Thiamin B1 Deficiency is called Beriberi In Holland Dutchman was brought back from East Indies with what natives called Beriberi or lameness In Japan sailors developed this and several died At this point all the rice was being 1 Funk discovered at a grain they all It has an outer bran The grain is what stays whole grain White like whole wheat bran Although they may of the layers stay the bleached refined and has max softness and whiteness The unbleached is tan colored with texture and nutritive qualities polished In 1912 Casimir vitamines When you look usually have same structure which we usually do not see and is what is involved in flour and flour which is soft is the endosperm part bleach the grain the textures same White flour is Food sources of Thiamin are meats such as pork legumes and whole and enriched cereal and bread Legumes are your meaty beans that are usually black red and brown Supplements include Thiamin HCl and Thiamin Monocitrate Stability They are water soluble not stable in alkaline medium and not heat stabile Forms include plants such as free thiamin vitamin and animal products which have TDP and TPP TPP and TDP are the same Co enzymes has 2 phosphates compared to vitamin form Thiamin bridge that holds the two rings together breaks apart very easily The co enzyme form This is just showing that adding two phosphates brings the vitamin into the co enzyme form Digestion It can be eaten in all forms Thiamin and TDP TPP In the intestine we take the phosphates off and put it back into the vitamin form Phosphorylated Co enzymePhosphatases free Thiamin We absorb it as free Thiamin At low concentrations we have active diffusion with carriers and if high concentrations we have passive diffusion Anti absorption factors inhibits crossing of brush border Thiaminases and Polyphenols Thiaminases cleave that bond between the rings It is found in raw fish and are thermolabile meaning they can be broken down by heat Polyphenol inactivates Thiamin by oxyreductive process They are found in coffee tea blueberries red cabbage and Brussels sprouts They are thermostabile and are facilitated by Ca and Mg Polyphenols are prevented by Vitamin C and citric acid There are foods that have anti and pro vitamin properties within the same food Back to the Japanese sailors from the first slide now we have polished rice with no whole grains and they have a high sushi coffee and tea diet which was a bad combination for disease 1 https www google com search safe off q husk seed bav on 2 or r cp r qf bvm bv 48572450 d eWU biw 1366 bih 643 um 1 ie UTF 8 hl en tbm isch source og sa N tab wi ei knHRUfOUJYTM9QSx0oGIAw um 1 safe off hl en tbm isc h sa 1 q grain seed layers oq grain se Inside the enterocyte Thiamin can be phosphorylated and can leave by active transport Ethanol interferes with transport across basolateral membrane Blood 90 is transported in RBC and the rest is bound to Albumin in plasma o So if this is your enterocyte and all the food you ate So your Thiamin comes in and it can either be used or it can leave The large dot is the transport protein and EtOH inhibits this which inhibits Thiamin from leaving and causes a buildup Thiamin is then trapped in the enterocyte The vitamin is then excreted through fecal matter and not absorbed in blood stream This just shows the conversion from vitamin to co enzyme form and vice versa Do not have to memorize enzymes TPP is the most often form that is used Tissues Thiamin must be phosphorylated to be active Remember phosphorylated means that it is in co enzyme form TDP TPP is mostly found in skeletal muscles liver kidneys and nervous system Although those are popular places they are in all tissues Thiamin is involved in Pyruvate Dehydrogenase Complex ketoglutarate Dehydrogenase Complex and Branched chain ketoacid Dehydrogenase A deficiency of not being able to breakdown the last enzyme can cause Maple urine disease So Thiamin deficiency can mimic this disease because of that enzyme It indirectly provides energy production because it is involved in a couple reactions that end in NADH Thiamin is used in the reaction of pyruvate into Acetyl CoA so we do need to utilize it for EtOH metabolism We can also get a buildup of lactate without having Thiamin HMP Shunt produces NADPH which can be used for FA synthesis desaturation MEOS pathway and cholesterol synthesis At the Ribose 5P we must decide whether we are going to go to the hexose mono phosphate or pentose route Your pentose will form nucleic acids for DNA and RNA while your hexose will form hexose for regeneration of G6P The Transketolase requires Thiamin Without Thiamin the pentose won t be able to be shuttled back into glycolysis and will have to only go to DNA and RNA synthesis Synaptic Function TPP released by synaptosome after action potential and may be needed for Na channel function TPP donates phosphate for that Na function So Thiamin is needed to get a signal out of one neuron and into the next No neural transmission without Thiamin Assessment Urinary excretion provides an index of dietary intake but does not provide information on whether Thiamin is being utilized in the tissues Excretion after load test You give them a large dose and measure the amount Alcoholics for example would have little in urine because of the problem of getting it from intestine to blood stream leading to fecal excretion rather than absorption There are Transketolases in other tissues including your RBC which you can use to test for different enzymes and proteins through that It is the most reliable way Deficiency You can get Beriberi and it has three general symptoms of cardiac abnormalities neurological problems we just discussed this in synaptic function and gastrointestinal problems There are two types of this deficiency Chronic and Acute Chronic is wet beriberi or dry Acute is known as infantile beriberi Chronic Beriberi can be either dry or wet Dry includes muscle wasting and weakness peripheral neuropathy includes sensory and nerve conduction problems and asymmetrical foot drop with tenderness of calf muscles Wet beriberi has to do with fluid retention It can cause an enlarged heart also called cardiomegaly tachycardia heart failure and edema Acute beriberi involves anorexia vomiting lactic acidosis because you don t have thiamin to convert pyruvate into acetyl coA and cardiomegaly It is most often found in infants due to lack of Thiamin in breast milk So if mom is deficient and nursing then infant can
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