Lecture 7-2024 Minerals PDF

Minerals Mineral Facts Essential nutrients, required in small amounts. Required for growth, acid-base balance, reproduction, lactation... 2 categories: Macrominerals essential at levels of ≥100mg/day for human adults Microminerals required at levels ≤ 100mg/day are often referred to as trace element...

Minerals Mineral Facts Essential nutrients, required in small amounts. Required for growth, acid-base balance, reproduction, lactation... 2 categories: Macrominerals essential at levels of ≥100mg/day for human adults Microminerals required at levels ≤ 100mg/day are often referred to as trace elements The Macrominerals vs the Microminerals Macrominerals (levels of ≥100mg/day) Calcium Ca Phosphorous P Potassium K Sulfur S Sodium Na Chlorine Cl Magnesium Mg Microminerals (trace elements) Iodine (I) Copper (Cu) Iron (Fe) Selenium (Se) Manganese (Mn) Molybedenum (Mo) Zinc (Zn) Macrominerals Sodium (Na) Sodium is the principal cation in extracellular fluid (ECF) Functions include: Primarily responsible for maintaining fluid balance and regulating blood pressure muscle irritability Maintenance of body fluid Transmission of nerve impulses Food sources: table salt, salty foods (potato chips, pretzels, etc.), baking soda, milk, soya sauce…… Absorption and metabolism: – readily absorbed – excreted in the urine and sweat – The hormone aldosterone increases reabsorption in renal tubules Sodium (Na) Plasma concentration: RR 135 -145 mmol/L sodium deficiency: hyponatremia – Nausea – Exhaustion – Muscle cramps sodium excess: hypernatremia – edema (hypertonic expansion ) – hypertension Potassium (K) Potassium is the principal cation in intracellular fluid (ICF) Food sources: vegetables, fruit (bananas), whole grains, meat, milk… Absorption and metabolism: – readily absorbed (more so than sodium) – excreted by kidney; also in sweat Functions: crucial for maintaining proper nerve function, regulating heart rhythm, and supporting muscle contraction Potassium (K) Plasma concentration: RR 3.5 – 5.2 mmol/L Deficiency: hypokalemia – causes: increased renal excretion (diuretics) severe vomiting and diarrhea cutaneous losses via perspiration – symptoms: confusion profound weakness of skeletal muscles (paralysis and impaired respiration cardiac anomalies: AV block (=cardiac arrest) Excess-Toxicity: hyperkalemia: irregular heartbeat (potentially life threatening). Chloride (Cl) an essential anion in ECF present in sea food, milk, table salt.. readily absorbed along with sodium excreted mainly in the kidneys; ~ 2% in feces and ~ 4-5% in perspiration Functions: acid-base balance, Maintenance of osmotic pressure. Key component of Hydrochloride acid in the gastric juice Activation of the salivary enzyme amylase by chloride RR 100-107mmol/L Deficiency : hypochloremia Causes: caused by fluid loss through nausea or vomiting or by existing conditions, diseases, or medications Symptoms: Imbalance in blood pH, imbalance in gastric acidity, psychomotor disturbances Calcium (Ca) Dietary source: milk, cheese, salmon, dark green leafy vegetables Controlled by parathyroid hormone (PTH), calcitonin and vitamin D Functions of calcium: – Bones and teeth formation (Found in largest amounts in bones (90%)) – Muscle contraction – Transmission of nerve impulses – Blood clotting – Normal heart action – Activates various enzymes (glycogen phosphorylase kinase, salivary and pancreatic amylase) Excretion: – urine and feces Calcium (Ca) Rickets Deficiency - hypocalcemia Tetany Hypo-parathyroidism, Retarded growth Rickets (children) Osteomalacia (adults) Osteoporosis Toxicity: – hypercalcemia Osteoporosis:Porous bone Tetany Osteomalacia (normally does not to occur) Causes: Hyper-parathyroidism, vitamin D intoxication, Effects: kidney stone, irregular heartbeat, confusion or dementia since calcium helps keep your nervous system functioning properly.…. Phosphorus(P) Phosphorus is the second most abundant mineral in the body Primarily found in Bones and teeth Food rich in calcium are also richest in phosphorus (milk, cheese…) Calcitriol (active form of vitamin D) promotes phosphate uptake along with calcium Functions: Formation of bones and teeth Maintain normal pH blood Constituents of phospholipids Major component of ATP Essential for several nucleotide coenzymes like NAD+, NADP+ Important components of nucleic acids like DNA & RNA……… Excretion: kidney Phosphorus (P) Deficiency: hypophosphatemia Causes: Diminished absorption from intestine or excessive wasting through kidney. Consequences: Rickets in children, Osteomalacia in adults. Abnormalities in erythrocytes, leucocytes, platelets, liver. Magnesium (Mg) Found in the body around 70% in combination with calcium and phosphorus; The remaining 30% occurs in the soft tissues and body fluids Source: green leafy vegetables, whole grains avocado, nuts, chocolate etc… Functions: Nerve transmission Activation of metabolic enzymes Synthesis of ATP Serves as cofactor for several enzymes Neuromuscular function Absorption: by intestinal cells through a specific carrier. The consumption of large amounts of calcium, phosphate and alcohol diminishes Mg absorption!! Deficiency: Hypomagnesemia: causes neuromuscular irritation, weakness and convulsions. Microminerals (Trace elements) Zinc (Zn) Sources: includes meat, se food, liver, eggs, legumes and dairy products…. Functions: - Biochemical & cellular functions: Protein & DNA synthesis Growth & cell development Tissue growth & wound healing Immunological functions: functions of neutrophils, T cells, B cells and NK cells Neurological function: memory, taste, vision, acuity Hematological function: Production of red blood cells, transport of oxygen Skeletal function: bone mineralization Endocrinological functions: reproduction, thyroid function, pancreatic function (insulin storage and release)…. Causes of deficiency: Dietary zinc depletion, Malabsorption Alcoholism Associated to other diseases like chronic renal disease, cystic fibrosis, liver disease …. Sign and symptoms of zinc deficiency: Growth retardation, Loss of appetite, and Impaired immune function. In more severe cases: hair loss, diarrhea, delayed sexual maturation, impotence, hypogonadism in males, eye and skin lesions Iron (Fe) Part of the RBCs and myoglobin structure and carry oxygen to all part of the body After absorption, iron is either stored in the form of ferritin in the mucosal cells or transported with the help of protein carrier named transferrin Dietary Sources: Liver, egg yolk, red meat, fish and shellfish, lentils, beans and soy food, green leafy vegetables and raisins; Milk is very low in iron Absorption:  It requires copper  The ferrous form (Fe2+) (more soluble) is better absorbed than the ferric form (Fe3+).  Absorption level depends on the gender and the physiological status of the person: 0.5 to 1mg/day in adult male 1-2mg/day in normal menstruating women 3-4mg/day during pregnancy Excretion: Iron is normally lost in very small amount by: exfoliation of intestinal mucosal cells into the stools sweating or in the urine vaginal or intestinal bleeding (serious mechanism of elimination) Disorders of iron metabolism Iron deficiency & iron overload are the major disorders of iron metabolism Iron deficiency: leads to a reduction in the rate of hemoglobin synthesis and erythropoiesis; Causes: – – – – excessive blood loss (parasitic, accidental, menstrual): is most common cause rapid growth in children with limited intake of iron malabsorption increased metabolic requirement: pregnancy, lactation or neoplasia hypochromic-microcytic anemia. Iron overload: Hemochromatosis and iron poisoning are conditions associated with iron overload: Hemochromatosis is a clinical condition in which iron is directly deposited in the tissues (liver, spleen, pancreas & skin) Iron poisoning: due to toxic effect of free iron in plasma which may life threatening. Copper (Cu) Functions: Required for iron absorption and incorporation of iron into hemoglobin Increases HDL and so protect the heart Synthesis of melanin and phospholipids Crucial role in the formation of collagen Cofactor for several enzymes involved in energy metabolism and antioxidant defense Sources: liver, kidney, meat, egg yolk, shellfish, cereals, nuts and green leafy vegetables. Milk is a poor source Absorption: About 10% of dietary copper is absorbed mainly in the duodenum metallothionein is a transport protein that facilitates copper absorption Zinc and Molybdenum decreases copper uptake Dietary deficiency is very uncommon. Toxicity from dietary resources is rare: Menke’s syndrome and Wilson disease are genetic causes of Cu deficiency and Cu overload respectively Wilson disease  Autosomal recessive disease characterized by large amount of copper accumulates in the liver ; leaks into the blood and is deposited in the brain, eyes and kidney. It leads to hepatic cirrhosis, brain necrosis and renal damages. Menke’s syndrome  X-linked disorder of intestinal copper absorption  caused by mutations in the ATP7A gene that is responsible for transport of copper throughout the body.  Symptoms: sparse and kinky hair; failure to gain weight and failure to thrive; deterioration of the nervous system, mental retardation, temperature instability abnormal bone formation and susceptibility to infection END!