Unsaturated Fatty Acids
Unsaturated fatty acids have a positive impact on health. Studies have shown that they are good for the heart and can help lower cholesterol levels 1.
Fatty acids generally consist of carbon, oxygen, and hydrogen (referred to as a carbon chain). When referring to unsaturated fatty acids, there is at least one double bond between two neighboring carbon atoms in the carbon chain. The carbon chain is not saturated with hydrogen atoms and is therefore unsaturated.
For example, the carbon chain of the omega-3 fatty acid alpha-linolenic acid consists of 18 carbon atoms and three double bonds between each two carbon atoms (18:3).
Cis and Trans Fatty Acids
The double bonds can be arranged in two different ways - in cis (Latin for "on this side, closer") or trans configuration (Latin for "on the other side"). In cis fatty acids, the hydrogen atoms at the carbon atoms of the double bond are on the same side. In trans fatty acids, they are on opposite sides. The presence of a cis bond in the fatty acid lowers the melting point (more liquid at room temperature). If a trans bond is present, the unsaturated fatty acid is solid at room temperature 2.
Due to the number of their double bonds, unsaturated fatty acids can be divided into two groups:
- monounsaturated fatty acids (one double bond)
- polyunsaturated fatty acids (multiple double bonds)
Omega-7 and Omega-9 fatty acids are among the monounsaturated fatty acids. The group of polyunsaturated fatty acids includes the essential Omega-3 and Omega-6 fatty acids.
Unsaturated fatty acids in plant-based foods
Below is a selection of unsaturated fatty acids found in vegan foods:
|Monounsaturated fatty acids||Carbon atoms: Double bonds|
|Myristoleic acid (Omega-5)
(Myristoleic acid foods)
|Palmitoleic acid (Omega-7)
(Palmitoleic acid foods)
|Oleic acid (Omega-9)
(Oleic acid foods)
|Eicosenoic acid (Omega-9)
(Eicosenoic acid foods)
|Nervonic acid (Omega-9)
(Nervonic acid foods)
|Polyunsaturated fatty acids||Carbon atoms: Double bonds|
|Linoleic acid (Omega-6)
(Foods with linoleic acid)
|alpha-linolenic acid (Omega-3)
(Foods with alpha-linolenic acid)
|Gamma-linolenic acid (Omega-6)||18:3|
|Eicosapentaenoic acid (Omega-3)||20:5|
|Docosahexaenoic acid (Omega-3)||22:6|
Of the polyunsaturated fatty acids, linoleic acid and alpha-linolenic acid are essential (essential fatty acids) and cannot be produced by the body. Therefore, they must be obtained through the diet.
Lipid peroxidation of unsaturated fatty acids
The more unsaturated a fatty acid is, the greater the risk of oxidation (lipid peroxidation). Therefore, foods with a high content of polyunsaturated fatty acids are especially affected (foods high in polyunsaturated fatty acids). If foods are affected by lipid peroxidation, they are said to have become rancid, which is equivalent to spoilage. To prevent oxidation, these foods should be stored in a cool and dark place, as heat and light can quickly lead to oxidation. Antioxidants such as vitamin E can protect unsaturated fatty acids from lipid peroxidation in cell membranes.
To prevent the rancidity of fatty acids, the food industry applies the chemical process of hydrogenation. This process hardens the fatty acids and makes them more durable. However, a disadvantage of this process is the formation of health-damaging trans fatty acids (found in chips and often in margarine). Trans fatty acids should be avoided due to their negative impact on health.
Partially replace carbohydrates and saturated fatty acids with unsaturated fatty acids
According to a 2005 study, partially replacing carbohydrates with unsaturated fatty acids (especially monounsaturated fatty acids) can lower blood pressure, improve lipid levels, and reduce the expected cardiovascular risk 3.
Newer study results from 2015 show that unsaturated fatty acids (especially polyunsaturated fatty acids) and/or high-quality carbohydrates from grains are suitable for replacing saturated fatty acids and thus reducing the risk of coronary heart disease 4.
Foods with Unsaturated Fatty Acids
Most foods contain both saturated and unsaturated fatty acids. Foods with monounsaturated fatty acids include peanuts (24.4 g per 100 g), pistachios (23.8 g), cashews (23.8 g), avocados (9.8 g), hazelnuts (45.7 g), as well as rapeseed oil (63.3 g) and olive oil (73 g).
Excellent sources with plant-based occurrence of polyunsaturated fatty acids are flaxseed (28.7 g), hemp seeds (38.1 g), chia seeds (23.7 g), Brazil nuts (24.4 g), and pine nuts (34 g) as well as flaxseed oil (67.8 g) and walnut oil (63.3 g).