Edited by Kate Findley, The Great Courses Daily
What nutrients are needed to keep our cells healthy? What do these nutrients actually do inside our body? Take a deep dive into the cell with Michael Ormsbee, Ph.D., looking at some of the individual cell components.
Cell Membrane: Your Body’s Gatekeeper
To uncover the link between nutrients and cell health, let’s start with the outermost component, the cell membrane.
The cell membrane is the boundary that separates the internal components of the cell from the outside environment. It keeps all the cellular contents safe so that they can function properly without being damaged.
The cell membrane is referred to as semi-permeable, which means it allows various nutrients to pass through the wall and sends the waste products out to be removed from the body. The permeability of this membrane also allows the cells to communicate clearly with one another.
The membrane must be fluid and mobile, rather than rigid, to allow for optimal functioning and adaptation to the internal environment. All of the dietary macronutrients—carbohydrates, fats, and proteins—are found in the cell membrane.
Fat is needed for proper cell structure and function, and the most abundant form of fat found in the cell membrane is the phospholipids.
The phospholipids have a hydrophobic or water-fearing tail and a hydrophilic or water-loving head. This love-hate relationship with water is what gives the membrane its unique structure and stability.
Cholesterol is another type of fat-related compound found in the cell membrane. Cholesterol improves the mechanical stability of the membrane and helps to regulate the fluidity. If the diet is too low in cholesterol, cell membrane structure can be compromised.
Protein’s Vital Role
The second major nutrient found in the cell membrane is protein. Proteins play a small role in forming the structure of the membrane, but they mostly contribute to the membrane functions.
Earlier thought in the nutrition field suggested that eating proteins only contributed to muscle function, quality, and size. However, proteins direct proper operations within each individual cell and also the healthy functioning of your entire body.
At the cellular level, proteins serve as pumps, gates, receptors, and catalysts for biochemical reactions. They’re responsible for the advanced communication that occurs between your cells, and they provide attachment sites for various molecules.
Cellular communication occurs at all times for various reasons. They communicate to take up nutrients from your bloodstream, to excrete waste products from the body, to signal chemical reactions, and more.
Proteins serve as channels by opening and closing when the cell receives a particular signal. They can also act as information transporters for what is going on outside the cell and within other adjacent cells.
Without this sophisticated communication network, the cells throughout your body will not work together, and bodily functions will start to fail. Think of it like a game of playing “Telephone.”
As soon as one message is not transmitted or received properly, the entire message is messed up. This ultimately creates an environment that is not optimal for body composition, health, or performance.
Lastly, carbohydrates are also found in the cell membrane, but in smaller amounts compared to fats and proteins. Carbohydrates contribute to membrane structure and also typically function to support cellular signaling.
Cellular DNA and Proteins
Now that you understand how the nutrients in our food form and sustain our cell membranes, let’s move on to the inside of the cell.
The next important cellular structure that is essentially built from our foods is the nucleus. The nucleus is the largest organelle, or specialized structure, within the cell and it contains the cell’s DNA.
The nuclear envelope surrounds the nucleus. This two-layer membrane is composed primarily of lipids and proteins.
It also contains minerals that are needed for activities within the nucleus itself. The nucleus can be referred to as your genetic storehouse because it contains all of your personal information within its membrane walls in the DNA.
DNA is a blueprint for every single one of the body’s proteins. The proteins that make up your tissues, organs, and chemical messengers originate from the coding of DNA and the quality of the food that we eat.
For this reason, it’s vital that the nucleus has a solid structure to keep the DNA safe from damage that occurs from normal metabolic and oxidative stresses, including aging itself. Nutrition also plays an important role in protecting your DNA.
DNA is one of two very important nucleic acids, with the second being RNA. These are made of a nitrogen base, a 5-carbon sugar unit, and a phosphate molecule.
RNA and DNA work together to provide the codes for your cells to produce new proteins and new cells themselves. You can see how what you eat influences your DNA.
Mitochondria: Your Cell’s Powerhouse
The final cellular structure is the mitochondria. You may remember the mitochondria as the powerhouse of the cell from your high school biology days.
This nickname was given to the mitochondria because it is part of the cell that is responsible for energy production. All of the nutrients from your food are turned into energy within the microscopic mitochondria of your cells.
Each cell that you have contains anywhere from several hundred to over 2,000 mitochondria, depending on the amount of energy that cell needs to function optimally. Your heart and your skeletal muscles are very hardworking organs that need a lot of energy. Cells within these organs may have up to 40 percent of their space occupied by mitochondria.
Again, just like the cell membrane and the nuclear membrane, the mitochondrial membrane is made up of fats and proteins. The mitochondrial membrane has an inner and an outer layer, both of which play important roles in energy processes.
The inner membrane is made up of about 75 percent protein. These proteins function in the final stage of energy production in something called the electron transport chain, which is a series of electron transporters embedded in the inner mitochondrial membrane.
The mitochondria also use many micronutrients to assist with producing energy. The B vitamins are particularly important micronutrients in the energy production processes.
Keep in mind that the structural and functional integrity of the mitochondrial membrane is absolutely critical to your health. If the structure and/or function is compromised, energy production from that cell will be compromised. This mitochondrial dysfunction can contribute to several chronic diseases, including diabetes, heart disease, and Parkinson’s disease.
Think about how important the nutrients you get from your diet are, now that you know the roles these nutrients play in the health of your body and the link between nutrients and individual cell health.
Dr. Michael Ormsbee is an Associate Professor in the Department of Nutrition, Food, and Exercise Sciences and Interim Director of the Institute of Sports Sciences and Medicine in the College of Human Sciences at Florida State University. He received his M.S. in Exercise Physiology from South Dakota State University and his Ph.D. in Bioenergetics from East Carolina University.