1 Metabolism Study Guide Exam 1 Metabolism of Vitamins and Minerals 1 What do we have to understand about nutrients The term nutrients is used to describe any substance that our body uses for essential reactions These fall into six separate classes Carbohydrates proteins fats vitamins minerals and water Yes water is considered a nutrient as every metabolic reaction depends on the presence of water The first three classes were the focus of metabolism one know the focus is one the vitamins and minerals 2 What is a vitamin A vitamin is an organic compound that is considered essential You take these out of the diet and your body will deteriorate You add them back in and then those problems will be reversed thus they are essential Understand that vitamins do NOT yield energy they regulate many reactions but they do not break down to energy like carbohydrates proteins and fats Vitamins are classified as water or fat soluble and this classification determines are the vitamin is absorbed fat soluble vitamins need fat and are absorbed with fat and how they are stored in the body water soluble are stored in water which you urinate out so water soluble are not stored in the body Because of these it is very hard to overdose on water soluble vitamins yet the fat soluble vitamins are stored in the body so overdose is much easier One thing that sucks about vitamins is that most are destroyed by the act of cooking and by the presence of UV light Tony Berardi 1 Some vitamins are cofactors meaning they assist in metabolic reactions Some are coenzymes so they are loosely attached to certain enzymes and determine reactions If they are tightly bound to an enzyme they are known as prosthetic groups 3 What is a mineral A mineral is an inorganic compound that the body requires in a very small amount Minerals cannot be made by us humans thus we need to consume them in food Unlike vitamins they are not destroyed by any means cooking or light Minerals come in two flavors like vitamins do The macro minerals and the micro minerals The macro minerals are needed by the body in larger quantities and consist of calcium The micro minerals are needed in smaller quantities but are as important Such as and potassium for example copper and zinc 4 How do you know how much to take This is great and all to know that our body needs them but how much do we take Over the decades the FDA has looked at the general population s intake and has created the DRI to determine the amount that we need to prevent chronic diseases The DRI is composed of the RDA and the EAR The RDA is the recommended dietary allowance which is pretty much the DRI This is what 98 of the population should be consuming for the respective nutrient The EAR is a form of the DRI that only encompasses 50 of the population So this value is what is recommended for half the population but the RDA covers 98 of the population s nutritional needs The UL is the limit of a nutrient that is safe for consumption Most vitamins have upper limits where above this value is detrimental to health An extreme example is with vitamin A At sufficient doses Vitamin A produces an acute untreatable and routinely fatal liver toxicity The action was initially discovered when several scientists doing Arctic research consumed polar bear liver for dinner Polar bear liver has enormous amounts of Vitamin A They all died So moral of the story is don t overdose Tony Berardi 1 The AI is a value assigned to a nutrient when there is not enough research to derive an RDA for So they choose a value high enough that seems the best Alcohol Metabolism 1 What are the guidelines concerning alcohol If you chose to drink they say to limit yourself to two drinks a day for men and one drink a day for women Now for the definition of a drink 12 ounces of beer 10 ounces of wine cooler 5 ounces of wine 1 5 ounce shot of 80 proof 1 ounce shot of 100 proof Next she shows how to calculate the amount of EtOH in calories present in beer liquor or wine Simply multiply 0 8 g mL by the percentage of alcohol in the drink then by the volume of the drink 2 What happens once the alcohol is in the body There are three systems in the body that work to metabolism the alcohol that you just consumed They are the alcohol dehydrogenase microsomal ethanol oxidizing system and catalase Our primary defense system is our good friend alcohol dehydrogenase This enzyme is focused in the liver and in the stomach and is capable of metabolizing one drink an hour It works by converting the toxic alcohol to acetaldehyde which is even more toxic this is what causes fibrosis by binding to proteins in the liver This needs NAD to work o Luckily the acetaldehyde is metabolized very quickly to acetate via acetaldehyde dehydrogenase Another NAD is required for this Tony Berardi 1 The microsomal ethanol oxidizing system is an alternate pathway although not utilized often It is located in the microsome of cells and uses riboflavin and NADPH to function The end products of this pathway are NADP water and acetaldehyde 3 What happens to the acetate that we just formed The alcohol is metabolized to acetate so now what 20 30 of it will remain in the live and form acetyl coA while the other 70 80 will enter the bloodstream and some will enter the muscle to become acetyl coA 4 How does the body react to ethanol EtOH slows down the metabolic reactions in the body in order to focus on metabolizing the alcohol This means alcohol is a priority fuel which means that the body will stop metabolizing carbohydrates stop metabolizing fat and focus all its efforts on detoxifying that alcohol So it will slow gluconeogenesis slow protein synthesis slow the krebb cycle and pretty much anything to do with energy In the stomach the alcohol will increase the HCl production to metabolize it faster It will increase the absorption of iron and increase your risk for gastrointestinal cancer In the kidney alcohol decreases the release of ADH this is released via the posterior pituitary and when this is no longer present the body does not reabsorb water thus alcohol will increase water excretion and cause dehydration In the brain it will decrease oxygen utilization I don t have notes for the other few slides Niacin B3 1 What are the sources and tea to an extent Tony Berardi Niacin is best found in meat and fish It is in its free form nicotinamide here so these are the best sources Remember that our body always absorbs the free form for everything Meat and fish are the best
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