A global team of researchers has taken aim at World Health Organisation draft guidelines that recommend people reduce their saturated fat intake, saying advice should be framed around foods, not nutrients.

Key points: WHO guidelines recommend keeping saturated fat below 10 per cent of total energy intake

Recent research shows saturated fats are not universally harmful, says international team of experts

Recommendations that focus on prioritising whole foods would be more helpful, the team says

The WHO draft guidelines, which were released last year, recommend keeping intake of saturated fatty acids (which are found in many animal products) to less than 10 per cent of total energy intake, and using polyunsaturated fatty acids (such as those found in seeds and some fish) as a source of replacement energy if needed.

But that approach glosses over recent research that shows saturated fatty acids can take many forms, and that they're not universally harmful, according to the team in an article published in the BMJ today.

"We think that recommendations to reduce intake of total saturated fat without considering specific fatty acids and food sources are not based on evidence and will distract from other, more effective, food-based recommendations," they wrote.

The WHO guidelines are rooted in a decades-old approach to nutrition science that focuses on single nutrients, but food research in recent years has demonstrated that focusing on whole foods and diet is a better approach for health, said the paper's co-author Manohar Garg of the University of Newcastle.

"We [now] know that saturated fat is not a single nutrient. There are a lot of saturated fatty acids ... and their effects on our health is different," Professor Garg said.

"Putting a blanket recommendation on saturated fat is inappropriate because not all saturated fats are harmful to health."

Because so many countries base their dietary advice on the WHO's recommendations it's especially important to get them right, Professor Garg said.

"If we can influence the WHO draft guidelines, in a way we are making an impact on the entire world."

The WHO has been contacted for comment.





What is a saturated fat and why does it matter?

At the molecular level, a saturated fat is one where the fatty acid chains have single bonds, but they're more familiar to us as the fats in dairy foods, egg yolks, meat, cocoa butter and coconut oil.

Professor Garg said foods that were naturally high in saturated fats were usually naturally high in other nutrients too.

"These foods are providing a lot of essential nutrients and if we avoid these foods we are going to miss out on essential nutrients, actually we might be increasing the risk of chronic disease," he said.

Polyunsaturated fats, which the WHO guidelines recommend people choose over saturated, are found in seeds, grains and some fish, as well as seed oils. (They have double bonds between carbon atoms.)

The WHO guidelines also say monounsaturated fats (one unsaturated carbon bond in the molecule; found in nuts, avocados and oils such as olive, canola and sesame), can be a replacement for saturated fats.

Another type of fat that's drawn headlines in recent years is trans fat: an unsaturated fat that has undergone changes due to the cooking process.

They're most commonly found in "discretionary" foods such as commercially fried foods, packaged baked goods and partially hydrogenated cooking oils.

Professor Garg said the evidence against trans fats was strong, but avoiding them fit with an approach that prioritises whole foods over processed.

A focus on whole food was a simpler, healthier way to approach making dietary recommendations, he said.

"If we stick to whole food, unprocessed food ... they're going to have health effects on the body. They're not rapidly metabolised, they're not causing harmful effects."

Building health guidelines for a global audience

The call to revise the WHO guidelines isn't unanimous among nutrition experts.

While Evangeline Mantzioris of the University of South Australia agreed with the sentiment of the authors of today's paper, she understood why the WHO chose to focus on nutrients rather than foods.

"I can see why WHO has given it as a number because it's a world-based guideline. [The authors of the BMJ paper] talk about dairy products, but there are a lot of countries that don't eat dairy products," Dr Mantzioris said.

"Maybe the WHO guidelines need to be interpreted by each country or region to work out how they roughly incorporate that level of saturated fats, but with the focus really being on reducing takeaway and processed foods."

In Australia, she welcomed the gradual shift away from a focus on individual nutrients toward a diet-based approach in our dietary guidelines, and hoped it would continue.

"If you look at the guidelines we had in earlier years, they were even more prescriptive," Dr Mantzioris said.

"It's gradually going towards a more qualitative approach to eating."