Trans fatty acids – a term that sounds unappealing to most people. But few people know exactly what is hidden behind this food ingredient: trans fatty acids are substances that occur particularly in industrially produced food, and specifically in those with hardened vegetable fats. They are found in almost all spreadable fats (especially margarine) and frying oil as well as convenience foods or fast food products such as baked goods and confectionery, dry soups, French fries, frozen pizza, breakfast cereals, sweet spreads, spray cream, puff pastry and potato chips.
Shopping tips
When shopping, a look at the list of ingredients on the packaging reveals where trans fatty acids are hiding: although they do not have to be declared in Germany under their name or the abbreviation TFA derived from English (Trans Fatty Acids), they do appear under the paraphrase “hydrogenated fats” or also “vegetable fat, partly hydrogenated”.
In addition, trans fats are also formed on the domestic stove during frying (from 130 °C) with vegetable oils, which have a high proportion of polyunsaturated fatty acids. And naturally, they are found in dairy products as well as in the meat of ruminants (beef, lamb), although their effect – in contrast to the artificially formed TFAs – does not appear to be harmful to humans.
Harmful effects
Scientists agree that foods high in trans fatty acids can harm our health. They increase the amount of LDL, or “bad” cholesterol, and lower the amount of HDL, or protective cholesterol, in the blood – increasing the risk of hardening of the arteries, coronary heart disease, heart attack and stroke.
Discussed, but not yet proven, are a negative influence on sugar metabolism with the risk of diabetes and an increase in blood pressure, allergy and cancer risk. A 6-year American study on monkeys has shown that an increased intake of trans fatty acids in the diet not only leads to weight gain, but the fat deposits especially in the abdominal region.
In the resulting “apple type,” the risk of cardiovascular disease and metabolic disorders (especially diabetes) is particularly high. The test animals were also found to have elevated blood glucose levels. Although the results cannot be readily transferred to humans, they fit with other studies and findings on this topic.
Avoid trans fatty acids in food
The recommended daily upper limit of trans fatty acids for adults is 2-3 grams. Expert bodies such as the German Nutrition Society (DGE) recommend that trans fatty acids provide less than one percent of dietary energy. However, since the exact amounts ingested are difficult to determine, here are a few general tips:
- When shopping, pay attention to the label and foods with hydrogenated fats are better left on the shelf.
- Do not overheat vegetable oils; cold-pressed, native oils best not at all.
- For hot frying, use highly heatable refined oils (eg coconut oil).
- As a spread, use butter or high-quality margarine.
- Fried, fat baked and breaded rather rarely consume, as well as fast food, convenience foods, puff pastries, chips and confectionery with fat glaze.
- The best prevention is varied, fresh whole foods.