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January 2014

5 a day: why bother with fruit and veg at all?

This week we’ve asked for evidence behind the 5 a day message, whether it’s working and how much it costs and how advice differs across the world. But what are the actual health benefits of eating fruit and vegetables in the first place? David Bender, Professor of Nutritional Biochemistry at University College London gave us a steer on what the current evidence tells us.

There is indeed good evidence that people who eat about 5 servings of fruit and vegetables a day are less at risk of atherosclerosis and coronary heart disease, as well as many cancers. There are a number of reasons for a protective or beneficial effect of a diet rich in fruit and vegetables.

  • A diet rich in fruit and vegetables is likely to be relatively low in fat, and especially saturated fat. Dietary fibre (which comes only from fruit and vegetables) provides bulk in the intestinal tract, so improving bowel function

  • Both dietary fibre and slowly digested and resistant starch are fermented to some extent by intestinal bacteria. The short-chain fatty acids produced provide a significant metabolic fuel for intestinal mucosal cells, and there is some evidence that (especially butyrate) provides protection against colo-rectal cancer.

  • Fruit and vegetables are generally good sources of vitamins and minerals. They also provide a significant amount of potassium with little sodium (unless you add salt in cooking or at the table). Hence a beneficial effect with respect to blood pressure.”

So it’s pretty clear there are proven health benefits to eating fruit and vegetables. This week I’ve been keeping track of my own efforts to hit the 5 a day target. So far I’m averaging a less than impressive 3 portions a day – but that is an improvement on normal. I’d also like to think I can take a little credit for improving the diet in the rest of the office – many of whom have upped their fruit and veg intake as a result of hearing me talk about it every day. So from the admittedly small sample of this office – when the 5 a day message reaches people, they do try and eat more.

Tomorrow in our Q&A with Public Health England I’ll find out whether eating extra portions at the end of the week can bring up my average to 5 a day – or whether that’s cheating.

5 a day all over the world?

Advice on how much fruit and veg you should eat every day varies hugely across the world. We’ve found out that depending on where you happen to live, you could be told to eat from 4 to 18 portions a day.

Volunteers and our Voice of Young Science network asked 40 governments for their fruit and veg recommendations, and the evidence they have to back them up. This map shows what we found. We’re still waiting for a few governments to get back to us – but we’re going to keep updating the map as the information comes in.

The World Health Organisation (WHO) guidelines recommend at least 400g of fruit and veg a day. Belgium, Germany, Slovakia, South Africa, Spain and the UK all follow the WHO guidelines and have interpreted this as 5 portions a day. Other countries recommend more. Canada advises 7-8 portions for women and 8-10 portions for a man - twice as much as the UK.

Austria also recommends 5 servings per day – but their servings are much larger than ours. According to the Austrian Government a serving of cooked vegetables should be 200-300g (100-200g if raw) and for fruit 125-150g. That’s potentially one and a half kilos of vegetables per day. To put that into perspective the UK 5 a day campaign reckons a portion is about 80g, so Austrians could be eating as many as 18 UK portions!

Singapore has a government backed campaign for ‘2+2 a day’ (two fruit and two vegetables) while Indonesia says ‘4 is healthy, 5 is perfect’. Perfect is quite a bold statement – I’m wondering what the perfect evidence is for that claim.

We also asked the 40 countries what evidence they based their recommendations on. Most gave the WHO guidelines. These guidelines date back to 2003 so we’ve asked the WHO what its role is in reviewing the evidence behind its recommendations. Should it be updated regularly based on new research? Finland, for example updated its recommendation from 400g per day to 500g based on a review of the current scientific data this month.

Come back tomorrow when we’ll be looking at the evidence behind the health benefits of eating fruit and veg, regardless of whether it’s 5 or 10 or 18 a day.

Interactive map – click the bananas!

Monday – Asking for Evidence on 5 a day.

Tuesday - 5 a day: is it working and what does it cost?

Thursday - Why bother with fruit and veg in the first place?

5 a day: is it working and what does it cost?

“5 a day” is possibly one of the most successful pieces of dietary advice in terms of how far and wide the message has spread. But has it actually be successful in getting us to eat more fruit and veg?

The scheme was launched in the UK in 2003 and despite an initial rise, the 2011 Health Survey for England reports our fruit and veg consumption has been in decline since 2006. Less than a quarter of men (and only slightly more women) meet the 5 a day target. The average adult in the survey managed only 3.8 portions per day.

What about those on low incomes? A 2012 report from the Department for Environment, Food and Rural Affairs found families on the lowest incomes were only buying 2.9 portions of fruit and vegetables per person per day. That’s almost a whole portion less than the average adult.

Children are also advised to eat 5 a day although portion sizes can be smaller depending on the child’s age and size – one portion is approximate to what fits in the child’s palm. The School Fruit and Vegetable Scheme aims to “help your child achieve 5 a day” by providing 4-6 year old school children with one free piece of fruit or vegetable every day. According to an analysis of the scheme – it’s working. Children in both deprived and affluent areas to eat more fruit and veg but children in affluent areas still eat more healthily overall.

How much has it cost?

Promotion of 5 a day has come under the Department of Health’s original budget at approximately £1 million a year. The campaign has benefited from free advertising (to an estimated value of £3.6 million between 2008 and 2010) by TV and radio broadcasters to fill gaps in airtime.

The School Fruit and Vegetable scheme costs £42 million – this is funded by people who play the National Lottery, not the taxpayer.

Is it worth it?

Sir Liam Donaldson, Chief Medical Officer to the government at the time of 5 a day’s launch, says he thinks it’s been a partial success.

"The middle classes did listen, and the supermarkets listened and they tend to respond to the middle class consumer particularly. I think it's been less successful in reaching the disadvantaged communities where those levels of fruit and vegetables were already low. It's a long-term project. It's the right project."

Tomorrow we ask 30 governments from around the globe what their advice on fruit and veg is and what evidence it is based on.

Asking for Evidence on 5 a day

by Chris Peters & Lydia Le Page

“5 a day”. It’s a phrase we in the UK know well. It’s used in adverts to sell smoothies and diet regimes and it’s even the basis for the School Fruit and Vegetable Scheme which aims to “help your child achieve 5 a day”. It seems you can't buy a banana orw a fruit juice these days without being told it "counts as 1 of your 5 a day". It’s important to Ask for Evidence behind claims like these to ensure those making the claims are held to account. And that’s why this week we’re taking a closer look at the fruit and veg advice here in the UK and abroad.  

The UK Department of Health adopted the scheme in 2003 and it’s quite possibly the most widely known piece of dietary advice. On Tuesday we’re going to be looking at whether it’s working and at what cost.

5 a day is based on the World Health Organisation’s (WHO) global strategy on fruit and veg consumption. The WHO advises eating at least 400g of fruit and veg a day – which the UK Government equates to five portions (of 80g each). But this advice is not country specific so it’s pretty surprising to see that governments across the globe don’t make the same recommendations. Canada recommends eating up to 10 portions a day. We’ve asked 40 governments around the world what their fruit and veg recommendations are and what evidence they have to back them up. You can see what they came up with on Wednesday.

Do you have questions about 5 a day? The evidence behind it and how the policy was put together? With higher sugar content should we be doing more to prioritise vegetables over fruit? On Friday this week Public Health England has kindly agreed to answer these and other questions in a short Q&A session. There’s still time to ask your questions so get in touch: [email protected]

Taking part in a live plant science Q&A session

Wendy Harwood is a plant scientist at the John Innes Centre, and is a member of our Plant Science Panel. She took part in our live Q&A about testing GM crop safety with animal feeding studies.

This was my third live on-line Q & A so slightly less scary than the first when I was not sure what to expect! The range of questions was fascinating, some drilling down into technical detail, some more general and some I would never have thought of asking at all.

It was useful of have a couple of questions in advance to get a head start and then once the live hour began, a new question, or several, arrived as soon as the answer to the previous one was dispatched. In a way it was good to have to provide a quick and relatively short answer. My usual approach, if given more time, would be to go off to double check some facts and then to write a longer more considered answer. However, looking back I am sure it is often better to give first thoughts and respond to the question without endless tweaking of the answer! The live hour passed incredibly quickly and the last few answers were added after the hour was up. Once things had calmed down it was possible to read the answers from the other panellists. Where two of us tackled the same question it was interesting to see that a different approach was often taken and perhaps the question interpreted in slightly different ways. In some cases I would have liked to be able to go back to the questioner with a question of my own along the lines of ‘what do you think about this?’

I suppose for me, the chance to respond to questions from anyone, anywhere who might be concerned about some of the issues was very rewarding. Normally I would only have a narrow audience and limited opportunity to respond to questions, for example at the end of a presentation. The organisation was, as usual, superb from the Sense About Science team and they made the whole experience painless and stress-free. It was reassuring to know that if a question popped up that I really did not feel able to answer, it could be sent to one of the others instead. I would recommend the experience of taking part in a live Q & A to colleagues.  It certainly makes you consider the issues from different points of view and is great for speed writing practice!

Read the Q&A's Wendy has participated in: