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Publication #FCS8809

Facts About Minerals1

R. Elaine Turner and Wendy J. Dahl2

Figure 1. 

What are minerals?


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Jonathan Lidbeck CC BY 2.0 http://flic.kr/p/4CRUjc


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What are minerals?

If the word "mineral" makes you think of rocks, you're right! Minerals are substances like calcium, phosphorus, iron, and zinc that are found in rocks and the soil. They also are needed for optimal nutrition. There are 16 different minerals that are known to be needed in our diets. Several other minerals may be needed in very small amounts.

Table 1. 

The 16 minerals that we need in our diet.

Macrominerals

Trace Minerals

Sodium

Iron

Potassium

Zinc

Chloride

Iodide

Calcium

Selenium

Phosphorus

Copper

Magnesium

Fluoride

Sulfur

Chromium

Molybdenum

Manganese

What are the different types of minerals?

Minerals are grouped as macrominerals and trace minerals. Macrominerals are those found in larger quantities in the body and needed in larger amounts in the diet. Calcium and phosphorus are two of the seven macrominerals that we need in our diets.

Trace minerals are found in small quantities in the body and are needed in small amounts in the diet. We need to include nine trace minerals in our diets, including iron and zinc.

What do minerals do in the body?

Minerals work in two ways in the body. Many minerals support body cells and structures. For example, calcium and phosphorus help build bones, and iron is an essential part of red blood cells.

Minerals also work to regulate many body processes. Sodium and potassium are important to nervous system function. Chromium helps keep blood glucose levels normal. The trace mineral selenium works with vitamin E as an antioxidant, preventing cells from being damaged by oxygen (1).

Where are minerals found in foods?

All of the food groups have foods rich in minerals. For example, milk is a good source of calcium, and red meat is rich in iron and zinc. Fruits and vegetables are good sources of potassium. Whole grains are rich in magnesium, selenium, and chromium. Nuts and seeds are sources of copper and manganese.

It’s important to eat a variety of foods from each of the food groups in order to get all of the minerals in your diet.

Are animal products better sources of minerals than plant foods?

Certain minerals (like iron and zinc) tend to be better absorbed by the body from animal foods than from plant foods. Phytate and oxalate, which are found mainly in whole grains, vegetables, and legumes, reduce absorption of some minerals (2). Still, plant foods are important sources of many minerals, so diets rich in a variety of plant foods can provide adequate amounts of minerals.

Does food processing affect the mineral content of foods?

Minerals are stable in food. They generally remain in the food even after cooking, canning, or freezing. However, food processing can still affect the content of certain minerals. For example, refining or milling will decrease the chromium content of foods, and processing steps involving food additives can increase the phosphorus content (3).

Processing also affects the balance of sodium and potassium in vegetables. Fresh vegetables are rich in potassium and naturally low in sodium. Canned vegetables are usually higher in sodium from added salt.

How much of each mineral do I need each day?

The amount of minerals we need is actually very small – much smaller than the amounts of carbohydrates, protein, and fats required for a healthy diet. Most adults need about 1,000 milligrams of calcium per day, but only about 10 to 15 milligrams of iron and zinc per day (4). Table 2 lists the Recommended Dietary Allowance (RDA) and Adequate Intakes (AI), the daily intakes that should meet the needs of most healthy people.

We need less than 100 micrograms of chromium, selenium, and molybdenum. To give you an idea of how little this is, a teaspoon of selenium would satisfy the daily needs of over 90,000 adults!

The Daily Value for a mineral on a food label shows you what percent of a typical healthy adult's need for that vitamin is provided by the food. For example, an 8-ounce glass of low fat milk provides 30% of the Daily Value for calcium.

Table 2. 

Recommended Dietary Allowance (RDA) or Adequate Intakes (AI) for selected minerals (4).

 

Calcium (mg/d)

Phosphorus (mg/d)

Magnesium (mg/d)

Iron (mg/d)

Zinc (mg/d)

Men

19-30y

1000

700

400

8

11

31-70y

1000

700

420

8

11

71+

1200

700

420

8

11

Women

19-30y

1000

700

310

18

8

31-50y

1000

700

320

18

8

51+

1200

700

320

8

8

mg/d = milligrams per day

y = years

Should I take supplements to get the minerals I need?

It is possible to get all the minerals you need by making healthy food choices from all of the food groups in MyPlate (see ChooseMyPlate.gov). But there are some situations where supplements may be needed:

  • Women in their childbearing years may find it hard to get all the iron they need from food.

  • People who are allergic to milk may have a hard time getting enough calcium.

  • Pregnant women should ask their physicians about the supplements that are right for them.

  • Sometimes taking a mineral supplement such as iron causes an upset stomach. If this occurs, try taking the supplement before bed, or use a slow-release supplement.

Table 3. 

A typical label from a mineral supplement.

Supplement Facts

Serving Size: 1 tablet

Amount Per Serving

% Daily Value

Calories 10

 

Total Carbohydrate 2g

<1%

Sugars 2g

 

Calcium 600 mg

60%

Magnesium 40 mg

10%

Zinc 7.5 mg

50%

Copper 1 mg

50%

Manganese 1.8 mg

90%

Boron 250 mcg

*

*Daily Value not established

Percent Daily Value based on a 2,000 calorie diet.

Can large amounts of minerals be harmful?

With minerals, as with many things in life, more is not necessarily better. Many minerals can be toxic in large doses, with side effects ranging from constipation to liver and kidney damage. Too much sodium may contribute to high blood pressure in some individuals.

There are recommendations for the maximum intakes for most minerals. Excessive mineral intake usually comes from high-dose supplements. That's why most people should choose to consume no more than the Tolerable Upper Limit (UL) for a mineral each day. The ULs for some minerals are given in Table 4.

Table 4. 

Tolerable Upper Limit (UL) for selected minerals.

 

Calcium (mg/d)

Phosphorus (mg/d)

Magnesium (mg/d)

Iron (mg/d)

Zinc (mg/d)

UL

2500*

4000

350

45

40

*For men and women over 50 years, the UL for Calcium is 2000 mg/d

mg/d = milligrams per day

If you currently are taking medications, you should check with your doctor or pharmacist to see if there are any reasons that you shouldn't take a mineral supplement. Also, ask if you need to adjust the timing of your mineral supplements and other medications.

Some minerals can interfere with how well a medication works in the body. Alternatively, some medications can interfere with how well the body uses a mineral. That's why it's important to ask your doctor or pharmacist before taking a mineral supplement.

Where can I get more information on minerals?

The Family and Consumer Sciences (FCS) agent at your local county Extension office may have more written information and nutrition classes for you to attend. Also, a registered dietitian (RD) can provide reliable information to you.

Reliable nutrition information may be found on the Internet at the following sites:

http://fycs.ifas.ufl.edu

http://solutionsforyourlife.ufl.edu

http://www.nutrition.gov

http://www.nal.usda.gov/fnic

References

Higdon, J. Micronutrient Research for Optimum Health. Linus Pauling Institute, Oregon State University, 2003 (Reviewed 2007), http://lpi.oregonstate.edu/infocenter/minerals/chromium/

Gibson R, Bailey K, Gibbs M, Ferguson E. A review of phytate, iron, zinc, and calcium concentrations in plant-based complementary foods used in low-income countries and implications for bioavailability. Food Nutr Bull. 2010 Jun 31 (2 Suppl):S134-46.

Benini O, D'Alessandro C, Gianfaldoni D, Cupisti A. Extra-Phosphate Load From Food Additives in Commonly Eaten Foods: A Real and Insidious Danger for Renal Patients. J Ren Nutr. 2010 Nov 3. [Epub ahead of print]

Dietary Reference Intakes (DRIs): Recommended Intakes for Individuals, Food and Nutrition Board, Institute of Medicine, National Academies Press, 2004, http://www.iom.edu/Activities/Nutrition/SummaryDRIs/~/media/Files/Activity%20Files/Nutrition/DRIs/5_Summary%20Table%20Tables%201-4.pdf

Footnotes

1.

This document is FCS8809, one of a series of the Department of Family, Youth and Community Sciences, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. First published December 2006. Revised January 2012. Visit the EDIS website at http://edis.ifas.ufl.edu.

2.

R. Elaine Turner, associate dean, College of Agricultural and Life Sciences, and Wendy J. Dahl, assistant professor, Food Science and Human Nutrition Department, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, FL 32611.


The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.