This week the World Health Organisation took aim at trans fats, saying that they created "huge health risks" and caused half a million deaths a year from coronary heart disease.
The organisation's director general, Dr Tedros Adhanom Ghebreyesus, condemned trans fats as having "no known benefit" while generating "huge costs for health systems".
"Put simply, trans fat is a toxic chemical that kills, and should have no place in food. It’s time to get rid of it once and for all," he said in a statement.
Dr Tedros’s broadside, coinciding with the release of a WHO report, Countdown to 2023 WHO Report on global trans fat elimination 2022, is part of efforts to encourage governments to take tougher action against trans fats.
According to the organisation, 43 countries have "best-practice policies" for combating the use of trans fats, protecting 2.8 billion people, leaving five billion unprotected, which "increases their risk of heart disease and death".
In December, the UAE unveiled the National Nutrition Strategy 2022-2030 aimed at eliminating trans fats and slashing salt and sugar from foods.
'Double trouble for heart health'
Davinder Pal Singh, a cardiologist at NMC Royal Hospital at Dubai Investments Park, said trans fats, also known as trans fatty acids (TFA), are "double trouble for heart health".
"They increase the bad cholesterol," Dr Singh said. "The diet that is easily available ― french fries and things that are deep fried ― the chance is they’re made with partially hydrogenated oil."
Because trans fats can increase levels of bad cholesterol, they are associated with an increased risk of heart disease, strokes, Type 2 diabetes and other health conditions.
While saturated fats too are linked to ill health, trans fats are seen as even more harmful, although the quantities most people consume are much lower.
In the UK, the government recommendation is that people take in no more than 5g a day.
According to figures published by the European Public Health Alliance, an extra gram of trans fat consumed per day results in a 5 per cent greater risk of a heart attack or heart disease.
Trans fats are found in small quantities naturally in some meat and dairy products, but concerns centre on artificially or industrially produced versions generated by the partial hydrogenation of vegetable oils.
These are often used as food ingredients, such as emulsifiers, which improve shelf life by ensuring that ingredients do not separate from one another. Trans fats may be found in cakes, doughnuts, ice cream, margarines, vegetable oils and breads.
They are also favoured by some fast-food restaurants, because they allow cooking fat to be used more often.
To reduce consumption, the WHO in 2018 introduced Replace, a multi-pronged initiative to eliminate industrially produced trans fat from national food supplies by 2023.
In terms of "best-practice" policy, the WHO recommends that countries introduce limits on trans fats in foods or ban partially hydrogenated oils, because these contain significant amounts of trans fats.
In 2004, trans fats were eliminated from foods in Denmark, the first country to introduce such restrictions, while in 2021 the European Union introduced a rule banning foods with more than 2g of trans fat per 100g of fat.
The use of trans fats in restaurants is banned or restricted in several countries, such as Canada, Denmark and Switzerland, as well as parts of the US, including California and New York City.
The WHO said the Eastern Mediterranean region has some of the highest trans fat intake globally, with an estimated 78,000 deaths per year attributable to that consumption.
Egypt has introduced a maximum trans fat limit of 2g of trans fat per 100g of total fat in all foods, in line with World Health Organisation standards, that will become mandatory in October.
More governments should take action
The WHO, and many health experts, say governments should take action.
"I think it’s the role of government to evaluate the evidence about trans fats and if there’s increasingly good evidence to suggest there are problems, it’s their responsibility, through good public health measures, to address the problem," said Richard Holt, a professor in diabetes and endocrinology at the University of Southampton in the UK.
"In general terms it’s important that the government has a regulatory role in terms of … looking after what’s being sold to the public."
More countries are beginning to take the same view, with several developing countries among those to have brought in "best-practice" rules in recent years, among them Bangladesh, India, Paraguay and the Philippines.
The WHO would like many more to join them, saying that nine of the 16 nations thought to have the highest proportion of deaths from coronary heart disease caused by trans fats do not have sufficient safeguards. This group includes Australia, Egypt, Iran, Pakistan and South Korea.
In the US, trans fat content has to be listed separately from total fat and saturated fat content, a requirement credited with reducing consumption by informing consumers and pressurising industry.
"In the United States, mandatory labelling coupled with consumer education and media campaigns that created high levels of consumer awareness led manufacturers to reformulate food products to reduce TFA content," a 2018 WHO Replace document stated.
Regulations vary, but there is a general trend towards further restrictions over time.
Dr Singh said manufacturers should make greater efforts to reduce the trans fat content of their products.
"You will see when you buy a product in the constituents whether the trans fat is there or not," he added.
The advice is to read labels carefully and avoid foods with ingredients that are hydrogenated, although the Mayo Clinic in the US says that consumers should ensure that trans fats have not been replaced with oils that contain a lot of saturated fat, such as coconut oil and palm oil.
Healthier alternatives include natural unhydrogenated fats, such as sunflower oil, olive oil and rapeseed or canola oil.
It is also recommended to limit intake of doughnuts, muffins, pies, cakes and biscuits, which the American Heart Association (AHA) says may all contain trans fats.
"Limit commercially fried foods and baked goods made with shortening or partially hydrogenated vegetable oils. Not only are these foods very high in fat, but that fat is also likely to be trans fat," the AHA says in an online briefing document.
When eating out, diners can ask what fat food is used to prepare food and so avoid trans fats, or, if visiting a large chain, check online to see whether it has stopped using trans fats in their country.