Chapter 10: Micronutrients Overview and Role as Antioxidants
Recall from chapter 1 that micronutrients are nutrients that are essential for body functioning, but are only needed in small amounts. The micronutrients include both vitamins and minerals. We introduced the vitamins and minerals in chapter 1. The table below summarizes some important differences between the two.
Table 10.01 Differences between vitamins and minerals
| Vitamins | Minerals |
| Vitamins are organic | Minerals are inorganic |
| All vitamins are essential | Only some minerals are essential |
| Vitamins are classified by solubility: fat-soluble vs. water-soluble | Minerals are classified by the amount needed: major minerals vs. trace minerals |
| Can be destroyed by heat and sunlight | Cannot be destroyed |
There are two common ways to teach about vitamins and minerals in nutrition classes. The traditional way is to start with fat-soluble vitamins and go down through the vitamins alphabetically (i.e. vitamin A, vitamin D, vitamin E, vitamin K). However, this method leads students to learn about vitamins and minerals more individually instead of how they work together. For instance, it makes sense to cover calcium with vitamin D, and iron with copper and zinc. We are going to cover vitamins and minerals based on their function rather than covering them by whether they are a water-soluble vitamin or trace mineral. The hope is that you will gain a more integrative understanding of vitamins and minerals from this approach.
We’ll first give an overview of each type of micronutrient, and then we’ll discuss the specific functions of each micronutrient in the body. The micronutrients will be grouped into the functional categories indicated in the table below. Notice that some micronutrients fit into more than one functional category. Each vitamin and mineral will be covered only in one section, with some mention of its overlap in other section(s) in certain cases.
Table 10.02 Functional categories of micronutrients
| Functional Category | Micronutrients |
| Antioxidants | Vitamin E, Vitamin C, Selenium, Iron, Copper, Zinc, Manganese, Riboflavin |
| Metabolism | All B vitamins, Vitamin C, Iodine, Manganese, Magnesium |
| Bones and Teeth | Vitamin D, Calcium, Phosphorus, Fluoride, Vitamin K, Magnesium, Vitamin A, Iron, Copper, Zinc |
| Blood | Vitamin K, Iron, Copper, Vitamin B6, Vitamin B12, Folate, Calcium |
| Electrolytes | Sodium, Potassium, Chloride, Phosphorus, Magnesium |
In chapter 10, we’ll first talk more about what vitamins and minerals are. Then, this chapter will describe what antioxidants are and discuss the three major antioxidant micronutrients: vitamin E, vitamin C and selenium.
Sections 10.1-10.2: Adapted from Jellum, et al. Principles of Nutrition and Fialkowski Revilla, et al. Human Nutrition.
Section 10.3: Adapted from Jellum, et al. Principles of Nutrition.
Sections 10.4-10.6: Adapted from Fialkowski Revilla, et al. Human Nutrition.
Minerals are solid inorganic substances that form crystals and are classified depending on how much of them we need. Trace minerals such as zinc, iron, or iodine are only required in a few milligrams or less per day. Major minerals such as calcium, sodium, and potassium are required in hundreds of milligrams per day.
Fat-soluble molecules are molecules that dissolve in oils and other lipids, not in water. Fat-soluble nutrients are found in foods containing fat and are absorbed first into the lymphatic system and then moved to the blood system. Excess fat-soluble vitamins are stored in fatty tissue or the liver.
Water-soluble molecules are molecules that dissolve in water, not in oils. Water-soluble nutrients are absorbed directly into the bloodstream. Excess water-soluble vitamins are removed in the urine.
