Trans fats - Everything you should know about the unhealthy fats
Fats are one of our basic nutrients and are essential for our body. Every day we are supposed to take in about 30% of our total energy in the form of fat. Despite this, fat has had a bad reputation in our society for years. But this isn’t because of the fat itself – it’s the trans fats that give fats such a bad reputation.But let’s start from the beginning: What are fats and how are trans fats different?
Characteristics of fats
Fats are long chains with up to 26 carbon atoms. A distinction can be made between chains that do not contain a double bond at any point and those that have double bonds between the carbon atoms. Fats without a double bond are called saturated fatty acids. They are mainly found in animal derived foods, such as butter, meat or milk. Fats that have one or more double bonds are monounsaturated or polyunsaturated fatty acids. These are often found in nuts, fish or vegetable oils.
The functions of fats
Fat has many different functions in our body. Here is a concise list of what fats can do:
- Supplies and stores energy
- Fats are part of the cell membranes
- We can use them to absorb fat-soluble vitamins
- They have a protective function – for example as a pressure cushion for our internal organs, such as the kidneys, the liver or the brain
- Prevent our body from losing too much heat
- Carry flavour and aroma
What exactly are trans fats?
Trans fats, actually “trans fatty acids”, are unsaturated fatty acids that have been modified using industrial hardening. A good vegetable fat is modified at its double bond in such a way that it is reversed. A so-called trans double bond is formed, which also gives the fat its name. In addition to a different structure, the new double bond now also has different properties. This process of fat hardening is often used in industry to make fats or food in general more supple. Bad fats – trans fats – are made from good fats. The same happens when you heat fat either very hot or several times in a row, for example when deep-frying.
A well-known example of trans fats: margarine
Probably the best-known example of industrial hardening is margarine. For a long time, no attention was paid to the amount of trans fat used in the production of margarine. This allowed the manufacturers to advertise the great spreadability of their products. Fortunately, that has changed today and margarine no longer contains as many trans fats as it used to.
Natural trans fats
In addition to industrially produced fats, there are also naturally occurring trans fats. When cows chew the cud (ruminate), microbial hydrogenation occurs.
This means the fat content in beef also contains trans fats, but in smaller amounts than are produced during industrial curing.
Trans fats list - Which foods contain trans fats?
| Food | Examples |
|---|---|
| Baked goods |
|
| Sweets |
|
| Fried potato products |
|
| Ready meals |
|
Fast food restaurants or dishes that have been deep-fried for a long time are also a trap for trans fats.
Why you should keep your consumption of trans fats to a minimum
Hardening of the fats results not only in a change in structure but also in a change in properties. This means that trans fatty acids no longer have anything in common with the good, unsaturated, vegetable fats. If you now consume more trans fats with food, this will primarily have a negative impact on our fat content in the blood. LDL-Cholesterol and triglycerides levels are increased and HDL cholesterol are lowered.
Trans fats also promote insulin resistance, strokes and cardiovascular disease. As you can see, it is important to keep your consumption of trans fats low!
Recommendations by WHO
WHO recommends: <1 E% trans fats / day
This corresponds to less than 2.2 g / day for a 2000-calorie diet
Example: a croissant contains about 1 g trans fatty acids, and a donut contains about 2 g!
How are trans fats declared on packaging?
In the UK, the government has not put a stop to the use of trans fatty acids, but they strongly encourage manufacturers to cut them out of their products or to clearly label them on the packaging. This makes it a little easier for the consumer to understand which foods contain trans fats. So you should be aware of the following written on your food packaging:
“Hydrogenated fats or hydrogenated vegetable oil”
“Partially hydrogenated”
And in general: the further up the list of ingredients something is, the more of it is in the food!
How to avoid trans fats
- Do not heat fat multiple times
- Use vegetable fats
- Do not let fats get too hot
- Check what is written on the packaging of industrially produced foods
- Use fats that can withstand hot temperatures better, i.e. are more heat-stable
Fats when cooking
- Generally you should make sure you use more vegetable fats than animal fats when cooking
- Keep an eye on the 8 tips for healthy eating – this is how you can keep the intake of trans fats low when cooking
- It is best to use sunflower, canola or corn oil for heating.
- For cold dishes, such as when preparing a salad dressing, it is best to use olive oil or linseed oil.
Conclusion
Overall it is fair to say: we need fats in our diet and they should not be left out. Only the type and amount of fats we consume is important. Be aware that eating too many trans fats will have a negative impact on your health over time. In principle, there is nothing wrong with having a croissant on Sunday morning. We should just make sure that it remains an exception. Vegetables and fruit should always be your first choice.
Frequently Asked Questions
Why are fats good for us?
Fats have many different functions in our body. For example, they supply energy and store energy for almost all of our organs in the body. They are also part of our cell membranes and thus give our cells stability. We also need fats to absorb fat-soluble vitamins such as ß-carotene. They also serve to protect our organs, such as the kidneys, liver or brain, or prevent our body from losing too much heat. Fat also carries flavour and aroma.
How are trans fats formed?
Trans fatty acids are formed when fats are hardened in industry to make food smoother or easier to spread.
How high is the intake of trans fats?
Studies have shown that the intake of trans fats is too high in many western countries. The WHO states that approximately 540,000 deaths each year can be attributed to intake of industrially produced trans-fatty acids. Thus WHO only recommends less than 2.2 g / day for a 2000-calorie diet. So here we should pay a little more attention to how much fat and, above all, what kind of fat we eat throughout the day.
What can I do if my blood lipid levels are already too high?
In this case, you should definitely change your diet. It’s important to be aware of what you’re consuming throughout the day. Make sure you eat lots of fibre, eat lots of complex carbohydrates and especially when it comes to fat, choose vegetable fat instead of animal fat. The 8 tips from the NHS can also help navigate your food choices. On our site you will also find many articles that will help you with a change in diet.
Sources
- Deutsche Gesellschaft für Ernährung e.V. (2016): trans-Fettsäuren und ihr Einfluss auf die Gesundheit, retrieved on 25.03.2021
- Deutsche Gesellschaft für Ernährung e.V. (2021): 10 Regeln der DGE, retrieved on 25.03.2021
- WHO (2018): Trans fats, retrieved on 16.01.2023
- NHS (2022): 8 tips for healthy eating, retrieved on 16.01.2023
