All living things including plants, animals, birds, insects, and humans need energy for the proper functioning of cells, tissues and other organ systems. This energy can be regarded as a source of fuel. Plants obtain their energy from sunlight. Animals obtain it by feeding on those plants. Similarly, humans generate energy from the food we eat. Our energy generation takes place inside our cells, in the mitochondria.
Mitochondria are structures in our cells which convert the energy from the nutrients in our food into a form that our cells are able to use. Each of our cells contains hundreds to thousands of mitochondria, which are located in the fluid that surrounds the cell’s nucleus (the cytoplasm). Our human DNA is packaged in chromosomes within the nucleus. However mitochondria have their own DNA known as mitochondrial DNA or mtDNA.
Our cells have varying numbers of mitochondria based on their particular energy needs. Cells that require more energy to function need more mitochondria. For example liver cells may have around 2,000 mitochondria per cell, whereas the cells of our heart, brain and eyes may have around 10,000.
Mitochondria are thought to have evolved from bacteria that developed a symbiotic relationship with us, through living within our human cells. There are many similarities between the genomes of mitochondria and those of other intracellular bacterium parasites, suggesting they do share a common ancestor.
Mitochondria are responsible for most of the useful energy derived from the breakdown of carbohydrates and fatty acids, which is converted to adenosine triphosphate (ATP) by the process of oxidative phosphorylation. ATP is commonly referred to as the “energy currency” of the cell, as it provides readily releasable energy. How well our mitochondria are functioning determines our level of energy.
The process of breaking down ATP to extract the stored energy requires protein. For example, when our muscles contract, they require energy. This energy comes from breaking down ATP molecules — a process called ATP hydrolysis. Enzymes that hydrolyze ATP are made of protein. Breaking down ATP by using enzymes doesn’t affect the enzymes themselves, as they’re unchanged in the reaction. But it does destroy the ATP, which is why we must continually supply nutrients so that our cells can continue to make more ATP. So in addition to providing energy, this breakdown of the ATP through hydrolysis serves a broad range of other cell functions, including signaling and DNA/RNA synthesis.
As research continues there seemingly are aspects of mitochondrial physiology that have connections to our human aging process. Aging is associated with evidence of an activation of the innate immune system that leads to a condition known as “inflammaging”. This is particularly true of elderly individuals who are aging less successfully than their peers. It is known that mitochondrial decline occurs with aging, which can result in organ dysfunction.
A study published in the Journal of Clinical Investigation (2018 Aug 31;128(9):3662-3670) revealed that … “Analysis of mitochondrial function in tissues, such as the skeletal muscle of older subjects, reveals a decline in mitochondrial respiratory capacity to roughly 50% of what is seen in younger subjects and a reduction in ATP. These mitochondrial deficits track closely with functional decline in muscle strength and are believed by most to be a causal factor for age-related sarcopenia.”
Healthy mitochondria also play a role in other critical processes and functions in our body, including:
- Helping to activate and direct our immune system
- Cell signaling
- DNA repair
- Preventing mutations of damaged cells, by stimulating apoptosis
- Detoxification regulation
- Water production for cells, which is a byproduct of energy production
Therefore focus on a lifestyle that supports mitochondrial health is of particular importance.
Lifestyle Support for Mitochondrial Health
We can use the analogy that our mitochondria are like our own ‘biological batteries’. If they are not fully charged, or if we don’t have enough of them, many processes in our body may be impacted. So knowing how to support and protect them is important knowledge for all of us to have.
The food we eat delivers complex messages to our body, with the potential of being both positive and negative, depending on what we are eating. Therefore it is best to be eating foods that have the beneficial nutrients we need, and can deliver the messages which support our mitochondria, our health and our wellness.
Ideally our diet should be ant-inflammatory, and low on the glycemic index, as well as containing the optimum balance of macronutrients from the proportions of protein, fat and carbohydrate necessary to support our lifestyle, while being cognizant of our present medical condition.
Cutting out processed foods and fast food, anything packaged, and unhealthy fats, is a way to support the mitochondria in our body. While there isn’t a one-size-ﬁts-all diet, it’s always a good idea to eat fresh ‘real’ foods, and lots of healthy vegetables. Micronutrients (vitamins and minerals) are also essential to support the body, the mitochondria, and our overall vitality. As in many situations – context always matters! The level of vitamins and minerals we need is dependent on many factors, including our diet, lifestyle, medical condition, gender, and age. Also of contextual relevance is whether our objective is to maintain existing health, or help overcome disease.
A decline in mitochondrial function is associated with the normal aging process. A ‘food as medicine plan’ can help us to optimize the functional integrity of our mitochondria and prevent associated conditions such as cognitive decline. Adopting a nutrient-rich strategy not only improves our mitochondrial function, but also lowers inﬂammation, decreases oxidative damage, and reduces our risk of disease and chronic health problems.
However dietary interventions are just one part of the overall picture of optimizing mitochondrial function. Other lifestyle considerations like exercise, movement, stress and sleep also play a role in mitochondrial health, and improve cellular energy production.
There are several lifestyle and environmental factors that can damage our mitochondria and disrupt their function. These include pathogens, parasites, heavy metals, medications, severe oxidative stress, and infections.