Full transcript of “Fat soluble vitamins-Part 1”. Click a timestamp to open the video at that moment. Need another video? Use the YouTube transcript generator.
0:16 welcome you all to the week seven video on vitamins. So here we are going to discuss about fat soluble and water soluble vitamins for this week. At the end of this session, the student will be able to understand the dietary requirements, ICMR, which is nothing but the Indian Council of Medical Research, RDA, recommended dietary allowances, bioavailability, toxicity, food sources, stability and clinical significance of vitamin A in the human health and nutrition and also to explore the dietary requirements, their RDA, bioavailability, toxicity, food sources and unique dual role of vitamin D as both a nutrient and a pro hormone. So in this uh particular uh session we are
1:02 going to talk only about vitamin A and D. Coming to the conceptual framework fats soluble vitamins are divided as vitamin A, D, E and K. Uh so when it comes to the dietary requirements uh the food sources stability and toxicity we'll be discussing about each and everything in detail. So the major concept of or the prime fats soluble vitamin is vitamin A. Vitamin A is a group of fats soluble retinoids including retinol, retinal, retinoic acid and provitamin A carotenoids which is nothing but the betaarotin. It it is essential for vision, epithelial integrity, immune function and reproduction.
1:50 So when we talk about the chemical forms of vitamin A, there is something called preformed vitamin A. In that you have this component called retinol, retinol and retinoic acid. Along with it there is a provitamin A, betaarotin, alphaarotin and uh beta cryptoanthin. this when when talking about the storage part the vitamin uh A is primarily stored in the liver as retinile esters 90% of the body stores are in the uh liver stored in the liver and the transport is the they are transported in the blood bound to retinol binding protein which is nothing but the RBP and trans transitin which is the TTR so this
2:36 is the transport uh part when it when we talk about the measurement it is expressed as retinol activity equivalence 1 R A is equal to 1 m of retinol which is equivalent to 12 m of betaarotin which is nothing but 24 mg of other provitamin A carotenoids. So uh vitamin E is so much important in our body that there is an RDA requirement and it goes increasing as we grow and as we age. So the children 1 to 3 years it is uh 300 for RDA and the upper limit is 600 whereas uh for 4 to 8
3:21 years it is 400 and 900 and for boys it is 600 and for girls it's the same and as we grow like especially pregnancy and lactation the requirements are a bit higher which is 770 and 1,300 mgram per day for an ice in Indian adults Men it is 600 mg uh retinol equivalents per day and for adult women it is uh 600 mg retinol equivalent per day. So the forms of vitamin A as I told there are three forms which is nothing but the retinol. It is the alcoholic form of vitamin A present in mammals and most abundantly it is present in liver oils. Retinol which is the alihide form
4:07 or retinaldihide. Retinyl functions along with opsin to form rodopsin which is a visual pigment of the uh body of the eye and retinoic acid. It is the acidic form of vitamin A. It is the most active form of retinol. And we have keratin which is also known as the pre provitamin A. It acts as a precursor for the vitamin A. So that is the keratin part. When we talk about the functions of vitamin A always uh remember that vitamin A is always involved with vision. So vitamin A plays an important role in various body functions essential for normal vision and functioning in dim light. It helps to maintain the integrity and
4:54 normal functioning of epithelial cells and it's also necessary for the growth of skeleton and has anti-infective functions. So coming to the epithelialization, it is present in the outer layer of the skin, the respiratory tract, gastrointestinal tract, genital urinary tract. Vitamin A is needed for the secretion of mucus by these epithelial cells. Thus, the vitamin A places its importance in epithelialization. And we do have appetite problems like uh like studies conducted in animals show that when their diet is deficient in vitamin A, their appetite seems to be poor. So
5:39 probably because the taste buds are being keratinized because of the vitamin A deficiency. When it comes to reproduction, earlier studies report that vitamin A aids in spermatogenesis in men. Fertility was supported with vitamin A supplementation in animals. Anti-infective functions. When we talk about uh vitamin A deficiency uh could lead to the keratinization of epithelial cells in the trachea. This causes reduction in mucus secretion including microorganisms. they thrive into the body thereby more prone to infections of respiratory tract. Vitamin A supplementation in respiratory illness and diarrhea may help the children to
6:24 recover faster and better. When it comes to bone growth, vitamin A is important for bone growth. Also, it is involved in the conversion of immature cells to osteoblast which is bone forming and osteoclass which is the breakdown of bone cells. So when we talk about the cellular functions vitamin A another function includes the control of expression of loads of proteins namely collagen and trans glutamines keratin and gluten collagenase. Coming to the bioavailability of vitamin A we have about preformed vitamin A, proformed vitamin A or pro vitamin A. So
7:10 when it comes to pre-formed vitamin A, 70 to 90% is highly bioavailable from animal sources. They're absorbed via passive diffusion after hydraysis by pancreatic enzymes. Similarly, there is about 3 to 14 percentage low bioavailability from the plant sources. They require cleavage by betaarotin uh 15 dioxy oxygenase. And when when we talk about the factors enhancing the absorption, there is increased dietary fat which is required for enhancing the absorption of fats soluble vitamins especially vitamin A. So when it comes to heat processing, emulsification, adequate protein and zinc status are all in the uh need. So which will enhance
7:58 the factors these are some of the factors which enhance the absorption of vitamin A. There are some factors which will decrease the vitamin A absorption also. So when there is a decreased dietary fiber intake in your body, polyphenols, parasitic infections, vitamin A, E deficiency, uh fat malabsorption, all that affects the bioavailability of vitamin A. So when we talk about the toxicity uh the acute toxicity includes about uh the consumption of single dose of greater than 1 lakh 50,000 mg retinol in adults greater than 7,500 mg in young children which leads to nausea, vomiting, headache, bulging fontel in
8:46 infants, dizziness and blurred vision. Even skin peeling can occur because of the disquamation and the liver damage at a very high doses. So when we talk about chronic toxicity, prolonged intake greater than 3,000 mg per day leads to alopeesia which is the hair loss, bone pain and skeletal abnormalities. Also we could find that there is a hepattogali because the vitamin A is uh stored in the liver and fibrosis, hypercalcemia, territogenicity especially in the first trimester of the pregnancy. So these are some of the sources that are rich in vitamin A. So which includes
9:33 beef liver, chicken liver, cod liver, egg yolk, whole milk and butter. So animal sources include uh these pre-formed retinol. And there are some plant sources of provitamin A which is nothing but the betaarotin. So if you see all those uh green colored and orange colored fruits and vegetables are very good source of vitamin A. So we start with drumstick leaves which has the highest vitamin A content in it and then followed by carrot cooked carrots about 852 mog retinol uh activity equivalent per 100 g. Sweet potato is also very good source of vitamin A and where if you get lot of sweet potatoes during one season try to
10:18 consume more so that you get enough vitamin A to the body and that con constitutes about 7 or 9 mg which is the retinol activity equivalent. Spinach which is cooked will have about 524 mg. In papaya 47 mg retinol uh activity equivalent and mango ripe has about 32 38 mg uh retinol equivalent per 100 g. Coming to the stability of vitamin A, most of the time uh they are stable to heat during normal cooking and they are destroyed by oxidation, UV light and prolonged high temperatures. Beta carotin in orange or yellow vegetables
11:04 is relatively stable. Loss is minimized by sealed low oxygen temperature and avoiding prolonged frying. That's it with vitamin D and the deficiency of vitamin D. Uh vitamin A includes uh all our um night blindness and uh nctalopia. we call it as nicalopia and also bod spots and all that. So that becomes a major uh deficiency and followed by toxicity the sources stability. Now we are moving to the vitamin D which is an very important fats soluble vitamin next to vitamin A. Vitamin D is a unique fats soluble
11:52 seoststereroid that functions both as a vitamin obtained from diet or supplements and a pro hormone synthesized in skin via UVB radiation. It is critical for calcium homeostasis, bone mineralization, bone immune modulation and cell proliferation. And uh if we talk about the uh vitamin D chemical forms, it is D2 algo calciferol and D3 koliciferol which is important uh from animal or skin synthesis. And from the skin uh D3 which is the choliciferol reaches the liver where it is forming the calcidol and in
12:40 the kidney the activation takes place which is a calcol and that's the active form of vitamin D and most of the vitamin D is stored in the adipos tissue and the muscle. Serum 25 hydroxy vitamin D is a standard marker of vitamin D status. When it when we talk about the deficiency, it causes ricketetts in children, osteomalia in adults and they are linked to osteoporosis, diabetes and immune dysfunction. So coming to the uh vitamin D sources, the first source is the sunlight that we uh get and when it comes to the food sources, we'll be talking about the food sources also. these requirements when it comes
13:27 to uh the infants and children and adults the requirements go as we age. So it starts from 400 AI till uh 800 IU which is the international units. When we talk about vitamin D bioavailability dietary absorption happens via passive diffusion in the small intestine which requires bile salts, micella solubilization and dietary fat. The comparison between D3 and D2 is D3 is called as a choliciferol which raises the uh serum 25 hydroxy vitamin D by 87%age more effectively than D2. Uh but
14:12 mostly D3 is preferred for the supplementation part. As I informed before uh vitamin D is a major source of from the sunlight. So UVB converts the 7day hydro cholesterol in the skin to previtamin D3 and then it converts to D3 which is and it happens most efficiently in tropical countries where we can see the sunshine all the time. So there are some factors which also limit the sun synthesis which includes the melanin which is a dark skin and uh sunscreen about uh sun protecting factor 30 blocks 95%age and so most of the time when we are
14:59 using sunscreen we may not get enough or adequate vitamin D age if it's elderly have about 75% reduced capacity to uh obtain the vitamin D uh clothing if you're having the full cover uh clothes season also varies and the latitude also plays an important role fat malabsorption like conditions where you find fat malabsorption include Crohn's disease, celiac disease and beriatric surgery. These things significantly impair vitamin D absorption. In obesity uh adipos tissue sequesters
15:44 vitamin D. Most of the obese individuals require two to three uh dosage higher dosages to achieve the same serum levels. So almost the obese people will have to be uh given more vitamin D supplement. So we all know that vitamin D deficiency causes uh ricketetts in children and osteomalacia in adults and they may have bored legs and they will have piggy chest and they also have um inadequate calcium also because of the bone. So vitamin D and calcium plays a very important role together. And uh when it comes to vitamin D toxicity, vitamin D toxicity is mostly called as
16:30 hypervitaminosis D. It is important uh because vitamin D toxicity does not occur from sun exposure. Usually skin will regulate the production. So it occurs only from the excessive supplement intake which is the D3 process. acute or chronic toxicity uh is uh serum 25 hydroxy D is great uh vitamin D is greater than 150 nanog per ml we consider them to be uh having a toxic levels and also uh if the there is a sustained intake of greater than 4,000 international units per day for a long term they may go for toxicity so the
17:16 primary mechanism includes excess vitamin uh would lead to hypercalcemia and hypercalcemia would lead to multi-organ damage. Always note that upper limit is 4,000 international units per day for adults. In clinical supplementation, the uh doses go up to 10,000 international units per day are used under supervision with monitoring of serum calcium and 25 hydroxy vitamin D. So when it comes to the symptoms and sciences we could uh divide them into system wise where we can see that uh in the gastrointestinal system nausea vomiting anorexia constipation occurs when it comes to the renal system
18:03 polyura polyypipssia nephroinosis kidney stones occurs and in cardiovascular we may find that soft tissue calcification and arythmias and hypertension is a major u symptom that you can find under the nervous system. We we may find a weakness, confusion, lethargy and bo uh bones also like we we could see that paradoxical bone resorption uh despite being a bone vitamin. So all these things can happen. So when we talk about natural food sources apart from uh vitamin uh D from sunlight, we do have uh natural food sources like cod liver oil which
18:48 contributes to the highest level of vitamin D which is about 450 mog per 100 g and salmon which is uh the fish variety mackerel sardins all these contribute to good amount of vitamin D. Even egg yolk has about 1.1 mgram. Beef liver has about 6. Whereas mushrooms which are UV exposed have about 4.9 mg per 100 g. Apart from the natural sources we do have some fortified foods where uh the foods are being fortified with vitamin D especially milk is being fortified and it's regulated by the FSSAI which has about 1 to 1.5 mg per 100 ml. That's the fortification level and even edible oil
19:36 um is fortified which is about 5 to 10 m per serving. Fortified breakfast cereals contribute about 1 to 2 mgram per serving. Coming to the stability uh usually vitamin D is relatively heat stable and they are minimally lost during cooking that less than 10%age only is lost during cooking. It is sensitive to prolonged UV uh light exposure, oxidation and prolonged storage. So if you see uh D3 is more stable than D2 and that's why it's being given as a supplement. Fortified milk loses about approximately 10%age on pasteurization. Packaging in opaque containers prevents
20:23 the photo degradation. Therefore uh I would like to conclude that uh as a part of fats soluble vitamin A and D uh these two nutrients are very much essential for vision immunity epithelial integrity calcium homeostasis and bone health their deficiencies remain highly prevalent in India despite their importance in maintaining overall health and disease prevention. Combating deficiencies require a multistrategic approach including food fortification, dietary diversification, safe supplementation and public health programs while also ensuring the
21:09 awareness about toxicity risks associated with excessive supplement intake. Always uh fats soluble vitamins. These two are having a very crucial role to play and having a lot of uh functional abilities. They being form the major uh fats soluble vitamins but their deficiencies are still predominance in India. Thereby we have to look out for uh combating these deficiencies by multiple programs like food fortification, safe supplementation and public health programs.
