Chapter 8. Introduction to Micronutrients
Introduction to Minerals
Similar to vitamins, minerals are essential to human health and can be obtained in our diet from different types of food. Minerals are abundant in our everyday lives. From the soil in your front yard to the jewellery you wear on your body, we interact with minerals constantly. There are 20 essential minerals that must be consumed in our diets to remain healthy. The amount of each mineral found in our bodies varies greatly and therefore, the consumption of these minerals also varies. When our diet is deficient in an essential mineral, health problems may arise.
Major minerals are classified as minerals required in the diet each day in amounts larger than 100 milligrams. These include sodium, potassium, chloride, calcium, phosphorus, magnesium, and sulfur. These major minerals can be found in various foods. For example, in Guam, the major mineral, calcium, is consumed in the diet not only through dairy but also through the mixed dishes, desserts and vegetables consumed. Consuming a varied diet significantly improves an individual’s ability to meet their nutrient needs.[1]
Trace minerals are classified as minerals required in the diet each day in smaller amounts, specifically 100 milligrams or less. These include copper, zinc, selenium, iodine, chromium, fluoride, manganese, molybdenum, and others. Although trace minerals are needed in smaller amounts, it is important to remember that a deficiency in a trace mineral can be just as detrimental to your health as a major mineral deficiency. For instance, iodine deficiency is a major concern in countries around the world such as Fiji. In the 1990s, almost 50% of the population had signs of iodine deficiency also known as goiter. To combat this national issue, the government of Fiji banned non-iodized salt and only allowed fortified iodized salt into the country in hopes of increasing the consumption of iodine in people’s diets. With this law, and health promotion efforts encouraging the consumption of seafood, great progress has been made in decreasing the prevalence of iodine deficiency in Fiji.[2]
| Micronutrient | Sources | Recommended Intakes for adults | Major functions | Deficiency diseases and symptoms | Groups at risk for deficiency | Toxicity | UL |
| Calcium | Yogurt, cheese, sardines, milk, orange juice, turnip | 1,000 mg/day | Component of mineralized bone, provides structure and microarchitecture | Increased risk of osteoporosis | Postmenopausal women, those who are lactose intolerant, or vegan | Kidney stones | 2,500 mg |
| Phosphorus | Salmon, yogurt, turkey, chicken, beef, lentils | 700 mg/day | Structural component of bones, cell membrane, DNA and RNA, and ATP | Bone loss, weak bones | Older adults, alcoholics | None | 3,000 mg |
| Magnesium | Whole grains and legumes, almonds, cashews, hazelnuts, beets, collards, and kelp | 320-420 mg/day | Component of mineralized bone, ATP synthesis and utilization, carbohydrate, lipid, protein, RNA, and DNA synthesis | Tremor, muscle spasms, loss of appetite, nausea | Alcoholics, individuals with kidney and gastrointestinal disease | Nausea, vomiting, low blood pressure | 350 mg/day from pharmacological agents and/or dietary supplements |
| Sulfur | Protein foods | None specified | Structure of some vitamins and amino acids, acid-base balance | None when protein needs are met | None | None | ND |
| Sodium | Processed foods, table salt, pork, chicken | 1,500 mg/day | Major positive extracellular ion, nerve transmission, muscle contraction, fluid balance | Muscle cramps | People consuming too much water, excessive sweating, those with vomiting or diarrhea | High blood pressure | |
| Potassium | Fruits, vegetables, legumes, whole grains, milk | 2600 mg/day
(Females) 3400 mg/day (Males) |
Major positive intracellular ion, nerve transmission, muscle contraction, fluid balance | Irregular heartbeat, muscle cramps | People consuming diets high in processed meats, those with vomiting or diarrhea | Abnormal heartbeat | ND |
| Chloride | Table salt, processed foods | 2300 mg/day | Major negative extracellular ion, fluid balance | Unlikely | none | None | 3,600 mg/day |
| Micronutrient | Sources | Recommended Intakes for adults | Major Functions | Deficiency diseases and symptoms | Groups at risk for deficiency | Toxicity | UL |
| Iron | Red meat, egg yolks, dark leafy vegetables, dried fruit, iron-fortified foods | 8-18 mg/day | Assists in energy production, DNA synthesis required for red blood cell function | Anemia: fatigue, paleness, faster heart rate | Infants and preschool children, adolescents, women, pregnant women, athletes, vegetarians | Liver damage, increased risk of diabetes and cancer | 45 mg/day |
| Copper | Nuts, seeds, whole grains, seafood | 900 mcg/day | Assists in energy production, iron metabolism | Anemia: fatigue, paleness, faster heart rate | Those who consume excessive zinc supplements | Vomiting, abdominal pain, diarrhea, liver damage | 10 mg/day |
| Zinc | oysters, wheat germ, pumpkin seeds, squash,, beans, sesame seeds, tahini, beef, lamb | 8-11 mg/day | Assists in energy production, protein, RNA and DNA synthesis; required for hemoglobin synthesis | Growth retardation in children, hair loss, diarrhea, skin sores, loss of appetite, weight loss | Vegetarians, older adults | Depressed immune function | 40 mg/day |
| Selenium | Meat, seafood, eggs, nuts | 55 mcg/day | Essential for thyroid hormone activity | Fatigue, muscle pain, weakness, Keshan disease | Populations where the soil is low in selenium | Nausea, diarrhea, vomiting, fatigue | 400 mcg/day |
| Iodine | Iodized salt, seaweed, dairy products | 150 mcg/day | Making thyroid hormone, metabolism, growth and development | Goiter, cretinism, and other signs and symptoms include fatigue, depression, weight gain, itchy skin, low heart rate | Populations where the soil is low in iodine and iodized salt is not used | Enlarged thyroid | 1110 mcg/day |
| Chromium | 25-35 mcg/day | Assists insulin in carbohydrate, lipid and protein metabolism | abnormal glucose metabolism | Malnourished children | None | ND | |
| Fluoride | Fluoridated water, foods prepared in fluoridated water, seafood | 3-4 mg/day | Component of mineralized bone, provides structure and microarchitecture, stimulates new bone growth | Increased risk of dental caries | Populations with non-fluoridated water | Fluorosis mottled teeth, kidney damage | 10 mg/day |
| Manganese | Legumes, nuts, leafy green vegetables | 1.8-2.3 mg/day | Glucose synthesis, amino-acid catabolism | Impaired growth, skeletal abnormalities, abnormal glucose metabolism | None | Nerve damage | 11 mg/day |
| Molybdenum | Milk, grains, legumes | 45 mcg/day | Cofactor for several enzymes | Unknown | None | Arthritis, joint inflammation | 2 mg/day |
- Pobocik RS, Trager A, Monson LM. Dietary Patterns and Food Choices of a Population Sample of Adults on Guam. Asia Pacific Journal of Clinical Nutrition. 2008; 17(1), 94-100. http://apjcn.nhri.org.tw/server/APJCN/17/1/94.pdf. Accessed February 16, 2018. ↵
- Micronutrient Deficiencies. Ministry of Health and Medical Services, Shaping Fiji’s Health. http://www.health.gov.fj/?page_id=1406. Published 2015. Accessed November 12, 2017. ↵
