Polyunsaturated fats (PUFA) are those fats that contain polyunsaturated fatty acids. PUFA can be cis or trans, in this article we will focus on healthy fats in natural cis form, trans fats are covered here. PUFAs are liquid at room temperature (and mostly also in the refrigerator). They melt at a lower temperature than MUFA (and even lower than saturated fats) and they are most susceptible to oxidation. PUFA come from animal sources (mainly ω-3) as well as from plant sources (mainly ω-6).
Individual fatty acids differ in chain length (number of carbons) and omega parameter. The vast majority of PUFAs are ω-3 or ω-6, with all ω-3 MKs also having a double bond on the 6th carbon from the end as well as ω-6. The two shortest ω-3 and ω-6 PUFAs are essential ones, others can be synthesized by the body.
PUFA sources:
- ω-3: (cold water, especially sea water) fish, fish oil, flax, walnuts – more info on fish here
- ω-6: freshwater fish, vegetable oils, seeds, nuts
Individual PUFA classes (ie ω-3 and ω-6) should be taken in the diet at the correct ratio, which is about 1:1 to 1:5 in favor of ω-6 (with focus mainly on ω-3). From this point of view you can find more detailed information on PUFA sources here.
By their nature, PUFAs are very susceptible to deterioration, both by oxidation and by partial hydrogenation. Therefore, they are not very suitable for:
- long-term storage and storage after opening whatsoever (PUFA-containing product is only durable in case of previous hydrogenation)
- thermal processing (frying etc.)
- consumption within industrially processed foods and in the form of refined oils (although these products are attractive for customers and inexpensive – more in the article on hydrogenation)
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