In addition to causing weight gain, its consumption increases the risk of cardiovascular disease and developing type 2 diabetes.
December 8, 2023 . Updated at 9:48 a.m.
THE Trans fat They constitute one of the great dangers for our health and are found in various ultra-processed foods that can be found in any supermarket. Hence the insistence of health professionals that we avoid consuming pre-cooked foods and industrial pastries. But what exactly are they and how do they harm our health?
There are two types of trans fatty acids. Although surprising, there is a natural form that comes from fat found in the milk or meat of animals such as cows, sheep or goats; in the gastric compartment where it is formed under the effect of its own intestinal microbiota. As the Spanish Society of the Heart (SEC) explains, these trans fatty acids They are absorbed and incorporated into the muscles and milk of animals. This is why they are found, although in small quantities, in the meat produced from them.
Thus, it is estimated that approximately 5% of the total human consumption of trans fatty acids comes from these types of sources. Whether by eating milk, meat or other types of food like butter or cream. However, the main source of trans fats in our diet is usually industrial and these are harmful to our body.
What are the different types of fats?
To understand how trans fats are produced in industry, we must first understand how they are formed and where the different types of fatty acids that are part of our diet come from. Here is how the SEC classifies them, taking into account their structure:
- saturated fatty acids. They have single bonds in their carbon atoms. That is, each carbon bond joins with a hydrogen bond. These types of fats are usually solid at room temperature and are found in animal foods like fatty meats, butter or lard. The exception is palm oil and coconut oil, which, although of plant origin, are also inherently saturated.
- unsaturated fatty acids. They have at least one double bond between these carbon atoms. In other words, they are not all bonded to a hydrogen. So, if there is only one double bond, they will be monounsaturated and if there are two or more, polyunsaturated.
- monounsaturated fatty acids. They are usually liquid at room temperature. They are present in olive oil, nuts or avocado. They can reduce total cholesterol and LDL cholesterol when they partially replace saturated fatty acids.
- polyunsaturated fatty acids.They are found mainly in foods of plant origin, as well as fish and shellfish. They are essential components of cell membranes and precursors of prostaglandins (molecules involved in inflammation). They are not synthesized in the body, so they must be supplied through food. In turn, they are divided into two groups:
- Omega-6: present mainly in seed oils (sunflower, corn and nuts such as almonds) and cereals.
- Omega-3: comes from seeds and nuts like nuts and grains, as well as fats from fish and shellfish. It has antiplatelet and vasodilator action, reducing blood pressure and thrombosis.
- trans fatty acids. In addition to those that exist naturally, industrial oils are formed by hydrogenating liquid oils into solid fats, introducing more hydrogen atoms. It’s called hydrogenated fat, but in popular culture it’s called trans fat.
Thus, the industry, by hydrogenating vegetable oils, obtains fats with a solid or semi-solid texture similar to those of animal origin. This variation in structure makes them more stable, durable and improves the texture of certain foods.
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Why are trans fats harmful to our health?
The SEC indicates that once consumed, the digestive system absorbs trans fatty acids, passing into the bloodstream: these pass into the blood, become incorporated into cell membranes and replace the fats that make up these membranes, which end up being lost or reduces its flexibility and fluidity. This prevents other molecules, such as cholesterol, from attaching to the membrane and remaining free.
Thus, one of its harmful effects is to increase the level of total cholesterol, particularly that known as bad or bad cholesterol. LDL. But they also increase the risk of type 2 diabetes and blood triglyceride levels. They increase the risk of cardiovascular disease, producing changes such as stiffness and loss of flexibility of the arteries (atherosclerosis). The latter hinders blood circulation and if it occurs in the carotid arteries, which carry blood to the brain, cerebral infarctions can occur. On the other hand, if obstruction occurs in the coronary arteries, myocardial infarctions occur.
Another risk of ingesting it is weight gain. Additionally, since most of them are found in nutrient-poor, high-calorie foods, this effect is compounded.
Understanding cholesterol: what is it and when is it a cause for concern?
What percentage of trans fats could we consume in our daily lives?
In this context, the World Health Organization (WHO) recommends that the consumption of fats (those outlined above) should represent between 30 and 35% of the total daily calorie intake. Of this percentage, between 15 and 20 percent should come from monounsaturated fats, less than 6 to 10 percent from polyunsaturated fats, and, to reduce cardiovascular risk, less than 10 percent from saturated fats. Finally, the consumption of trans fats should be Less than 1%.
However, it must be taken into account that in 2021 the legislation that regulates the content of the latter type in food came into force. Since that time, the European Commission has limited the use of trans fats (those that are not naturally trans fats) to a maximum of two grams per percent of fat in foods. The industry has a two-year window to adapt to the products, so their removal from supermarket shelves has a current deadline: the end of this year.
In what foods are trans fats found?
Trans fatty acids are generally found in:
- Some precooked foods such as pizzas, cannelloni, croquettes, etc.
- Ice cream and frozen yogurt.
- Sausages and hamburgers.
- Bagged potato chips and other types of industrial snacks.
- Industrial pastry and bakery.
They can be identified on the label as hydrogenated fats.
Source: Spanish Society of Endocrinology and Nutrition (SEEN).