Saturday Aug 23, 2014 (foodconsumer.org) -- Some restaurants and food processors have stopped using trans fat or partially hydrogenated fat due to the concern about its effect on the risk of heart disease.  Some of them turn to use palm oil to replace trans fat in their food formulations or recipes.  Unfortunately, palm oil high in saturated fat may too increase risk of heart disease and type 2 diabetes mellitus even though it may not be as bad as trans fat when it comes to their detrimental effects on the heart.  Both trans fat and saturated fat can increase bad-cholesterol in the blood and increase risk of heart disease and type 2 diabetes mellitus. Trans fat is even worse as it can also lower the good cholesterol.

Some individuals encourage the public to eat high amounts of saturated fatty acids (SFAs), which are found high in meat, animal fat (lard), coconut fat, and palm oil among others, by claiming that saturated fat is important for human nutrition.   But keep in mind that saturated fat is not an essential fatty acidand you do not have to eat it to live a better life.  And it actually increases bad cholesterol and has been associated with risk of heart disease and type 2 diabetes mellitus.

A report by University of Toronto recently published in American Journal of Physiology: Regulatory, Integrative and Comparative Physiology again reminds the public of the dangers of saturated fatty acids.  The report says that high intake of saturated fatty acids is linked to the development of circadian dysregulation, obesity, and type 2 diabetes mellitus.  

In contrast, according to the report, polyunsaturated fatty acids (PUFAs) can improve insulin sensitivity or increase glucose tolerance or help treat diabetes mellitus, reduce weight gain and relieve obesity-induced inflammation.  

Keep in mind that there are two types of polyunsaturated fatty acids,  omega 3 polyunsaturated fatty acids, which are found in cold water fatty fish such as salmon, and omega 6-polyunsaturated fatty acids, which are found in vegetable oils such as soybean oil and corn oil.  Many nutritionists believe that Americans eat too much of omega-6 PUFAs from vegetable oils and too little of omega 3 PUFAs from seafood.

The current study was intended to examine how saturated fatty acid palmitate and omega-3 PUFA docosahexenoic acid (DHA) on circadian rhythms on an immortalized murine neuronal model.   Palmitate or palmitic acid, or hexadecanoic acid is found high in palm oil, meats, cheeses, butter, and dairy products while DHA, a type of mega-3-PUFA, is found in oily fish like  small forage fish including sardines, herring and anchovies and other larger pelagic fish including salmon, trout, and mackerel.

The study shows that palmitate after applied to the neuronal model significantly increased the transcriptional expression of a core clock gene called Mmal1, which was easy to observe because the model neurons express three core clock genes, Mbal1, Per2 and Rev-erbα. In other words, palmitate can disrupt the molecular clock and may cause disruption of circadian rhythms.

DHA was found to alter the circadian expression of Mbal1 but in a different way.  In the presence of DHA, the disruptive effect of palmitate on Mbal1 was not as pronounced.  This suggests that DHA protects against the disruption of circadian rhythms potentially induced by palmitate.

The study concludes "These studies are the first to identify the potential for omega-3 PUFAs to protect against palmitate-mediated dysregulation of circadian parameters, and will ultimately improve the understanding of circadian control mechanisms." (David Liu, PHD)

Greco JA, Oosterman JE, Belsham DD.  Differential effects of omega-3 fatty acid DHA and palmitate on the circadian transcriptional profile of clock genes in immortalized hypothalamic neurons.  Am J Physiol Regul Integr Comp Physiol. 2014 Aug 20.