Minerals are substances typically found in nonliving things such as rocks or metal ores. Although minerals also are found in plants and animals, they do not occur there naturally. Instead, plants sometimes take up minerals from the soil in which they are planted. Animals obtain minerals when they eat these plants.
Minerals are substances made up of structures of single atoms (elements). They are inorganic and typically do not feature the carbon, hydrogen and oxygen atom chains that are part of organic compounds. Unlike vitamins, minerals cannot be broken down into other substances and instead always retain their chemical identity.
The rate and extent to which minerals are absorbed and used (bioavailability) varies from mineral to mineral. Some foods have substances such as phytates or oxalates that bind chemically with minerals and prevent the minerals from being absorbed. In addition, the presence of certain minerals can prevent the absorption, metabolism or excretion of others. Certain foods may also help the body absorb certain types of minerals.
Minerals typically are named after their location of origin or after a descriptive feature, such as color. All minerals are categorized as one of two types:
- Major minerals. Required by the body in large amounts. The body maintains a steady supply of about 5 grams (g) of each of the major minerals and principal electrolytes. A person needs to consume about 250 milligrams (mg) a day of each of these minerals to keep supplies of the mineral steady and to make up for amounts that are naturally lost over the course of a day.
- Trace elements. Required by the body in tiny amounts. The body stores less than 5 g of each of the trace elements. A person needs to consume fewer than 20 mg a day of these trace elements to maintain steady levels in the body.
When a mineral enters the body, it is absorbed in the intestines and moved through the body or stored. Some minerals move directly into the bloodstream and are carried into cells. Other minerals attach to proteins and become part of the body structure.
The major minerals that are essential for human beings include the following:
The most common mineral in the body, people obtain it from their diet. It is crucial to building and maintaining strong bones and teeth. In addition, calcium is involved in many other body processes, including maintaining fluid balance, muscle and blood vessel contraction, regulating the heartbeat and conducting nerve impulses to send messages through the nervous system. Calcium is also needed for proper blood clotting.
Present in tiny amounts in the body. It has many different roles, including helping to make bone and other tissues, converting food to energy, and aiding in the activity of more than 300 enzymes (chemicals that regulate various bodily functions).
Like calcium, phosphorus is obtained from the diet and is essential for strong bones and teeth. It also helps transmit the genetic code of genes and chromosomes from cell to cell during cell division and growth. Phosphorus is part of the protective sheath around nerve cells (myelin sheath). Other tasks performed by this mineral include metabolizing carbohydrates and maintenance of the body’s pH balance.
A mineral that is an integral component of all proteins. Sulfur is involved primarily in protein and certain enzyme synthesis. People who consume adequate levels of protein also get adequate levels of sulfur.
Three of the major minerals are also known collectively as the principal electrolytes. They work together to regulate the flow of fluids into and out of the body’s cells. They also transmit nerve impulses. The three electrolytes are:
A compound made up of the poisonous gas chlorine and sodium or hydrogen. This combination results in a nutrient required by the body. It is the major anion (negatively charged ion) contained mainly in the fluid outside body cells. Chloride helps the body maintain a normal balance of fluids.
Found in all living cells, including those of plants and animals. It is an essential part of electrical and cellular functions within the body and has various roles in metabolism. The digestive system, heart, kidneys, muscles and nerves all require potassium to function properly.
Occurs naturally in food and helps regulate the fluid balance of cells and plasma (the fluid portion of blood). Salt regulates both blood pressure and blood volume. Too little sodium in the body can result in dehydration because the cells are unable to retain water. Proper fluid balance is important to nutrition because it helps move nutrients into the cells and carries waste products out of the cells.
Trace minerals are present in the body in tiny amounts. They include:
Boosts the activity of the hormone insulin and appears to play a direct role in carbohydrate, fat and protein metabolism. It is found in certain enzymes in the body. Without adequate amounts of chromium, blood sugar levels may rise and a person may develop a diabetes-like condition.
Found in all body tissues, it plays several vital roles in the body. It is necessary for the body’s absorption and use of the mineral iron. It is an antioxidant and helps deactivate free radicals, which are chemicals that bind together to damage body cells. Copper also helps the body create collagen and heal wounds, and is essential to many of the metabolic reactions that release energy for bodily processes.
Component of the mineral fluorine that is naturally present in soil, water, air and certain foods (e.g., meat, fish, eggs, tea leaves). When fluoride enters the body, it is deposited into the teeth and bones, strengthening teeth during a process called remineralization (the rebuilding of tooth enamel). It is commonly added to community drinking water, and may be added to various foods and beverages during processing.
Plays a key role in the metabolism activity of cells and growth of tissues. It is part of the thyroid hormones thyroxin and triiodothyronine, which perform various roles in the body.
Found in many foods, it is essential for good health. Iron helps red blood cells to carry oxygen throughout the body. However, many people experience iron deficiency, which may cause fatigue, weakness and other health problems. People with certain health conditions may be at risk of consuming too much iron, leading to iron overload, which may be toxic.
Essential component of enzymes that metabolize carbohydrates and fats. It is vital to maintaining a healthy immune system. In addition, pregnant women who consume manganese help to support the proper growth of fetal tissue such as bones and cartilage.
Part of several enzymes that metabolize proteins. It is mostly found in beans and grains, but may also appear in dairy products and drinking water.
Boosts the performance of enzymes, which help the body carry out many chemical reactions that are crucial for brain and body functions. It is required for the body to function normally, but only in small amounts.
Promotes cell division and growth, boosts the immune system and is involved in the repair of body tissues. It is necessary for normal growth and development during childhood, adolescence and during pregnancy. It also is important in boosting male fertility.
Other trace minerals do not appear to have a role in the health of the body. These include arsenic, boron, nickel, cobalt, silicon and vanadium.
Minerals help to trigger or regulate many important body processes. They help the body maintain a proper fluid balance and play a key role in muscle contractions and nerve impulses. Minerals also give structure to bones, teeth, muscles and blood.
Some minerals are extremely easy to obtain through a normal diet. In the United States, it is rare to experience deficiencies of minerals such as copper, fluoride, phosphorus, magnesium, sulfur, manganese, chromium or molybdenum. However, deficiencies of other minerals are more common. These include calcium, iodine, iron, selenium and zinc.
Symptoms of mineral deficiency vary depending on the mineral. For example, a lack of calcium can impair the ability of the blood to clot, while an iron deficiency can cause anemia (a lack of red blood cells) that results in fatigue and an increased sensitivity to cold temperatures.
Consuming too much of some minerals also can lead to health problems including, in rare cases, death. Minerals that can be toxic when taken in large amounts include calcium, fluoride, iodine, iron, magnesium, molybdenum, phosphorus, selenium and zinc. Symptoms may include irregular heartbeat and cardiac arrest.
In addition, consuming excess amounts of certain minerals can prevent the body from absorbing or using other minerals. Examples of this include:
|Mineral in Excessive Amounts
||Magnesium, iron, zinc
Minerals are found in many different foods, with some foods containing more of a specific mineral than other foods. For example, whole-wheat breads contain magnesium, dairy products are rich in calcium and meats provide phosphorus and sulfur. In addition, some foods may be fortified with certain minerals. A well-balanced diet that incorporates foods from each of the five basic food groups (e.g., fruits, vegetables, grains, milk, meat/beans) is the best way to ensure an adequate supply of most of the major minerals and trace elements.
Many minerals also are available in supplement form. In some cases, these may be beneficial for people. For example, iron supplements can boost the supply of iron in a woman who loses excessive blood during her menstrual period. Pregnant and breastfeeding women also may benefit from taking certain supplements.
Men who are extremely sexually active may use a zinc supplement to replace the zinc they lose during ejaculation. Studies have also shown that men who take a selenium supplement may reduce their risk of prostate cancer by two-thirds.
However, mineral supplements should not be used without a physician’s approval. Certain mineral supplements may interact poorly with certain medications. For example, calcium may fasten antibiotics such as tetracycline into compounds the body cannot break apart. This prevents the body from absorbing the medication, nullifying its positive effects. Drinking milk or consuming dairy products also can have this type of negative impact on tetracycline.
Patients may wish to ask their doctor or registered dietitian the following questions related to mineral basics:
- How will I know if I’m getting too little or too much of certain minerals?
- Is the soil in this area rich in certain types of minerals? How will this affect my diet?
- Who can I talk to about planning a diet with an appropriate amount and variety of minerals?
- What types of foods offer the best variety of minerals?
- What foods do you suggest I eat to increase my intake of certain minerals?
- Do you advise taking mineral supplements to prevent certain diseases or for other reasons?
- What type of supplements do you recommend?
- Should I take these supplements with food?
- How can I make sure my child is getting enough of certain minerals in school meals?
- Will I have to alter my diet when taking antibiotics or other medications?