Required in the diet and present in the body in large amounts compared with trace minerals.
Inorganic elemental atoms or ions.
Not changed during digestion.
Not destroyed by heat, alkalinity or light.
Assist enzymes.
Some have structural roles.
Minerals in Foods
Foods from both plants and animals are sources.
Animal tissues contain minerals in the proportions that animals need.
The mineral content of plants can vary dramatically depending upon the minerals in the soil.
The maturity of the vegetable, fruit, or grain can affect the mineral content.
Mineral Bioavailability
The GI tract absorbs a smaller proportion of minerals than vitamins.
Excess minerals are difficult for the body to flush out.
The body adjusts mineral absorption in relation to needs.
Some minerals compete for absorption sites; megadosing with one mineral can impede absorption of another.
High-fiber diets reduce absorption of iron, calcium, zinc, and magnesium.
Phytate (a component of whole grains) binds minerals and carries them out of the intestine unabsorbed.
Oxalate (found in spinach and rhubarb) binds calcium, reducing its absorption.
Sodium
Essential nutrient.
Component of sodium chloride (table salt).
Major extracellular cation.
Sodium Functions
Fluid balance (osmolarity).
Maintains proper body water distribution and blood pressure.
Nerve transmission and muscle function.
Controls the body’s acidity.
Sodium Food Sources and Recommended Intake
Limit to 2,300 mg/day (DV).
Processed foods contribute the most sodium.
The GI tract absorbs nearly all dietary sodium.
The kidneys excrete excess.
Hyponatremia
Abnormally low sodium concentrations in the blood due to excessive excretion of sodium, prolonged vomiting, or diarrhea.
Replacement of water without sodium.
Symptoms resemble dehydration.
Severe hyponatremia causes extracellular fluid to move into cells, causing them to swell.
Hypernatremia
Abnormally high sodium concentrations in the blood due to increased kidney retention of sodium or rapid ingestion of large amounts of salt.
Hypervolemia – an abnormal increase in the circulating blood volume.
Leads to Edema and an increase in blood pressure.
Excess dietary sodium can contribute to osteoporosis by increasing calcium loss in the urine.
ADA Dietary Guidelines for Americans
Consume less than 2,300 mg of sodium per day.
Individuals with hypertension, blacks, and middle-aged and older adults should aim to consume no more than 1,500 mg of sodium per day, and meet the potassium recommendation (4,700 mg/day) with food.
Potassium
Major intracellular cation.
If people with hypertension eat a diet rich in potassium containing foods (fruits and vegetables), their blood pressure often improves.
Potassium Functions
Muscle contractions.
Transmission of nerve impulses.
Helps regulate blood pressure.
Potassium Food Sources and Recommended Intake
Fresh vegetables and fruits, especially potatoes, spinach, melons, and bananas.
Hypokalemia
Low levels of blood potassium.
Severe deficiency results from potassium depletion (excessive losses).
Prolonged vomiting, chronic diarrhea, laxative abuse, use of diuretics.
Hyperkalemia
Abnormally high blood potassium.
Malfunctioning kidneys or an excess of intravenous potassium can cause hyperkalemia.
Can slow and eventually stop the heart.
Chloride
Anion in table salt.
Major extracellular anion.
Chloride Functions
Fluid balance.
Combines with H+ to form HCl (hydrochloric acid in the stomach).
White blood cells use chloride to kill invading bacteria.
Assists in the transmission of nerve impulses.
Chloride Food Source
Most of our chloride comes from salt.
The kidneys secrete excess chloride and some is lost in sweat.
The only known cause of high blood chloride is severe dehydration.
Hypochloremia
Frequent vomiting (bulimia nervosa) can cause a chloride deficiency which can lead to dehydration and metabolic alkalosis (high blood pH).
Calcium
About 1.5-2% of total body weight.
Essential for healthy bones and teeth.
Calcium Functions
Bones and tooth structure contain 99% of calcium.
Remaining 1% in blood and soft tissues which contributes to muscle contraction, nerve impulse transmission, blood clotting, and cell metabolism.
Bone Structure
Bone is made up of cells and an extracellular matrix.
Osteoblasts and osteoclasts continually remodel our bones.
Osteoblasts secrete the collagen protein matrix that forms the framework.
Minerals in the form of hydroxyapatite (calcium and phosphorus) surround the collagen fibers.
We achieve peak bone mass at around 30 years of age.
Calcium Food Sources
Dairy products.
Green leafy vegetables such as spinach have high levels of calcium, but it is mostly bound to oxalate and therefore cannot be absorbed.
Chinese cabbage, kale, and turnip greens have significant amounts of bioavailable calcium.
Some food products are fortified with calcium.
Calcium Recommended Intake
Adequate Intake (AI) for adults 19 to 50 yrs: 1,000 mg/day.
AI for adults aged 51 and older: 1,200 mg/day.
AI for adolescents 9 to 18: 1,300 mg/day.
Regulation of Blood Calcium
Three hormones regulate blood calcium:
Calcitriol (active form of vitamin D)
Parathyroid hormone (PTH)
Calcitonin
These hormones control intestinal absorption of calcium, bone calcium release, and calcium excretion by the kidneys.
Calcium Absorption
Between 25% to 75% of dietary calcium is absorbed.
High during pregnancy and infancy, low during old age.
Requires adequate levels of vitamin D.
Inversely related to calcium intake.
Phytates (in nuts, seeds, grains) and oxalates decrease absorption.
Calcium from supplements taken between meals and at lower doses of 500 mg or less assists in absorption.
Hypocalcemia
Deficiency of calcium in the blood, rare because the body uses bone calcium to maintain blood levels.
Chronic dietary deficiency causes osteoporosis.
Hypercalcemia
Major causes are cancer and overproduction of PTH by the parathyroid gland.
Excess Calcium Supplementation
May cause mineral imbalances by interfering with the absorption of other minerals, such as iron, magnesium, and zinc.
Phosphorus
Widespread in the food supply.
Most abundant intracellular anion.
Phosphorus Functions
Plays an important role in bone as part of the mineral complex hydroxyapatite.
Helps activate and deactivate enzymes in a process known as phosphorylation.
Essential component of ATP.
Component of DNA, RNA, and phospholipids in cell membranes and lipoproteins.
Phosphorus Food Sources and Recommended Intake
Abundant in the food supply.
Foods rich in protein (milk, meat, eggs) are also rich in phosphorus.
RDA for adults is 700 mg/day; for adolescents is about 1,250 mg/day.
Hypophosphatemia
Underlying disorders affect absorption or excretion and cause hypophosphatemia.
Hyperparathyroidism (often due to a tumor)
Vitamin D deficiency
Overuse of aluminum, magnesium, or calcium containing antacids that bind phosphate.
Hyperphosphatemia
Causes include kidney disease, underactive parathyroid gland, too many vitamin D supplements, overuse of phosphorus containing laxatives, and excessive dietary intake (i.e. too much soda).
Excessive phosphorus can bind calcium leading to muscle spasms, convulsions, and increased bone loss.
Magnesium
50 – 60% is in bone, remainder distributed between muscle and other soft tissues.
Mostly resides in cells. Only 1% is extracellular.
Magnesium Functions
Participates in more than 300 types of enzyme-mediated functions.
Assists in DNA synthesis, protein synthesis, and energy production in the ETS and glycolysis.
Participates in muscle contraction and blood clotting.
Magnesium Recommended Intake
RDA:
Adults 19 – 30 years [Men]= 400 mg/day.
Adults 19 – 30 years [Women]= 310 mg/day.
Adults 31-70 years [Men]= 420mg/day.
Adults 31-70 years [Women]= 320 mg/day.
Magnesium Food Sources
Dietary intake comes primarily from plants with whole grains and vegetables being good sources.
Clinical Signs and Symptoms include nausea and general weakness.
Sulfur
Not used alone as a nutrient.
Present in certain organic compounds (vitamins biotin and thiamine and amino acids methionine and cysteine).
Disulfide bridges help proteins form their tertiary and quaternary structures.
Adequate protein intake ensures enough sulfur; deficiency is unknown in humans.
Hypertension
High blood pressure.
Major risk factor for heart disease, kidney disease, and stroke.
Diets rich in calcium, magnesium, and potassium reduce blood pressure.
Osteoporosis
Means “porous bone”.
In osteoporosis, bone mass or density declines and bone quality deteriorates.
Normal development and mineralization of bones requires calcium, phosphorus, fluoride, magnesium, vitamin D, vitamin A, vitamin K, and protein.
Trace (Minor) Minerals
Inorganic substances needed by the body in small quantities.
Includes iron, zinc, copper, manganese, iodine, selenium, chromium, fluoride, and molybdenum.
Typically difficult to measure in the body and in food.
Iron
Heme iron is part of hemoglobin and myoglobin in animal flesh, non-heme iron comes from vegetables, grains, and supplements.
RDA: 18 mg/day for adult women, 8 mg/day for adult men (drops to 8mg/day after menopause).
Most common trace mineral deficiency worldwide.
Ferritin: Iron-binding protein in small intestine.
Transferrin: protein that binds iron and transports it through the body (needs copper).
Iron Functions
Component of proteins, enzymes, is needed for energy metabolism, drug and alcohol metabolism in the liver, neurotransmitter synthesis, and the immune system.
Iron Deficiency
Iron deficiency anemia.
Pale skin, fatigue and weakness; pica for ice and spoon shaped nails.
Iron and UL
UL – 45 mg/day.
Hemachromatosis- genetic disorder that can cause liver disease and heart failure.
Zinc
Protein rich meat and seafood, whole grains are food sources.
Mucosal block similar to iron (metallothionein).
Function: more than 300 different enzymes require zinc.
Low appetite, impaired growth, decreased taste, immune dysfunction and other deficiency symptoms.
Zinc UL
40 mg/day-usually people who take supplements.
Copper
Liver, shellfish, nuts, seeds, mushrooms, soy and dark chocolate are food sources.
Copper balance controlled by copper absorption and influenced by iron and zinc status.
Copper Functions
Iron metabolism In family of enzymes that act as antioxidants..
Deficiency rare - Menkes disease and is linked to genetic mutation.
Genetic disorder Wilson’s disease can affect transport and regulation of copper.
Manganese
Whole-grain cereals, nuts, legumes and tea are food sources.
Absorbed in small intestine, transported with protein carriers, excreted in bile
Manganese Functions
Shares functional similarities with Zinc and Copper (cofactor for enzymes, energy metabolism).
Iodine
Saltwater seafood, seaweed, iodized salt, molasses and dairy products are food sources.
Component of thyroid hormone so needed for normal metabolism.
Iodine Deficiency and UL
Goiter (enlarged thyroid) and cretinism (poor growth).
UL – 110 micrograms/day – Enlarged thyroid gland, increased risk of thyroid cancer.
Selenium
Seafood, meats, cereal grains and nuts are food sources; soil dependent.
Easily absorbed, excess is excreted in urine.
Anti-oxidant defense network, Synthesis of thyroid hormone
Selenium Deficiency and and UL
No specific disease but deficiency can cause Keshan disease (congestive cardiomyopathy).
UL – 400 micrograms daily – Nausea, diarrhea, fatigue, hair loss, change in nails, and skin rashes.
Chromium
Nutrient databases inadequate.
May improve insulin function and help normalize blood sugar, although supplements have not been shown to be beneficial.
Fluoride
Fluoridated water, tea, seafood and seaweed are food sources, which can also be found in toothpaste and mouthwash.
Promotes bone and dental health.
Fluoride Deficiency and UL
Associated with an increase in dental caries.
UL – 0.1 mg/kg body weight daily up to 8 years old.
Ultra trace Minerals
Needed in very small amounts but essential for many enzymes