Trans fats

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

Trans fats are found especially in processed foods like pastries, fries, chips and similar snacks, in instant soups, fast food, in hardened frying fats, but also in so-called breakfast cereals that have little in common with traditional muesli. Even otherwise healthy nuts can contain trans fats if they were roasted with hardened or partially hydrogenated fats.

Trans fatty acids also occur naturally in the stomachs of ruminant animals 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 generally referred to as trans fats. The latter are not well processed by the body and are considered more harmful than saturated fatty acids.

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

Trans fats particularly raise the amount of LDL cholesterol and triglycerides in the blood. LDL cholesterol is often called "bad" cholesterol. These blood fats are more likely to deposit as plaques on the vessel walls, speeding up vascular calcification atherosclerosis. At the same time, the level of the good HDL cholesterol decreases.

You can think of trans fats as a turbocharger for atherosclerosis their damaging effect on the vessels is that strong.

In addition to these life-threatening consequences, people who eat a lot of processed foods and therefore many trans fats also tend to suffer more from depression.

The WHO updated its guidelines on fats in 2023. They especially emphasize the importance of fat quality and the amount consumed and their effects on health. They recommend that adults get at most 30% preferably less of their total dietary energy from fats. From the age of two, this should be mainly unsaturated fatty acids. Saturated fatty acids should make up no more than 10% of total energy intake, and trans fats no more than 1%. For trans fats it does not matter which source they come from whether industrially produced or from ruminant products.

Unfortunately, trans fats are not subject to mandatory labeling in Germany. Only dietary foods must carry that information. Therefore it is difficult to know how much of the dangerous fatty acids are in which products. If the ingredients list mentions hydrogenated or partially hydrogenated fats, you can assume trans fats are present.

You can avoid this by cooking fresh meals yourself and choosing mostly plant-based foods. That way you can choose the appropriate fat or oil for the cooking method.

The decisive factor is the oil's smoke point the temperature at which the oil's fatty acids begin to oxidize and break down. The oil will start to smoke and that should be avoided. Oil that has started to smoke should not be used anymore. Healthy, mostly unrefined or cold-pressed oils with a high content of polyunsaturated fatty acids have a low smoke point. You should use them only for cold preparations. Better suited for high temperatures are refined oils rich in monounsaturated fatty acids, which hardly break down at high heat. The same applies to saturated fats, although these are generally considered less healthy.

For high-heat searing, oils with a high smoke point are suitable. These are mainly refined, i.e. heat-pressed, oils. Soybean and coconut oil as well as palm kernel oil are alternatives that, because of their natural fatty acid composition, are also suitable for high-heat searing. So-called high-oleic oils, produced from specially bred rapeseed, safflower or sunflower varieties, also tolerate relatively high temperatures well even when cold-pressed.

Many people prefer butter for frying. Since butter is heat-stable only up to about 175°C, it is recommended to use clarified butter instead. Milk proteins, milk sugar and water are removed from it. This makes it more stable and allows it 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

Sources:

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 01/2026).

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

Sources:

Registry: