The polyunsaturated fats are essential fatty acids (EFA), meaning humans can not make them. We require approximately 5% of our energy from essential fatty acids. The EFA families are named by the location of the first double bone counting from the methyl/ omega end. There are two main families: the omega 3 and the omega 6 families.
The omega 3 family: linolenic acid is the starting compound and has 18 carbons. The 20 carbon member is eicosapentenoic acid (EPA) and the 22 carbon is docosahexaneoic acid (DHA). Humans are very inefficient at elongating and desaturating linolenic acid to receive the 20 and 22 carbon fatty acids. This means that we can not readily make the EPA or DHA. Linolenic acid is found in canola oil, walnuts, and purslane. The 20 and 22 carbon omega 3 fatty acids are found in fatty fish.
The omega 6 family: linoleic acid is the starting carbon and has 18 carbons. The 20 carbon member is arachidonic acid; humans can readily elongate and desaturate linoleic acid to synthesize arachidonic. Linoleic acid is found mainly in vegetable seed oils (corn, soybean, safflower); the main dietary source of arachidonic is beef.
The omega 3 and omega 6 fatty acids of 20 carbons or longer are used to synthesize eicosanoids which are hormone-like compounds; they are called “hormone-like” as they can work like hormones but they work where they are made (and hormones travel by the blood from where they are made to where they work). The omega 3 family makes eicosanoids that are anti-inflammatory, anti-aggregation, and vasodilators. The omega 6 family makes eicosanoids that are proinflammatory, proaggregatory, and vasoconstrictive. The 20 carbon members of the families compete at the starting enzyme so the predominant fatty acid will determine what set of eiconsanoids are made. The health benefits from the omega fatty acids are related to the blood ratio of the two fatty acid families. The typical American diet is high in omega- 6 due to the use of vegetables oils and their products (margarine, mayonnaise, commercial salad dressings). Some years ago, health professionals in the US started to address this by suggesting patients consume fish oil pills. Your writer does not support this practice as all polyunsaturated fats will increase oxidation, which will contribute to a list of diseases. I suggest that people minimize their intake of vegetable oils; this would decrease the omega-6 fatty acid in the body and would allow any longer chain omega 3 fatty acids present to work without excessive hindrance.
Triglyceride is a lipid that has a glycerol backbone with three fatty acids attached to it. Triglyceride is the lipid that supplies energy both in food and in us (triglyceride is what is stored in the adipose tissue). The 3 fatty acids are a mixture of fatty acids with some saturated, some unsaturated. The fatty acids that predominate give the naming to a food as being a source of saturated fat, monounsaturated fat, or polyunsaturated. However, no food is purely 1 type of fatty acid. Interestingly, although beef is labeled a source of saturated fat, it contains mainly monounsaturated fat.
Trans fats are produced primarily in an industrial process. They are made by adding hydrogen to polyunsaturated fats (liquid vegetable oils). The process is called “hydrogenation”. This solidifies the oil, which is how margarine and vegetable shortenings are made. hydrogenation also makes the oil less likely to oxidize (become rancid). This increases the shelf-life of food. Foods with a long-shelf life, like commercial baked goods, are high in trans fatty acids.
The health concern with trans fatty acids is that in the body they can replace cis or the natural fatty acids in phospholipids and other places where one would fine triglycerides. The trans fatty acids are unnatural to the body and have been consistently linked to an increase risk of chronic diseases, especially cancer and heart disease. Some of this research has involved measuring the amount of trans fatty acid present in the adipose tissue. As these fatty acids are not naturally found in the body (i.e., we do not make them), any present in the adipose would be from the diet. Your writer has long felt that as any food with trans fatty acids is not a healthy food, counseling people to eat a more healthy diet would minimize the intake of trans fatty acids.
Cholesterol is a lipid that is a sterol. It is only found in animal foods and does not supple any energy. Cholesterol is used to make some hormones (estrogen, testosterone); is a starting compound for vitamin D synthesis in the body; it is part of bile; it is an essential structural part of cell membranes; and it is part of lipoproteins.