0:04 [music] I welcome you all to the week 8 on the micromineral uh compos components which is going to be on iron, iodin, zinc, copper, manganese, chromium and selenium. At the end of this session, the student will be able to understand the definition functions mechanism dietary requirements, ICMRs, RDA, bioavailability, toxicity, food sources of iron, iodine, zinc, copper, manganese, chromium and selenium and their critical roles in oxygen
0:50 transport, enzyme systems, thyroid function, immune defense, antioxidant defense and metabolic regulations. So the common features of uh the micro minerals include uh these micro minerals are required in very small quantities compared to the macro minerals which is less than 100 mg per day and that's how they are distinguished from the macro minerals. They function primarily as enzyme co-actors and they also provide the structural components of the uh body. There is a narrow margin between the deficiency and toxicity which will be precisely uh coming under the dietary balance critical. Most of it are tightly regulated by absorption control rather than the excretion. So the first component under micro
1:37 minerals include iron. uh iron uh is a very important uh trace element mineral according to the uh WH which is a world health organization and a critical component of hemoglobin myoglobin and numerous enzymes involved in oxygen transport electron transfer and energy metabolism iron deficiency is most common and widespread nutritional disorder in the world affecting over 2 billion glo people globally and India also it's a major concern with regard to uh pregnancy pregnant women adolescent girls and also women of childbearing age. So coming to the total body content of iron is about 3 to 5 g in adults
2:24 whereas 70% of hemoglobin is uh the functional iron and 25% is stored as feritin hemoceterine and 5% in myoglobin and enzymes. The blood level of uh serum ion is about 60 to 170 mgram per deciliter for men and it's 50 to 150 mg per dilator for women and the different forms of iron present in the body includes hem ion which is a hemoglobin myoglobin cytochromes and non-heem which includes the feritin transferin and the enzymes. Transport includes uh it is bound to the transferin in the blood. Each transferin carries two uh Fe3+ ions and they are stored as feritin and
3:11 hemocidarin in liver spleen and bone bone marrow as well. If you talk about the regulation aspects heepsidin uh the liver hormone that regulates the iron absorption and inflammation always raises the hepsiden thereby blocking the ion absorption. So there are different functions of uh iron. So starting with oxygen transport, we have a multiple functions that is being carried out by iron. The first one is oxygen transport. Iron is a major component of hemoglobin that carries oxygen from the lungs to the tissues. Uh oxygen storage. When we talk about iron storage, iron is a major component of myoglobin which stores the oxygen in the muscle cells for use during exercise.
3:59 The uh energy production is also one of the major component of ion where iron is present in cytochromes of the electron transport chain and is essential for ATP synthesis. DNA synthesis also it is playing a major role where iron acts as a co-actor for ribboucleotide reductase which converts the ribboucleotides into the deoxyboucleotides. When we talk about the immune function, iron is required for lymphocy proliferation and neutrfil activity. [snorts] Uh iron is also important in the neurological function which includes ion dependent enzymes which are involved in the synthesis of neurotransmitters such as the dopamine and serotonin. Iron uh is also a major portion uh
4:47 involved in the antioxidant functions where enzymes such as catalies and peroxidase enzymes which help in destroying the hydrogen peroxidase. So talking about the mechanism of iron uh dietary iron uh there are different mechanisms the basically two mechanisms that are being uh postulated. The first mechanism is the oxygen transport and second one is the ion absorption where we can see that iron is getting transported to the various tissues and finally it is also getting circulated as uh RBC uh lifespan is only 120 days. So the cycle gets repeated again. Similarly for ion absorption it is taking place as a hem ion absorption and non-heem ion
5:32 absorption which is given in this particular uh slide. Talking about the dietary requirements and uh ICMR recommended dietary allowances there are uh different uh age groups having different iron requirements. So starting from infants till uh lactating women there are lot of uh recommendations that's being uh given by the ICMR Indian council of medical research where we can see that infants uh start with 0.5 mg per day as we as they grow uh the requirements keeps increasing for adults men it is 17 mg per day and for uh
6:18 global RDA it becomes 8 mg per day. For adults women 19 to 50 years, it is 21 mg per day. And for pregnancy and lactation, it is being increased with 35 mg. And for lactating women, it is 21 mg per day. And for [snorts] post-menopausal women, it is 11 mg per day. ICMR significantly is higher uh in account and they are also looking into the non-hemian for vegetarian uh diets and all that. So that's the uh recommendation that's being given by ICMR. So talking about the bioavailability of iron, there are a lot of factors which are involved uh when we talk about the absorption of iron and its bioavailability to the body. Heem iron is about 25 to 40%age absorbed from
7:05 meat, poultry, fish and it is minimally affected by dietary inhibitors. Whereas non-ne ion which is got a very high absorption which is 20 to 20 uh two to 20 percentage absorbed from plant sources and they are strongly influenced by enhancers and inhibitors. Vitamin C plays a very important role and as a potent uh enhancer that reduces the ferestopheric ion and marketkedly increases the nonhemion absorption. So when we understand the difference between hemion and non-heem the absorption of hemion is more comparatively uh than the non-heem ion there are meat factor which is the meat fish poulry mpf enhances a nonheem ion absorption when it is consumed together
7:52 similarly pitates are the major inhibitors which are present in cereals and legumes and they significantly reduce the iron absorption polyphenols which are found in tea coffee and Red wine uh tannins strongly inhibit the non-heem ion absorption and also if you see calcium will inhibit both heem and non-heem ion absorption. Milk with meals when we consume the milk along with the meals it can reduce absorption of iron. Feritin status also has a role to play when it comes to the bioavailability. When there are low iron stores in our body that helps to increase absorption of iron while high stores uh reduce the absorption via hepsidian regulation.
8:40 The last one is going to be cooking in cast iron vessels. There will be an increase in dietary iron content uh when the food is cooked in cast iron vessels and they may improve the iron intake. Coming to the toxic toxicity levels. Uh acute toxicity is seen when there is an accidental iron uh supplement injection in children causing nausea, vomiting, uh GI bleeding, shock and liver failure. Hereditary hemocromattosis occurs. It's going to be a genetic disorder where there is excess of iron absorption that takes place that takes place in iron uh because of the iron getting deposited in the liver, heart, pancreas and joints. Chronic iron overload would lead to
9:27 liver cerosis, cardiomyopathy, diabetes, bronze skin pigmentation. The pro- oxidant effect uh also is seen with ion toxicity where we can find that excess of free ion will generate the hydroxal radicals via the fenton reaction that leads to oxidative damage. Food sources of iron include a liver uh beef which is going to be 6.5 mg per 100 g that is called as a heem iron. uh drumstick leaves as about 7.5 uh 7.0 mg per 100 gram that's the non-heam and amaranth leaves uh horse cramm seeds bajra ground nuts ragi are in the next positions.
10:15 So talking about the stability iron as a mineral is not destroyed by heat. However cooking in acidic medium like tamarind or tomato increases the iron solubility and absorption. Traditional cast iron uh cookware significantly increases the iron content of food beneficial practice in Indian cooking. So that was also discussed in the previous slide where cooking in the cast iron vessels may improve the iron absorption as well. Iron deficiency anemia causes a lot of complications. So uh if we see when the absorption is not appropriate that would lead to iron deficiency anemia which
11:01 could which is a very serious uh complication. When we talk about uh anemia that is being uh evident in uh pregnant women u adolescent girls and women of childbearing age they are the vulnerable group of uh developing into iron deficiency anemia. So proper care and adequate iron intake is a must when we talk about uh iron deficiency anemia to be prevented and there are a lot of u programs being initiated by the government like anemia muktarat which is a very common initiative that's been carried out by the uh government of India and that's been practiced uh for the past three to four years uh as a part of uh nutrition uh education programs and national nutrition month
11:46 also it's being created as an major awareness. Next we move on to the next trace mineral called iodin. According to WH iodin is an essential trace mineral required for the synthesis of thyroid hormones, thyroxine and triidothyin which regulates the metabolism, growth, development and organ function throughout the life. Iodine deficiency is the world's leading preventable cause of intellectual uh disability. So when we talk about the total body content uh 15 to 20 mg in adults uh is present in the body 70 to 80% of iodine is present in thyroid gland. The active forms include thyroxine which is a T4 and it
12:34 has about four iodin atoms triidothyonin which is a T3 and it has three ioden atoms which are more active. The regulation of the iodine includes like this where the hypothalamus is uh also involved with regard to the pituitary gland and that in turn activates the thyroid uh hormones for uh synthesis and there's a negative feedback loop as well. The deficiency includes ID which is called as the iodin deficiency disorders which is covering up uh goer hypothyroidism cretinism intellectual disability and still birth in India sub himaon regions gangitic plains and inland areas historically they are found to be iodine
13:20 deficient. Universal salt iodization programs mandates the iodized salt usage in all over the uh India. So when we talk about the mechanism the dietary iron is available as the iodide and that gets absorbed as uh uh majorly in the gut and uh it is also involving the thyroid gland. If you see the uh step one includes the oxidation and step two includes the uh organ uh organ organification and then it goes as major feedback mechanism which is a negative feedback mechanism and when there is a high u intake what happens when there is a high levels of thyroxine
14:07 what happens and the low levels of thyroxine what happens that's been clearly depicted in the picture here. So when we talk about the functions of uh iodine, it is essential for the synthesis of thyroid hormones like T3 and T4. Without iodine, these hormones cannot be produced. And the iodine also regulates the basal metabolic rate increasing the oxygen consumption and heat production in the cells. It is also required for normal physical growth and development. Deficiency can cause dwarfism and stunted growth. It is critical for fetal and early childhood brain development. The deficiency may lead to irreversible intellectual disability and cretinism. Uh the iodine
14:52 is also involved in the stimulation of protein synthesis and cellular differentiation. It helps to regulate the heart rate and cardiac output as well as the blood pressure. Iodate also acts as an antioxidant and the thyroid gland from the iodine peroxide generates during the uh synthesis of it. So dietary requirements include u as per the food age groups. So if you see infants uh require about 90 uh muggram and uh adults require 150 m per day. For pregnancy and lactation, the values go high which is about 220 mgram and 250 mg per day.
15:41 So talking about the bioavailability nearly 100%age of iodine gets absorbed from all dietary sources. Iodized salt is most reliable source. Gitrogens uh grogens are substances which will inhibit the iodine uh intake that includes raw cabbage, cauliflower, cassava and the millets. There are few millets which can be uh called as gitrogens and they block the ioden uptake into thyroid. Therefore cooking may destroy most of the gitrogens. So when we consume raw cabbage or raw cauliflower these glyrogens can have an impact. So when it comes to the cooking part, this will help to reduce a very high portion of grogens. Therefore, cooking will destroy most of the
16:28 groyens. So when we talk about the toxicity, there are numerous toxic effects are reported with regard to thyroid. So first is thyroiditis which is the nothing but the inflammation of thyroid gland and the second is hyperthyroidism where excess iodine uh gets uh passed on as excess T3 T4 and all these will cause an increased metabolism, weight loss and palpitations. And there is another condition which is very common among people is hypothyroidism which is also called as a ulf chaikoff effect where paradoxically there is a very high iodin that acutely blocks the thyroid hormone synthesis. So there is another complication called goer which
17:14 is enlargement of the thyroid gland that is because of iodine uh toxicity. Iodin induced goer is where you can see that chronically excess of iodine would lead to thyroid enlargement. The food sources of iodine includes the first thing is iodized salt which is being uh popularized and being commonly asked to be consumed which is about 15 to 30 m per gram and seaweed also has about 2,984 mg per 100 gram. Codfish also have good amount of uh iodine which is about 99 mogram per 100 gram. Whereas cow's milk has about 55 to 65 mg per 100 ml and eggs and curd also have a good
18:01 contribution of iodine in them. Talking about the stability, iodin is volatile and it's lost by heat, humidity and sunlight. Iodized salt loses up to 50% of iodine if stored in open containers. So always iodized salts are preferred to be uh stored in airtight cool dark containers. And we have to add salt after cooking and not during cooking to preserve the iodin content. That's it with regard to the iodin. So when we talk about iodine we have also listed about the ID which is the iodin deficiency disorders and there are a lot of uh things which has been going through when we talk about iodin to
18:47 prevent iodin deficiency uh iod iron and iodin fortification food products are available like iron iodin fortified rice is available iodin fortified bread is available iodin fortified oil and everything is being coming up now so common vehicle of fortification has been identified as salt. So that is why people use been asked to use iodiz salt to prevent the iodine deficiency at maximum because it may lead to cretinism, still birth, miscarriages. So iodine plays a very important role for uh women especially when they are in the childbearing age. they have to be uh having enough iron so iodine so that it
19:33 doesn't lead to major complications. So the next uh major mineral we are going to talk about is zinc. According to WH uh zinc is an yet another essential trace mineral that serves as a structural component of cat catalytic co-actor for over 300 enzymes and over thousand transcription factors playing critical role in immune function protein synthesis wound healing DNA synthesis cell division normal growth and development. So the total body content of zinc includes 2 to three gram in adults and is distributed throughout all tissues and they are highest in the muscles with
20:19 about 60%age and in bones 30%age. It it is present in liver, skin and prostrate plants. The blood level includes serum zinc is supposed to be at 70 to 120 mg per deciliter which indicates the poor marker of zinc status. Unlike iron, zinc has no detected storage pool. So zinc is not stored basically just like iron. So the daily intake is very much essential and zinc uh transport when we talk about zinc transport it is bound to albamin as a major component and um absorption part is regulated by metalothionin in entroytes zinc binding protein that controls
21:05 intestinal zinc retention. So coming to the deficiency of zinc we call it as acro dermatitis entropathikica which is a genetic deficiency which is caused by uh growth retardation hypoganadism delayed sexual maturation poor wound healing impaired immunity and the major term is referred to as acroeratitis entropatha. It also leads to skin lesions seen in um various parts of the body and there will be a growth retardation in that particular case. So that is called acromatitis entropatha. So the mechanism of uh dietary zinc includes this these are the pathways. The mechanism one is with the z zinc
21:51 finger proteins. Mechanism two is carbonic andhydrates and mechanism three is immune function. And mechanism four is how zinc copper uh super oxidismutates antioxidants are being having a major role. So these are uh the mechanisms which have to be uh remembered when we talk about zinc because zinc plays a very important role for immunity as an antioxidant and also as a major co-enzyme and co-actor and also zinc finger proteins for various uh activities like metalion and all that. So there are a lot of uh functions when we talk about zinc. So zinc plays a major role as an catalytic component for
22:38 more than 300 enzymes including carbonic anhydrates, caroxyic peptidase, alkaline phosphotase and DNA and RNA polymerase. So zinc plays a very important role in this aspect. So when we talk about the immune function, it is essential for tlymphocy development, natural killer cell activity and thimolin hormone production synthesis. Zinc is also important for wound healing required for collagen, cell proliferation and tissue repair growth and development. Uh when we talk about uh growth and development, zinc is very much needed for IGF1 signaling and protein synthesis and cell division. Zinc is also involved in antioxidant
23:24 function like uh zinc is a major structural component of copper zinc super oxide dismutase which is an important antioxidant enzyme. Zinc finger proteins regulate the transcription of more than thousand genes and zinc is also very much important for the taste and smell uh of the humans. It is a major component of gustin which is the carbonic anhydraics which helps in maintaining the uh taste and smell acuty. The dietary requirements of zinc include um with variety of uh things the components present and the age group it varies starting from infants to lactating women. For infants it is two and it goes on increasing as the age uh
24:10 increases. For adults men it is 12 mg per day and for adult women it is 10 mg per day and for pregnancy and lactation it remains the same as 12 mg per day. When we talk about the bioavailability uh the bioavailability is more towards animal sources where 40 to 60%age of uh zinc is absorbed from oysters meat poulry and he proteins will enhance the zinc absorption. Plant sources include 10 to 20%age absorbed with high phitate content in cereals, legumes and they are strongly uh inhibit the zinc phitates major majorly they are the significant inhibitors and the zinc and phitate molar ratio if it is greater than 15 to
24:57 15 is to1 they will severely reduce the absorption. Vitamin A will enhance the zinc absorption and mobilization. Whereas iron when it is excess it will compete with zinc for the absorption. Especially for the particular transporter iron supplements will reduce the zinc absorption. So there are toxicity includes a lot uh copper deficiency and zinc deficiency always have a role to play. Most significant zinc and copper compete for absorption. Whereas excess zinc will deplete the copper. Lot of GI disturbances will be there with regard to nausea, vomiting, diarrhea at greater than 40 mg per day. And the immune suppression happens with paradoxically
25:44 high zinc which is greater than 100 mg per day that suppresses the immune function. So these are some of the toxic effects which are given in the picture. Whereas you can see nausea, vomiting, loss of appetite, abdominal cramps, headaches and diarrhea. Food sources include the first being oysters which 78 mg, beef uh having about 6.3, NCM seeds, ground nuts, chickpeas, whole wheat, ragi, pumpkin seeds also have equal amounts of uh zinc in it. Zinc stability uh zinc is a mineral that is not destroyed by heat or cooking. However, phitate reduction happens
26:31 through fermentation, soaking, sprouting and cooking will significantly improve the zinc bioavailability from the Indian plant-based diets. So uh when we talk about zinc deficiency it leads to acromatitis entropathica that again would have uh seen a lot of uh complications and uh reduced uh immunity delayed u uh immunity and also having other complications. So definitely zinc plays a very important role as an antioxidant and also having uh major trace mineral uh function. So all the three are have been discussed as a major part of trace mineral.
