Your 10-a-day: why slaying a sacred cow of health advice is dangerous

Your 10-a-day: why slaying a sacred cow of health advice is dangerous


Bacon; cheese and ham sandwiches; red meat; tea; various forms of alcoholic drink – with apparently conflicting advice on which foods are good and which are bad, the public could be forgiven for being confused. Or needing a drink. Thank goodness that some pieces of dietary advice never change. "Get your five a day" is as sure and as steady as health advice can be – after all, it's based on solid scientific facts, right? A study examining how fruit and veg consumption affects mortality could be about to slay a sacred cow of food advice, suggesting five portions of fruit and veg a day is just not a high enough target.


First of all, a mea culpa: as a food scientist, I and some of my colleagues can sometimes be the source of this confusing advice. By publishing articles examining the various benefits of different diets, foods and nutrients, we inadvertently provide a stream of material to feed the hunger for food fads. Very often, these ideas are based on good scientific results, but when our scientific language is turned into the stuff real people can understand, some of the caveats, the warnings and the uncertainties get lost in translation.


There's little doubt with this one – this is a really excellent study. It may seem like a no-brainer to suggest that eating more fruit and vegetables is good for you. Indeed, lots of work has been done to link high-fruit-and-veg diets with a lowered risk of cardiovascular disease, which can cause heart attacks or strokes. But this is one of the first studies to show clearly that a diet high in fruit and vegetables lowers the risk of premature death. There are some unanswered questions: the researchers raise an interesting perspective – that people who ate more frozen or tinned fruit seemed more likely to die than those who ate less. Cue another odd piece of advice: "Tinned fruit causes death", perhaps? Well, no. The question arises because of the method used. The researchers were not able to distinguish between the two, making it impossible to make a distinction in later analyses.


Perhaps more significantly is the suggestion that this is the end of five-a-day. Of course, those who have lived abroad will tell you it is not a hard-and-fast rule. In Denmark it's six. In Canada they suggest between seven and 10. In Japan, it's 17. Most British people don't even eat five portions a day. Be honest: how many did you have yesterday? The average is two portions of fruit and 1.5 of vegetables. So any efforts that will encourage people to eat more fruit and veg are welcome.


But messing with the sacred cows of health advice is dangerous: we run the risk of undermining the strength of such messages. If officials change advice every time there is new health data, the risk is that scientists begin to lose credibility and people who are most in need of improving their diet give up.


By Gunter Kuhnle,


The Telegraph, 1st of April 2014.


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