Minerals Flashcards
Calcium sources
Animal:daily products, sardines with bones
Plants: calcium-set tofu, broccoli, black-eyed peas, whole grain flour
Calcium-set tofu: calcium sulfate is sued during the setting process
Calcium dietary role
Major structural component of bone, along with phosphate and collagen
Also important in mediating intracellular signals
Certain clotting factors depend on calcium in serum
Regulates excitation of neurons and all types of muscle
Clotting factors II, V, IX and X depend on extracellular calcium for activation
Intracellular calcium is tightly regulated, and acts as a second messenger within cells.
Calcium plays key roles in excitation -contraction coupling and synaptic transmission
Calcium phosphate gives hardness to bone - 99% calcium found in bone
Calcium deficiency
rickets in children, osteoporosis in adults
Calcium toxicity
Constipation, interference with magnesium and iron absorption, kidney stones
High blood levels of most of the major minerals don’t result from dietar overconsumption - usually due to renal or fluid balance disorders
Calcium RDA
Young children: 200-500mg Chidren: 800 mg Teens: 1300mg adults: 1000 mg >1200 mg RDA of calcium varies widely over the lifespan reflecting: peak bone mass development and Osteoporosis protection
Phosphorus role
Major component of bone
Important in acid-base balance (buffer)
Important constituent of DNA, RNA, phospholipids, energy carrying compounds, some proteins
Phosphorus is usually found as phosphate anion
Most prevalent anion inside the cell
chemical characteristics allow the phosphate groups of ATP to store energy for cellular metabolism
about 85% found in bone
Phosphorus source
Found in most foods, whether plant or animal
Deficiency and toxicity are rarely seen clinically
Phosphorus deficiency
Although deficiency is rare, symptoms include bone pain and muscular weakness
Phosphorus toxicity
Toxicity is also rare - an include calcification of soft tissues. Phosphate can be found as part of phytic acid - binds and removes calcium, iron, zinc, and magnesium
Phosphorus RDA
DRI levels
RDA: 700 mg/day
Tolerable upper intake level 4000 mg/day
Magnesium
Similar to B-vitamins-used in wide variety of enzymes, essential for release of energy from energy-yielding nutrients
Affects the regulation of potassium, calcium, vitamin D
Essential in building proteins
Aids in relaxation of muscles during excitation-contraction coupling
holds calcium in enamel for maintenance of healthy teeth, mostly located in bones. Cofactor in energy metablism, as well as DNA & protein synthesis
Magnesium source
plentiul in most plants, including cereals, leafy green plants, beans
lower in highly processed foods
present in dairy products
Magnesium dificiency
Rare, since it is present in most plant foods
Symptoms include weakness, confusion, tetany, hallucinations and convulsions
Magnesium toxicity
Only seen with use of supplements symptoms include diarrhea, low blood pressure, nausea, acid-base disturbance
Magnesium RDA
RDA: 300-400 mg/day
Tolerale upper limit: 350 mg/day from supplements
Sodium role
Regulates balance of fluid between the inside and outside cells, as well as blood volume
Instrumental in electrical excitation, including action potential generation, muscle contraction, etc.
Also important for acide base balance
Sodium source
No known diet can result in a deficiency of sodium present in almost all foods
Key concern is processed foods that contain large amounts of sodium, such as processed meats, soups, and sauces
Sodium deficiency
Almost impossible to consume a diet low in sodium
Hyponatremia linked instead to fluid imbalances (extremes of dehydration or fluid resuscitation, excessive water intake)
Sodium toxicity
dietary sodium can increase blood pressure, edema, kidney disease or older than 50
Sodium is responsible for depolarization phase of action potential
With age, kidney funtion declines and blood pressure increases
Potassium, calcium and mangnesium consumption can help decrease blood pressure, in addition to sodium reduction
Sodium RDA
RDA: >70 years - 1200 mg/day
Adults - 1500 mg/day
Tolerable upper intake 2300 mg/day
Most North American diets provide over 30000 mg/day
potassium physiological role
Main cation within cells - like sodium important for regulating fluid balance and electrical events in excitable cells
Increasing potassium, magnesium and calcium intake helps transport excess sodium out of the body via kidneys
Potassium chloride tastes very similar to sodium chloride, allowing for substitution in the diet
Potassium mediates the repolarization phase of action potentials
It is closely regulated with sodium through the renin-angiotention-aldosterone hormone system
Potassium food source
Rich sources include fruits & vegetables
Dairy products, meats and whole grains are also good sources
Less potassium content in processed foods
Potassium toxicity
Although no tolerable upper intake level is set, extreme supplement use can result in serious heart problems, muscle weakness and vomiting (usually overdoses are vomited)
Potassium RDA
RDA: 4700 mg/day in adults Tolerable upper intake: none set Banana =422 mg Baked potato=844 mg ½ cup lima beans =486 mg Orange juice =496 mg Processing “breaks apart” cells, and results in potassium loss
Chloride physiological role
Major negative ion in extracellular fluid
Roles include regulation of fluid/pH balance as well as mediating electrical signals in the cell
Chloride food source
No known diet lacks in chloride, most common food source is table salt
Chloride toxicity/Deficiency
Deficiency and toxicity are due to renal abnormalities, not dietary ones
With the exception of calcium, magnesium and potassium, it is rare to see deficiencies (or situations where supplementation is warranted) with regard to the major minerals
Sulphur Physiological role
Two amino acids (cysteine, methionine) include sulphur in their chemical structure
Sulphur food source
Required by almost all proteins
Most proteins contain cysteine and or methionine – therefore protein in the diet provides ample sulphur
Sulphur deficiency, toxicity and RDA
Deficiency is unheard of – diets deficient in sulphur result in protein-energy malnutrition first
Toxicity is unheard of
No DRI value set
Iron physiological role
Trace mineral.
2.5 g in the body. Important for oxygen-carrying molecules (hemoglobin and myoglobin)
Component of enzymes that participate in energy production in mitochondoria
Hemoglobin carries oxygen within red blood cells, myoglobin stores oxygen within muscle. Most iron is a component of these two proteins.
Iron is essential for function of citric acid cycle (Krebs cycle) enzymes and the electron transport chain
Iron must be stored to “protect” the rest of the body – it is capable of doing oxidative damage to cells
Iron food source
Heme iron – iron that comes from myoglobin and hemoglobin, most efficiently absorbed – about 25%. Found in meat products. Meat products also contain a factor (called MFP) that improves non-heme iron absorption
Non-heme iron-all other iron sources dark leafy vege, enriched or whole wheat flours, other cereal grains, beans & legumes, sunflower seeds, cooking in iron skillet and 2-20% of non-heme iron is absorbed, depending on body’s iron stores.
Vitamin C and stomach acid improve absorption.
Tannins (black tea) phytate (beans seeds tofu, whole grains chickpeas most legumes) and dietary fibre impair absorption
Iron deficiency
Very common
Significant iron is lost due to menstruation
During pregnancy, iron demands are particularly high due to increased blood volume and iron requirements of developing fetus
Iron deficiency anemia = red blood cells with diminished levels of hemoblobin
Symptoms=fatigue, exercise intolerance, poor attention, irritability, feeling cold
Iron toxicity
Acute: nausea, vomiting, liver failure, renal damage
Common especially in kids, with significant mortality
Chronic =iron overload-caused by disease or supplements
Presents with cirrhosis, diabetes, heart problems
Diseases that can result in iron overload include hemochromatosis and types of anemia that necessitate frequent transfusions
Iron RDA
Men, women>50:8 mg/day Women 19-50: 18 mg/day Pregnant women:27 mg/day Chidlren: 7-11 mg/day Tolerable upper intake levels >40 mg/day for children, 45 mg/day for adults Non-meat conversion factor – RDA values increase by 90% (multiply by a factor of 1.8) 3 ozs of beef =3 mg 1 cup of spinach = 6 mg 1 cup of lentils = 6 mg ¼ cup of sunflower seeds = 2.5 mg 2 slices of whole wheat bread = 2mg ½ cup of beans = 2 mg 1 cup of enriched cereal =8mg
Zinc physiological role
Trace mineral. Cofactor in a wide variety of enzymes Important for cellular signalling Important in immune function Wide range of other roles, including Heme production Energy metabolism Pancreatic hormones And digestive enzymes Production of visual pigments in retina Important part of endocrine signalling involving steroid hormones, calcitriol, retinol and thyroid hormone
zinc food source
Supplementation is common – zinc lozenges as “immune boosters” for common cold
Meat, shellfish, dairy products
Plant sources: legumes whole grains, zinc-enriched cereals
Leavened breads make zinc more available – yeast reduces phytate
zinc deficiency
Can occur in those eating diets high in phytates and generally malnourished. Wide range of symptoms, including poor growth, lack of sexual development, impaired immunity, gastrointestinal problems (poor appetite, diarrhea)
Like iron, phytate limits zinc absorption. Iron competes with zinc absorption, but this rarely causes deficiency
Zinc toxicity
Due to supplementation
Interfere with copper and iron absorption
Reduces HDL cholesterol, damages heart muscle, vomiting, diarrhea
zinc RDA
RDA 8-11 mg/day for adults (higher for breastfeeding women)
Children 2-5 mg/day
Tolerable upper intake level
40 mg/day for adults
7-34 mg/day for children depending on age
Copper physiological role
Helps to build hemoglobin and collagen
Helps a variety of enzymes “handle” oxygen
Important component of an antioxidant enzyme
Copper and iron physiology go hand in hand – copper is necessary for the body to use iron effectively
Needed for the function of superoxide dismutase, an important enzyme for disposing of free radicals
Copper food source
Organ meats (liver, kidney), seafood Nuts, seeds, whole grains and chocolate!
Copper deficiency
Rarely caused by dietary deficiency – usually due to problems with absorption
Symptoms: anemia, impaired growth, nervous system disorders (ataxia, peripheral neuropathy) heart problems
Deficiency can be caused by zinc over supplementation – excessive antacid use – genetic disorders (menke’s disease)
Heavy iron or vitamin C supplementation interfere with copper absorption
Copper toxicity
Very rare – supplementation or copper contamination
Diarrhea, vomiting, abdominal pain, liver toxicity
As with all trace minerals, toxicity can be fatal.
Wilson’s disease – an uncommon genetic disorder where copper is not eliminated from the body
Selenium physiological role
Important part of enzymes that limit free radicals
Necessary for thyroid hormone synthesis
Important for the function of glutathione peroxidase, an anti-oxidant enzyme in the liver
Cooperates with vitamin E in eliminating free radicals
Selenium food source
Meats, seeds and whole grains are all good sources of selenium
Selenium content of various foods depends on its content in the soil
No good reason to supplement selenium
Selenium deficiency
Deficiencies in selenium were seen in areas with low soil content where people only ate locally-grown food
Muscular discomfort, weakness, heart disease
Selenium toxicity
Nausea, diarrhea, abdominal pain, nail changes, hair loss
Selenium RDA
RDA 20-55 ug/day Lower range for children Pregnancy 60-70 ug/day Tolerable upper intake children 90-280 ug/day Adults 400 ug/day
Iodine physiological role
Trace mineral Sole purpose is for synthesis for thyroid hormone
Thyroid hormone is crucial for regulation of overall body metabolism and development of a wide range of organ system
Iodine food source
Table salt, seafood, dairy products
High RDAs for pregnant and breastfeeding women reflect the needs of developing fetus and significant levels of iodine in breast milk
Iodine deficiency
Rare with adequate intake of seafood and or iodized salt
Children, adults – goitre, poor school or work performance, sluggish
Fetus – iodine deficiency in mother an cause fetal death or severe mental retardation called cretinism
Iodine toxicity
Rare.
Poisoning with one or a few large doses can cause death
High chronic intake can cause goitres (enlargement of the thyroid gland) as well
Iodine RDA
90 ug/day for kids 150 for adults
220 for pregnant women, 290 if breastfeeding
Tolerable upper intake level 600-1100 ug/day for adults and older children, less for younger children
Chromium physiological role
Interact with insulin to improve insulin function
Supplementation may improve glucose levels in type II diabetes
In those with adequate intake, it does not increase muscle mass or aid weight loss
Chromium food source
Liver, nuts whole grains and cooking ith stainless steel implements. Dairy products and vegetable are poor sources
Chromium deficiency
Deficiency rare, include diabetes-like symptoms
Chromium toxicity
Not yet recognized, although it is commonly supplemented
Chromium RDA
25-45 ug/day
No level set for tolerable upper intake level (unique)
Molybdenum and Manganese physiological role
Molybdenum: associated with many enzymes
Manganese: associated with a variety of enzymes and superoxide dismutase, including one that combats free radicals in mitochondoria
Molybdenum and Manganese food source
Molybdenum: meats, daily products, cereal grains, and legumes
Manganese: whole grains, nuts, fruits, vegetables
Molybdenum and Manganese deficiency
Molybdenum: naturally-occurring deficiency has never been reported.
Manganese: no naturally occurring deficiencies
Molybdenum and Manganese toxicity
Molybdenum: has not been reported in humans
Manganese: caused by environmental exposure, associated with inhaled dust in mines
