Trans-fatty acids (TFA) are acids with one double carbon bond in the trans configuration. It can be produced by partial hydrogenation of fish and vegetable oils. It can also occur at lower levels naturally in meat and dairy products from sheep, goats, and camels. In the late 19th and early 20th centuries industrially produced TFA was introduced into the food supply. 

The partially hydrogenated oils are mostly found in fried and baked foods, pre-packed snacks, cooking oils, and spreads. To increase the shelf life of foods and oils by lowering their oxidation potential and a replacement for animal fats such as butter, they were developed. 

In 1970, partially hydrogenated became popular with the discovery of negative health impacts of saturated fatty acids (SFA). In the 20th century, various studies on the negative metabolic effect of TFA were evidenced. 

Risks in Trans Fatty Acids

Low intake of fats and oils increase the risk of inadequate intakes of Vitamin E of fatty acids and may contribute to changes in triglycerides. The following risks are associated with the intake of trans fatty acids on human health. 

Coronary Heart Disease

Many years of research have shown that people consuming diets in SFA have a high level of serum cholesterol and carry chances of coronary heart disease. It is accepted that a high level of cholesterol promotes the development of predisposing heart disease. TFA has effects on serum lipid levels. 

In 2006 it was reported that saturated fat and TFA had almost equal effects on low-density lipoprotein (LDL) on a calorie basis. When we compare with either saturated or unsaturated fat, TFA reduced high-density lipoprotein (HDL) and increased the ratio of total cholesterol to HDL. It has become widely accepted that lowering LDL by virtually safe means will reduce the risk of heart disease. 

These adverse effects of trans fatty acids have been confirmed by metabolic studies. These studies reported a high risk of heart disease associated with the intake of trans fatty acids.  

Breast Cancer

There is strong evidence concerning the possibility of breast cancer due to TFA. Research showed that breast cancer differs greatly in dietary fat intakes. As the result, TFA showed a positive association with breast cancer, not attributing to the differences in body, age, or hormone. 

The analysis of trans and cis fatty acids in the blood serum of women showed that there is an increase of breast cancer with the increase in TFA level, reflecting the processed food consumption. It is said that women with elevated serum levels of TFA have double the risk of developing breast cancer when compared to women with low TFA.  


Research proves that TFA may increase weight and fat deposits in the abdomen despite similar calorie intake. As a result, obesity in childhood increases the risk of pediatric multiple sclerosis. Industrially produced TFA and TFA from ruminants contain calories of the same quality as other edible fats. Certain acids that are present at a very low level in ruminant fat increase the level of insulin resistance in men with abdominal obesity.    

Ways to Reduce TFA in the Products

Change in the Hydrogenation Process

Modifying the process of hydrogenation affects the fatty acids of the oil, including the TFA, melting point, and solid fat of the content. There is a possibility in making equal performance of low trans fats by increasing the degree of hydrogenation, which reduces the level of TFA but increases the level of SFA. This modification can be used to prepare low-trans baking shortenings.  

Usage of Fractions High in Solids from Natural Oils

Fractions high taken from natural oils such as palm and coconut are not at all new to the food industry and have been components of ingredients for years. If the fat is melted and cooled down slowly, the triglycerides will form a crystalline which can be configured from the liquid part. They can be used as single fractions or in a combination with other fractions to meet the needs. 

New Laboratory Protocol

“Global protocol for measuring fatty acid profiles of food with emphasis on monitoring trans fats originated from partially hydrogenated oils” is WHO laboratory protocol which provides a globally harmonized method to measure trans fats in foods. This protocol will enable many countries in assessing the levels of TFA in the food supply. Also to understand the sources of TFA in the diet as well as to monitor the effectiveness of the policy implemented to reduce industrially produced trans fatty acids.  

Increased TFA intake is always associated with coronary heart disease and mortality. Industrially produced TFA is used in fried and baked food. Packed snacks and oils that are used in restaurants and at homes. 

By 2023, the reduction of industrially produced TFA from the global food supply is the main target of WHO. It has been supporting countries to take action to eliminate industrially-produced TFA from the national food supply. For some countries, it is important to collect data on TFA levels in foods so that they can monitor changes over time. This is the first globally-harmonized laboratory protocol that can be adapted for measuring TFA levels in national food supplies. 

In the upcoming year, WHO is planning to conduct workshops using the laboratory protocol, and target the countries and regions to develop laboratory capacities as a way to accelerate actions in eliminating industrially produced TFA.