00:00 Hello, this is the first in a series of two lectures on water soluble vitamins. 00:07 We're going to explore the majority of the B vitamins in this lecture. 00:11 We'll begin by looking at thiamin. 00:15 Thiamin is B1. 00:16 Why don't we just work our way straight through the numbers. 00:19 In this lecture I'm going to highlight the parts that you need to know about each of these vitamins. 00:26 Yes, there are many more potential functions. 00:29 And things that you could know. 00:32 But these are the highlights that you need for your exams. 00:35 First of all vitamin B1, thiamin, is the most -- is a very important cofactor in many metabolic processes. 00:42 You can see here for example, pryuvate dehydrogenase and alpha-ketogluterate, really depend on the B1 vitamin as a cofactor. 00:53 This is found in many foods. 00:56 And we fortify many foods with it also. 01:00 And so we rarely see a deficiency in the United States. 01:06 The one exception though is in the condition of alcoholism. 01:10 Because often in alcoholism the majority of calories are coming from alcohol unless there is some deficiency in other nutrients. 01:19 And so there are three conditions associated with B1 deficiency that you should be very clear about. 01:28 Those three conditions are Dry Beri-Beri, Wet Beri-Beri and Wernicke Korsakoff. 01:34 In dry beri-beri we have predominantly effects of the nervous system. 01:39 We'll see things like symmetrical muscle wasting. 01:43 So both sides are getting very weak. 01:45 As well as peripheral neuropathy, confusions. 01:50 Sometimes difficulty speaking and involuntary eye movements. 01:55 So nystagmus would be constant in this case. 01:59 So looking at someone's whose eyes are constantly shaking back and forth. 02:04 Nystagmus would be a good indication of dry beri-beri and perhaps vitamin 1 deficiency. 02:11 Wet beri-beri on the other hand has much more to do with cardiac systems. 02:17 Individuals may have signs of both dry and wet beri-beri. 02:22 And in the case of wet beri-beri we have shortness of breath, rapid heart rate. 02:28 More things associated with the circulatory system like edema in the lower legs. 02:34 And this can even lead to cardiac failure. 02:37 On top of this we could stack wernicke korsakoff. 02:41 So these two have neurological and cardiac symptoms respectively. 02:48 Wernicke korsakoff will start seeing both of those also and more extensive neurological symptoms. 02:56 Wernicke korsakoff is described as a set of symptoms that lead to confusion. 03:04 Again we'll have not just the involuntary eye movements but perhaps even constant. 03:09 Nystagmus. 03:10 Aphasia where an individual is sort of moving in and out of understanding things. 03:16 Ataxia as well as memory loss. 03:21 And confabulation is one of the biggest symptoms. 03:26 So individuals with wernicke korsakoff have mamillary body damage in the brain areas. 03:32 And they will tend to confabulate meaning make up stories. 03:38 That are sounding really extreme explanations for what's actually going on. 03:44 So there's a certain sort of detachment from reality. 03:49 It's a pretty clear syndrome. 03:51 When you see someone presenting with this type of confusion and very extreme exaggerated types of stories. 03:59 There's a possibility that it could result from a B1 deficiency and alcoholism. 04:05 Moving on to vitamin B2, riboflavin. 04:09 Riboflavin is also involved in many metabolic pathways. 04:15 For example, that's involved in the synthesis of FAD. 04:19 Here we call FAD is an electron carrier and thus is involved in energetic relationship. 04:26 So you'll notice a lot of these B vitamins are involved in metabolic processes. 04:32 As well as production of red blood cells. 04:34 So this is a fairly common B. 04:37 Deficiency in riboflavin is very rare in the US. 04:41 I have for eating fresh foods, with vegetables and good diet than it shouldn't really be an issue. 04:49 Plus, we supplement many of our packaged foods with riboflavin. 04:54 Causes of riboflavin deficiency could be malnutrition in developing countries, alcoholism, vegan diets, and pregnancy. Signs and symptoms are cheilitis, glossitis, and stomatitis; pharyngitis; normocytic normochromic anemia; red-eye and photophobia; and seborrheic dermatitis on the scrotum, vulva, philtrum of the lip, or the nasolabial folds.
The lecture Vitamin B1 and B2 by Georgina Cornwall, PhD is from the course Nutrition. It contains the following chapters:
Which of the following enzymes uses vitamin B1 as a cofactor?
A patient presents to you with ataxia, nystagmus, and is confused. He also consumes large quantities of alcohol. A deficiency in which vitamin is most likely responsible?
A patient presents with cracks and sores around the corners of the mouth. He also complains of fatigue and sensitivity to light. A peripheral blood smear reveals normocytic normochromic anemia. Which vitamin is most likely deficient in this patient?
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I have learned a lot through her lectures, I love her lectures, she explains things very well.
I love her lectures ! Relevant for the USMLE and fun ! Recommended !