Trans fats

One of the biggest diet-related causes of cardiovascular diseases such as high blood pressure, stroke, heart attack and similar conditions are trans fatty acids (short: trans fats). They are a problem of our time, when food is mainly produced industrially: the manufacturing process must be cheap and the final product must have a long shelf life.

Trans fats are found especially in processed foods like baked goods, fries, chips and similar items, instant soups, fast food, in solid (hydrogenated) frying fats, but also in socalled breakfast cereals that have little in common with traditional muesli. Even otherwise healthy nuts can contain trans fats if they were roasted in hydrogenated or partially hydrogenated fats.

Trans fatty acids also occur naturally in the stomachs of ruminants and in their products that is, in meat, milk, cream, butter and the like. There, unsaturated fatty acids can be converted into trans fats. These natural trans fats are considered less concerning than the artificially hydrogenated fats that are generally meant by trans fats. The latter cannot be processed well by the body and are regarded as more harmful than saturated fatty acids.

Besides industrial hydrogenation, trans fats are also formed when oils with a high share of unsaturated fatty acids are heated strongly for example when deepfrying or panfrying. In this process, these otherwise harmless fatty acids can be turned into trans fatty acids that are hard to break down.

Trans fats especially raise the level of LDL cholesterol and triglycerides in the blood. LDL cholesterol is often called bad cholesterol. These blood lipids are increasingly deposited as plaques on the vessel walls. In this way they accelerate calcification of the vessels atherosclerosis. At the same time, the level of protective HDL cholesterol falls.

You can think of trans fats as a turbo for atherosclerosis their damaging effect on the blood vessels is that pronounced.

In addition to these lifethreatening consequences, people who eat a lot of processed food and thus a lot of trans fats also show higher rates of depression.

The WHO updated its guidelines on fats in 2023. These particularly emphasize the importance of fat quality and the amount consumed and their impact on health. It recommends that adults get at most 30% (preferably less) of their total dietary energy from fats. From the age of two, this should mainly be unsaturated fatty acids. Saturated fatty acids should make up no more than 10% of total energy intake; trans fats no more than 1%. For trans fats, it makes no difference whether they come from industrial sources or from ruminant products.

Unfortunately, trans fats are not subject to mandatory labeling in Germany. Only in special dietary foods must they be declared. Therefore it is difficult to see how much of these harmful fatty acids a product contains. If the ingredients list mentions hydrogenated or partially hydrogenated fats, you can assume trans fats are present.

You can avoid this by cooking fresh and as plantbased as possible yourself. That way you can choose the right fat or oil for each cooking method.

The crucial factor is the oil's smoke point the temperature at which an oil's fatty acids begin to oxidize and break down. When that happens, the oil starts to smoke and that must be avoided. Oil that has started to smoke should not be used anymore. Healthy, mostly virgin or coldpressed oils with a high content of polyunsaturated fatty acids have a low smoke point. Use them only for cold preparations. Better suited are refined oils rich in monounsaturated fatty acids; they remain stable even at high temperatures. The same is true for saturated fats, which are generally considered less healthy.

For highheat searing, use oils with a high smoke point. These are mainly refined i.e. hotpressed oils. Soy and coconut oil as well as palm kernel fat are alternatives that, because of their natural fatty acid profile, are also suitable for highheat searing. Socalled higholeic oils are produced from special varieties of rapeseed, safflower or sunflower; they tolerate relatively high temperatures well even when coldpressed.

Many people prefer butter for frying. Because butter is only heatstable up to about 175 °C, it is recommended to use clarified butter (ghee) instead. Milk proteins, lactose and water have been removed from it. That makes it longerlasting and able to tolerate temperatures up to about 205 °C.

Oil	Smoke point in °C
Argan oil	180
Safflower oil	150
Peanut oil (refined = hotpressed)	230
Peanut oil (unrefined = coldpressed)	130
Palm kernel oil	220
Lard (pork fat)	121 - 218
Ghee (clarified butter)	205
Butter	approx. 175
Refined oils	> 200
Rapeseed oil (coldpressed)	130 - 190
Rapeseed oil (refined)	220
Coldpressed olive oil	130 - 175
Hotpressed olive oil (refined)	> 220
Hemp oil	120
Coconut oil	185 - 205
Flaxseed oil	-
Soybean oil	235
Sunflower oil (refined)	210 - 225
Sunflower oil (unrefined)	107
Light, untoasted sesame oil (unrefined)	220
Dark, roasted sesame oil (unrefined/partially pressed)	177
Grapeseed oil (refined)	200
Grapeseed oil (unrefined)	130
Walnut oil (unrefined)	160

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This article comes from BloodPressureDB – the leading app since 2011 that helps hundreds of thousands monitor their blood pressure every day. Our content is based on carefully researched, evidence-based data and is continuously updated (as of 03/2024).

Author Sabine Croci is a qualified medical assistant with many years of experience in internal medicine and cardiology practices as well as in outpatient care, and has led BloodPressureDB's specialist editorial team since 2015. Thanks to her extensive additional qualifications as a paramedic, first responder and in various therapy and emergency areas, she provides solid, practical and reliably reviewed information.

Trans fats

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