Why we are talking that much about trans-fats? What are trans fats? Why they have been banned in Canada? What’s so special about them?
Fat is an important part of a healthy diet. It provides essential fatty acids and energy, and helps the human body absorb vitamins A, D and E. Fatty acids are sources of energy because, when metabolized, they yield large quantities of ATP (adenosine triphosphate).
Many cell types can use either glucose or fatty acids for this purpose. In particular, heart and skeletal muscle prefer fatty acids. Despite long-standing assertions to the contrary, fatty acids can be used as a source of fuel for brain cells.
Industrially produced trans fats
Trans fats are fats found in foods, but not common in nature. Trans fats are produced industrially from a liquid vegetable oil, which transforms into a solid fat. Trans fat is often added to processed foods because it can improve taste and texture and helps the food stay fresh longer. They have been used in margarine, snack food, packaged baked goods and frying fast food since the 1950s.
Fatty acids that are required by the human body but cannot be made in sufficient quantity from other substrates, and therefore must be consumed from food, are called essential fatty acids.
There are two major types of fatty acids:
- Saturated fatty acids are long-chain carboxylic acids that have no carbon–carbon double bonds.
- Unsaturated fatty acids have some double bonds between carbon atoms in the chain.
What are TRANS FATS?
Trans fats are a kind of unsaturated fats. There are two main types of trans fats found in foods:
- naturally-occurring trans fats – produced in the gut of some animals and foods made from these animals may contain small quantities of these fats.
- artificial trans fats – created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid.
Meat, milk, and butter naturally contain small amounts of trans fats. The trans fat found naturally in foods is different than manufactured trans fat and does not increase your risk of heart disease.
Foods with trans fats
Processed food packed with trans fats
The primary dietary source for trans fats in processed food is “partially hydrogenated oils.” Look for them on the ingredient list on food packages.
Scientific evidence has shown that dietary trans fats can increase your risk of developing coronary heart disease, the worldwide leading cause of death. To combat this, you can choose food for yourself and your children that contains little to no trans-fat.
What “TRANS” actually means? A little bit of chemistry
Most artificial trans fats are chemically different from natural trans fats.
Fats contain long hydrocarbon chains, which can either be unsaturated, i.e. have double bonds, or saturated, i.e. have no double bonds. In nature, unsaturated fatty acids generally have cis as opposed to trans configurations.
Cis/trans isomerism (geometric isomerism, configurational isomerism) is a term used in organic chemistry to refer to the relative orientation of functional groups within a molecule. The terms “cis” and “trans” are from Latin, in which cis means “on this side” and trans means “on the other side” or “across”.
In food production, liquid cis-unsaturated fats such as vegetable oils are hydrogenated to produce saturated fats, which have more desirable physical properties, e.g. they melt at a desirable temperature (30–40°C). Partial hydrogenation of the unsaturated fat converts some of the cis double bonds into trans double bonds by an isomerization reaction with the catalyst used for the hydrogenation, which yields a trans fat.
Although trans fats are edible, consumption of trans fats has shown to increase the risk of coronary heart disease in part by raising levels of the lipoprotein LDL (so-called “bad cholesterol”), lowering levels of the lipoprotein HDL (“good cholesterol”), increasing triglycerides in the bloodstream and promoting systemic inflammation.