SINGAPORE - The Ministry of Health (MOH) will be introducing a ban on partially hydrogenated oils (PHOs), a key source of artificial trans fat, in all foods sold in Singapore from June 2021.

On Thursday (June 6), the MOH said that the ban will include fats, oils and pre-packaged foods, whether manufactured locally or imported.

The new ban will also apply to packaged food, like noodles and cookies.

Here are seven things to know about trans fat.

1. What are trans fats and PHOs?

Trans fats are unsaturated fatty acids that can come from natural or industrial sources.

Naturally occurring trans fats come from cows and sheep, while industrially produced or artificial trans fats are formed in an industrial process that adds hydrogen to vegetable oil, according to the World Health Organisation (WHO).

This converts the liquid into a solid, resulting in partially hydrogenated oils, which increase the shelf-life of products.

Around 10 per cent of oils, fats and pre-packaged food products in Singapore currently contain PHOs. These products include peanut butter spreads, potato chips, cookies and instant noodles.

2. Where is it found?

Trans fat occurs naturally in very small amounts of animal and dairy foods, but the majority of trans fat consumed are from commercial products, said Ms Jaclyn Reutens, a dietitian from Aptima Nutrition & Sports Consultants.

Many might be disappointed to hear that some favourites such as fried doughnuts, baked goods including cakes, pies, and cookies, and stick margarine and other spreads contain trans fat.

But not all hope is lost.

While baked and fried street and restaurant foods often contain industrially produced trans fat, all of these products can be made without it, said the WHO.

It has to be noted that even if a food item is labelled as trans fat free, it may not be so. Under labelling guidelines, if a product has less than 0.5g of trans fat per 100g, it can be labelled as trans fat free.

3. Why is it bad for you?

Trans fat increases the risk of developing heart disease and stroke, according to the American Heart Association (AHA). It is also associated with a higher risk of developing type 2 diabetes.

Trans fat also raises your bad (LDL) cholesterol levels and lower your good (HDL) cholesterol levels.

Approximately 540,000 deaths each year can be attributed to the intake of artificial trans fat, said the WHO in 2018.

It said that high trans fat intake increases the risk of death from any cause by 34 per cent, coronary heart disease deaths by 28 per cent, and coronary heart disease by 21 per cent.

Trans fat has no known health benefits, the organisation added.

4. If it is so bad, why do companies use it?

"Trans fats are easy to use, inexpensive to produce and last a long time," said the AHA.

They also give foods a desirable taste and texture. Many restaurants and fast-food outlets use oils with trans fats for deep frying because these oils can be used many times in commercial fryers, added the association.

PHOs are solid at room temperature and prolong the shelf life of products. They were first introduced into the food supply in the early 20th century as a replacement for butter and lard, said the WHO.

"They are not a natural part of the human diet and are fully replaceable," the organisation emphasised.

5. How much trans fat can you take in before it has adverse effects on your health?

The daily limit is 1 per cent of the total calories consumed in a day, said Ms Reutens.

The average consumption of trans fat globally was estimated to be 1.4 per cent of total energy in 2010, with a range of 0.2 to 6.5 per cent of total energy across countries, according to the WHO.

6. How to reduce intake of trans fat?

Some tips from the AHA include encouraging the use of naturally occurring, unhydrogenated vegetable oils such as canola, safflower, sunflower or olive oil more often, and looking for processed foods made with unhydrogenated oil rather than partially hydrogenated or hydrogenated vegetable oils or saturated fat.

On a more macro level, the WHO said that mandatory national limits on industrially produced trans fat are the most effective way to reduce trans fat in the food supply.

Countries like the United States, Canada and Thailand have banned PHOs.

7. What are the alternatives to trans fat?

Ms Reutens suggested alternatives such as butter, which has saturated fats, and other vegetable oils high in saturated fats such as palm oil or kernel oil.

The WHO advised that PHOs can be replaced by oils rich in polyunsaturated fatty acids such as safflower oil, corn oil, sunflower oil, soybean oil, and oils from fatty fish, walnuts and seeds.

Oils rich in mono-unsaturated fatty acids are also an alternative. These include canola oil, olive oil, peanut oil and oils from nuts and avocados.

SOURCES: The Straits Times, World Health Organisation, American Heart Association