Too much of a good thing can be detrimental

1. Too much of a good thing can be detrimental By Jezabel Olvera

2. Iron is an essential mineral for normal cellular physiology, but an excess can result in cell injury. Levels of some antioxidants are decreased during iron overload, a finding suggestive of ongoing oxidative stress. Reduced cellular levels of ATP, lysosomal fragility, impaired cellular calcium homeostasis, and damage to DNA all may contribute to cellular injury in iron overload.

3. MECHANISM To be absorbed, dietary iron must be in its ferrous Fe2+ form. A ferric reductase enzyme on the enterocytes' brush border, Dcytb, reduces ferric Fe3 to Fe2+. A protein called divalent metal transporter1[DMT1], which transports all kinds of divalent metals into the body, then transports the iron across the enterocyte's cell membrane and into the cell. These intestinal lining cells can then either store the iron as ferritin or the cell can move it into the rest of the body, using a protein called ferroportin.

4. Iron is taken into cells by receptor-mediated endocytosis of monoferric and diferric transferrin. These receptors engulf and internalize both the protein and the iron attached to it.

5. Ferro-transferrin binds to transferrin receptors on the external surface of the cell. The complex is internalized into an endosome, where the pH is lowered to about 5.5. Iron separates from the transferrin molecule, moving into the cell cytoplasm. Here, an iron transport molecule shuttles the iron to various points in the cell, including mitochondria and ferritin. Ferritin molecules accumulate excess iron. Lysosomes engulf aggregates of ferritin molecules in a process termed "autophagy".

6. Men and people who are exposed to high levels of iron in their food, water or occupation, are more susceptible to iron toxicity. Accidental overdose of iron-containing products is the single largest cause of poisoning fatalities in children under 6 years of age. Iron toxicity can come from a variety of sources. It is found in animal products especially meats. Shellfish, liver and organ meats are rich in iron. It is found in kale, collard greens and spinach, but is not easily absorbed from them. Dried fruits, berries and nuts are good sources. Acidic foods cooked in iron cookware will pick up iron from it. Some communities have iron water pipes which can deposit iron into the water. Iron supplements not prescribed by a physician can contribute to iron toxicity. Breads, cereals and other white flour products contain iron. Beer and wine also contain iron.

7. Toxicity The oral dose of elemental iron is approximately 100-300 mg/kg of body weight. Considerably less has been fatal. Symptoms of acute toxicity may occur with iron doses of 20-60 mg/kg of body weight. Iron overdose is an emergency situation because the severity of iron toxicity is related to the amount of elemental iron absorbed.

8. Acute toxicity • Within 1-6 hours of ingestion, symptoms may include nausea, vomiting and abdominal pain, tarry stool, lethargy, weak and rapid pulse, low blood pressure, fever, difficulty breathing and coma. • If not fatal, symptoms will subside for 24 hrs. • Symptoms may return 12 to 48 hrs. after ingestion and may include signs of failure in cardiovascular, kidney, liver, blood and central nervous system. • Long term damage to the central nervous system, liver and stomach may develop 2-6 weeks after ingestion.

9. Long term over consumption • Most often diagnosed after tissue damage has occurred. • Enlarged liver • Skin pigmentation • Lethargy • Joint diseases • Loss of body hair • Amenorrhea • Impotence • The list is extremely long. Many diseases are caused by high iron consumption.

10. Synergists Iron absorption is enhanced by the amino acids histidine, lysine and vitamin C, vitamin E, citric acid, lactose, fructose, glucose, sucrose, and sorbitol. Ingestion of acidic foods such as; alcohol and animal proteins, enhances iron absorption. States of anemia, B6 deficiency, iron deficiency and hypoxia also enhance iron absorption.

11. Psychological effects of iron toxicity • Iron toxicity is commonly associated with personality characteristics of a strong ego,rigidity, tenaciousness, hostility stubbornness and irritability. • Iron also deposits in the amygdala, a portion of the brain associated with feelings of anger and hostility.

12. Treatment • The first part of treatment for ingestion of iron is gastric emptying, but this is only useful if the tablets were taken less than 4 hours ago. If the tablets were slow-release preparations and if tablets are left in the bowel after gastric emptying, then whole-bowel irrigation may also be performed. • Deferrioxamine is the chelating agent that is used to treat iron intoxication. It should be given immediately if the poisoning is thought to be severe. • Hepatic, renal, blood and liver function should be monitored.

13. Conclusion Iron is essential in the diet. It is found in many different foods and other things we use on a daily basis. There is synergists that enhance its effect in our cells. Long term exposure to high quantities of iron results in many diseases. Unfortunately, most who are exposed to high amounts of iron don’t know it until they experience symptoms of a particular disease which was caused by excess iron. For those who take iron supplements without a doctor’s order, they run the risk of getting iron toxicity. People who try to eat many foods rich in iron, are running the same risk of iron toxicity.

14. Sources http://www.portfolio.mvm.ed.ac.uk/studentwebs/session2/group29/index.htm http://www.drhoffman.com/page.cfm/120 www.food-info.net/uk/min/iron.htm http://www.arltma.com/IronToxDoc.htm