Minerals in your body

Minerals: Their Functions and Sources

Topic Overview

The body needs many minerals; these are called essential minerals. Essential minerals are sometimes divided up into major minerals (macrominerals) and trace minerals (microminerals). These two groups of minerals are equally important, but trace minerals are needed in smaller amounts than major minerals. The amounts needed in the body are not an indication of their importance.

A balanced diet usually provides all of the essential minerals. The two tables below list minerals, what they do in the body (their functions), and their sources in food.

Macrominerals

Major minerals

Mineral	Function	Sources
Sodium	Needed for proper fluid balance, nerve transmission, and muscle contraction	Table salt, soy sauce; large amounts in processed foods; small amounts in milk, breads, vegetables, and unprocessed meats
Chloride	Needed for proper fluid balance, stomach acid	Table salt, soy sauce; large amounts in processed foods; small amounts in milk, meats, breads, and vegetables
Potassium	Needed for proper fluid balance, nerve transmission, and muscle contraction	Meats, milk, fresh fruits and vegetables, whole grains, legumes
Calcium	Important for healthy bones and teeth; helps muscles relax and contract; important in nerve functioning, blood clotting, blood pressure regulation, immune system health	Milk and milk products; canned fish with bones (salmon, sardines); fortified tofu and fortified soy milk; greens (broccoli, mustard greens); legumes
Phosphorus	Important for healthy bones and teeth; found in every cell; part of the system that maintains acid-base balance	Meat, fish, poultry, eggs, milk, processed foods (including soda pop)
Magnesium	Found in bones; needed for making protein, muscle contraction, nerve transmission, immune system health	Nuts and seeds; legumes; leafy, green vegetables; seafood; chocolate; artichokes; "hard" drinking water
Sulfur	Found in protein molecules	Occurs in foods as part of protein: meats, poultry, fish, eggs, milk, legumes, nuts

Trace minerals (microminerals)

The body needs trace minerals in very small amounts. Note that iron is considered to be a trace mineral, although the amount needed is somewhat more than for other microminerals.

Trace minerals

Mineral	Function	Sources
Iron	Part of a molecule (hemoglobin) found in red blood cells that carries oxygen in the body; needed for energy metabolism	Organ meats; red meats; fish; poultry; shellfish (especially clams); egg yolks; legumes; dried fruits; dark, leafy greens; iron-enriched breads and cereals; and fortified cereals
Zinc	Part of many enzymes; needed for making protein and genetic material; has a function in taste perception, wound healing, normal fetal development, production of sperm, normal growth and sexual maturation, immune system health	Meats, fish, poultry, leavened whole grains, vegetables
Iodine	Found in thyroid hormone, which helps regulate growth, development, and metabolism	Seafood, foods grown in iodine-rich soil, iodized salt, bread, dairy products
Selenium	Antioxidant	Meats, seafood, grains
Copper	Part of many enzymes; needed for iron metabolism	Legumes, nuts and seeds, whole grains, organ meats, drinking water
Manganese	Part of many enzymes	Widespread in foods, especially plant foods
Fluoride	Involved in formation of bones and teeth; helps prevent tooth decay	Drinking water (either fluoridated or naturally containing fluoride), fish, and most teas
Chromium	Works closely with insulin to regulate blood sugar (glucose) levels	Unrefined foods, especially liver, brewer's yeast, whole grains, nuts, cheeses
Molybdenum	Part of some enzymes	Legumes; breads and grains; leafy greens; leafy, green vegetables; milk; liver

Other trace nutrients known to be essential in tiny amounts include nickel, silicon, vanadium, and cobalt

Steps for Special Consideration

Some minerals need the help of other nutrients to perform their functions well in your body. These include:

Calcium: Vitamin D helps you to absorb the calcium from foods. Vitamin D is found in fortified milk and soy or rice beverages, eggs, fish (for example salmon and tuna), and organ meats like liver and heart. You don't need to take the vitamin D at the same time as the calcium but it is important to get vitamin D each day.

Iron: Plant sources of iron are not as easily absorbed as animal sources. Choosing vitamin C rich foods at the same time as plant sources of iron will help you to absorb more iron from the plant foods. Vitamin C rich foods include citrus fruits, tomatoes, potatoes, sweet peppers and strawberries. For example the vitamin C in tomatoes will help your body absorb iron from beans in a vegetarian chilli.

Most people can meet their mineral needs through a healthy diet. Certain people need extra minerals in the form of a supplement, in addition to following the CFG. These include:

Calcium: If you have osteoporosis, you need 1200 milligrams (mg)/day of calcium. In addition to following CFG you may also need a supplement to meet your needs. Don’t get more than 2000 mg of calcium from food and supplements per day. It is important to make sure that you get 800-2000 IU of vitamin D per day to help you absorb the calcium.

Iron: Pregnant women need extra iron in order to meet their own and their baby's needs. Most women find it hard to get enough iron from food and would benefit from an iron supplement of 16-20 mg per day during pregnancy (the amount usually found in prenatal supplements).

Taking minerals in large doses may cause harm. Iron supplements are especially harmful for children and should be kept out of their reach at all times.