Types of fatty acids:
There are three kinds of fatty acids: Saturated Fatty acids, Monounsaturated fats and Polyunsaturated fats. Saturated fatty acids (SFAs) are comprised of carbon bonds that are saturated with hydrogen molecules. The body prefers these fats to burn as energy. Monounsaturated fats (MUFAs) have a link in their carbon chain where two carbon molecules share, not one, but two bonds with each other. Body fat contains MUFAs and can be converted into energy that the body burns as easily as saturated fats. Polyunsaturated fats (PUFAs) have two or more double bonds in their carbon chain.
Some PUFAs are used for energy but most have other vital functions in the body. All fats and oils are a mixture of fatty acids; for example, beef fat is 51% SFA, 44% MUFA, and 4% PUFA. Olive oil is 14% SFA, 77% MUFA, and 9% PUFA. Safflower oil is 9% SFA, 12% MUFA, and 78% PUFA. Whichever fatty acid predominates determines classification.
What are Essential fatty acids?
There are two fatty acids that are from the PUFA category and that the body cannot make, therefore called essential fatty acids (EFAs). They are linoleic acid (LA) and linolenic acid (LNA). LA has two double bonds in its carbon chain, the first being between the numbers 6 and 7 carbon. LNA contains three double bonds, the first being between the 3 and 4 carbon. Because the human body does not have the enzyme that is necessary for inserting these obligatory double bonds, it needs to obtain them from an outside source. The presence of a double bond in a carbon chain is noted by the Greek letter for omega, hence, LA is in the omega-6 series and LNA is in the omega-3 series. Once the body has omega-3 and omega-6 fatty acids, it can make other necessary fatty acids from them. The ability of the omega-3s to make other fatty acids can be interfered with, however, if the ratio of omega-6s are too high in the diet as they both compete for the same enzymes in performing their conversions. Omega-6s are more prevalent in the diet principally because of the extensive use of polyunsaturated oils in cooking and food processing.
EFAs are invaluable for the production and movement of energy throughout the body. They regulate the transport of oxygen and are vital in maintaining the integrity of cell structure. They are crucial for blood clotting, for support of the immune system, and for synthesizing hormones such as prostaglandins which regulate numerous biological processes including the healing mechanism.
Omega-3s are particularly important in protecting the nervous system and the integrity of cell membranes in the brain, especially important to fetal and early childhood development. A deficiency can impair mental functions like learning and intelligence; and there may be an association with depression, attention deficit disorder, and autism.
Chemical configuration of PUFAs, the double bonds in the carbon chain, tend to be unstable making them very susceptible to oxidation, a process that can create free radicals. Free radicals are highly reactive molecules that can cause extensive damage in the body involving enzymes, DNA, cellular structure, and the immune system. As a result, premature aging of cells and tissues, arterial disease, and even cancer are some of the conditions that can develop.
When fatty acids oxidize they begin to turn rancid. Most PUFAs oxidize quickly when exposed to heat or air. Oils that are not commercially cold processed are exposed to heat as well as chemical solvents. Safflower and flaxseed oils oxidize most rapidly when heated; grapeseed oil can be heated to 485 degrees before damage occurs. Once nuts and seeds have been roasted or chopped, they begin to oxidize. Buying them raw and toasting them in a fry pan right before eating minimizes harmful effects. Never reuse fat in cooking; deep fried foods in restaurants are especially hazardous.
A recent study showed significant damage to the lining of arteries in participants soon after they ate foods cooked with used fat in restaurants.
MUFAs are more resistant to oxidation, supply fat needed by the body for energy, and are rich in omega-3s. They also lower blood cholesterol. Extra-virgin olive oil, which is the first pressing, or cold-pressed canola oil, are good oils to use in cooking. Hydrogenated fats or partially hydrogenated fats contain trans fatty acids (TFAs). TFAs are unnatural forms of fatty acids that develop when unsaturated fatty acids are exposed to heat during commercial extraction to make oils, when exposed to heat and light after extraction, and when hydrogen is added to their molecular structure, as in the making of margarine. TFAs increase cholesterol levels in the body, which can result in atherosclerosis. TFAs can have damaging effects on cell membranes, the immune system, hormonal function, and can promote heart disease and cancer. Artificially created trans fats are the unhealthiest of fats, even worse than saturated fat.
The foods may also include cholesterol. Cholesterol does not produce any energy like triglycerides, but is important for many biochemical processes and hormone production. Elevated cholesterol levels in body are associated with increased risk of cardiovascular disease. The cholesterol in body is mostly made in liver and there are three different types: High Density Lipoproteins, Low Density Lipoproteins and Very Low Density Lipoproteins. Having higher HDL cholesterol levels can decrease your risk of cardiovascular disease, while elevated LDL cholesterol will increase that risk.
Fats and cholesterol have a number of important functions, which is summarized as under
- Lubrication of body surfaces
- Components of cell membrane structures
- Formation of steroid hormones
- Energy storage
- Insulation from cold
- Carrying fat soluble vitamins A, D, E, K