Magnesium
Optimal level of Magnesium for human consumption ranges 300-400 mg/day. The main source of Magnesium includes cereals, beans, leafy vegetables and fish. The normal serum level of Magnesium is 1.8 to 2.2. mg/dl.
Functions of Magnesium
(a) Irritability of neuromuscular tissues is lowered by Magnesium
(b) Magnesium deficiency leads to decrease in Insulin dependent uptake of glucose
(c) Magnesium supplementation improves glucose toleranceDecrease in Magnesium content leads to the condition called as hypomagnesemia. It causes increase in urinary loss. Causes such as liver cirrhosis, protein calorie malnutrition and hypo para thyroidism leads to hypomagnesemia. Increase in thelevel of Magnesium is called as hypermagnesemia. The main causes of hypermagnesemia includes renal failure, hyper para thyroidism, rickets, oxalate poisoning and multiple myeloma.
Intext Questions
1. Optimal level of ………………. for human consumption ranges 300-400 mg day.
2. Irritability of neuromuscular tissues is lowered by ……………….
3. Magnesium supplementation improves ………………. tolerance
(a) lactose (b) glucose (c) toxin (d) microbial
Iron
Total body content of iron is 3 to 5 gm out of which 75 % is recorded in blood and rest of them are recorded from liver, spleen, bone marrow and muscle. The normal limit for iron consumption is 20 mg/day for adults, 20-30 mg/day for children and 40 mg/day for pregnant women. The main source of iron is jaggery. Other source of iron includes leafy vegetables and meat etc., Milk is considered as a poor source of iron.
Factors influencing absorption of iron
Iron is absorbed by upper part of duodenum and is affected by various factors (a) Only reduced form of iron (ferrous) is absorbed and ferric form are not absorbed(b) Ascorbic acid (Vitamin C) increases the absorption of iron(c) The interfering substances such as phytic acid and oxalic acid decreases absorption of iro
Regulation of absorption of Iron
Absorption of iron is regulated by three main mechanisms, which includes
(a) Mucosal Regulation
(b) Storer regulation
(c) Erythropoietic regulation
In mucosal regulation absorption of iron requires DM-1 and ferroportin. Both the proteins are down regulated by hepcidin secreted by liver. The above regulation occurs when the body irons reserves are adequate. When the body iron content gets felled, storer regulation takes place. In storer regulation the mucosal is signaled for increase in iron absorption. The erythropoietic regulation occurs in response to anemia. Here the erythroid cells will signal the mucosa to increase the iron absorption.
Iron transport in blood
The transport form of iron in blood is transferin. Transferin are glycoprotein secreted by liver. In blood, the ceruloplasmin is the ferroxidase which oxidizes ferrous to ferric state.Apo-Transferin + 2Fe2+ ??? Transferin combined with 2Fe3+ Storage form of iron is ferritin. Almost no iron is excreted through urine. Feces contains iron as well as iron trapped in the intestine cells.
Anemia
Anemia is the most common nutritional deficiency disease. The microscopic appearance of anemia is characterized by microcytic hypochromic anemia. Iron toxicity or excess of iron is called as hemosiderosis. Iron toxicity occurs due torepeated blood transfusion. The abnormal gene responsible for hemosiderosisis located on the short arm of chromosome No.6. The main causes of irondeficiency or anemia are.
(a) Nutritional deficiency of iron
(b) Lack of iron absorption
(c) Hook worm infection
(d) Repeated pregnancye)
(e) Chronic blood loss
(f) Nephrosis
(g) Lead poisoning
Intext Question
1. Match the following
Adults 20 – 30 mg/day
Children 40 mg/day
Pregnant women 20 mg/day
2. ……………… is the most common nutritional deficiency disease
3. The transport form of iron in blood is ………………
