As Public Health England’s chief nutritionist, I’m often asked what we’re doing about confusing messages in the media about nutrition, which lead to an incorrect assumption that official advice is always changing.
Glance at any prominent media outlet and you’ll come across plenty of stories promoting new diets and differing nutrition advice from ‘experts’, often contradicting previous coverage on another study.
One day saturated fat might be bad for your health, the next day it’s not so bad. It’s no wonder there is confusion (for what it’s worth, less than 10% of calories should come from saturated fat).
This is a challenge to public health as confusion and misunderstanding will only lead to poorer health for the UK population.
It would be easy to criticise the PR people at the institutions producing new research, or the media, for sensationalising, overblowing or misleading with its output.
However, I don’t think this is the answer. They are both under pressure to get their content noticed; there’s only so much research funding available, papers need to be promoted or clicks generated. Journalists in particular, may have less time to properly interrogate new research.
So it's important that we keep making the point that any one study, no matter how good it is, is highly unlikely to lead to a change in government advice on its own.
There was a good example of this recently. The Lancet published two studies - one study on fruit and vegetables by Miller et al and the other on fat and carbohydrate balance of the diet by Dehghan et al. The associated press releases had the following headline and opening:
Replacing fat with high carbohydrate intake may be linked to worse health outcomes, according to study
Reducing total fat intake, and replacing it with a high intake of carbohydrates may be linked to worse health outcomes, according to an international study of diets, published in The Lancet.
In low and middle income countries, 3-4 servings of fruit, vegetables and legumes per day may be more realistic target for health
Eating three to four servings of fruit, vegetables and legumes per day (375-500g) achieves a similar benefit against the risk of mortality to higher portions, according to a study of more than 135000 people around the world published in The Lancet.
It lead to widespread media coverage, with headlines including: “Low-fat diet may increase chance of an early death”, “Forget fat - it's carbs that kill, say experts”, “Low-fat diets could kill you, shows major study” and “Three servings of fruit and veg a day 'are enough'”.
None of which are particularly helpful for the public as, on closer inspection of the studies themselves, the inference of the headlines are misleading.
Looking more closely at the studies, we can see:
- Miller at al say to eat 3, 125-150g portions of fruit a veg a day to receive maximum benefits, or 375-450g a day. UK advice for many years has been to eat at least 5, 80g portions of a variety of fruit and veg a day, so 400g. The only difference was portion size. People don’t achieve the 5 x 80g portion size as it is, so the likelihood of them almost doubling a single portion is slim.
- Dehghan et al said the lowest quintile of carbohydrate intake (46·4% of energy [95% CI 42·6 to 49·0]) was associated with lower risk of total mortality. UK advice says total carbohydrate should make up about 50% of energy in the diet. Again, the study is in line with our recommendations.
- Dehghan et al also said the highest quintiles of total fat intake (35.3% total fat [95% CI 33.3 to 38.3]) were associated with lower risks of total mortality, stroke and non-cardiovascular disease mortality. Once again, this is a similar to UK recommendations of energy from total fat being no more than 35% of food energy.
- The dietary implications of these two studies may not be directly applicable to the UK because the cohort is not comparable to our population. The studies are mainly based on participants from 11 middle-income and 4 low-income countries where different social, and/or lifestyles and dietary patterns may influence risk.
In short, the factual conclusions from these papers did not differ from existing UK guidelines. So why are they, and countless other studies, presented in a way that could confuse the public into thinking advice needs changing?
You’d have to ask PR people, but I’m pretty sure the health of the nation may not be at the top of the reasons why.
The circus surrounding diet reporting may actually undermine confidence in long standing and very carefully considered evidence-based, dietary advice, and encourage unhealthy diet choices.
UK government recommendations on nutrition have been fairly constant over the years.
The only recent significant changes were in 2015 when maximum sugar recommendations were halved and fibre ones increased.
Those changes were made following a thorough analysis of hundreds of high-quality studies into carbohydrates, fibre and health. Dietary guidelines do not change after one study is published (for more information on government advice on a healthy balanced diet take a look at the Eatwell Guide).
Diet related chronic disease is a major problem in the UK and is a leading cause of morbidity and early death.
What we all need is advice that reflects the best available evidence, reported and interpreted accurately in helpful and meaningful terms. This approach has been the cornerstone of UK government advice and the approach that Public Health England looks to deliver.
What the public don’t need is sensationalist headlines that make them question well considered advisory messages.
And in this case, they certainly don’t need to be told to eat fewer fruit and veg, more saturated fat or unbalanced diets missing starchy, high fibre carbohydrates.