What is Magnesium’s fundamental role?
There is a host of scientific studies linking magnesium to many different health conditions, but reviewing these effects one by one is overwhelming and confusing. Instead, it’s more helpful to look at magnesium’s underlying physiological mechanisms. Understanding what magnesium does fundamentally will let us better understand how insufficient magnesium levels might affect our bodies and our daily lives. Magnesium’s hundreds of roles can be roughly categorized into four basic functions:
Magnesium activates enzymes
We are kept alive by trillions of chemical reactions that occur inside the body. Carbohydrates are broken up and harvested for energy. New tissue is created. Cellular waste products are removed. New strands of DNA are synthesized. This collection of chemical processes is called metabolism. The speed a reaction occurs will depend on factors like temperature, pressure, solubility and concentration of molecules. We use these factors every day. You might notice that sugar dissolves in hot water faster, or refrigerating food will slow the rate of decay. When you make a campfire, a hotter flame will burn wood faster.
Our metabolism needs to occur at a certain rate to keep us alive. but we don’t have the liberty of turning the body into a raging furnace to speed up these reactions, not without causing a lot of damage anyway. That’s where enzymes come in.
Enzymes are bits of protein that catalyze and regulate almost all metabolic reactions. As catalysts, they reduce the energy needed to spark a chemical reaction and speed up reactions. Without enzymes, reactions that would normally take milliseconds to occur might take hours or days. Some enzymes require additional ions or molecules called co factors to function. Without a co factor bound to its structure, an enzyme may float dormant and be unable to catalyze any reactions. Magnesium is a co factor for several important enzymes in the body, like DNA/RNA plymerases used to transcribe new DNA/RNA strands, and guanylate cyclase, used to regulate the movement of minerals across cell membranes.
A 1968 estimate suggested that magnesium was a required co factor for 300 enzymatic reactions. This figure is found in many medical texts and quoted in many scientific papers. Since then, many more enzymes that rely on magnesium have been identified. A search of today’s enzymatic databases reveals over 600 enzymes that magnesium is a co factor for and another 200 enzymes that need magnesium to be activated.
2. Magnesium creates cellular energy
Arguably the most important enzymes that magnesium is a co factor for are the ones that produce cellular energy. These enzymes form a series of pathways (glycolysis, Kreb’s cycle, phosphorylation) that convert organic compounds like glucose sugars into smaller molecules called adenosine triphosphate (ATP). ATP acts as our main unit of cellular energy.
Every one of our hundred trillion cells manufactures ATP to store and shuttle intracellular energy. ATP stores a tremendous amount of potential energy in the bonds of the second and third phosphate groups. When the cell wants to carry out a function like cellular division or transport molecules across the cell membrane, it breaks this bond and releases the energy.
We use a tremendous amount of ATP all the time. The typical adult only stores about 50g of ATP in the body so each ATP molecule is recycled over a thousand times a day. Since cellular pathways are magnesium dependent, we need quite a bit of magnesium on hand to fuel a continuous production of ATP.
3. Magnesium helps to create, repair and protect DNA and proteins
When a protein needs to be created, specific DNA nucleotide sequences are read and copied (transcribed) onto another molecule called RNA. The RNA strand is then moved out of the nucleus where enzyme-like organelles called ribosomes use it as a guide to synthesize chains of amino acids that form the desired protein.
This protein synthesis relies on all sorts of enzymes to work, from helicases that open up the DNA strand to be read, to RNA polymerases that create RNA based on the original DNA sequence, to protein kinases. Magnesium is a co factor for most of these critical enzymes. The ribosome, while not technically an enzyme, is the most important catalyst for stitching together amino acids into proteins. Lots of magnesium is needed to keep this complex riboprotein stable.
Without enough magnesium, protein is impaired. And since protein is used for most of the structural components and nearly all metabolic functions in the body, a lack of proteins can have widespread consequences.
4. Magnesium in the cell membrane regulates concentrations of other minerals
Some of those 3751 proteins dot the surface of our cell membranes and perform a variety of roles, like receiving signals from hormones (signal transduction), enzymatic activity and transporting things across the membrane. In particular, magnesium-dependent proteins are used to facilitate the transport of different minerals into and out of cells, acting as gates for sodium (Na+), potassium (K+), and calcium (Ca+).
Many of these are active transporters, for instance pumping sodium out of cells even though it’s against the concentration gradient.
Imagine a flooding basement. Water naturally flows downhill, so you’ll need a pump to move the water out of the basement, against the flow of gravity. Magnesium-powered ion pumps shunt sodium, against its concentration gradient out of the cell to maintain normal concentrations of sodium and potassium in and out of the cell. Just like the water pump in your basement, the ion pumps in your body are necessary to restore homeostasis and balance.
Source: Fall 2017: Vol 3. No. 2 Nd Notes – Magnesium & Me pgs. 3-5