ROLE OF IRON IN HUMAN HEALTH

1. ROLE OF IRON IN HUMAN HEALTH Arun Malik and Hariom Yadav NATIONAL AGRI-FOOD BIOTECHNOLOGY INSTITUTE, MOHALI , PUNJAB, INDIA Email: yadavhariom@gmail.com

2. WHY DO WE NEED IRON • Iron is a mineral found in every cell in • the body. • It is vital for both physical health and • mental well-being.

3. Iron has three main functions : • carrying oxygen from the lungs to the rest of • the body. • maintaining a healthy immune system. • (Body protects itself from antigens, which includes virus, bacteria and • foreign substances that make sick) • aiding energy production. • (Iron is constituent of several enzymes including : iron catalase, • peroxidase, and cytochrome enzymes)

4. INSUFFICIENT DIETARY IRON CAN RESULT IN IRON DEFICIENCY • fatigue • lethargy • more frequent infections • reduced resistance to cold • impaired learning • Hypoferrimia

5. TYPES OF IRON • There are two types of iron in food: • Heme iron, derived from the hemoglobin and myoglobin found in meat tissue • Non-heme iron, derived mainly from cereals, • legumes, fruit and vegetables.

6. HEME IRON • Heme iron is found only in animal foods. The iron in • meat is approximately 40% heme iron and 60% non-heme • iron. Plant foods do not contain any heme iron . • Heme iron is well absorbed and relatively unaffected by other • factors . • It is influenced to some extent by the body’s iron stores. • The average absorption of heme iron in meat is about 25%.

7. NON-HEME IRON • Non-heme iron is found in plant foods. • It is not as well absorbed as heme iron and is affected • by both the iron status of an individual, and components • in foods eaten at the same time. • Absorption of non-heme iron can vary from under 1% in • an individual with replete stores to 20% in an individual • with depleted iron stores . • Generally non-heme iron absorption is less than 5%.

8. VITAMIN CIMPROVE NON-HAEM IRON ABSORPTION • Vitamin C can increase the absorption of non-haem • iron by two to three times. • There is a dose-related effect; the more vitamin C in a meal, the greater • the iron absorption - up to a limit of around 100mg vitamin C . • Vitamin C is found in fruit and vegetables. Both heat and air reduce • vitamin C content, so care should be taken when cooking and storing fruit • and vegetables.

9. FACTORS AFFECTING NON-HAEM IRON ABSORPTION

10. IRON SUPPLEMENTS • Iron supplements should only be used when advised • by a dietitian or prescribed by a medical practitioner for • diagnosed iron deficiency. • Iron supplements should be used • cautiously as they may interfere with the absorption of • other nutrients such as zinc and calcium.

11. IRON ABSORPTION IN HUMAN BODY

12. HEME IRON UPTAKE HEME IRON HEME IRON TRANSPORT ENDOCYTOSIS FERROUS IRON LIBERATED WITH IN ENDOSOME

13. NON-HEME IRON UPTAKE FERRIC IRON REDUCED BY ASCORBIC ACID INCLUDE DUODENAL CYTOCHROME B FERROUS IRON TRANSFERRIN FERROPORTIN HEPHAESTIN

14. HEPCIDIN REGULATES IRON ABSORPTION • Hepcidin is 25 amino-acid peptide hormone. • Hepcidin is synthesized by hepatocytes. • Hepcidin binds to ferroportin1 and causes its internalization and degradation thereby decrease iron transfer to blood. • Hepcidin function to regulate(inhibit) iron transport across gut mucosa there by preventing normal iron level.

15. HOW HEPCIDIN REGULATES IRON ABSORPTION

16. Hepcidin regulation by Inflammation • IL-6 a prominent inducer of hepcidin, through STAT-3 dependent transcriptional mechanism. • Other cytokines may also induce hepcidin independent of IL-6. • Macrophage also express hepcidin in response to micobial stimulation. • Hepcidin may function in autocrine manner to degrade macrophage ferroportin, causing local retention of iron in macrophages.

17. EFFECT OF MUTATION OF SPECIFIC PROTEINS

19. HUMAN DISEASE ASSOCIATED WITH IRON

20. CARDIOVASCULAR DISEASE • Heme iron are associated with cardiovascular diseases(CVD) risk. • Such as saturated fats or other dietary and lifestyle factors associated with meat intake.

21. HEMOCHROMATOSIS PROTEIN HFE • Hereditary hemochromatosis is inherited disorder that results from an excess accumulation of iron in many organs which is manifested by liver cirrhosis, cardiomyopathy, diabetes mellitus, arthritis, skin pigmentation and if left untreated death. • The gene responsible for hereditary hemochromatosis is closely linked to locus for the human leukocyte antigens and has been identified as major histocompatibility complex-encoded class-1 like HFE. • Hereditary hemochromatosis is more prevalent than other inherited diseases such as cystic fibrosis, sickle cell anemia, phenylketonuria and Tay-Sachs disease.

22. THE FRIEDRICH’S ATAXIA PROTEIN • Farataxin is mitochondrial protein which involved in mitochondrial iron homeostasis. • Farataxin deficiency is due to hyper-expansion of polymorphic GAA trinucleotide repeat which inhibits transcription and falls in levels of mature faratxin mRNA. • Farataxin deficiency in patients leads to develop Friedrich’s ataxia which is a progressive neurological disorder and cardiomyopathy and finally leads to death.

23. MELANOTRANSFERRIN • Melanotransferrin reported to expressed in amyloid plaques in brain of patients with Alzheimer’s disease. • Melanotransferrin mRNA widely expressed in tissue and also in salivary glands. • Levels of melanotransferrin mRNA do not change in presence or absence of an iron chelators or iron source. • Functional studies shown that melanotransferrin transports iron from iron-citrate complexes but not from iron-transferrin complex. • Melanotransferrin has minor role in iron uptake from iron citrate complexes.

24. IRON BIOAVAILABILITY IN VEGETABLES

25. IRON BIOAVALABILITY IN FRUITS

26. IRON BIOAVALABILITY IN GRAINS

27. MORE HEME IRON RICH FOODS

28. RECOMMENDED DIETARY IRON INTAKE

29. CONCLUSION • Heme and non-heme iron are absorbed differently. • Meat, fish, poultry and vitamin C improve the absorption • of non-heme iron. • Tannin, oxalate, phytates and dietary fibre all reduce the • absorption of non-heme iron.