Trans fats

One of the biggest diet-related causes of cardiovascular diseases such as high blood pressure, stroke, heart attack and the like is trans fatty acids (commonly called 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, solid (hydrogenated) frying fat, 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 hydrogenated or partially hydrogenated fats.

However, trans fatty acids also occur naturally in the stomachs of ruminants and in products derived from them - that is, in meat, milk, cream, butter and the like. Here, unsaturated fatty acids can be converted into trans fats. However, these are considered less concerning than artificially hydrogenated fats, which are commonly referred to as trans fats. The latter cannot be processed by the body and are considered more harmful than saturated fatty acids.

Besides the industrial hydrogenation of fats, trans fats also form when oils with a high proportion of unsaturated fatty acids are heated to high temperatures or used for deep-frying or frying. In this process, these otherwise harmless fatty acids can be converted into trans fatty acids that are difficult 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 certainly think of trans fats as a turbocharger for atherosclerosis; their damaging effect on the blood vessels is that strong.

In addition to these life-threatening consequences, people who eat a lot of processed foods and therefore consume a lot of 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, the amount consumed, and their effects on health. They recommend that adults get no more than 30%, but preferably less, of their total dietary energy from fats. From the age of two, these 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 products derived from ruminants.

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 making them as plant-based as possible. That way, you can make sure to choose the appropriate fat or oil for each cooking method.

The decisive factor is the oil's smoke point. This is the temperature at which the oil's fatty acids begin to oxidize and break down. The oil then starts to smoke-and this must be avoided at all costs. Oil that has smoked should no longer be used. Healthy, mostly virgin or cold-pressed oils with a high content of polyunsaturated fatty acids have a low smoke point. They should be used only for cold preparations. Refined oils with monounsaturated fatty acids, which hardly break down even at high temperatures, are better suited. The same applies to saturated fatty acids, 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 = hot-pressed)	230
Peanut oil (unrefined = cold-pressed)	130
Palm kernel fat	220
Lard	121 - 218
Clarified butter	205
Butter	approx. 175
Refined oils	> 200
Rapeseed oil (cold-pressed)	130 - 190
Rapeseed oil (refined)	220
Cold-pressed olive oil	130 - 175
Hot-pressed 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, toasted sesame oil (unrefined/cold-pressed)	177
Grapeseed oil (refined)	200
Grapeseed oil (unrefined)	130
Walnut oil (unrefined)	160

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This article is from Tensana – the leading app since 2011, helping hundreds of thousands of people 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 outpatient care, and has headed the specialist editorial team at Tensana since 2015. Thanks to her extensive additional qualifications as an emergency medical technician, first responder, and in various areas of therapy and emergency care, she provides well-founded, practical, and reliably verified information.

Trans fats

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