Is sugar in fruit healthier than in doughnuts?

Here's a sweet question to get things started....
12 March 2019


A selection of ring doughnuts



Is the sugar in fruit any healthier for you than the sugar found in things like doughnuts and cake?


Chris Smith put this sweet question from Annie to cambridge physiologist Sam Virtue. It also sparked debate among fellow panellists chemist Ljiljana Fruk and technology journalist Tim Revell...

Sam - Well, the answer to that is no, simply. And in fact actually some of the sugars that are commonly found in fruit might actually be worse for us than those found in doughnuts, in particular, sugar called fructose which its name comes in part from fruit. And so doughnuts will the made in the UK with your classic Tate & Lyle white granulated sucrose, fruit will contain the sugar this from fructose and this fructose has been shown in particular to be very harmful to our livers. Now it does have some advantages, which is maybe why it’s not quite so bad for us unless we take huge quantities, which is that it’s sweeter than sucrose and glucose so you may need less of it. Although that will appear to suggest doughnuts might be healthier than fruit, the truth is very different because whilst a doughnut might have slightly healthier sugar it does have vastly more of it. A normal sized apple has about 19 g of sugar, a doughnut has 48, but also the doughnut contains piles of fat so one normal sized apped maybe has 95 calories, a doughnut will have about 800 if it's the same size. So you need to eat eight apples to get about the same amount of calories.

Chris - Ljiljana "Fruk-tose"!!!??

Ljiljana - I'm glad you said that, yes! But it's very nice that you mentioned apples because there is one myth I want to enhance because I've just learned that you should really eat an apple a day to keep the doctor away because the apple peel contains a compound which is called quercetin. And it has been found that quercetin, if you give it to aged mice, they can actually become younger their cells become younger.

Chris - Is it an antioxidant or something?

Ljiljana - Well, it's antioxidants but it's also called anti-senolytic which means that it removes senescent cells which are a normal product of ageing. They are also called zombie cells, funnily, because they have enhanced metabolism but they don’t divide, and this quercetin from apples seems to removing these senescence cells and allowing normal, healthy cells to grow better.

Chris - So we should be saying an apple a day keeps dementia at bay rather than a doctor away?

Ljiljana - As well, yes.

Chris - But going back to your point, Sam, about the fact that there is a lot of sugar in fruit, why is fruit beneficial when because if you look at all the data we are being fed - excuse the pun - on a regular basis, we are being told to eat your five a day and that includes healthy portion of fruit so why is that good?

Sam - Obviously, as part  of the advice on eating five a day there is a focus on eating a lot of vegetables as well in there and trying not have too much as your component of five a day. For example, only one helping is suggested to be fruit juice and, again, that’s because the sugar which you’re trying to limit, but what fruit has lots of great things in it like vitamins and minerals. And if you’re gonna eat something sweet because we all have to have some enjoyment in our lives, we can’t just all eat things that we think are boring and savoury. If you want something sweet, it’s not about the fruit is necessarily good, it is the fruit is sweet which is nice for you and it’s not as bad as a doughnut.

Chris - Tim looks relieved. He’s allowed the odd treat. You look terribly pleased when he said initially "oh, there’s loads loads in the doughnut and the fruit, and the fruit isn’t actually much better than the doughnut” and you went “excellent!”  I saw your face, and when he said well,it’s actually not that good you looked really upset.

Tim - Well, the thing is doughnuts are amazing. And while she was talking I was just wondering why we can’t make something that has all the benefits of fruit but tastes as delicious as a doughnut.


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