11 April 2017

Bridget Benelam
Nutrition Communications Manager

Opinion (noun). A view or judgement formed about something, not necessarily based on fact or knowledge (Oxford Dictionaries)

Media coverage of nutrition science is often based on studies published in respected journals, but inevitably the headlines can’t capture all the details that would be found in a journal. At BNF we’re often trying to look behind the headlines to see what a study actually did. Perhaps the story on blueberries curing cancer was actually based on a small study on rats fed huge quantities of blueberry extract, or the headline linking consumption of potatoes with diabetes on a study that didn’t distinguish between boiled potatoes and deep fried chips.

Alongside research studies and systematic reviews, many journals also publish opinion pieces. These may by a single author or a group of authors that provide their view on a particular area of science. Although they are published in a scientific journal and often provide references, in an opinion piece there are generally no details on how they chose these. As a reader you have no way of knowing whether the authors have looked comprehensively at the literature or have simply cherry picked the studies that support the points they wanted to make. This doesn’t matter if this distinction is clear and there is transparency

Indeed such articles can add an interesting dimension to scientific publishing.

The problem is that often the difference between opinion and evidence base is lost in translation from scientific journal to newspaper headline. The opinions of the authors are restated as scientific fact, as ‘published in the Journal of…'.  In addition, opinion pieces may cover areas of particular controversy with a veneer of scientific credibility but without the scientific balance and rigour.

There are a number of examples of this in recent years; the paper that appeared in Nature in 2012 entitled ‘The toxic truth about sugar’ and an editorial in the BMJ in 2015 ‘It is time to bust the myth of physical inactivity and obesity: you cannot outrun a bad diet’, both of which provided only one particular slant on the science but gained  plenty of coverage suggesting this was the established scientific thinking.

Another opinion piece that caused a stir in the media was the National Obesity Forum (NOF) report entitled ‘Eat Fat, Cut the Carbs and Avoid Snacking to reverse obesity and type 2 diabetes’. Three key conclusions of the report were that fat intake is not related to weight gain, that a diet high in saturated fatty acids is not a health concern, and that limiting starchy carbohydrates can prevent and reverse type 2 diabetes. This report was highly controversial. It  not only contradicted evidence-based public health nutrition recommendations given by expert bodies from around the world but because Board  members of the NOF had not had a chance to review the report and some of them, disagreed with its conclusions. The report was the subject of a Facts Behind the Headlines article by BNF published in Nutrition Bulletin, which explored the evidence behind the claims in the report and highlighted the nonsense of suggesting Government dietary guidelines are causing the current levels obesity and ill health when only a tiny minority of the population actually follow them.

Much as I would love to see the headline ‘Revealed: balanced diet good for health!’ across the front pages, I appreciate that the tendency of scientists to talk in shades of grey, reflecting the complexity of science, does not make a good story. Those who can make extreme statements, without consideration of the full breadth of the evidence will always get more coverage then those who are more measured. For us at BNF this means we need to do all that we can to get evidence-based nutrition science across in an engaging way. Beyond this, it would be a really positive step if coverage of science in the media made the distinction between opinion pieces and research studies, so that people can decide whether what they are reading is really science or just opinion.

Public Health England's Chief Nutritionist Alison Tedstone has recently written a great blog on this subject - read more: Clearing up confusion caused by flip flopping diet news.