3. Magnesium

4. Magnesium
Atomic No Atomic mass: 24

5. Magnesium (Mg)
Mg assures the strength and firmness of bones and makes teeth harder.
As Mg participates in many biochemical reactions, it's no surprise that it is essential for healthy bones and teeth.
Also Mg is essential for absorption and metabolism of calcium.

6. FUNCTIONS Mg is an essential cofactor in 80% of all cellular enzymes.
It is necessary for the conversion of Vitamin D into its active form and a deficiency of Mg can lead to a syndrome known as vitamin D resistance.
The enzyme that is required for forming new Ca crystals, alkaline phosphatase, also requires Mg for activation, and if levels are low, abnormal bone crystal formation can result.
Even mild Mg deficiency is reported to be a leading risk factor for osteoporosis.

8. FUNCTIONS
Mg has a role to play, together with the thyroid and parathyroid glands, in supporting bone health.
It stimulates the thyroid’s production of calcitonin, and regulates parathyroid hormone.

9. FUNCTIONS
Mg is a cofactor in more than 300 enzyme systems that regulate diverse biochemical reactions in the body, including ;
Protein synthesis
Muscle and nerve function
Blood glucose/ control, and
Blood pressure regulation.

10. FUNCTIONS Mg is required for; Energy production
Oxidative phosphorylation, and
Glycolysis
Structural development of bone
Is required for the synthesis of DNA, RNA, and
Antioxidant glutathione

11. FUNCTIONS
Mg also plays a role in the active transport of Ca and K ions across cell membranes, a process that is important :
Nerve impulse conduction
Muscle contraction and
Normal heart rhythm

12. FUNCTIONS
Mg is cofactor of hundreds of enzymes involved in lipid and nucleic acid synthesis.
Mg stabilizes cell membranes.
It also antagonizes calcium and functions as a signal transducer .
It is therefore believed that alterations in Mg homeostasis has an impact on cell and tissue functions.

13. FUNCTIONS
Like Ca much of the body’s reserves of Mg are held in the bone (60%), and the bones act as a storage reservoir, releasing Mg into the blood when needed.
Adequate daily intake of Mg is important throughout life to keep the Mg that is stored in the bones from being lost.
Low Mg intake, as well as low blood and bone Mg levels, has been widely associated with osteoporosis in women.

14. Sources Mg is an abundant mineral in the body.
It is naturally present in many foods.
Available as a dietary supplement, and
Also present in some medicines (such as antacids and laxatives).

15. Generally we ignore the fact that
Mg and Ca function together and deficiency of one affects the metabolism of the other.
In fact, increasing Ca supplementation without increasing Mg can actually increase Mg loss.
Similarly, the use of Ca supplements in the face of a Mg deficiency can lead to Ca deposition in the soft tissues, such as the joints.
Where it can promote arthritis or
In the kidney, contribute to kidney stones.

16. Magnesium and the Bone:
Molecular Insights
About 60% of total Mg is stored in the bone.
One third of skeletal Mg resides on cortical bone either on the surface of hydroxyapatite or in the hydration shell around the crystal .
It serves as a reservoir of exchangeable Mg ,required to maintain ECF conc. of the cation .

17. Bone surface Mg levels are related to serum Mg
Bone surface Mg levels are related to serum Mg. Accordingly, surface bone Mg increases with Mg loading
The larger fraction of bone Mg is probably deposited as an integral part of the apatite crystal and its release follows the re-sorption of bone.

18. Apart from a structural role in the crystals, Mg is essential to all living cells, including osteoblasts and osteoclasts.
Mg is vital for numerous physiological Intracellular functions.
Mg is fundamental for ATP, the main source of energy in the cells.

19. Magnesium Mg is one of three major minerals in human body
4th most abundant
20 – 35 grams is total body content
Lowest in amount of the three major mineral

20. DISTRIBUTION Serum level is 1.5 – 2.5 mEqt/L
60 – 70% is complex with calcium and phosphorous in bones
Remainder is present in the body fluids and concentrated Within cells.
Mg : calcium( within cells) is about 3 : 1
Whole blood contains about twice as much Mg as in serum,as is concentrated in RBCs
2% of the body’s Mg is in ECF
Serum level is 1.5 – 2.5 mEqt/L

21. DISTRIBUTION (Contd.) 80% is ionized and diffusible
20% bound to proteins
Muscles contain more Mg than Ca++.
(As is required as activator for many of phosphate group transfer enzymes)

22. REVIST OF Functions
Essential element because is catalyst for numerous biologic reactions
It helps maintain the electrical potential in:
Nerves for the transmission of nerve impulses Muscle membrane for the muscle contraction
3. Involved in active transport across cell membrane
4. Inhibits ATP ase Activity

23. Functions (Contd.)
Its salts are irritant to intestine, used as purgative while its hydroxide are used as antiacids.
CNS depressant and lowers neuro - muscular irritability
7.In Kidney insufficiency, level in blood increases,
Increased level have adverse effect on cardiac muscle

24. Dietary deficiency is rare
Dietary Sources
Widely distributed in foods
Richest sources include
Nuts
Sea foods
Whole grain
Dried beans
Peas
Green leafy vegetables
Dietary deficiency is rare

25. Recommended Dietary Allowances
Infants 0 – mg
0.5 – mg
Children 1 – mg
4 – mg
7 – mg

26. Recommended Dietary Allowances (Contd.)
Adults Male Female
11 –
15 –
19 –
23 –
Pregnancy and Lactation mg

28. Absorption and Metabolism
40 – 45% of dietary Mg++ absorbed from an average diet
With High Mg++ diet the %age of absorption falls
Low Mg++ diet the %age of absorption increase
Absorption occurs mostly in small intestine

29. Absorption and Metabolism (Contd.)
Ca++ and Mg++ competes for absorption sites in the intestinal mucosa,  intake of one  requirement for other
Mg++ and K+ are conc. inside the cells.
Any change in balance produces neuromuscular irritability

30. Absorption and Metabolism
Many of the Factors affecting Ca++ affects Mg++
Excess fat
phosphates
oxalic acid and
phytic acid

31. Control and excretion
Body Mg++ level and pool is mainly controlled by kidney
Filtered out of the blood by glomeruli
Reabsorbed by renal tubules
Unabsorbed is Excreted in feces

32. HYPOMAGNESEMIA Increased loss - Diabetic ketoacidosis Diuretic therapy
Hyper aldosteronism
Assoc. with hypercalcaemia
Renal Mg wasting

33. Clinical Manifestation
Deficiency or imbalance develops slowly due to persistent poor dietary intake or increased excretion. Mg++ slowly mobilized from bone.
b. Low plasma level is associated with imbalance in ECF, leading to altered electrical potential of nerve and muscle cells.
Deficiency: Leads to neuromuscular dysfunction.

34. Clinical Manifestation (Contd.)
Mg++ deficiency causes
muscular hyper excitability ,Tremors and convulsion.
d. Behavioral disturbances are some time seen
e. symptoms similar to Hypo calcaemic tetany are seen which can be differentiated by determining blood level of Ca++ & Mg++

35. Mg++ deficiency can occur with
Cirrhosis liver
Malnutrition
Mal-absorption,
Diarrhea,
Laxatives
Impaired intake
Impaired absorption
Chronic alcoholism

36. Hypermagnesemia. severe dehydration Aldosterone deficiency
With decrease in urinary excretion,
plasma level is raised Hypermagnesemia.
Chronic renal disease
severe dehydration
Aldosterone deficiency
oral intake of MgSo4 for constipation
(specially with impaired renal functions). .

37. Reference values serum / plasma: 1.5 – 2.5 meqt/L
0.65 – 1.05 mmoles/litre
CSF: up to 3.0 meqt/L
Muscles: up to 20 meqt/L
RBCs: – 7.8 mg /dl (5 meqt/L)