Changing 5-a-day to 10-a-day would be bananas
8 March 2017
Student life
Last week, the UK news was flooded with the message that we should be eating 10 portions of fruit and veg a day, not five. If we all ate 10 portions of fruit and vegetables, 7.8 million premature deaths a year worldwide would be avoided, the media reported. As a DPhil student in public health, a life-long vegetarian and a natural cynic when it comes to nutrition headlines, I thought I’d have a look at the paper that was published to see if science journalists had been swept up in the post-truth movement, or if we really should be changing 5-A-DAY to 10-A-DAY.
The authors of the study, based at Imperial College London, aimed to find out what the optimal level of fruit and vegetable intake is to reduce the risk of coronary heart disease (CHD) and premature death. They specifically wanted to establish a dose-response relationship; we already know that eating plenty of fruit and veg is good for us, but how much better is eating five portions compared to two? They did a systematic review and meta-analysis of 95 cohort studies relating to fruit and vegetable consumption and risk of incidence of mortality from coronary heart disease, stroke, total cardiovascular disease, total cancer and all-cause mortality.
They found that for every 200g increment increase in fruit and veg intake, there was an 8-16% reduction in the risk ratio (RR) of CHD, 13-18% reduction in risk of stroke, 8-13% reduction in the risk of CVD, 3-4% reduction in total cancer and 10% reduction in all-cause mortality. For fruits and vegetables combined, the lowest risk was observed at an intake of 550-600g/day (around 7-8 portions/day) for total cancer, with little evidence that there is an additional benefit for intakes higher than this. The lowest risk observed for coronary heart disease, stroke, CVD and all-cause mortality was at 800g/day (10 portions/day), which also happened to be the maximum intake range across all studies.
So, should policy makers be rushing to change 5-A-DAY to 10-A-DAY? What didn’t get picked up in the media is that the findings showed the steepest reduction in risk was seen up to 400g/day and previous studies have found that there is no additional risk reduction for all-cause mortality for intakes above five portions a day. In summary, this paper showed that the more fruit and veg you eat, the better. Does it have any policy implications? In an ideal world, everyone would eat a diet based on fruit and vegetables, smash the 10-a-day target and live healthier, longer lives. In reality, setting a target of 10-a-day is completely unrealistic. Critics of the five-a-day target (including doctors) argue it’s unachievable because for many it’s unaffordable.
How much would it cost to buy 10-a-day for two weeks? Breakdown of prices taken from the Tesco website, March 2017.
Product | Details | Price per pack (£) | Portions per pack | Number of packs | Total portions | Spend (£) |
Apples | Gala apples | 1.50 | 5 | 2 | 10 | 3.00 |
Bananas | Bag of small bananas | 0.90 | 6 | 2 | 12 | 1.80 |
Clementines | Easy peeler pack | 1.25 | 6 | 2 | 12 | 2.50 |
Pears | Conference pears | 1.29 | 5 | 2 | 10 | 2.58 |
Plums | Ripen at home plums | 0.89 | 5 | 1 | 5 | 0.89 |
Blueberries | Blueberries, 1 pack | 3.00 | 3 | 1 | 3 | 3.00 |
Peppers | Mixed peppers | 0.96 | 3 | 2 | 6 | 1.92 |
Raspberries | Frozen raspberries | 2.00 | 4 | 1 | 4 | 2.00 |
Tomatoes | Cherry tomatoes | 0.90 | 4 | 2 | 8 | 1.80 |
Cucumber | Whole cucumber | 0.50 | 4 | 2 | 8 | 1.00 |
Lettuce | Whole iceberg lettuce | 0.70 | 4 | 2 | 8 | 1.40 |
Carrots | Bag carrots | 0.45 | 12 | 1 | 12 | 0.45 |
Onions | Bag onions | 0.59 | 12 | 1 | 12 | 0.59 |
Courgettes | Prepacked | 0.89 | 6 | 1 | 6 | 0.89 |
Lentils | Red split lentils, dried | 1.15 | 6 | 1 | 6 | 1.15 |
Red kidney beans | Can | 0.30 | 2 | 2 | 4 | 0.60 |
Chickpeas | Can | 0.50 | 2 | 2 | 4 | 1.00 |
Spinach | Frozen leaf spinach | 1.40 | 11 | 1 | 11 | 1.40 |
TOTALS | 141 | 27.97 |
Lauren Bandy is a first year DPhil student. Her work looks at monitoring the nutritional quality of the food supply and profiling food and drink manufacturers in terms of their public health impact.
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