Saturated fats may not be created equal

Written by William Fredericks, MS, CPT-ACSM on Monday, 03 February 2014. Posted in The Perpetual Athlete

Saturated fats may not be created equal

Saturated fats may not be created equal
It’s funny how these blogs come together sometimes. In a moment of personal discloser this particular blog topic was chosen after two random events. Both of these events got me thinking about fats. Dietary fats are of interest because first the varieties that exist and second because of the various effects on physiology each have. So when a friend mentioned that the current thought was that saturated fats were not as bad as once assumed, I immediately took interest. This was followed up by a decision to read The Paleo Diet by Dr. Loren Cordain in which a distinction was made with saturated fats. The coincidence of these two events led me to do a little research on the topic of saturated fats to get a better understanding of the topic which now I gladly pass on to you the reader.
     First here are the basics of fats. Fats come in multiple forms with the major types being saturated (SFA), monounsaturated (MUFA), and polyunsaturated (PUFA) classifications. Generally speaking health promoting fats are MUFA and PUFA while those considered disease promoting fats are SFA. The major health implication with fat intake is heart disease especially coronary artery disease (CAD) in which plaques formed with cholesterol accumulates on arterial walls leading to blocked vessels. Fats are also implicated in some cancers and the onset of type II diabetes but for the sake of this blog we will focus on heart disease.
     Fats are further complicated by trans fatty acids which are a byproduct of oil hydrogenation. The process of oil hydrogenation is to make a solid fat out of an otherwise liquid fat for use in baked goods and to produce a product that stands up to heat better. Trans fatty acids are actually unsaturated fats but because of the geometry are not health promoting but disease promoting. Trans fats have been strongly indicated in heart disease because of the effect on blood lipid profiles but also because of its ability to cause systemic inflammation. The combination of increased LDL cholesterol and increased inflammation is what leads to atherosclerosis and eventually CAD.
     With the disease implications associated with trans fats, a concerted effort is being made to remove them from the diet. For this to be accomplished a new solid fat source must be produced that can be used instead of hydrogenated oils. Fat sources that are solids at room temperature are generally high in SFA which brings us back to my initial reason for writing this blog. There are multiple SFA which include Lauric acid, Myristic acid, palmitic acid and stearic acid. Each is named based on the number of carbons found in the molecule. These are all long chain fatty acids but may not be created equal. Of interest is stearic acid which may not possess the disease promoting properties associated with the other SFA.
     Stearic acid is the longest of the four SFA mentioned earlier and has been studied for its role in heart disease progression. It has been established that diets high in SFA can lead to an increase in LDL cholesterol and the progression of CAD but stearic acid by itself may not. A review article by Hunter et al in the American Journal of Clinical Nutrition (2010) performed a meta analysis of stearic acid when compared to other SFA and trans fats. In contrast to other SFA and trans fats, stearic acid actually was neutral with both blood lipids and with systemic inflammation. What this means is that while other SFA and trans fats increase LDL cholesterol, decrease HDL cholesterol and increase markers of inflammation in blood, stearic acid does not.
     The findings with stearic acid are fascinating in that like many I was always taught that all SFA were bad and should be reduced. The case of stearic acid as the main SFA taken in via the diet can be made. Foods that are high in stearic acid include beef fat, lard, butter, and cocoa butter among others. Since these sources contain other SFA and cholesterol remember to use in moderation. Currently to replace trans fats, interesterified oils which use stearic acid are being tested to see the efficacy.
     Well that’s all I have on saturated fats. Unsaturated fats are still the best option for health promotion but the next time you sit down to eat a steak you can feel less guilty about it. Have a healthy week!

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