This article on fats focuses on four types: saturated, monounsaturated, polyunsaturated, and trans.

Saturated vs Unsaturated

The previous article described how fatty acids consist of long chains of carbon-carbon bonds, with the carbon mostly “saturated” with hydrogen atoms. When two saturated adjacent carbon atoms exchange one hydrogen bond for an additional bond with its neighboring carbon, e.g. C-C to C=C, these carbons become “unsaturated” with hydrogen atoms.

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Monounsaturated, Polyunsaturated, and Cis

One unsaturated pair of carbons makes the fatty acid monounsaturated. Two or more make it polyunsaturated.

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When each of the two remaining hydrogen atoms for these C=C bonds are on the same side, they are in the “cis” configuration. This creates an angle, or bend, in the carbon chain. Virtually all unsaturated fatty acids in nature have their hydrogen atoms in this cis configuration.

The more bending, the less able are neighboring fatty acids to connect with each other to form a solid at room temperature. To illustrate, olive oil is primarily composed of the monounsaturated fatty acid, oleic acid, and remains a liquid even at lower temperatures. Polyunsaturated fatty acids have even more bending which extends their liquid range to even lower temperatures. On the other hand, coconut oil is 90% saturated fat which makes it a solid at room temperature.

Trans-fats

Returning to the double bond between the carbon atoms in an unsaturated fatty acid, if the hydrogen atoms on the unsaturated pair of carbons are on opposing sides, rather than the same side, they are said to be in the trans position. Unlike their cis fatty acid counterparts, trans-fats do not bend. Their straight nature allows forces, Van der Waals, to hold them together tightly. This makes them solid at room temperature, like saturated fats.

Trans-fats occur infrequently in nature but are found in low amounts in beef and dairy (1%) and they are present in some plant foods in insignificant trace quantities.

Before being banned from US food processing in 2018, trans-fat production occurred by hydrogenating many of the unsaturated fatty acid bonds present in vegetable oils. This partial hydrogenation converted many cis fatty acids to trans, making them more solid at room temperature.

The production of margarine provides a clear example. Prior to the ban, partially hydrogenated vegetable oils, resulting in the production of trans-fats, were permitted in the US food supply. Due to discovery of health issues, trans fats can no longer be added. The World Health Organization recommends consuming less than 1% of calories from trans-fats.

Conclusion

Saturated and trans-fats are associated with cardiovascular problems as they adversely affect cholesterol levels. See my previous article on cholesterol. Polyunsaturated fats, in general, favorably affect blood cholesterol levels.

Refined oils, including olive oil, even though unsaturated, generally have a higher ratio of omega-6 to omega-3 fatty acids, making them potentially proinflammatory. Please refer to my previous article on essential fatty acids.

So, for heart health and reducing inflammation, consuming mono and polyunsaturated fats from their natural sources, e.g., avocado, nuts, and seeds, can limit the influx of omega-6’s while gaining the benefits of the polyunsaturated fats in them in quantities consistent with natural consumption. Consuming marine sources of fats such those containing the essential and polyunsaturated omega-3 fatty acids in algae and fatty fish, have low omega-6 to omega-3 ratios and improve cardiovascular outcomes and inflammation. Limiting intake of foods high in saturated and trans-fat further protects against cardiovacsular system assaults and other chronic diseases.

If needing to improve lipid panels or reduce inflammation, consulting with a well-versed registered dietitian with expertise in this area is vital.

Patrick Traynor, PHD, MPH, RD, CPT is a registered dietitian with an insurance-based practice, MNT Scientific in South Lake Tahoe & Sacramento, CA, Minden, NV, Ashland, OR, and does telehealth. Inquiries can be directed to Dr. Traynor at (530)429-7363 or info@MNTScientific.com. Instagram: @dr.patricktraynor