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Trans fats in food *

​​​​​Fat is one of the three macronutrients that make up our diet. Fat is important in our body because it serves different functions, such as thermoregulation, protecting internal organs, hormone synthesis, transport of fat-soluble vitamins related to the condition of the skin, calcium absorption, coagulation.

Among the different fats provided by the diet, there are cholesterol esters (cholesterol and fatty acids) and triglyceride (glycerol and fatty acids).

The food we consume has macro and micronutrients. Macronutrients are carbohydrates present in starches and sugars, lipids or fats and proteins such as meat, dairy, and legumes. Micronutrients are vitamins and minerals that are found mainly in fruits and vegetables.

Why is fat important?

Fat is one of the three macronutrients that make up our diet. Fat is important in our body because it serves different functions, such as thermoregulation, protecting internal organs, hormone synthesis, transport of fat-soluble vitamins (A, D, E, K) related to the condition of the skin, calcium absorption, coagulation.

Among the different fats provided by the diet, there are cholesterol esters (cholesterol and fatty acids) and triglyceride (glycerol and fatty acids).

Fat may be solid (lard), semisolid (butter, margarine), or liquid (oils), depending on whether it consists of saturated or unsaturated fatty acids, (with double bonds or not). Each has different effects on metabolism.

Saturated fatty acids confer rigidity to the molecule; they are solid fats with no double bonds; they are difficult to digest and therefore tend to accumulate on the walls of blood vessels and form plates diminishing their light.

Unsaturated fatty acids may have a double bond (monounsaturated, olive oil) or various double bonds (polyunsaturated, corn oil) which increases fluidity. The double bonds may be cis or trans type, which determine the position of hydrogen atoms on the same side of the double bond, or on opposite sides respectively.

The cis-type is the most present in nature. Trans usually originates from industrial processes such as the hydrogenation of oils or semi-solid fat, to turn them into more solid compounds.

What are essential fatty acids (EFAs)?

Essential fatty acids are those that the body cannot manufacture and must be ingested through food or food supplements. The difference with the non-essential fatty acids (monounsaturated and saturated fatty acids) is that the latter may be obtained from protein, carbohydrates or alcohols.

What are the essential fatty acids?

The Omega-3 (linolenic acid) essential fatty acids, found in seed oils or plants with dark green leaves, such as linseed oil or purslane and in nuts such as walnuts, green leafy vegetables, cereal, soy, mustard, pumpkin seeds. The fatty acids of animal origin are found in blue fish from cold and deep water, such as salmon, tuna, sardines. Notable in this group are eicosapentaenoic acid and docosahexaenoic acid.

Ground flax seeds, turned into oil, offer many health benefits and contain more Omega-3 than fish, but their use is not recommended for pregnant women because they can cause menstruation. They are also not recommended for women who breastfeed because they can affect hormones.

The Omega 6 (linoleic acid) fatty acids. The most important in this group is gamma-linolenic acid (GLA). It is found in currant seed oil, borage or evening primrose. Valerian or borage contains the same principle throughout the plant.

Other Omega 6 fatty acids are:

A. Arachidonic acid, found in Brussels sprouts, garlic, carrot, soy and sesame oil; in nuts such as walnuts, sunflower seeds and wheat germ. This acid has anti-dermatitic, hepatoprotective, immune-stimulant and anticancer properties. 

B. Dihomo-linoleic acid present in evening primrose oil.

Furthermore, these polyunsaturated fatty acids, with a high proportion of bonds located in the cis position are easily degraded to simpler structures in the body and therefore do not accumulate as do the trans fatty acids.

Since polyunsaturated fatty acids are easily degraded, food industry, through hydrogenation tries to provide them with greater stability, to increase the shelf life of many foods containing them, thereby improving texture and softness especially if they are products used for bakery. Trans bonds are generated during this manufacturing process.

What is the origin of trans fats?

Trans fats consumed in foods have biological or technological origin. A significant amount of trans fat comes from the so-called “unseen fat.” This is used as the raw material for the manufacture of processed foods.

What are trans fats?

These are semi-solid fats that are obtained by heating vegetable oil in the presence of hydrogen and nickel.

The resulting product is hardened long life oil that is useful for storing for long periods and making it easier to transport. It is commonly found in margarine, commercial cooking and manufacturing processes.

Does trans fat consumption have health risks?

The risk of chronic disease has increased with changes in customs and food habits and the increasing incorporation of processed foods rich in sugar, salt, fat, many with a high content of trans fatty acids (TFA) commonly called trans fats, produced industrially.

Why is the consumption of trans fat considered harmful to our health?

Fat has negative effects on human health because it increases the risk of cardiovascular disease and sudden cardiac death because it increases the level of bad cholesterol, decreases good cholesterol, it accumulates on the inner walls of the arteries, in adipose tissue and prevents the formation of new polyunsaturated acids needed in neural structures.

Vegetable fat of natural origin may be harmless and yet become a health risk factor due to hydrogenation processes which increase the number of hydrogen atoms to the polyunsaturated fatty acids which predominate in the seed oils (sunflower, soybean), they change its natural cis structure to an artificial trans type, which provides a different, more stable consistency.

What are the adverse or negative effects of trans fat on human health?

High consumption of trans fat is a risk factor for cardiovascular health.

It increases the risk of bleeding and thrombosis because these fats are atherogenic, that is, they stick to the walls of arteries, thickening them and making them rigid.

Food products containing trans fats increase the levels of bad cholesterol (LDL) and decrease the good cholesterol level (HDL).

A continuous consumption of trans fats is associated not only with increased risk of coronary heart disease, but also obesity, diabetes, stoke, respiratory, dyslipidemia and some cancers.

Trans fats can inhibit the transformation of some essential fatty acids, slowing the growth and maturation of brain structures, so it is important to avoid eating trans fat in early childhood.

Recent studies on the effects of trans fats on human health reveal conditions in adults, children and even during pregnancy (in embryos and fetuses before birth).

It has been suggested that accumulation of trans fats in the mother’s diet can influence the baby’s weight at birth, predisposing to cardiovascular disease.

Are there foods that contain trans fats naturally?

Trans fats are found naturally in meat, milk and dairy products from grazing animals (cattle, sheep and goats), however, they are less than those in industrial products.

Why is there trans fat in the meat and milk of grazing animals?

Because grazing animals, due to a process of partial biohydrogenation, convert the unsaturated fatty acids that were incorporated (oleic, linoleic and linolenic acid) by consuming grains, leaves, stems, roots and concentrates, through chemical processes into trans fats. These reactions are performed by microorganisms, bacteria and protozoos present in the grazing animals.

Is the amount of trans fat (TFA) in meat and milk of grazing animals significant?

The meat, fat and milk (and derivatives) of grazing animals contain small amounts of trans fat. The meat can contain 1 g of TFA/100 g, fat can be found containing 5-6 g/100 g, butter 2-7 g/100 g, and whole milk from 0.07 to 0.1 g/100 g.

How can trans fat be produced otherwise?

It also has a technological origin, called Industrial hydrogenation.

Can trans fat be produced at home?

Some domestic treatments, such as fritters, may end up transforming fatty acids into trans. Food that is fried at high temperatures will eventually break down and oxidize the oil, changing its structure. The repeated reuse of the same oil in the frying process favors the increase of viscosity up to a solid state and the production of trans fat. The recommendation is that fat should not be heated above 180° C, oil should not be reused more than three times, and it should never be reused when blue smoke is observed during heating.

How much trans fat can be consumed a day?

WHO and FAO recommend that consumption of trans fatty acids be less than 1% of daily calories.

For nutritional experts, a diet with plenty of fruits and vegetables and less energy-dense foods, especially foods high in saturated fat and sugar, is an important step to help the body’s natural defenses.

Is there any rule requiring reporting that a product contains trans fats?

In Colombia, in accordance with Resolution 288 of 31 January 2008, food manufacturers have begun to include this information on the food label. Therefore, you should check the nutritional information and prefer food free of trans fats.

What products of the food industry carry trans fats?

Margarine, industrial fat, oil, household and industrial frying oil, confectionery and bakery products, popcorn, pasta, sweets, chocolates, fast food and a variety of snacks (snacks) such as chips, fried bananas, etc.

The ranking of trans fats 

Trans fats are found mainly in foods processed with vegetable oil. It is important to remember that a daily dose of 5 grams of trans fat is considered dangerous.

List of 10 foods high in this type of fat:

  • Potato chips (150 g): 0.7 gr. trans fat
  • Industrial cake (1 unit): 5-6 gr. trans fat
  • Hamburger (200 gr.): 3 gr. trans fat
  • Individual cheese (1 unit): 2.2 to 5.2 gr. trans fat
  • Biscuits (1 unit): 1 to 2.1 gr. trans fat
  • Cookie (2 units): 1.3 gr. trans fat
  • Margarine (1 tablespoon): 0.9 gr. trans fat
  • Commercial bread roll (1 unit): 0.85 gr. trans fat
  • Chocolate bar (80 grams): 0.75 grams of trans fat
  • Cereal bar (1 unit): 0.4 g of trans fat

Trans fats are found mainly in foods industrially processed in vegetable oils.

For more information:


*Office of Nutritional Health, Food and Beverage 

Ministry of Health and Social Protection (Colombia)


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