Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
The nutrition world is consistently focused on the latest, greatest vitamin and how it can transform your health. When it comes to minerals, though, less information is widely available to the public. Professor Anding explains what minerals can do for you and how they relate to vitamins.
What Are Minerals?
Before distinguishing between vitamins and minerals, let’s start by defining minerals. Minerals are inorganic substances that the body needs in minute amounts in order to provide structure to components of tissue and cellular compounds, such as forming bones and teeth.
Additionally, minerals help to maintain chemical gradients such as acid-base balance, heart rhythm, contractility of muscles, and neural conductivity. Minerals also regulate the function of enzymatic activities at the cellular level. Seven major minerals are essential to life.
The definition of “major” varies, depending on the source that you read, but it generally means the amount that you need in your diet, but isn’t related to the importance of that mineral. In general, greater than 100 milligrams (mg) per day falls into that definition of a “major” mineral.
Calcium, phosphorus, potassium, sulfur, sodium, chlorine, and magnesium are considered major minerals. As a companion, there are 14 trace minerals, meaning that they are needed in amounts less than 100 mg per day, but still vital to human nutrition.
These 14 trace minerals include iron, selenium, iodine, chromium, zinc, fluoride, copper, manganese, molybdenum, boron, silicon, vanadium, nickel, and strontium. Again, you still need trace minerals but in small amounts.
Vitamins Versus Minerals
Let’s compare and contrast the difference between vitamins and minerals in human nutrition. Vitamins catalyze, which means cause or accelerate, chemical reactions in the body without becoming part of the reaction byproducts. Think of them as the spark plug in your engine.
On the other hand, some minerals become part of the body’s structure and chemicals, such as calcium in bone and iron in hemoglobin. Another key word to understand is “bioavailability.” Bioavailability is the amount of any particular mineral that you eat in your diet that your body will actually be able to absorb and use.
For example, spinach contains a lot of calcium, but the body is only able to absorb and use about 5% of it. The same is true for dietary iron. The average efficiency of its absorption in the intestines is approximately 10%.
Multiple factors play a role in the bioavailability of minerals and food sources, and one is the type of food. Minerals in animal products are more biologically available and readily absorbed by the small intestine.
Animal products do not contain plant binders and dietary fibers that can slow digestion and hinder absorption. Diets high in fiber retard the absorption of calcium, iron, magnesium, and phosphorus.
If you take a fiber supplement in the morning along with your multivitamin, you may be getting too much fiber in that one meal; it will bind and retard the absorption of essential minerals. Fiber binds to the minerals and causes them to pass through the GI tract unabsorbed.
Vitamins and minerals interact with each other in a way that affects how each is absorbed. For example, vitamin D enhances calcium absorption and vitamin C enhances iron absorption. Those two minerals are better absorbed in the presence of those two vitamins.
At the same time, many minerals compete with each other for absorption because they are of similar molecular weight. According to Professor Anding, you should not consume an excess of any one mineral because it can negatively affect another mineral’s absorption. Additionally, as with most things, minerals can have harmful side effects if consumed in excess.
One of Professor Anding’s close friends was diagnosed with aggressive breast cancer and went through a stem cell transplant. She called Andings one day, saying she thought her cancer had come back. She believed this because she had chronic diarrhea, and no dietary changes helped.
“Well, as I went over to her house to give her some comfort, I saw all these mineral supplements on her kitchen table,” Professor Anding said. “Actually, when I added up the amount of magnesium she was taking—think Milk of Magnesia—she was taking enough to cause diarrhea, so it wasn’t, thank goodness, a metastasis or a return of her cancer. It was actually a magnesium overdose.”
This article was edited by Kate Findley, Writer for The Great Courses Daily, and proofread by Angela Shoemaker, Proofreader and Copy Editor for The Great Courses Daily.
Professor Roberta H. Anding is a registered dietitian and Director of Sports Nutrition and a clinical dietitian at Baylor College of Medicine and Texas Children’s Hospital. She also teaches and lectures in the Baylor College of Medicine’s Department of Pediatrics, Section of Adolescent Medicine and Sports Medicine, and in the Department of Kinesiology at Rice University.