What are oils and fats ?
Every day, we eat fats and oils. As dressing in our salads. To cook vegetables, meat or fish. As an ingredient in our cakes. As an ingredient of so many food products.
“Oil”, “fat” or “lipid” are all different names for the same thing. Oils and fats can come from seeds, nuts, kernels or fruits (e.g. sunflower, rapeseed, palm, etc.) or from animals (beef, pig, goose, chicken, fish, etc.).
And vegetable oils and fats ?
Vegetable oils / fats are substances obtained from mostly seeds (e.g. sunflower, rapeseed), fruits (e.g. olive, palm) and nuts (e.g. coconut, walnut).
Vegetable oils can be produced by two different methods : cold pressing and refining. Cold pressed oils are more typically used as salad dressings, and in other cold or low temperature applications whereas refined oils are usually more suitable for cooking.
For more info on why vegetable oils and fats are refined look here.
Simplified graph of the various steps of the refining
Composed of different fatty acids in different proportions
Oils and fats vary in their fatty acid composition, which results in differing nutritional properties. Fatty acids are essential building blocks of cell membranes. The exact fatty acids composition in vegetable oils and fats depends on the natural botanical origin. Vegetable oils and fats also contain other components such as fat-soluble vitamins, notably vitamin E.
Oils and fats are always a mixture of saturated and unsaturated fatty acids, but in different proportions depending on their origin.
The fatty acids are:
■ Unsaturated fatty acids, which are divided into
- Polyunsaturates (also referred to as “PUFA”), including Omega 3 and Omega 6 fatty acids
and
- Mono-unsaturates (also referred to as “MUFA”)
■ Saturates (also referred to as “SAFA”)
■ Trans (also referred to as “TFA”)
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Typical Fatty Acid composition of vegetable oils and fats
* Figures based on average market value. There may be natural variations inherent to each botanical origin and depending on their geographical origin. For this reason, PUFA, MUFA and SAFA sum up to 99%.
Ratio omega 3 and omega 6 of vegetable oils and fats
Unsaturated fats are either monosaturated fats (1 double bond) or polyunsaturated fats (more double bonds). Omega-3 fatty acids and omega-6 fatty acids are polyunsaturated fatty acids with two or more double bonds in the chemical structure. The number behind the omega-sign is derived from the place where the first double bond is in the molecule. The best-known omega-3 fatty acids are the plant alpha-linolenic acid (ALA) and the fish fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). The best-known omega-6 fatty acid is linoleic acid. The polyunsaturated fats linoleic acid (omega-6 fatty acids) and alpha-linolenic acid (omega-3 fatty acid) are essential fatty acids meaning that the body needs them, but cannot make them itself. Omega-6 fatty acids are present in many vegetable oils like sunflower oils. Omega-3 fatty acid can be found in walnuts and linseed, linseed oil, soy oil and rapeseed oil, among others.
Based on scientific evidence, there is no rationale for a specific recommendation for omega-6 fatty acids (LA) to omega-3 fatty acid (ALA) ratio. Coronary Heart Disease endpoint data indicate that both ALA & LA are beneficial and that recommendations should focus on the absolute intakes of omega-6 fatty acids and omega-3 fatty acid. Furthermore, dietary fats are just one component of a healthy diet, and overall dietary patterns also play a crucial role in maintaining good health.