The evolution and genetics of taste

17 April 2018

Interview with 

Andrea Smith, University College London

COFFEE-BEANS

A cup on its side, with coffee beans spilling out of it

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How has our taste developed and evolved over time? And can we attribute our taste preferences to our genes? Chris Smith spoke to UCL’s Andrea Smith looks at how our genes and the environment we live in affect our food and drink preferences. So how might genes influence the process?

Andrea - It links back to the humans’ evolutionary origins where, when the human was still in prehistoric times, it was important for the human to taste and sense the environment where, ultimately, the ability to taste was acting as the perfect survival strategy. So being able to identify sweet tastes were incredibly important as they indicated food that is safe and will give you energy quickly. On the other hand, being able to taste bitter foods, and having evolved the taste receptors that identify bitter foods would indicate the foods that are poisonous and potentially harmful. And being able to detect them quickly would also select the individuals that could survive and procreate.

Chris - Indeed! Because lots of the chemicals, these plant alkaloids, that we try to avoid because they taste horrible are the ones that are poisonous. Things like deadly nightshade, the taste would not be good. But then again, there are some examples where we actually end up quite liking things that we should be averse to, shouldn’t we like caffeine is another plant alkaloid it’s there to poison insects, but we’re hooked on the stuff?

Andrea - And it’s every bitter! If you taste coffee for the first time it’s very very bitter and people don’t like it. But the interesting thing about when you drink coffee, over time we can learn to associate the kind of invigorating effect of caffeine and bitterness to feeling alert and we learn to like it.

Chris - Certainly I’ve learned to like it. I can endorse that comment. Given that in the modern era we don’t have the problem of not knowing where our next calorie’s coming from; we have supermarkets. We also tend to have someone watching out what we should and shouldn’t eat and we educate kids what to avoid and so on. Why do we still have these strong drivers towards what we do and don’t like?

Andrea - We unfortunately cannot change our DNA, so what we have been given and our universal ability to taste is still within us. And it’s also important to think about the fact that we have our DNA which has given us our receptors now in our environment. But there are many other influences that also shape what we like and do not like, so there are other sensors. In our environment right now, we do not only rely on our taste preferences and there are also genetic differences in sight and the pleasure pathways in our brain that still shape this behaviour. In our environment right now where we are being targeted by all these delicious foods, we’re essentially in this crazy environment where we are being exploited and our genetic tendency to like sweet and fatty foods is just completely expressed.

Chris - Do you know the genes which govern our intake in this way? And are there any populations who eat stuff which, compared with other populations, you’d think wow, they like that, why on Earth do they like that and you can pin their appeal for certain foodstuffs on a genetic cause?

Andrea - It’s more complex, unfortunately, than just having one single gene that regulates your food intake. It’s this whole storm of genetic differences, and a whole range of taste receptors that influence our behaviours. I think when you compare populations, it’s really important to think about what the foods and drinks are that people are exposed to, and their parents are exposed to, that explain these differences more that actually the genetics when you compare over time or between different cultures.

Chris - Andrea: personally, as I’ve got a bit older there are certain things that I detested when I was little and I actually quite like now I’ve got older. Now that can’t be genetic because I might be evolving a bit but I’m not evolving that quickly, so there must be more to this than just genes what we do and don’t like as we age?

Andrea - Indeed! Everybody is born with this underlying universal ability to taste, but it emphasises that our lifestyle behaviours and our environment also overrules and displaces these genetic influences over time. I think just touching back on the coffee, for example, which is a very bitter taste and most people when they first taste coffee really dislike bitterness. But, over time, when  they realise that drinking coffee gives you this feeling of being alert and having a lot of energy, you associate it with feeling great and you learn to love that bitterness.

Chris - So you think that, basically, you’re genes endow you with a sort of template of things you generically do and don’t like but then, as we go through life and we have life experiences, we can paint on that blank sheet, that blank canvas, if you like and so there are some things where we’ll override the genetic guidance because we’ve discovered it might be incompatible with what our genes are saying, but it’s quite nice?

Andrea - Yeah, exactly!

Chris - Any particular other examples you bring to mind - a personal one?

Andrea - Alcohol is also another typical example which a lot of people when they first drink alcohol it doesn’t taste great. I remember drinking beer or wine for the first time and I hated it and I thought I would never like it. But then, when you associate it for example also to a social situation - having a laugh with your friends - you start to really appreciate the flavour as well over time.

Chris - I don’t know, I never had any problem with that. Perhaps that explains a lot. But it also explains why we have some of the most expensive wines you can have sitting in the studio and we’re going to taste some later on.

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