Edited by Kate Findley and proofread by Angela Shoemaker, The Great Courses Daily
Like vitamins, minerals are an essential micronutrient—in very small amounts—to be included in our diets because we don’t make them naturally. Even if you include them in your diet, you may not be getting the full benefit of those minerals. Professor Ormsbee explains.
Why Minerals Matter
Ingestion of a mineral-containing food does not necessarily translate to 100% absorption of the mineral. This concept is called mineral bioavailability.
In other words, even though you consume food with minerals, there are several factors that can affect how much of this mineral is actually absorbed from the gut to the bloodstream. To understand why this is significant, you first need to understand the purpose that minerals serve.
Minerals are inorganic molecules—meaning molecules without carbon. Similar to vitamins, minerals also serve many different regulatory functions in our bodies.
They work as cofactors, meaning they assist enzymes in energy transformation, contribute to the production of other cells and enzymes, and help form red blood cells and bones. Minerals are involved in nerve impulses, body growth and development, water balance, muscle movement, and metabolism.
The Power of Electrolytes
If you have heard of electrolytes, then you may know one function of minerals. When you or your child is ill with the flu, or losing fluids because of vomiting and/or diarrhea, you may have bought a drink that had electrolytes in it to help protect against dehydration.
Electrolytes are minerals that keep our nervous system firing properly. They are electrically charged particles that most commonly include sodium, potassium, magnesium, and chloride.
They help with establishing the electrochemical gradient across cells, which is necessary for proper nerve communication. They also assist with muscle contraction and modulate fluid exchange within the body’s fluids compartments.
That means that the electrolyte minerals play a big role in how we store water and where we store water. In this way, they influence our body composition and body water content quite a bit.
Types of Minerals
Because we need minerals in very small amounts, it is even more critical not to underestimate the value that they have in our bodies. Think small but mighty.
The two types of minerals are major minerals, also called macrominerals, and trace minerals, also called microminerals. The major minerals include calcium, phosphorus, sodium, and magnesium, among others, and they are required in amounts greater than 100 mg per day. Just a quarter teaspoon provides about 600 mg of sodium.
Trace minerals, on the other hand, include selenium, iron, and zinc, and these are required in amounts less than 100 mg per day and typically even less than 15 mg per day.
Minerals and Bioavailability
When it comes to mineral consumption, your body does not necessarily absorb the full amount. This is where you must take bioavailability into account.
In our foods, there are molecules like oxalates and phytates that can alter mineral absorption, and these are often called binders. They may bind up minerals in the food and change the way you can access or use them—that is, they can change the bioavailability of the minerals. In general, there are four factors involved in mineral bioavailability.
First, the type of food that contains the minerals matters. Typically, animal sources have better bioavailability of minerals than plant sources.
This is because meat has a high mineral content but no binders that can inhibit absorption of minerals. Plants, on the other hand, have a relatively high concentration of binders, making it more difficult to absorb the nutrients within.
The second factor in mineral bioavailability is mineral-to-mineral interaction. Because minerals tend to move through similar receptors in the gastrointestinal tract, high amounts of one mineral may inhibit or slow down absorption of another mineral.
For example, calcium will inhibit iron absorption. Thus, if you are targeting foods to increase your iron, as with an iron deficiency, it’s best to avoid eating foods high in calcium, like dairy, at the same meal.
Third, there are some vitamin-mineral interactions that will affect mineral bioavailability. One positive interaction example is that vitamin C intake actually improves iron absorption.
In this case, it might make sense to consume orange juice and a supplement with iron at the same time if you are trying to fix an iron deficiency. A dietician will have additional information about foods that you can pair to optimize your supplementation strategies for minerals.
Finally, the fourth factor in mineral bioavailability is a fiber-mineral interaction in which fiber can bind to minerals and block or slow their absorption. Typically our dietary fiber comes from plant sources—this is another reason that animal sources may often be superior in terms of mineral bioavailability.
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.
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 MS in Exercise Physiology from South Dakota State University and his PhD in Bioenergetics from East Carolina University.