Our panel of experts

A cardiologist, physicist, immunologist and wine expert, and geneticist and dietitian take on your questions.
03 December 2019


Naked Scientists QnA Panel


Chris Smith got chatting to this month's guests: James Rudd, Francesca Chadha-Day, Clare Bryant, and Giles Yeo. First up, Chris asked Giles what has caught his eye recently...

Giles - There's always all kinds of pseudo-scientific BS that's out there. I mean, one of my favorite ones is this company has just launched a DNA diet test. Now so far, so not new because I think lots of people have done it, but they have now incorporated one of these watch-Fitbitsy type of thing, watch thing, which goes red or green. And so what happens is you get your DNA test, you have an app as everything does, and then you go to the supermarche, and then for example, you then scan the barcode of item X, and then you'll watch this watch thing pings red or green. Whether or not you should eat it.

Chris - They're saying then that they can tell based on your genetic profile whether that food is fit and suitable for you to eat?

Giles - That's correct.

Chris - To achieve what? Because your aims might be different from one person to the next, so how would it know?

Giles -  No, no, exactly. I mean, do you know, do you have a heart problem? Do you have irritable bowel syndrome? Are you type two diabetic, all this information? Who knows? And anyway, as you stood at the beer aisle for example, is it really ever gonna flash green? When is it ever going to flash green? I love beer, but when is it ever going to flash green at the beer aisle?

Chris - Well I don't know. There's some quite good stuff in beer, isn't there? I mean, if you drink Guinness, cause we, you know, certainly some older people have been advised to drink Guinness. Isn't Guinness got certain fortifying things, which if you have a fairly meager diet in other ways can, can help to pep you up a bit?

Giles - No. So, I don't know if this is apocryphal or not. It's supposed to be quite high in iron. I don't know if this is true. You know, how much of it is available. I think that probably is true. And it's high in calories for sure.

Chris -  Hmm. Yeah, that's certainly true.

Giles -  But it's like eating soup.

Chris -  Yeah. But is it not true, though, that more about in terms of what foods are and aren't going to agree with you and be good or bad for your health, that's more to do with the microbes that live inside you than just your genetic makeup, isn't it?

Giles -  I don't know about more to it, or not. I think certainly the microbes are going to play a very, very large role. I don't know, I don't know if more is actually true. I think there are going to be genes which indicate whether or not you prefer fatty food or sugary food and whether or not you want to eat more or less. That's true, but none of that is going to be predictive based on some DNA test.

Chris - Absolutely. Giles, thanks very much. So Giles is here if you want to ask him anything about diet, about your genetics and how that predicts, what sort of things might happen to your metabolism, weight gain, weight loss and so on, now is your chance to ask Giles those questions. Sitting next to Giles is immunologist and wine expert. We always, we always have your, when we talk about stories about wine, Clare, that's Clare Bryant, but you actually, you are a professor of immunology, I mean ,that's your day job, is it not?

Clare - That is, that is my day job, Chris, it is indeed. But you do always wheel me out as the wine expert.

Chris - So, anyway, now's your chance to tell us about something that you've spotted this week.

Clare - Which of course does have something to do with wine. So yeah, the thing that perplexes me a lot and in fact it follows on quite nicely from what Giles has just discussed. So there's this Silicon Valley startup company, which says that what it can do is by taking your DNA sample, it can predict what wines you would like to drink and it will then send you a case of very expensive California wines tailored perfectly to your palate. And this company has been sustaining. It's still going after two, three years I first saw, well, it came to my attention and it is particularly perplexing because in fact there were probably only three or four genes that have been sequenced that have anything really significantly to do with taste and certainly to do with the taste of wines and given your taste in wine is very personal and is also affected by food and how you're feeding and your immune system - I have to get the immune system in there somehow - it's remarkable.

Chris - Someone did point out to me as well, cause they were studying what happens when you put food, including wine, in your mouth, and because of the microbes in your mouth, some wines actually taste different to some people at different stages of the drinking process. So as you put wine in, the evolution of the flavor is because if you have certain populations of mouth microbes, they actually metabolize on the fly some of the things in the wine and change the taste. So as it evolves you will get that hit of flavor that other people who don't have those bugs don't get.

Clare - Absolutely, particularly pronounced, actually, if you do cheese. Cheese and wine and the evolving taste of the cheese and the evolving taste of wine in your mouth. It's amazing one wine does not taste like another.

Chris - So how is this company getting away with flogging this? Cause it just seems this DNA business has just gone too far and it's now being used as this black box, which is, everyone's impressed by it. It's a bit like AI, you know, 10 years ago we were putting the letter I in front of everything. If you had I in front of something, it was amazing. Everyone's all, it's gotta be impressive then. Now it seems to be the AI or something with DNA in front of it.

Clare - Yeah, I mean it is bizarre, but I guess it's so hard to predict what wines you're going to like that maybe if you just don't have the time or are not prepared to put the time in, that you'll believe anything that anyone tells you. And if somebody tells you 'yep, your genes tell you that and we're gonna sell you the wine that matches it'.

Chris - Well, don't get taken in by anything from this program. You can believe everything you hear here. If you have any questions about anything you've heard there, or how the immune system works, we're going to talk later on about antibiotic resistance and that kind of thing. Clare's going to take those questions. Also with us, Fran Chadder-Day, who is a physicist and works on dark matter and basically how the universe works. So from really complicated things about DNA to really simple things like how the universe works.

Fran - Trivial, I assure you.

Chris - And what have you spotted that you'd like to share with us?

Fran -  So, one thing that's been in the news recently is reports that scientists have discovered a new fifth force. So, the forces we know about are gravity, electromagnetism, the strong force which holds nuclei together and the weak force, which is relevant in some nuclear decays. But scientists studying nuclear decays of helium and beryllium, very rare decays, have discovered some anomalies.

Chris - This is radioactive decay you're referring to, isn't it, when the atoms fall apart spontaneously?

Fran - Yes, that's right. They have discovered some anomalies that could point the existence of a new fifth force and everyone's gone 'I'm very excited about it'. I would as always with these kinds of stories, urge caution. Often, these things are a systematic problem with the experiments. These experiments are very complicated and there's very often an explanation that isn't anything to do with new physics.

Chris -  Well, one person said if this turns out to be true, that's straight away a Nobel prize.

Fran -  That's true. Yes. But I don't think we should be rewriting the textbooks just yet.

Chris - So a skeptical maybe from Fran. So, anything to do with how the universe works, send your thoughts in for Fran. Also with us is James Rudd. Now, we haven't had James on for a little while, but the last time you were on here you were talking about radioactive toothpaste. You're a cardiologist, you're a heart doctor.

James - I'm a heart doctor and a heart researcher. Yes, Chris. And we have been using a scan on patients who have valvular heart problems and also people who are at risk of heart attacks, and we inject them with a compound that's very similar to toothpaste. It's called sodium fluoride and the sodium fluoride sends to hone in on the patient's arteries and heart valves. And we use that information to try to predict people who are going to have heart attacks and strokes, and also people are going to have valve disease in the future.

Chris - I think we should point out there, James, that you are one of the inventors and the pioneers of this technology.

James - Well, me and many, many other people who've worked on this around the world. Yeah, indeed.

Chris -  Because it's a massive problem. We know that people with narrowed heart arteries have symptoms when they get angina, pain in the chest and when they exercise and things. But what we don't know is the people who are going to have a heart attack because all of a sudden one of those narrowings is going to cause blood to clot in the artery and your work is actually giving us a clue as to where those hotspots might be that we currently had no way of spotting before.

James - I mean, in a sense they are a bit like dark matter because the ones that tend to go pop and cause the sudden death and heart attacks are often the ones that are very, very small areas of the artery and not really causing a big narrowing, so actually very hard for us to spot using our traditional scans.


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