Do you really need to eat ten portions of fruit and veg a day?

Only a quarter of UK adults manage to eat the officially recommended five portions of fruit and vegetables a day. In fact, almost half eat less than three a day. It seems unlikely, then, that most people would be able to reach the ten a day suggested by several pieces of research published in the last few years.

Most recently, a paper in the International Journal of Epidemiology laid out evidence that upping your intake of fruit and veg to ten portions (800g) a day would further reduce your risk of cancer, cardiovascular disease and premature death. But how strong is this evidence, and how practical is this advice for most individuals or society as a whole? A closer look suggests we need to be cautious about turning this complex research into simple and useful recommendations.

The five-a-day mantra goes back to recommendations from the World Health Organisation in 1990 and numerous developed countries have adopted it as official advice. Since then, further research has shown that each of the first five 80g portions of fruit and veg a person eats every day is associated with about a 5% decrease in overall and cardiovascular deaths. But the link between vegetables and disease prevention isn’t always that clear. For example, in 2010 the massive European Prospective Investigation into Cancer and Nutrition (EPIC) found only a small decrease in cancer risk associated with eating fruit and veg.

Then came two studies that have put forward the case for eating even more than five a day. The first, in 2014, linked lifestyle information on 65,000 English adults from the Health Survey for England to mortality records. It reported that the more fruit and veg people ate, the less likely they were to die from cardiovascular disease or cancer. The death rate among those who ate on average under one portion a day was twice that among those who ate more than seven a day.

But fruit and veg intake wasn’t the only thing related to the death rate. The one-a-day group were also more likely to be very elderly, male, less well educated, smokers, physically inactive and heavy drinkers. So the researchers analysed the data in a way that took account of these other factors, although they couldn’t do this for unrecorded things such as saturated fat intake.

After this correction, the data showed that those who ate three to five portions of fruit and veg were still 25% less likely to die than those in the one-a-day category. Those who ate five to seven portions a day were a further 6% less likely to die and those who ate more than seven a day saw another 3% drop. This meant the biggest benefit was from increasing fruit and veg consumption to up to five a day.

The more recent study brought together the results from 95 cohort studies that each tracked a large group of people over a time. It found a strong association between eating up to ten portions of fruit and veg a day and reduced death – overall, and from cardiovascular disease in particular. But again, the study showed these benefits were biggest as consumption increased up to five a day and were markedly smaller after that. There was also a decline in cancer deaths as people ate more fruit and veg but it was smaller and flattened out earlier.