumed is converted to superoxide (a type of free radical). Usually these pumped up oxygen molecules can be shut down through various mechanisms (antioxidant police), however when these molecules can’t be, cell damage occurs. Think of these cycles or chains like busy factory lines, all parts need to be working efficiently and the end product needs to be shipped out swiftly to the customer (you).

So how does this all translate into real life? Say you have an athletic individual consuming a moderate amount of calories; this individual has a reasonably high energy demand so electrons flow down the ECT and free radical leakage is limited because the ATP is used up. Similarly, for someone who isn’t consuming enough calories but is reasonably active, free radicals leakage is limited because not many electrons flow down the ECT but oxygen is still available. Less business for the factory isn't the end of the world (within reason). This should give you a clue as to why fasting won't kill you.

Now the real problem occurs with the sedentary individual with high energy consumption. Here the cells don’t need the energy (lack of demand) but the electrons and ultimately ATP is flowing freely. It’s like a free bar. Free radicals (very drunk people) walk around like they own the place, tipping over tables (excess leakage means cell damage) and ultimately damaging the venue beyond repair (apoptosis, cell death). This is why keeping the balance of energy in vs energy out is important.

Improving mitochondrial function

Before we dive into the compounds that help mitochondria, I just want to do a quick reminder that some exercise is important - you want to be using up that ATP so that the chains within the mitochondria flow freely.

First off, will begin with the B vitamins. These, by far, have the greatest impact on cellular metabolism. Without the B vitamins, neurotransmitters fail to connect properly (B6 in particular). Each of the B vitamins has their specific role in the mitochondria for making energy so you want to be taking a good food state B complex. For example, B2 (Riboflavin) plays a key role in shuttling electrons from the TCA cycle and B12, known as cobalamin, is involved in several important metabolic functions including the generation of s-adenosyl methionine (SAMe) which is part of the protein sub units that make up the ETC.

Magnesium (see my other post for types) has countless benefits for just about every system in the body and particularly the enzymes involved in cellular respiration. Without magnesium, you will not be able to relax properly because it regulates calcium. Calcium keeps the muscle in a contracted state. Magnesium also plays an important role in heart health because without it, vasoconstriction can occur. This means less blood flow and ultimately less oxygen. Less oxygen means that oxidative phosphorylation in the mitochondria can't operate effectively.

Coenzyme Q10 is probably the king antioxidant for mitochondria. It plays a vital role in many aspects of energy production and particularly the ECT. It can even take free radicals and sooth them back into the ECT for energy. CoQ10 is like that friend in the group who keeps everything nice and organised. Its present in almost every cell in the body and decreases as we age so I think this one is particularly handy if you're passing the 40 year mark. Because of CoQ10's role in cell health, it has benefits for a broad range of health conditions. Typically you'll find it as Ubiquinol (look for a soft gel) as a supplement which is best absorbed.

Lastly compounds like L-carnitine (an amino acid) and Alpha Lipoic Acid (ALA) are also handy for keeping mitochondria happy in their busy lives.