Vitamin B3, B5, B6 and B7

00:00 Moving on now to vitamin B3, niacin.

00:04 There's a little bit more to say about niacin that you need to know.

00:08 Again it's involved in electron carriers as a cofactor.

00:12 Also involved in nerve functioning.

00:15 So naturally it has some critical roles.

00:18 And finally we know that it's involved in cholesterol production.

00:23 Now here I let you know that we have the vitamin B6 also coming into play.

00:30 Because B6 is a cofactor for the enzyme that converts tryptophan to niacin.

00:36 So a deficiency in B6 or tryptophan could also lead to a deficiency in niacin.

00:45 So that's one thing to keep in mind.

00:47 We'll again address it when we come to B6 of course.

00:51 Because there's a reciprocal relationship there.

00:54 Niacin excess is an interesting condition because often we use niacin to treat high cholesterol levels.

01:04 So sometimes we'll see patients that have the symptoms of niacin excess.

01:10 And one of the side effect is facial flushing.

01:13 It's kind of a blotchy appearance.

01:15 Very simple to alleviate though.

01:18 We just remove B3 niacin because when we remove the B3, it will be removed, extra excess will be removed in urine.

01:28 And the individual will return to normal.

01:30 Niacin deficiency however, shows up as a condition called Pellagra.

01:36 And the way that I remember the condition of pellagra is by using three Ds.

01:41 Dementia, Diarrhea and Dermatitis.

01:47 And the dermatitis often appears as cracked skin.

01:51 Specially around the corners of the mouth.

01:53 Now some people will call it four Ds because death could result.

01:57 I prefer to stick with the three Ds.

02:00 Because it's much less likely in the United States.

02:02 But three Ds, dermatitis, dementia, diarrhea are signs of this pellagrin niacin deficiency.

02:10 And you should understand those for your exam.

02:15 Moving on to B5 which is pantothenic acid.

02:20 We find that again it's in many of the foods we eat.

02:25 We have relatively good diet in the United States and in manufactured foods it's in there as a supplement also.

02:31 So it's rare to have a deficiency.

02:34 But if there is a deficiency, it leads to a syndrome called "Burning Feet Syndrome." Again involved in metabolic processes.

02:43 As you will see over here involved in the synthesis of coenzyme A.

02:48 So B5 is a cofactor for the synthesis of that enzyme.

02:52 Moving on now to B6 or pyridoxine.

02:57 There are few more things to say about this vitamin.

03:01 It is a cofactor again.

03:03 No surprise in many metabolic processes.

03:06 Not going to go into the details of each of those.

03:09 But particularly it's a cofactor in protein metabolism.

03:14 Because it helps transaminases do their job.

03:17 We call transaminases, they are going to be removing amino group.

03:21 So when they are not functioning well, protein metabolism is an issue.

03:26 We also see issues with neurotransmitter production.

03:31 Neurotransmitters particularly the catecholamine, such as epinephrine, norepinephrine, dopamine and serotonin.

03:40 So some of the side effects of pyridoxine deficiency could be in the realms of depressions for early science.

03:48 Also we see that pyridoxine is important in red blood cell production.

03:55 Now we could go into super detail on each of these processes.

04:01 And where the vitamins come into play.

04:03 And there are some of them well have been featured in your biochemistry course.

04:08 But here the purpose is for us is just to cover specifically what you need to know about each of these vitamins for the exams.

04:16 So that you can score best on the exam.

04:19 Otherwise we could be here for weeks just talking about all of the roles of different vitamins in the biochemical processes.

04:25 So these are just the highlights that we're covering.

04:28 When we see deficiency again in B6, you probably remember just a few moments ago that we discussed a bit of vitamin B3 or niacin.

04:40 And so B6 being a cofactor for the production of niacin.

04:45 Again we can see niacin shortage because of B6 deficiency.

04:50 And this can also lead to peripheral neuropathy.

04:55 As well as seizures and anemia.

04:59 Now it makes sense, right.

05:01 If you look back to the slide of what B6 is involved in.

05:06 You would expect that perhaps there were some other issues with the nervous system as well as anemia.

05:14 Because it's involved in red blood cell production.

05:16 So you can pretty much predict what the symptoms of deficiency are by understanding what the vitamin is used for.

05:26 So now moving on to biotin.

05:31 Biotin, there's not a whole ton to say about it.

05:35 Biotin is plentiful in most of our diets.

05:38 Cell growth is one of the things that it's particularly involved in.

05:41 It assists with the synthesis of fatty acids And guess what production of red blood cells.

05:48 So we have explored the first set of our water soluble vitamins.

05:56 And I look forward to seeing you in the next lecture.

05:58 Where we get into a little bit more detail talking about B9 and B12.

06:04 Because those two have some specific interactions which are really important to look at.

06:10 I hope to see you there soon.