Metabolism Explained

Hello friends!  

Today’s post is a special one. This is a celebratory blogpost to commemorate the 1 year anniversary of my PhD thesis defense! On June 18 of last year, I stood in a room for two hours presenting the culmination of five years of research to my doctoral committee and a handful of peers marking the end of my PhD training. That day will forever hold a special place on my calendar because it represents my ability to do hard things, stay the course and persevere through challenges.

To honor this milestone, I wanted to share a bit about what I studied during my PhD and give you a glimpse into the scientific foundation behind my passion for health and nutrition.

My PhD Research

I began my college career intent on becoming a registered dietitian (that dream is still very much alive...just on pause for now). I was introduced to research and became fascinated by metabolism. I wanted to explore how the body transforms nutrients into energy, how those processes go wrong, and how that contributes to disease. This curiosity ultimately led me to pursue a PhD in Molecular Nutrition, a field rooted in cellular biology, metabolism and metabolic disease.

My doctoral research centered on a very famous cell organelle that is central to metabolism. Everyone who's ever taken a high school biology class will recognize it as the "powerhouse of the cell". This organelle is more scientifically known as the 'mitochondria'.

One of the main functions of the mitochondria is to generate energy to sustain cellular health, hence the term "powerhouse of the cell". You can think of them as tiny battery packs dispersed throughout the cell. In the absence of the energy supply typically provided by mitochondria, cells lose their ability to function and as a result they die. This eventually manifests as disease at the tissue level. This is known as mitochondrial disease and can occur as a result of genetic mutations passed down through the maternal line. Mitochondrial disease is extremely debilitating because it affects virtually all tissues in the body. It's especially detrimental to tissues that are very metabolically active (think brain, liver, muscle etc.). This essentially was the basis of my PhD research. My work aimed to find new and effective therapies to combat mitochondrial disease specifically in skeletal muscle as it is one of the more predominantly affected tissues. I worked primarily with skeletal muscle stem cells derived from mice and human patients and screened thousands of drugs to find a few that exhibited therapeutic potential. Through this work, I learned an obscene amount about mitochondrial biology and skeletal muscle physiology. It was hard work, but I can honestly say I achieved what I set out to do: to truly understand molecular metabolism and how it connects to human health and disease. Those five years taught me far more than facts or lab techniques. They gave me a deep, working knowledge of how the body transforms food into energy, how those processes can break down, and why that breakdown can lead to real, tangible illness.

Now you might be wondering: What does this have to do with nutrition?

Well, let me tell you. One of the most valuable returns from pursuing a PhD is that you learn more than just how to run experiments. My thesis centered two things: mitochondria and skeletal muscle. Throughout my training I was deeply immersed in skeletal muscle anatomy and physiology and all things mitochondrial biology. In terms of relevance to nutrition, the mitochondria is the central hub of energy metabolism. Everything that happens after nutrients from food intake are absorbed involves the mitochondria. The mitochondria produces the majority of the energy that our cells need. Take carbohydrates as an example. Once digested, glucose enters our cells and moves through a series of metabolic steps, including two major pathways that occur inside the mitochondria. If mitochondrial function is disrupted, these pathways slow down or fail, energy production drops and cells can’t meet their demands. Over time, this results in tissue and organ dysfunction.

Metabolism Explained

In conversations centering metabolism you often hear things like:

• Fast vs slow metabolism

• Someone who eats a lot of junk food but remains skinny has a fast metabolism and the opposite of this is deemed slow metabolism.

Biochemically speaking this is inaccurate as metabolic rate is dictated by muscle mass rather than how much a person weighs. This means a person with a higher percentage of muscle mass will likely have a higher metabolic rate compared to a slender person with low muscle mass.

What is metabolism?

A depiction of the complexity of human metabolism

Metabolism describes the combination of all the chemical processes that occur in the body and is divided into two arms: catabolism and anabolism. Catabolism, in simple terms are metabolic reactions that break down complex molecules like protein, fat and carbohydrates into smaller molecules that are used to support cellular processes. Catabolism results in the release of energy to support movement, tissue repair and other molecular processes. Anabolism is the process of using energy to build complex molecules from smaller molecules eg. protein from amino acids. This process is responsible for building muscle, repairing tissue etc., and requires energy.

Mitochondria's role in metabolism

As mentioned before, the mitochondria is the cornerstone of metabolism. Aside from its role in

energy generation, the mitochondria is involved in regulating protein synthesis (process of making proteins), lipid oxidation (breakdown of fat), DNA synthesis, cell signaling and many more molecular processes.

If I tried to cover every aspect of mitochondrial biology, this blog post would turn into a textbook. So instead, I want to focus on two major metabolic pathways inside the mitochondria that work together to generate the bulk of the cell’s energy.

The first is the TCA cycle. This pathway takes the breakdown products of carbohydrates, fats, and proteins and converts them into high‑energy molecules. These molecules are then passed to the next pathway, the electron transport chain, which uses them to produce ATP, the cell’s main energy currency.

Together, the TCA cycle and the electron transport chain form the core of mitochondrial energy metabolism. When they’re running smoothly, your cells thrive. When they’re disrupted, energy production drops, and the effects ripple outward to tissues and organs.

I could go on forever, but I wanted share this post to open our community up to the molecular metabolism world. Expect to see more content on metabolism and how it is impacted by nutrition.

Wishing you holistic health,

Dr. Edwards :)