What is Polyunsaturated Fat

Polyunsaturated fats (??????????????? ????) are fats in which the constituent hydrocarbon chain possesses two or more carbon-carbon double bonds. Polyunsaturated fat can be found mostly in nuts, seeds, fish, seed oils, and oysters. “Unsaturated” refers to the fact that the molecules contain less than the maximum amount of hydrogen (if there were no double bonds). These materials exist as cis or trans isomers depending on the geometry of the double bond.

Polyunsaturated fat Definition (??????????????? ???? ?? ???????)

Polyunsaturated fats are a type of healthy fat that includes omega-3 fatty acids and omega-6 fatty acids, which are essential for brain function. You must obtain them from food, as your body cannot make them.

While it is the nutritional aspects of polyunsaturated fats that are generally of greatest interest, these materials also have non-food applications. Drying oils, which polymerize on exposure to oxygen to form solid films, are polyunsaturated fats. The most common ones are:

• Linseed (flaxseed) oil (???? ?? ???)
• Tung oil (???? ???)
• Poppy seed oil (???? ?? ???)
• Perilla oil (?????? ???)
• Walnut oil (????? ?? ???)

Omega-3 and omega-6 fatty acids (????? -3 ?? ????? -6 ???????? ????)

Both omega-3 (?-3) and omega-6 (?-6) fatty acids are important components of cell membranes and are precursors to many other substances in the body such as those involved in regulating blood pressure and inflammatory responses. There is increasing support for omega-3 fatty acids in protecting against fatal heart disease and it is known that they have anti-inflammatory effects, which may be important in this and other diseases. There is also growing interests in the role of omega-3 fatty acids in the prevention of diabetes and certain types of cancer.

Polyunsaturated fat Benefits (??????????????? ???? ?? ???)

Bad Fats (???? ????)

Saturated fats have hydrocarbon chains which can be most readily aligned. Eating foods rich in trans fats increases the amount of harmful LDL cholesterol in the bloodstream and reduces the amount of beneficial HDL cholesterol. Trans fats create inflammation, which is linked to heart disease, stroke, diabetes, and other chronic conditions. They contribute to insulin resistance, which increases the risk of developing type 2 diabetes. Even small amounts of trans fats can harm health: for every 2% of calories from trans fat consumed daily, the risk of heart disease rises by 23%.

Potential benefits (??????? ???)

Because of their effects in the diet, unsaturated fats (monounsaturated and polyunsaturated) are often referred to as good fats; while saturated fats are sometimes referred to as bad fats. Some fat is needed in the diet, but it is usually considered that fats should not be consumed excessively, unsaturated fats should be preferred, and saturated fats, in particular, should be limited.

In preliminary research, omega-3 fatty acids in algal oil, fish oil, fish and seafood have been shown to lower the risk of heart attacks. Other preliminary research indicates that omega-6 fatty acids in sunflower oil and safflower oil may also reduce the risk of cardiovascular disease.

Among omega-3 fatty acids, neither long-chain nor short-chain forms were consistently associated with breast cancer risk. High levels of docosahexaenoic acid (DHA), however, the most abundant omega-3 polyunsaturated fatty acid in erythrocyte (red blood cell) membranes, were associated with a reduced risk of breast cancer.

The DHA obtained through the consumption of polyunsaturated fatty acids is positively associated with cognitive and behavioral performance. In addition, DHA is vital for the grey matter structure of the human brain, as well as retinal stimulation and neurotransmission.

Contrary to conventional advice, evaluation of evidence from 1966-1973 pertaining to the health impacts of replacing dietary saturated fat with linoleic acid found that participants in the group doing so had increased rates of death from all causes, coronary heart disease, and cardiovascular disease. Although this evaluation was disputed by many scientists, it fueled debate over worldwide dietary advice to substitute polyunsaturated fats for saturated fats.

Pregnancy (??????????)

Polyunsaturated fat supplementation does not decrease the incidence of pregnancy-related disorders, such as hypertension or preeclampsia, but may increase the length of gestation slightly and decreased the incidence of early premature births.

Expert panels in the United States and Europe recommend that pregnant and lactating women consume higher amounts of polyunsaturated fats than the general population to enhance the DHA status of the fetus and newborn.

Cancer (?????)

Results from observational clinical trials on polyunsaturated fat intake and cancer have been inconsistent and vary by numerous factors of cancer incidence, including gender and genetic risk. Some studies have shown associations between higher intakes and/or blood levels of polyunsaturated fat omega-3s and a decreased risk of certain cancers, including breast and colorectal cancer, while other studies found no associations with cancer risk.

Polyunsaturated fat Food sources (??????????????? ???? ?? ????? ?????)

Food sources of polyunsaturated fats include:

Reference: https://en.wikipedia.org/wiki/Polyunsaturated_fat