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March 6th 2013 Nutrition Lecture.docx

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Kinesiology & Health Science
KINE 4020
Roger Kelton

March 6 2013 Nutrition Lecture Aneta is a health consicious 45 yr old woman,…? Cereal has fortified with K. The says 2% of daily requirement of cereal. IF she consumes 2 servings per day with 2% milk at breakfast, which of the following is true (**TEST TYPE QUESTIONS) Ans: A and E. (Calculation gives 188mg Kday. Milk too contains potassium) Vitamin A and Beta-Carotene Vitamin is one of the fat soluable vitamins , and in body exists as RETINOIDS: retinol ; retinal and retinoic acid. All are forms of Vit A but have specific roles Retinol (reproduction) Retionic Acid (has its own function) Retinal (vision) You don’t get VIT A form food or plant, you get COMPOUND (carotenoids )that can be converted to Vit A The most well-known is beta carotene (because it gets converted to VIT A much easily, readily, compared to the other compounds called retinyl esters) Animal foods  retinyl esters and can be converted to retinol If you want to determine how much VIT A is in your system? You can measure by measuring it how much VIT A is in your blood and you measure retinol (that is the form that moves from one part to another) Fat soluable vit don’t move freely in the blood they need to be carried around. VIt A also needs to have Retinol Binding protein from one tissue to another. Beta cartotene absorption is poor because. Beta carotene absorption is not as good compared to retinyl esters. Even when u have absorbed beta carotene u need 12 units of betacarotene for 1 unit of VIT A that is produced. Diff forms of vit A performs diff functions Retinal to retinol and retonic acid conversion is easy You cannot back from retinoic acid to retinal or retinol VIT A helps maintain the cornea conversion of light energy into nerve impulses Rhodopsin is made up of opsin and cis-Retinal(form of VIT A). When you have light shining on Rhodopsin it basically leads conversion of cis-retinal to trans-retinal. When you have that transformation the trans Retinal cannot bind to opsin. The serration of Rhodopsin that leads to destruction of membrane which nerve cells send messages to brain and you are able to see. Retinal maintains integrity of cornea VIT A is important in Protein synthesis and Cell Differentiation Epithelial cell: Cells that lie on the external surfaces of the body. The surfaces of the GI tract. All the way from esophagus to colon. Urinary , reproductive, the trachea, all have ephitleial cells Vit A is very important as it stimulates globulet cells to make mucus which helps keeps the surface moist. Vit A maintains healthy cells in the mucous membranes. Roles in the body Reproduction invovled in sperm production -invovled in embryo development -VIT A involved in protein synthesis, BONE DEVELOPMENT.  VIT A, is involved in Osteoclasts (bone breaking) Osteoblast (making bones) Remodeling of bones osteoclasts is first process it breaks bones and new bones are made using osteoblasts Lysosomes = bag of enzymes they degrade proteins/ need vit A to do what they have to do. Beta-carotene can do something as VIT A. AS you can convert VIT A to Beta- carotene. VIT A you can get from beta carotene Beta-carotene can act as an antioxidant VIT A and Beta-Carotene VIT A  stored in liver. For how long somebody can go without VIT A depends on diff factors? Depends on their Protein Status Vit A Deficiency is a big nutrition problem. Lack of VIT A it can have implication for their immune status. -Measles the severity depends on the VIT A People living in third world coutries have access to sufficient amount of vit. A maize contains a lot of beta carotene The region in which the main source of food is corn and they consume some sort of corns that contain beta carotene the consumption of a lot of beta carotene can help produce or maintain vit. A, levels one of the signs observed with vit A deficiency is night blindness , If u sit in the dark for a couple of min and then u turn on the lights u will experience a moment of darkness but u recover because u have enough retinal ( the process has been described) People living in regions of the world where they have problems regarding their vit A requirements, one of the things they will experience is night blindness that is they are not able to see or work at night The lack of vit A in retina leads to this the part of eye involved is retina The role of vit A in eye (two regions discussed) If somebody has a lot of retonic acid in their body can they experience night blindness? Even though an individual has enough of vit A in retinoic acid form. Retinoic acid is kind of a dead end when it comes to the end of conversion so this individual might have a lot of retinoic acid but if he lacks retinal in retina he is going to end up like night blindness. Somebody having vit a deficiency in any other any other part of the eye can experience more devastating effects specifically blindness simply because if we don’t have enough retinal in the cornea u r able to maintain integrity of that site that is going to lead to cirrhosis which is why the
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