12.1 Minerals. Chapter 19 Problem Sets #5 and 6 (Vitamins and Minerals) Chapt 19# 1,2, 5,10,11,17,46. Nutritional minerals: the various elements that are essential for proper functioning of the human metabolism, ie. for good health.
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12.1 Minerals Chapter 19 Problem Sets #5 and 6 (Vitamins and Minerals) Chapt 19# 1,2, 5,10,11,17,46
Nutritional minerals: the various elements that are essential for proper functioning of the human metabolism, ie. for good health. Living beings simply cannot generate minerals in their own bodies. All of our minerals became part of the earth at its creation and enter our bodies only from the earth, directly through the plants we eat or indirectly from the animals that feed on plants. MINERALS: Macro- and Micro-
Fats 20% 20% Protein, Carbohydrates, Calcium, Phosphorus Water 60% Vitamins and all other minerals (less than 1%) Of the nearly 90 naturally-occurring elements, only 11 of them make up over 99% of the mass of the human body.
Major Elements of the Human Body Element Symbol % by weight % by atoms Oxygen O 64.6 25.5 Carbon C 18.0 9.4 Hydrogen H 10.0 63.0 Nitrogen N 3.1 1.4 Calcium Ca 1.9 0.3 Phosphorus P 1.1 0.2 Chlorine Cl 0.40 0.06 Potassium K 0.36 0.03 Sulfur S 0.25 0.05 Sodium Na 0.11 0.04 Magnesium Mg 0.03 0.01
Elements: H ,C ,N ,O, (S) (from macronutrients) Macro Minerals: Ca, P, Mg, Na, K, Cl, (S) (over ~400 mg) Trace Minerals: F, I, Fe, Cu, Zn, Cr, Mo, (under 15 mg) Mn, Co, Se Probable Trace: Ni, Si, Sn, V, B, As (in animals )
For the essential nutritional minerals of our diet: the 'metals' are present as cations, eg. Na+,Ca++ the 'non-metals' occur as anions, eg. I-, PO43- As a consequence they are water-soluble, are excreted and may need to be replaced. Overcooking foods in boiling water will leach out many of the minerals. Many mineral supplements are not as readily absorbable as "natural sources'. Concentrations of many trace minerals are dependant on others, ie. ratios are important.
The nutrient minerals have varied functions: components of enzymes, structural components in bones and teeth, electrolyte balance in body fluids and as transport 'vehicles'. The minerals must be maintained in balanced amounts, with no deficiencies and no excesses. Many of the body’s minerals, because they are water-soluble, are excreted daily in the feces, urine and sweat and must therefore be replenished. For most of the minerals, the amount excreted each day is very nearly the amount ingested.
There are 46 different minerals in the human body, 21 of which are known to be essential. The seven macrominerals make up about 4% of body weight. They are calcium, phosphorus, magnesium, sodium, potassium, chloride and sulfur. The macrominerals are necessary in building bones, maintaining body fluids, maintaining proper pH in body tissues, transmitting nerve impulses, maintaining cell membrane structures and facilitating enzyme action.
Sodium , potassium and chloride, as ions (Na+,K+, Cl- ), are essential to electrolyte balance in body fluids. Electrolyte balance, in turn, is essential for fluid balance, acid–base balance and transmission of nerve impulses. When there is extreme fluid loss through vomiting, diarrhea traumatic injury, electrolytes must be supplied to restore their concentration in body fluids . Name Function Sodium (Na+) Major extracellular ion Potassium (K+) Major intracellular ion
Sodium is a vital micronutrient, but is present in most NA diets through excessive intake of salt (sodium chloride). Physicians recommend ingesting about 1.2 grams of sodium/day (or ~ 3gms of salt). This is twice the estimated minimum requirement. Many N.Americans exceed the recommended daily intake by 3X. For example, a typical “double burger” contains nearly 1g of sodium. Normal daily urinary excretion of sodium is in the range of 1.4 to 7.8g for adults. If excess sodium is not eliminated, water is retained, which may lead to edema (swollen legs and ankles). Various clinical studies have shown that increased levels of sodium raise the blood pressure of some individuals but have no effect on the blood pressure of others. The high salt diets of 70 g per day in certain areas of Japan have traditionally produced an unusually high frequency of heart attacks .
Food limerick #1 There was an old fellow called Walt Who seasoned his food with much salt His blood pressure rose From his head to his toes So his doctor told him to halt!
Potassium Though less abundant in the body than its sister element, sodium, is still essential to intra–cellular enzyme activity and the transmission of nerve impulses. Peaches, watermelon, bananas and potatoes are rich sources of potassium and can be eaten to meet the estimated 2g (2000 mg ) daily requirement.
The regulation of the concentration of K+ relative to Na+ is especially important for the proper rhythmic beating of the heart. In the case of some nutrient elements, good health depends on the element being present in the proper amount and in the proper ratio to one or more other elements. An example of an important ratio is the potassium/ sodium ratio (K/Na ratio) which has to be within certain limits to facilitate the transmission of electrical signals between nerve cells .
Typical values of the K/Na ratio are greater than 1. Some K/Na ratios for specific tissues are: muscle, 4; liver, 2.5; heart,1.8; brain,1.7 and kidney,1.0. Natural, unprocessed food have high K/Na weight ratios. Fresh, leafy, vegetables average a K/Na ratio of 35. Fresh, non-leafy vegetable and fruits average a ratio of 360, with extreme values of 3 for beets and 840 for bananas. K/Na ratios in meats range from 2 to 12.
Potassium and sodium compounds are quite soluble in water. During processing (and cooking, if foods are boiled), both potassium and sodium compounds are dissolved by water and discarded. The sodium is replenished by “salting” of the food (addition of sodium chloride). Potassium is usually not added to the food.
In general • No nutritional need for us to add salt to our foods • Already enough present!!
Calcium • the major component of bones and teeth • needed for blood clotting, • required for muscle contraction and transmission of other nerve impulses. • slows down the heartbeat by increasing electrical resistance across nerve membranes. Calcium is metabolized in the body by a hormone synthesized from (vitamin D). Fat slows down calcium absorption but lactose speeds it up.
Bones and Teeth If mineralization and demineralization occur at the same rate, there is a state of dynamic equilibrium between these two opposing reactions and no net loss results: Demineralization Ca5(PO4)3OH 5Ca2+ + 3PO43- + OH- Mineralization NB: -OH + H+ H2O Excess H+ removes -OH causing demineralization Substituting F for OH produces a more stable crystal and 100 times less soluble in acids.
Hydroxyapatite fluoride effects • Structural reinforcement
Fluoridation of Drinking water • NaF at 1 ppm level used since 1960 in most Canadian cities: substantial reduction in tooth decay • Also Sodium monofluorophosphate in toothpaste Na2PO3F: source of F- • Do we need both? • Argument against “ Fluoride is toxic”
Cheaper fluoride sources • Hydrofluorosilicic acid (HFSA) now used extensively (cheaper than NaF) • By product of wet scrubbing of phosphate fertilizer factory smokestacks • CaF2.93Ca3(PO4)2: Fluoroapatite mineral source • H2SiF6 is shipped as a 23% solution, then diluted 180,000 : 1 with municipal water • Contains very low levels of lead and arsenic impurities
Gatineau City council decision • In favour of fluoridation • Niagara Regional Council: rejected motion to fluoridate on Jan 24, 2008 • Still controversial! Ottawa Citizen Letters to Editor Feb 4, 2008! • What do you think?
Osteoporosis A deficiency of calcium, usually in older persons and especially in post-menopausal women, can lead to loss of 'bone density' or brittle bones. The hormone estrogen suppresses bone dissolution.To maintain good bone density, one should ingest 1) ~1.5g/day of 'soluble' Ca2+; 2) adequate Vit.D3) adequate Mg2+This must be accompanied by sufficient weight bearing exercise.NB. Caffeine in 5-6 cups of coffee/day inhibits Ca uptake by 30%!
Bone Density Profiles Dens i t y + yrs 10 20 30 40 50 60 _ general pop’n, pre 1980post menopause, pre 1980 general, 2000! In women over 65/70 more deaths due to'complications' of broken hips/pelvis/vertebrae than from breast cancer! NB. Increasing number of women not reaching adequate bone density by 30/35 years.
Why the change over the last 27 years? • Lifestyles becoming more sedentary • Poorer nutrition • Too much caffeine?
Hormone Replacement therapy (HRT) • Menopausal women given Estrogen supplements- (recall: estrogen inhibits bone dissolution) • Also helps control “hot flashes” • Downside: increases breast cancer risk • risk/benefit ratio needs to be considered!
Bone Structure osteo normal
Magnesium (Mg++) Uses: 'energy production'; nerve function; bone & teeth formation; helps regulate heart rhythm; assists blood clotting;aids in insulin function. RNI (Recommended Nutritional Intake): ~200mg/day Deficiency: risk of heart disease and diabetes Sources: whole grains, nuts, legumes, green veggies, shellfish( largely eliminated in processed foods) Demo: Magnesium in chlorophyll (peas)
Chorophyll The “antenna” that plants use to harvest sun’s energy -Absorbs both red and violet light:hence reflected light appears green
Cooking green vegetables (peas) Central magnesium ion (Mg+2) in chlorophyll is replaced by 2 protons (H+) from citric and malic acids in the food. This changes the amount of E needed to excite the electrons, hence changing the colour: yukky green peas!!
Effect of baking soda (NaHCO3) • Neutralizes the acids in the vegetables • Green colour maintained (more appetizing)
A penny for your pots! • Green chlorophyll colour does not fade when a penny is added to the pot • Acids in the peas cause a bit of the Cu to dissolve and the Cu+2 ion displaces the Mg+2 in the chlorophyll, producing a more stable complex with a central copper ion.
Keeping pickles looking fresh and green • Grandma may have added a penny to the pickle jar! Vinegar will discolour vegetables over time. • “Canning lime” or “pickling lime”: hydrated CaO used to keep pickles crisper (less mushy). Ca+2 ion displaces Mg+2.
Phosphorus (PO43-) Uses: necessary component of bones/teeth, phospholipids and Adenosine TriPhosphate (metabolic energy-transfer agent) RNI: 1000mg(1g)/day Deficiency: rare Sources: meat/fish/poultry, dairy products, colas
Sulfur (-SH, SO42-) Uses: component of two amino acids and vitamins; important functional group in 10 protein structure; part of sulfate anion RNI: not established Deficiency: unknown Sources: all protein (plant & animal): from amino acids cystine and methionine
Essential Trace Minerals Ten are confirmed as essential for humans: iron, copper, zinc, manganese, iodine, fluoride, chromium, selenium, molybdenum, cobalt, Essential for mammals, but not yet confirmed for humans, are: nickel, vanadium, silicon (plus arsenic, boron, tin)
Manganese in blueberry juice • Sharper MRI (magnetic resonance imaging) signals seen for bile ducts and other parts of GI system • Mn atomic number 25 (electron configuration: 1s2, 2s2,2p6,3s2,3p6,4s2,3d5 has 5 unpaired electrons, hence acts as a relaxation agent for water and faster MRI signals
Blueberry juice :rich in manganese • Given to patients at St. Paul’s Hospital Vancouver before MRI scans on GI system.
Micronutrient Terminology in Canada RNI (Recommended Nutrient Intakes) - the re- commended amount of essential nutrients for healthy individuals in each age/gender group. RDI(Recommended Daily Intakes) - the highest recommended RNI value for each nutrient (used on food labels).
Micronutrient Terminology in USA RDA(Recommended Dietary Allowances) - intake levels of essential nutrients that are 'adequate to meet the known nutritional needs of practically all healthy persons'. USRDA(Recommended Daily Allowances) - standards for nutritional information on food labels (based on RDAs). Similar to, respectively, RNI and RDI in Canada
Nutritional Values - NA 'Harmonization' Canadian & US nutritional scientists are establishing consistent values for all food-related categories. These will be called Dietary Reference Intakes (DRIs) and will cover the following categories: 1) calcium, vit.D, phosphorus, magnesium, fluoride; 2) folate and other B vitamins; 3) antioxidants; 4) macronutrients; 5) trace elements; 6) electrolytes and water; 7) fiber and other food components Compendia for the first two categories are now (2001) published.
Iodine (I-) Uses: essential for thyroid gland to produce thyroxine, a hormone that regulates all cell metabolism, ie. growth/development. RNI: 160 mcg/day Deficiencies: enlarged thyroid(goiter); severe mental retardation(cretinism) of newborns can occur if pregnant women are deficient. Sources: salt water fish/vegetation, iodized salt
Thyroid gland enlargement • Expands in an attempt to produce enough thyroxine!
Iodine deficiency was virtually eliminated in NA in 1924 by a Public Health initiative requiring the inclusion of potassium iodide(KI) in table salt by the Morton Salt Co. Worldwide ~1.6 billion people still suffer from iodine deficiency. In the 1990's an epidemic of fetal brain development/mental retardation was reported from the interior of China leaving ~1 million with some retardation(>100,000 as cretins)!
Iodized salt • Mostly NaCl, but KI added
Also present in salt • SiO2 (sand!) as a very fine powder • Stops caking by absorbing moisture • Not metabolized!
Thyroxine – the Thyroid Hormone Tyrosine(essential a.a.) I2 Thyroxine