Confused about what to eat for better health? NHMRC’s dietary guidelines might set you straight

Media messages about food and portion size are confusing and aren’t always based on sufficient evidence. Floodkoff

When it comes to diet-related health claims, even the “good” newspapers are usually wrong, making recommendations about which foods people should eat (and avoid) that aren’t based on sufficient evidence.

That’s the unsurprising conclusion of a study of British newspapers that came out earlier this year. And there’s no reason to believe the Australian media is any different.

Part of the problem is that stories on research into diet and health are more “newsworthy” and attract more readers if they suggest (or imply) the reader should be eating more or less of a particular food.

Pedestrian discussions about “evidence bases” and “evidence grades” – the sorts of things public health authorities debate extensively before they are prepared to make dietary recommendations – don’t make for a good read. But by not putting new findings into this context, we risk having a detrimental impact on public health.

Our concern is that the constant media drum beat of diet-related health claims that are not supported by sufficient evidence undermines confidence in diet-related health advice that is based on evidence. It also breeds apathy in individuals, as well as those who have the power to help change the nation’s diet – retailers, food manufacturers, schools, and so on: why worry about changing our diets today, if the evidence is only going to change again tomorrow?

Evidence-based dietary advice hasn’t changed much over the past decade – but you wouldn’t know that by reading the papers. dsevilla

The National Health and Medical Research Council’s draft Australian Dietary Guidelines, released for public consultation today, aims to set the record straight. They show the evidence for the types of diets that maximise health and well-being (with plenty of fruit, vegetables and wholegrain cereals, not too many kilojoules, and so on) has not changed significantly. It has actually strengthened considerably over the past decade.

That’s the good news. The bad news is that the messages that are coming through loud and clear from the evidence are not being translated into effective action.

More than two-thirds of Australians are now overweight or obese, and the rising tide of diabetes and other diet-related disorders shows no signs of receding. At the same time, some Australians suffer from dietary deficiencies through socioeconomic disadvantage and remote living.

To turn the tide, food manufacturers, retailers, organisations that serve or sell food, health-care professionals, government and community leaders will all need to come together and decide which levers to pull, and in what order.

The options that have already been discussed on The Conversation include targeting consumers, with more advice on food choices, portion size, lap-band surgery, and bans on junk-food advertising. Or changing the environment, by altering the make-up of foods or the “walkability” of our streets.

Whichever prevention strategies are used, the crucial first step will be to gain a clear understanding of the strength of the evidence linking diet and long-term health.

Consumers need the whole picture about the nutritional value of food, not just selected information from a handful of studies. Bruce A Stockwell

It’s not enough to know that when a few people eat lots of food X for a short period of time it reduces the amount of Y in their blood, and that low blood levels of Y are associated with less disease Z – this is the sort of study you may read about in any newspaper, on any day. It may make for a good read and the original research and publication may be good science. But it’s not enough to suggest, as many media reports do, that at the current time Australians should be eating more food X.

What you need is a systematic assessment of multiple studies, preferably including studies of thousands of people living in environments similar to Australia, that demonstrates eating a particular diet leads to longer, healthier lives.

This is where NHMRC’s Australian Dietary Guidelines come in. They are not based on one study or two, or 10 or 20. They’re based on the evidence included in its 2003 dietary guidelines, and on 55,000 new studies, each scrutinised to see if it has found sufficient evidence to support its conclusions.

Such detailed reviews of scientific evidence are rarely reported in newspapers. Most consumers, food-industry executives, policy makers, and even some heath-care professionals are unaware that they even exist. But every major public health organisation – NHMRC and the World Health Organisation included – make them the bedrock of their health recommendations to the public.

When NHMRC’s draft Australian Dietary Guidelines are released for public consultation today, anyone who is interested will be able to delve in and see for themselves. The Guidelines are written in plain English and couched in terms of whole foods rather than nutrients, to better help policy makers, retailers, food manufacturers and health professionals find ways to help Australians eat healthier diets.

The final version of the Australian Dietary Guidelines will be released next year under an open-access copyright licence to encourage the widest possible use.

And to ensure that Australians have a way to check those diet-related health claims that they hear about through newspapers, television and word-of-mouth, NHMRC will also launch a website, Facebook page and Twitter feed dedicated to providing up-to-date diet and health information that is grounded in evidence.

Until then, NHMRC looks forward to reading the public feedback on the draft Australian Dietary Guidelines.

This article was co-authored by Dr Rachel Nowak, a science policy, analysis and communications specialist at Rachel Nowak and Associates, who has advised the NHMRC. Dr Nowak was Australasian Editor of New Scientist from 2000 to 2009.

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