Module 1: Minerals Flashcards
Zinc percentage normal absorption
Via which transporter?
30% absorption, 2-3g stored in tissues, RDA 10-15mg
Absorption in the duodenum and jejunum via ZIP4 transporter
Different types of Zn receptors in different organ systems
Zinc biological involvements and functions
Heavy metal involved in: carbohydrate metabolism, wound healing, immune function, inflammation and oxidative stress
Functions:
1) protein structure stabilization, ex. TF zinc finger motif)
2) catalysis
3) regulation of gene expression
Percent zinc distribution
60% goes to muscles and 30% goes to bones via ZIP13
Selenium is part of which non-standard AA?
selenocysteine - component of glutathione peroxidase and other antioxidants
selenomethionine
Selenium function
acts as cofactor for antioxidants: glutathione peroxidase, thioredoxin reductase iodothyroninedeiodinase
toxic in excess
About iron
transition metal
used as a prosthetic group by things involved with O2:
hemoglobin, myglobin, cytochrome c, peroxidases, hydroxylases
Structure of hemoglobin
4 subunits (2 alpha, 2 beta)
Requires iron for functional heme group along with histidine coordinates carrying oxygen
Iron content in the body and requirements
Av. daily intake: ~15mg (2mg absorbed)
Body contains 3-4g of iron, 60% in blood
How is iron lost?
occult losses (through intestine), skin shedding, menstruation and lactation
Iron deficiency about
80% are iron deficient
Anemia symptoms: pale skin, shortness of breath, fatigue, poor temp maintenance, inflamed tongue, poor cognition, decreased immune function
Anemia occurs in alcoholics, infections, inflammatory or neoplastic (cancerous) disease
Iron excess about
Genetic: African/hereditary hemochromatosis, porphyria (decreased heme, increase porphyrins), hyperferritinemia (increased iron storage as ferritin)
secondary hemochromatosis
due to excessive alcohol or iron supplementation
Iron excess causes
damage to liver, pancreas, and adrenals
hypothyroidism, impotence, cardiac dysfunction, pigmentation
Types of thyroid hormones
Receptor
T3 - triiodothyronine (3 iodine) and T4 - thyroxine (4 iodine)
T3R nuclear receptor type II (RXR Heterodimer)
Iodine is necessary for
thyroid health and production of thyroid hormone (T3/T4)
Presence or absence of thyroid hormones to bind nuclear receptors (iodine dependent) will affect transcriptional activity
Iodine sources
Kelp, seafood, iodized salt, dairy
Iodine deficiency symptoms
Thyroid related disorders (secondary)
infant mortality, neurological defects, retardation (cretinism), decreased reproduction, hypothyroidism, goiter
anemia, arthritis, eye enlargement/inflammation, hair loss, premature greying, IBS, depression
What is goiter?
How is it caused?
Goiter is caused by impaired thyroid hormone production (due to iodine deficiency) which leads to increased thyroid cell production to try and produce more hormone (which it can’t)
Goiter can also be from excess iodine which results in inhibition of thyroid production
Can be caused by selenium deficiency bc Se acts as cofactor for iodothyroninedeiodinases
Sodium role
Major role in absorption and transport of nutrients, blood pressure and water balance based on electrochemical gradients
Nerve signal conduction and muscle contraction/relaxation
Sodium intestinal transport role absorption and secretion for fluid balance
Fluid Balance:
1) Active transport of Na across basolateral cell membrane via Na/K ATPase to ensure transport of Cl- and water into bloodstream (passive Na transport on apical side)
2) Passive transport of Na+ and K+ and water, with active transport of Cl- NKCC transporter (basolateral) and apical transport channels
Na involvement in glucose absorption
Glucose Absorption:
In intestine 1) Apical SGLT1 co-transport of 2Na+ and glucose into enterocytes and
2) Basolateral GLUT 2 glucose transporter and simultaneous Na+ via channels
In kidney SGLT1/SGLT2 reabsorption of glucose
SGLT2 1:1 ratio of absorbance (lower affinity)
Highest source of Na in food?
Bakery products, prepared foods, processed meats
Especially high intake with men
Ca, Na and K as a signaling molecule in taste
Ca, K and Na acts as signaling molecules in taste receptors conveying signal to cellular machinery
Ca IP3 signaling pathway tastes
L-glutamate and glycine bind umami receptor
Sucrose/fructose/artificial sweeteners bind sweet receptor
- b/c aspartame can bind to sweet receptor it is perceived as sweet
Quinine, denatonium and salicin bind bitter receptor
Zinc transporters intestines, skin/bone, brain, mammary glands, and pancreas
Intestines: ZIP4
Skin/Bone: ZIP13
Mammary Glands: ZnT2
Pancreas: ZnT8
Brain: ZnT10
