Palm oil is a much-discussed oil, used in the food industry both for its low cost and its pleasant taste, and here are some studies of 2015-2016.

In September 2015, a group of researchers (1) engaged in lengthy research showed that the association between palm oil intake and cancer might be controversial due to some important factors such as:

• population heterogeneity
• difficulty to consider other risk factors
• other pathological conditions

 However, it reiterated recently, that a growing number of tests have highlighted the negative effects of excess palmitic acid on mitochondrial function mediated by oxidative stress, an effect otherwise known as lipotoxicity. Whereas, with regard to cardiovascular risk, bearing in mind the previous important factors, contrasting results have been reported, above all because the tests were carried out on subjects with normal cholesterol values ​​who had taken normal doses of polyunsaturated fatty acids.

Another 2015 study reiterated the high saturated fat content and provided discouraging results on the increase in harmful LDL cholesterol (2).

Comparing palm oil and sunflower oil, palm oil was confirmed as a highly saturated vegetable oil, which can induce dysfunctions of the lipid metabolism of the liver before touching the serum lipid levels. On the other hand, sunflower oil, a highly unsaturated vegetable oil, has been shown to be well metabolised in the liver (3).

All these studies agreed in attributing to palm oil a high content of saturated fats and, in a long and articulated examination of the biological and nutritional properties of the oil, carried out by a group of researchers of the University of Naples, controversial results were produced. We can see in Figure 3, which is of particular interest, the areas involved in the human body (4).

A study aimed at detecting mutations produced in palm oil, used for frying potato chips, found that thermo-oxidative changes took place in the composition of fatty acids and alterations in the colour were produced at temperatures of 150°, 165° and 180°. Therefore, the more the temperature increases, the more the oxidation of palm oil increases (5).

It has a relatively high content of saturated fats of about 50%, of which palmitic acid represents 45% (6).

References______________________________________

(1) Biological and Nutritional Properties of Palm Oil and Palmitic Acid: Effects on Health.
Mancini A, Imperlini E, Nigro E, Montagnese C, Daniele A, Orrù S, Buono P.
Molecules. 2015 Sep 18;20(9):17339-61. doi: 10.3390/molecules200917339. Review.  

(2) Palm Oil Consumption Increases LDL Cholesterol Compared with Vegetable Oils Low in Saturated Fat in a Meta-Analysis of Clinical Trials.
Sun Y, Neelakantan N, Wu Y, Lote-Oke R, Pan A, van Dam RM.
J Nutr. 2015 Jul;145(7):1549-58. doi: 10.3945/jn.115.210575. 

 (3) Effects of palm and sunflower oils on serum cholesterol and fatty liver in rats.
Go RE, Hwang KA, Kim YS, Kim SH, Nam KH, Choi KC.
J Med Food. 2015 Mar;18(3):363-9. doi: 10.1089/jmf.2014.3163. 

(4) Biological and Nutritional Properties of Palm Oil and Palmitic Acid: Effects on Molecules. 2015 Sep 18;20(9):17339-61. doi: 10.3390/molecules200917339.

(5) The effect of frying on glycidyl esters content in palm oil.   - Aniołowska M, Kita A. Food Chem. 2016 Jul 15;203:95-103. doi: 10.1016/j.foodchem.2016.02.028. 

(6) The effect of pan frying on thermooxidative stability of refined rapeseed oil and professional blend
Magda Aniołowska, Hamdy Zahran, Agnieszka Kita
J Food Sci Technol. 2016 Jan; 53(1): 712–720. Published online 2015 Sep 16. doi: 10.1007/s13197-015-2020-z