Trans Fats, also known as trans-unsaturated fatty acids and trans fatty acids, are a type of unsaturated fat. They are not widely available from natural sources but have been industrially produced on a large scale from vegetable fats since midway through the twentieth century.
They are commonly used in margarine, snack foods and commercially baked or fried foods and have been linked to an increased risk of coronary heart disease, which is the most common cause of mortality worldwide.
On a molecular level, all fats are made of long hydrocarbon chains. The bonds between each carbon atom can either be singular or double, known as saturated and unsaturated respectively.
Unsaturated fatty acids can either have a cis or a trans configuration, which relates to the positioning of the atoms around the double bonds and affects the properties of the fat. In nature, only cis fat is abundant, whereas trans fat is may be present in commercially produced fats. This occurs when cis unsaturated fats are hydrogenated to remove the double bonds and become saturated fats with more favorable properties, however some cis bonds are converted to trans bonds.
Inside the human body, trans fats have an effect on cholesterol levels by raising lipoprotein LDL cholesterol and lowering the lipoprotein HDL cholesterol, as well as increasing triglycerides. As a result of these changes, people who regularly eat trans fats are more likely to suffer from coronary heart disease.
Trans fat also has an effect on systemic inflammation, which increases when more trans fat is consumed.
Natural Trans Fat
Small amounts of trans fats can be found in nature in vaccenyl and conjugated linoleyl, which are often present in meat and dairy products. However, trans fats that occur naturally are seen separately to those produced artificially in commercial processes and the health effects of natural trans fats have yet to be established.
In fact, some research has suggested that the naturally occurring trans fat may have beneficial properties and help to lower cholesterol levels and hence reduce the risk of coronary heart disease.
Trans fat does not offer any known benefits to the consumer but is associated with higher risk of coronary heart disease due to increased cholesterol levels and should, therefore, be consumed as little as possible.
Some foods that often contain artificial trans fat are:
- Margarine and coffee creamer
- Microwave popcorn with trans fat for cooking or flavoring
- Ready-baked cakes cookies, piecrusts and crackers often contain shortening, a type of hydrogenated oil that contains trans fat.
- Potato, corn and tortilla chips that have been baked or fried with the use of trans fat.
Where possible, it is best to avoid foods that contain trans fats. Although regulations vary in each country, it is not compulsory for food manufacturers in many countries to specify the quantity of trans fat when the product contains less than 0.5 g of trans fat. As a result, it can be difficult to know how much trans fat is actually being consumed. Identifying partially hydrogenated vegetable oil on the ingredients list can be a useful way to determine if a product contains trans fat.
Fats should always be consumed in small quantities in respect to other aspects of the human diet, but natural fats are preferable to trans fats. Butter is a naturally occurring saturated that can be recommended in small quantities but unsaturated fats that are found in nature, such as olive oil, are the best option of fat intake.