om temperature.
Knowing the connection between chain length, degree of saturation and the state of the fatty acid (solid or liquid) is important for making food choices. If you decide to redirect your intake of fat products, choosing unsaturated fat is more beneficial than choosing a saturated fat. Examples of foods high or rich in unsaturated fats include avocados, olive and canola oils(monounsaturated), most vegetable and fish oils (polyunsaturated), nuts and seeds. Conversely, tropical oils are an exception to this rule in that they are high in saturated fat. Palm oil and coconut oil are both highly saturated and have been shown to raise blood cholesterol. Shortening, margarine, and commercially prepared products (in general) report to use only vegetable-derived fats in their processing. But even so, some of these contain fats that may be in the saturated and trans fat categories.
Cis or Trans Fatty Acids?
The introduction of a carbon double bond in a carbon chain, as in an unsaturated fatty acid, can result in different structures for the same fatty acid composition. When the hydrogen atoms are bonded to the same side of the carbon chain, it is called a cis fatty acid. Because the hydrogen atoms are on the same side, the carbon chain has a bent structure. Naturally occurring fatty acids usually have a cis configuration.
In a trans fatty acid, the hydrogen atoms are attached on opposite sides of the carbon chain. Unlike cis fatty acids, most trans fatty acids are not found naturally in foods but are a result of a process called hydrogenation. Hydrogenation is the process of adding hydrogen to the carbon double bonds, thus making the fatty acid saturated (or less unsaturated, in the case of partial hydrogenation). This is how vegetable oils are converted into semisolid fats for use in the manufacturing process.
According to the ongoing Harvard Nurses Health Study, trans fatty acids have been associated with increased risk for coronary heart disease because of the way they negatively impact blood cholesterol levels.1
Interestingly, some naturally occurring trans fats do not pose the same health risks as their artificially engineered counterparts. These trans fats are found in ruminant animals such as cows, sheep, and goats, resulting in trans fatty acids being present in our meat, milk, and other dairy product supply. It seems that any positive effect naturally occurring trans fats have are counteracted by the presence of the saturated fatty acid molecules in these animal products.1 Harvard School of Public Health. “It’s Time to End the Low-Fat Myth.” Introduction to “Fats and Cholesterol: Out with the Bad, In with the Good” in The Nutrition Source. Accessed June 21, 2019.
Nonessential and Essential Fatty Acids
Fatty acids are vital for the normal operation of all body systems. The circulatory system, respiratory system, integumentary system, immune system, brain, and other organs require fatty acids for proper function. The body is capable of synthesizing most of the fatty acids it needs from food. These fatty acids are known as nonessential fatty acids. However, there are some fatty acids that the body cannot synthesize and these are called essential fatty acids. It is important to note that the term nonessential fatty acids doesn’t mean unimportant; the classification is based solely on the ability of the body to synthesize the fatty acid.
Essential fatty acids must be obtained from food. They fall into two categories—omega-3 and omega-6. The 3 and 6 refer to the position of the first carbon double bond and the omega refers to the methyl end of the chain. Omega-3 and omega-6 fatty acids are precursors to important compounds called eicosanoids. Eicosanoids are powerful hormone-like molecules that control many other hormones and important body functions, such as in the central nervous system and the immune system. Eicosanoids derived from omega-6 fatty acids are known to increase blood pressure, immune response, and inflammation. In contrast, eicosanoids derived from omega-3 fatty acids are known to have heart-healthy 