What causes the “red wine headache”? Is it sulfites? A histamine reaction? Andrew Waterhouse, Professor Emeritus of Enology in the Department of Viticulture and Enology at UC Davis and Apramita Devi, Postdoctoral Scholar in the Department of Viticulture and Enology at UC Davis have identified a flavanol that can interfere with the metabolism of alcohol. That flavanol is quercetin, a natural product made in grape skins in response to sunlight. It is a natural sunscreen produced to protect the fruit from ultraviolet light.

This conversation covers why quercetin may be more prevalent in high end wines, how skin contact during wine production impacts quercetin levels, and why sulfites may play a role in “red wine headache”.

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[00:00:00] Beth Vukmanic: What causes. The red wine headache? Is it sulfites or a histamine reaction?

[00:00:10] Welcome to sustainable wine growing with the vineyard team. Where we bring you the latest in science and research for the wine industry. I'm Beth Vukmanic executive director. I've been your team. Since 1994, we've brought you the latest science-based practices, experts growers and wine industry tools through both infield and online education. So that you can grow your business. Please raise a glass. With us as we cheers to 30 years.

[00:00:37] In today's podcast, Craig Macmillan, critical resource. Manager at Niner wine estates with long time sip certified. Vineyard and the first ever sip certified winery. Speaks with two university of California Davis researchers. Andrew Waterhouse. Professor emeritus of enology and the department. of, viticulture and enology. And. Oprah meta Debbie. Post-doctoral scholar and the department of viticulture and enology.

[00:01:04] They have identified a flavonol that can interfere. With the metabolism of alcohol. And that flavonol is called quercetin. A natural product made in the grape skins in response. To sunlight. It's a natural sunscreen produced to protect. The fruit from ultraviolet light. This conversation covers. Why quercetin may be more prevalent in high end wines. How. Skin contact during wine production impacts quercetin levels. And why sulfites may still play a role in that red wine headache.

[00:01:36] Want to be more connected with the viticulture industry. But don't know where to start become a vineyard team member. Get access. to the latest science-based practices, experts, growers, and wine industry. The tools. Through both infield and online education so that you. You can grow your business. Visit vineyard team.org. And choose grower or business to join the community today.

[00:01:57] Now let's listen. in.

[00:02:01] Craig Macmillan: Our guests today are Andrew Waterhouse, Professor Emeritus in Enology in the Department of Viticulture Davis, and also Aparmita Devi. She is a postdoctoral scholar, also in the Department of Viticulture & Enology Davis. Thank you both for being here.

[00:02:17] Andrew Waterhouse: Oh, we're glad to be here.

[00:02:19] Craig Macmillan: Today we're going to talk about a really interesting topic. It's the role of quercetin , in wine headaches. The two of you recently co authored a paper on this one particular mechanism that might cause some people to get a headache after drinking even a small amount of red wine. But before we get into that, I want to ask you, how did you get interested in this topic?

[00:02:37] Andrew Waterhouse: Well I've been talking to Steve Mathiasson. He's a Napa winemaker for actually quite a while, some years back. He suffers from headaches when he drinks certain wines. And we were chatting about possible mechanisms, and we even did a study many years ago with another postdoc in my lab to investigate a question we had or a theory we had, and that didn't pan out. But more recently we were chatting again, and I got interested in the topic again, and that's what got me interested, you know, just somebody knowledgeable who was suffering from headaches and. for listening. It was, it makes it more real and it's like, well, maybe we can figure something out. So that's what got us started.

[00:03:17] Craig Macmillan: Apramita , how same for you.

[00:03:19] Apramita Devi: Yeah. Same. Like I've been in touch with Andy and we have been talking about this project many years. So I was always interested because I come from biological science and metabolism and stuff I got interested after talking to Andy.

[00:03:33] Craig Macmillan: Well, let's start with some basics. What is quercetin?

[00:03:38] Andrew Waterhouse: Well, basically, it's a natural product made by grapes, but it's a very specific one. It's in the class of polyphenolic compounds, and it's in the class of flavonoids called flavonols. And what makes it interesting, I think, is that it is made By grapes, in the skin of the grape, and only in the skin of the grape, in response to sunlight. It's sometimes referred to as sunscreen for grapes. And it specifically absorbs UV light that would cause damage to, say, DNA and other macromolecules. So it's very clear that the grapes are producing this in order to protect themselves from ultraviolet light.

[00:04:22] Craig Macmillan: Right.

[00:04:22] Andrew Waterhouse: So the amount that's present in wine is highly dependent on the amount of sunlight the grapes experience. Not the vine, but the grapes themselves, And a friend of mine, Steve Price, was the first to note this. In a study way back in the 90s on Pinot Noir, he noted that there was more quercetin in sun exposed Pinot Noir grapes. And that observation has been confirmed many times now in different studies. where sun exposure is correlated with quercetin levels.

[00:04:58] Craig Macmillan: and this is true just for red grapes as opposed to white grapes.

[00:05:02] Andrew Waterhouse: Oh, no, no, there's more in white grapes. But when you make white wine, you throw away the skins. So there's no opportunity to get those materials into the wine. Now, an exception might be orange wine. But I don't know of any data on orange wine.

[00:05:21] Craig Macmillan: Apramita , maybe you can talk about the metabolism part, the biology part. So when people consume alcohol, it's metabolized down certain pathways. Quercetin is also metabolized by the body into other forms?

[00:05:33] Apramita Devi: Yeah, so the pathway for alcohol and quercetin are a bit different, but the location is liver, where it goes. So when people consume alcohol, it goes to the liver and then there are two enzymes which work on the alcohol. So the first enzyme is alcohol dehydrogenase, which convert it into alcohol into acetaldehyde. The acetaldehyde is the like the toxic metabolite in the body and it can have many side effects. That's why body has to get rid of it out of the liver system. So it has a second enzyme which is called the acetaldehyde dehydrogenase. So that convert acetaldehyde dehydrogenase into a non toxic component, which is acetate or acetic system.

[00:06:24] So it comes out of the body. What happens when you consume quercetin along in the body, the quercetin also goes to the liver. Because quercetin adds too much quercetin as such is not good for the body and it has low bioavailability. So liver tag it in the form of quercetin glucuronide and then the body knows that it has to be flushed out of the system. So the interesting part is that when you consume alcohol and quercetin together, You are taking the both the metabolite acetaldehyde and quercetin gluconide in the same location inside the liver. And it gives the quercetin gluconide to interact with the acetaldehyde dehydrogenase enzyme. And that acetaldehyde dehydrogenase enzyme now cannot work efficiently. to convert the acetaldehyde into the acetate. So basically you are building up acetaldehyde in the body and it's not coming out of the system and you are seeing all those negative effects of the acetaldehyde in the form of flushing or headache or not. The other systems like what's like sweating. so we think that there is a correlation between these two pathways, which might be associated in red wine system.

[00:07:47] Craig Macmillan: And how did you design your study?

[00:07:51] Apramita Devi: The first when I talked to Andy, like he told me that he thinks that this system is because of inflammatory pathways and inflammation system. So he was kind of like, there is something in red wine, which is Triggering this kind of pathways or there is some system so, but we were not sure what exactly are those inflammatory system.

[00:08:16] So we went back and saw some literature and we kind of find that there are some studies which told that quercitans inhibit the dehydrogenase enzymes and that what triggered us that okay alcohol is metabolized by these dehydrogenase enzymes. And wine also has these phenolics. So what kind of phenolics, other kinds of phenolics, or what types of phenolics can do this inhibition?

[00:08:45] The method was basically in, was based on having different phenolics, which are present in red wines more compared to white wines, select them. And then just, we find this enzyme kits in the market to do this dehydrogenase. Inhibition tests like you put the test compound and it tells whether the enzyme is the inhibited or not.

[00:09:09] So we just did that in a test tube system, like we added our phenolics with the enzyme, and we saw that which kind of phenolics are inhibiting this enzyme and screening them out. out of all. So while doing that, we screened different types of quercetin, like quercetin glucoside, quercetin galactosides, and other forms.

[00:09:32] Then we also tested other phenolics. I can for all my rest in and other stuff. And we also choose quercetin gluconide because that is the metabolite which is circulating in the body. And then we kind of screen them based on the in the enzyme system and we see how much inhibition is happening there.

[00:09:54] Andrew Waterhouse: Yeah. So what we did was a very basic test to experiment. We didn't test anything on people.

[00:10:01] We basically tested to see which of these compounds could inhibit that enzyme because we knew that if that an enzyme could be inhibited the acetaldehyde would accumulate and you'd end up with people in that condition would end up with Flushing, headaches, as Aparmita said, all kinds of other symptoms.

[00:10:20] Craig Macmillan: And this would vary by person. Different people may have a proclivity to produce more of certain enzymes than others. Is that true?

[00:10:29] Andrew Waterhouse: We don't really have any information about that. That's going to take a lot of more work to test you know, the, the details here. For instance. Some people get red wine headaches and some don't, but we don't know whether, for instance, perhaps their enzymes are more inhibited by quercetin glucuronide, or maybe they're just more sensitive to acetaldehyde.

[00:10:52] So that's going to take, you know, human studies where we measure a bunch of things. And try to figure out, try to sort through the, the details of how this impacts people individually.

[00:11:04] Craig Macmillan: What would a study , with people, investigating this, what would the design be like? How would somebody go about doing that?

[00:11:12] Andrew Waterhouse: Okay. So a human study. Could have a couple different possible designs. The one we'll probably use is we'll simply find two wines, two red wines, one that's low in quercetin and one that's high. And then those will be administered to people who get red wine headaches. We'll give it to them blind, they'll have to agree of course to participate in the study.

[00:11:37] And then we'll see if their experience of headaches is related to the quantity of quercetin. Now, there's some other designs we could imagine using, which might be a little more straightforward, but we're not sure how relevant they would be or whether we could get approval to do this. So, for instance, one approach would be to find a red wine that's low in quercetin and then simply add it.

[00:12:00] Now adding it is tricky for a number of technical reasons. Quercetin itself is very insoluble, so we would have to add what's called a glycoside of quercetin. So we'd have to get our hands on something that would dissolve, et cetera, et cetera. We're not sure we could get approval for that because we're adding a chemical to wine.

[00:12:21] Now, the chemical would probably be classified as a supplement, and so it might be approvable, as it were. And then another very simple experiment, which we thought about a while ago, you can buy quercetin as a supplement in the market. It's readily available.

[00:12:38] So, one possibility is to simply give our subjects a glass of vodka and give them pills that either contain quercetin or a placebo and see if there's a relationship between administration of quercetin and headaches.

[00:12:54] Now the, the quercetin itself, as I mentioned, is very insoluble. So we may have to get these more bioavailable forms of quercetin for that experiment.

[00:13:04] Craig Macmillan: That leads to a wine making question. So, if it's relatively insoluble is quercetin extracted from skins more in the alcohol phase at the end of fermentation?

[00:13:11] Andrew Waterhouse: Yeah. It's, it's, it's extracted fairly quickly because it's in the skin, in the grapes, it's in the form of what are called glycosides. So these, Has the quercetin molecule with the sugar attached. That makes all those forms very soluble.

[00:13:27] Craig Macmillan: Oh, okay. Okay.

[00:13:29] Andrew Waterhouse: There's actually an occasional problem with certain red wines, most commonly Sangiovese, where after bottling the wine has had a large quantity of quercetin glucosides. And after bottling, they break down, the glycosides break down, releasing just a simple a glycone, quercetin, and you get this disgusting looking gooey brown precipitate in the bottle.

[00:13:56] Craig Macmillan: ha

[00:13:57] Andrew Waterhouse: Every few years I know the folks at ETS in Napa get somebody showing up with a bottle of Sangiovese that's got this. Disgusting sludge in it, and they can tell them without analyzing that. Yes, another case, of course, it's in precipitate in the bottom.

[00:14:15] Craig Macmillan: Huh, that's interesting. I believe it was mentioned in the paper that , obviously different growing conditions are going to lead to different levels of quercetin and grapes based on how much sun exposure they have, etc. And that also different winemaking techniques would have an impact.

[00:14:29] If consumers are looking for products if they know they have a headache issue Is it possible they could experiment with different product types? Products that were made with different production methods if they can find that out that might Impact their sensitivity or might impact how often it happens

[00:14:46] Andrew Waterhouse: Yeah, it's a pity that. Consumers wouldn't have information on the level of quercetin. We would very much like to do a study along those lines, but we haven't been able to find any funding for that, just in case somebody wants to support that kind of work, we're happy to work with them. but anyway you know, it hasn't really been an issue for winemakers, so there isn't a lot of data out there.

[00:15:08] There are a few studies that published amounts of quercetin, you know, in wines from different places, but the data is very, very limited and not really useful in providing consumers guidance. The one thing we can say is because, as I mentioned earlier, sun exposure is very important, in general if you look at a particular type of wine, a varietal, say Cabernet or Pinot Noir, that the grapes that are grown on very large vines, will have less sun exposure.

[00:15:39] Essentially if you have a very highly productive vineyard making targeting an inexpensive line, you probably have much more shading of the fruit as a consequence of lower quercetin levels. Compared to a very high end vineyard, usually, the amount of sunlight is very tightly controlled, and one of the reasons for that is that there's very good data showing that wines that are high in quercetin have a better mouthfeel, better texture in the mouth. And it's not clear whether quercetin is directly responsible or whether it's a marker for something else that's produced under those conditions that leads to that. many years ago, we did a study looking at phenolics in Cabernet, and we observed that the very high end Cabernets that we tested were much higher in quercetin than the sort of average price type product.

[00:16:35] And I think that that was true then. It's probably true now that, you know, a very good cabernet is, is made with very tight control of sun exposure. And there is a fair amount, of course, it can't be a complete sun exposure, or they probably get raisins by the end of the harvest, by the time you get to harvest, but there's a very deliberate management of sun exposure in high end wines. And it's for a reason to, get to higher quality product.

[00:17:04] Craig Macmillan: Right, exactly! And, We know that the managed sun exposure, quercetin is a part of it but also it's connected to just total phenolics in general. Lots and lots of different compounds that are, you know, semi related. And I actually wanted to go back Aprametia you identified the quercetin glucuronide as being The highest in the ones that you tested, were there other things in that test and that assay that all were also stood out, maybe not as high as that, but really kind of stuck out as being different than the rest.

[00:17:39] Apramita Devi: Actually, the quercetin gluconide was a standalone as a very high, like it's like 78%. The other things were around in that 30 percent range, so I'm not sure how significant was the impact of that, but there were quercetin glycosides forms, which were like around 30 percent inhibition of the enzyme, but

[00:18:03] all others were very low.

[00:18:04] Craig Macmillan: yeah, so it really stood out basically as it was head and shoulders above it. I would like to put this work into context a little bit. I, I work with the public quite a bit as part of my job and I have for years. And this topic comes up. All the time. This information definitely helps me my goal, when I talk to a consumer that has an issue with, wine headache or whatever it's not that I'm trying to sell them a product as much as it is.

[00:18:29] They want to enjoy wine. They tell me this, they say, Oh, I love to have it. I just can't. Da da da. And then they'll say, it's like sulfites. And then I'll kind of explore that with them a little bit. Like, so can you eat dried fruit? Do you eat canned fruit? Do you have reactions to this or to that? Are you asthmatic?

[00:18:48] Kind of sort that out and go, okay, I don't think maybe that's it. Maybe it's not. The other ones that I just learned about about 10 years ago was a biogenic amines, which made a lot of sense to me in terms of things like histamine reactions. What is your feeling about sulfites is contributing biogenic amines.

[00:19:04] Maybe there's other things we haven't hit on, on this topic. What are your feelings about the, kind of the big picture of what potential for a diagnosing assist?

[00:19:15] Andrew Waterhouse: Why don't you talk about amines

[00:19:16] Craig Macmillan: Yes, please,

[00:19:18] Apramita Devi: Biogenic amines like mostly the histamine and tyramine are the main ones people talk about whenever they come with this headache stuff. So I think because it's formed in the wine during the fermentation process, and there are these spec microbes which can convert the amino acids into this, biogenic amines the histamines are part of inflammatory reactions. People know that in biology and immunology. So it's very easy to be people connected that it might be a reason why people get headache. But what I always focus is like, there are far more other food products, for example, fermented meat products, which has far more higher amount of these biogenic amines. do people get headache if they have something similar with alcohol eating together with alcohol or something like that? But there is no mechanism told till now, they just tell that, oh, since it's histamine and it's related to this inflammatory reactions, it might be the cause. But there is no solid proof that it is the cause.

[00:20:27] so I don't know whether it's there or it might be a pathway or not.

[00:20:33] Craig Macmillan: One of the things that I find fascinating is how we evolve our, Hypotheses about things over time, and somebody has an hypothesis and they test it out, maybe they find something, maybe they don't, but then that kicks off this whole set of what I call naive science making up stories about why.

[00:20:53] It's kind of a just so story. It's like, well, obviously then somebody comes along and checks it and says, Hey, wait a second. And we're no, or if this was true, then that would have to be true. And that's not true. You know, and that kind of thing and how we keep coming around to new ideas, which is what you folks have done, which I think is really, really cool.

[00:21:10] Andrew Waterhouse: I was going to answer your question about sulfites. It's a really big question actually. Partly because sulfites have so much visibility and there's so much concern about it. I think sulfites themselves Have been studied pretty carefully there's one study where if they gave subjects a very high level of sulfites in wine, it was like very small, but statistically significant increase in headaches.

[00:21:39] Or some adverse reaction, but other studies have shown no correlation. By the way, sulfites are antioxidants in case you hadn't heard that. So it seems very unlikely that sulfites by themselves are some sort of bad actor in this regard. Like you, I get these questions all the time. And what I heard so many times was. Oh, it's cheap wine. It gives me a headache.

[00:22:06] Craig Macmillan: Yes.

[00:22:07] Andrew Waterhouse: And have you heard

[00:22:08] Craig Macmillan: I've heard that many times. And then on the opposite side of things, I've heard stuff like, Oh, I get headaches from American wine, but I don't get it from French wine. Or I always get headaches from European wines, but I never from California wine. So I'm trying to figure out, is there something going on?

[00:22:26] Like, can you be allergic to burgundy? You know what I'm saying? Cause I mean, it could be, it could be something about burgundy. It's just stuff going on. And then the opposite. I had a guy who says, no, I don't have any that. But he says I was traveling in France, and we were drinking wine like it was water, and I never had a hangover symptom, and I did it, and I was like, I don't know dude, like I

[00:22:45] Andrew Waterhouse: Yeah. Well, there's, there's one answer to some of this, which is if you're on vacation and you don't have to get up early and you're relaxed and you probably don't get as many headaches.

[00:22:58] Craig Macmillan: Right.

[00:22:59] Andrew Waterhouse: So I think that's a large part of it, especially for Americans visiting Europe. They're on vacation. but I think there is something to the sulfites question. And that is that inexpensive wine often, not always, but often has more bound sulfites.

[00:23:18] Craig Macmillan: Yep.

[00:23:19] Andrew Waterhouse: And this is probably because those grapes have a little bit more mold on them or a lot more mold. And when they get to the crusher, the winemaker goes, Oh, there's mold on these fruits. So we're going to add sulfites to, to take care of the botrytis, right?

[00:23:34] We don't want the fruit to get oxidized and damaged. They had a bunch of sulfites. The consequence of that is that in the finished line, There's a lot more. Bound to SO2, which shows up in the total SO2 number.

[00:23:47] You know what it's bound to?

[00:23:49] Craig Macmillan: No.

[00:23:49] Andrew Waterhouse: It's bound to largely acid aldehyde.

[00:23:52] Craig Macmillan: Really?

[00:23:53] Oh! Well that would make sense. Yeah, that would make sense.

[00:23:56] Andrew Waterhouse: And the, the reason for that is that during the fermentation, the yeast are converting all this sugar the alcohol, but there's an intermediate step which is acetaldehyde.

[00:24:06] Craig Macmillan: Right.

[00:24:07] Andrew Waterhouse: If you have SO2 floating around, as you would if you'd added a lot of it up front, it binds that acetaldehyde before it gets reduced to ethanol, to alcohol. if you start a fermentation with a high level of added SO2, then you will end up with a wine that has more bound acetaldehyde. And that could be a marker, say, of less expensive wine.

[00:24:31] So it's possible that those people are, what they're experiencing is direct ingestion of acetaldehyde, which is being released into the blood and that that's causing them a problem.

[00:24:45] Now, I've looked and looked, and I cannot find any data on what's called absorption of acetaldehyde from wine, or from food for that matter. I keep, I'm going to keep looking,

[00:24:56] but for some reason or other, this hasn't been subject of a published study, although maybe I just haven't been competent enough to find it.

[00:25:05] Craig Macmillan: I doubt that.

[00:25:07] Andrew Waterhouse: Well, sometimes these are, you know, they're very specialized and they're indexed in funny ways. And,

[00:25:13] You know, and the other thing was, you know, when the study came out, I had all these questions. I was talking to this one reporter and she said, well, I can drink natural wine.

[00:25:24] It doesn't give me headaches. And I was like, oh boy, what's this about?

[00:25:27] Craig Macmillan: Yeah.

[00:25:28] Andrew Waterhouse: But thinking about that further when you make natural wine, you don't add any sulfites or at least you're not supposed to, Right. And consequently in the finished wine, the level of acetaldehyde would have to be very low or else it would smell like sherry.

[00:25:41] Craig Macmillan: Right. Right.

[00:25:43] Andrew Waterhouse: And yes, granted, many natural wines have funky smells, but they don't by and large smell like sherry.

[00:25:49] So it's possible that natural wines have in general, Much less acid aldehyde than conventional one. you know, all these questions have brought up some interesting issues, I think, you know, the industry should be looking into you know, these are these issues like how much acid aldehyde Do we want in our wine and how can we reduce it if we want to reduce it?

[00:26:15] I don't think anybody's really looking at that yet. I think that would be a very interesting question to pursue. Oh

[00:26:24] Craig Macmillan: you just, you just reminded me of, of something two things that I, I had forgotten about. One I used to teach like enology for babies, enology for dummies thing for the public. I am in no way qualified other than just experience to do that.

[00:26:39] But I broke it down in that I do that sugar aldehyde, alcohol arrows, and I'd say, okay, this, this acid aldehyde. Remember this one? This one's coming back. We're going to see this again later. So write this one down. We're going to get to that later. And sure enough, now it's just through the body and, and I think breathalyzers work based on that.

[00:27:00] Don't they? It's like density. Something like that. So the aldehyde, they're actually,

[00:27:05] I think so. I got to look that up again, but because by the time it gets to your breath, your body's, Processing it, right? Hugely important. Not just that compound, but aldehyde is just kind of a general well, maybe we should all invest in like some kind of, I don't know, AO unit or wine X ray or something at our house.

[00:27:21] And then we could get the totals and know before we drink it you know, maybe we could figure out if somebody could come up with a consumer friendly, you know, put it in a vial and shake it and it turns blue. Don't drink it kind of thing. I'm just being silly. I don't know.

[00:27:34] Andrew Waterhouse: idea.

[00:27:35] Craig Macmillan: You go to different like wine shops and stuff, and there's all kinds of stirs and additives and strainers and funnels and stuff that are supposed to take things out.

[00:27:45] And I've always really wanted to see what those things do. They do anything or not, or I don't know. I'd like to try it. Finally, is there one takeaway on this topic, this question to both you, one takeaway you'd like people to know, I

[00:27:57] Andrew Waterhouse: well, I think the key thing is that we haven't done any experiments on people yet.

[00:28:03] Craig Macmillan: Right.

[00:28:04] Andrew Waterhouse: And so what we have here is, I would call it a well founded theory,

[00:28:09] Craig Macmillan: Mhmm.

[00:28:09] Andrew Waterhouse: I think people shouldn't rush out and start changing the way they drink yet. They might want to try some experiments. But we don't have the final word yet.

[00:28:20] Craig Macmillan: Right, right.

[00:28:24] Apramita Devi: Same. Yeah. This is just very preliminary study. And we just have a theory out. So we still don't know, like, what happens in the actual body.

[00:28:34] Craig Macmillan: Well, I hope that we can do that.

[00:28:36] Andrew Waterhouse: We're always looking for support for experiments. If anybody wants to support that, get in touch.

[00:28:43] Craig Macmillan: You know, another creative thought that I have when I'm preparing for this is like, you know, , people either get headaches from wine or they don't. If I'm someone who wants to enjoy wine, but gets headaches, I would be really attracted to a product that had a back label if we could make health. statements, which we cannot, that would say now low in quercetin or, you know, headache free, you know, no, we would never get that through TTP, obviously, but but, but, you know, but we went round and round with that on sulfites, you know you know, organic waste, no added sulfites, you know, you can say that.

[00:29:14] Andrew Waterhouse: I think it would be possible to perhaps have a declaration on a bottle about the level of quercetin, whether it's high or low. I suppose. I don't know.

[00:29:24] One company did get a label through that had resveratrol levels on it, but then TTB stopped approving that. So only one company has that approval. But I think in that case the reason for denying the label is that it is a proxy for health claim. Thank you.

[00:29:44] Quercetin, you know, whether it's high or low is really, it's not, it's not making a health claim. We're not claiming that this wine is healthier for you than the other has to do with headaches or not headaches.

[00:29:55] And I don't see that as really a health claim.

[00:29:58] Craig Macmillan: Well, let's just see how this develops. You never know. Let's face it. I mean, we're talking about nutrition. This is August of 2024, the date for this recording. We're talking about having nutritional labeling on wine. Right? Which I think would be a very interesting nutritional label, quite frankly.

[00:30:13] I would, I would love to see that, you know. Zero percent of the RDA of everything, again, at the end of one of my lectures I'd introduce potassium, and at the end I'd say, so how much wine do you have to drink to get your RDA of potassium? You have to drink a gallon and a half of wine a day. So, maybe not a big contributor. Maybe not a big contributor. Where can people find out more about both of you?

[00:30:37] Andrew Waterhouse: Well, I think probably the best starting point would be our LinkedIn pages.

[00:30:43] Craig Macmillan: And those will be in the show notes.

[00:30:45] Andrew Waterhouse: and I do have a website at UC Davis called waterhouse. ucdavis. edu.

[00:30:52] Craig Macmillan: And that will be in there as well. What about you, Apremita?

[00:30:54] Apramita Devi: For me, LinkedIn page.

[00:30:58] And if people want to see about my research or my past research, they can go to my Google Scholar page to

[00:31:05] Craig Macmillan: Awesome. Thank you. Well, thanks so much for being here. Our guests today were Andrew Waterhouse, Professor Emeritus in the Department of Viticulture and Enology at UC Davis, and Apramita Devi, a postdoctoral researcher in viticulture and knowledge at UC Davis. Really interesting work.

[00:31:21] I'm glad that you folks are doing it. I've been a big fan of you, Dr. Waterhouse, for a long time, and now that I've seen your work, I'm a big fan of you. Apremita. You've done some pretty cool stuff in the last five years. So again, thanks. And thank you for listening to Sustainable Wine Growing with Vineyard team.

[00:31:38] Please keep downloading episodes. Please visit the show page. Lots of information there. And we also have a new publication, Understanding Wine Chemistry by Andrew Waterhouse, Gavin Sachs, and David Jeffrey. Is that correct?

[00:31:53] Andrew Waterhouse: That's correct.

[00:31:55] Craig Macmillan: This is out in the world now.

[00:31:57] Andrew Waterhouse: It's just out this month.

[00:31:59] Craig Macmillan: That sounds like a must have.

[00:32:01] Andrew Waterhouse: I agree.

[00:32:03] Craig Macmillan: That sounds like a must have. , I will leave the name out, but there was a very famous book written by a group of folks from CSU Fresno and some collaborators. And I don't have a copy because I bought five copies in my cellar. People stole them every single time. So, this is the same kind of book, folks.

[00:32:20] Maybe buy five copies. And just hand them out to give one to your assistant winemaker. Give one to your cellar master and just say, here, these are yours. I'm keeping my copy. Thank you very much. That's, that's really cool. And again, thanks for being on the podcast.

[00:32:33] Beth Vukmanic: Thank you for listening today's podcast was brought to you by wonderful laboratories. Wonderful laboratories operates two state of the art high throughput laboratories. He's located in Shaffer, California to support pathogen detection and nutrient analysis. The team provides full service support to customers with field sampling. Custom panels and special projects. They're. Customers include pest control advisors, growers, consultants, seed. Companies, backyard gardeners, ranchers, and more.

[00:33:10] Make sure you check out the show notes. To learn more about. Andrew. And Oprah meta. To read a great article about their research. Why do some people get headaches from drinking red wine?

[00:33:19] And if you're looking. Looking for. Some more fun wine at trivia to share at holiday parties this season. Listen into sustainable Winegrowing podcast episode. 74, the spirit of wine.

[00:33:31] If you liked the show, do. It's a big favor by sharing it with a friend subscribing and leaving us a review. You can find all of the podcasts@vineyardteam.org slash podcast. Podcast. And you can reach us at podcast@vineyardteam.org until next time, this is sustainable. Winegrowing with the vineyard team.

[00:33:49]

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255: Red Wine Headache? Quercetin May be the Cause

Sustainable Winegrowing