Magnesium Flashcards
Food sources
Whole Grain Legumes Nuts Green leafy vegetables Tofu Chocolate Water Intermediate meats Fruits
People who have cravings such as chocolate may be deficient in what?
Magnesium
What is hard water and soft water?
Hard water is high in magnesium
Soft water is high sodium
Where does magnesium absorption mainly occur?
In the small intestine
~40-60% absorbed
How is magnesium absorbed in the intestine?
By passive diffusion or active transport
In small intestine = paracellular diffusion
Large intestine = TRPM6 (main) and TRPM7 (a little)Ho
Substances that enhance absorption of magnesium
Vitamin D
Carbohydrates
-Lactose
-Fructose
Substances that inhibit absorption
Phytate
Fiber
Excess unabsorbed fatty acids
Magnesium interacts with which nutrients?
Calcium
phosphorus
Potassium
Protein
How is magnesium transported?
55% free as mg2+
30% bound to albumin
15% complexed with citrate, sulfate, phosphate
Serum mg ranges
1.8-2.3mg/dl
Does Mg have a specific transporter?
No, similar to calcium
Magnesium is regulated how?
It is regulated by the amount you excrete which is regulated by the kidneys
high excretion = high intake
low excretion = low intake
How does alcohol effect urinary Mg?
It increases it. More excretion.
Where is magnesium stored in the body?
Most of it is found in the skeleton (bones)
What are the functions of Mg?
Important intracellular cation
Ionized Mg2+ binds well to anions
Stabilize enzyme complexes
Most intracellular Mg is associated with what?
ATP, ADP, and associated enzymes
Mg-ATP is used in
Glucose metabolism Energy storage and transfer Signaling pathways Ion transport Lipid metabolism
What does Mg do to RNA and DNA
Stabilizes it because the negatively charged ribose phosphate has high affinity for Mg
Mg reacting with the hydrophilic phosphate heads of cell membranes affects what? What does this influence?
Affects the fluidity and permeability of the cell membrane
This influences ion channels, transporters, and signal transducers
Disruption of the Na K ATPase by Mg depletion may lead to what?
Hypokalemia (low blood potassium)
What is the Magnesium-Calcium interaction?
Mg is required for c-AMP formation because it is dependent on Mg
cAMP is required for PTH secretion
What are the functions of PTH?
Bone calcium mobilization
Kidney calcium resorption
What signals PTH to be secreted?
Low blood calcium
The deficiency of Mg can inhibit the secretion of which hormone?
PTH
Mg deficiency is related to osteoclasts how?
Osteoclasts become unresponsive to PTH in Mg deficiency
- Bone remodeling is reduced
- blood ca decreases
Mg Assessment
Plasma Mg poor indicator because it is maintained in a very tight range
anything below 1.8 indicated Mg depletion
How can Mg deficiency occur?
Not by diet
Mutation in TRPM6
Mutation of TRPM6 leads to what?
Familial hypomagnesemia and hypocalcemia, seizures, and tetany
Can you get enough Mg without the TRPM6 protein?
No. It does not absorb much but what its enough to not be deficient. Removing this will cause there to be a deficiency
In animals, Mg deficiency causes and can they be reversed?
- Low plasma Mg
- Hypocalcemia
- Hypokalemia
- Abnormal neuromuscular function
- low PTH
- Low 1,25(OH)D3 (Calcitriol)
Yes they can be reversed
Severe Mg deficiency causes what?
Tetany (all muscles are locked up)
convulsions
neuromuscular tremors
Clinical Mg Deficiency
- Surgery
- Blood transfusions: citrate chelating (citrate can bind to Ca and Mg. Ca is important for blood clotting. if you have a bag of blood stored, you do not want blood to clot. They add a lot of citrate to prevent all of the clotting factors. With so much citrate in the blood, the citrate will also bind to a lot of the Mg and render a state of Mg deficiency and that Mg is no longer metabolically active because it has been chelated to Citrate”
- diabetic ketoacidosis
- alcoholics
- chronic malabsorptive problems
Suboptimal Mg status has been associated with?
Cardiovascular and neuromuscular disease
diabetes
osteoporosis
migraines
The UL for Mg represent what?
Pharmacological agents only.
They do not include intake from food and water
Mg toxicity
Adverse effects only with supps
-primarily diarhhea (Mg supps can help with constipation)
-cathartic effect (vomiting)
Can not get toxic from food
