Palm oil is obtained from the pulp of the plant by a process of breaking the plant and squeezing the marrow.

Nutritional Profile (per 100 grams).

• Calories Approximately 884 kcal, typical for vegetable oils.
• Protein Negligible, as with most oils.
• Fat About 100 grams, with a significant presence of saturated fats, but also contains monounsaturated and polyunsaturated fats.
• Carbohydrates None.
• Fiber None.
• Vitamins and Minerals Rich in vitamin E, particularly tocotrienols, powerful antioxidants. May also contain small amounts of other fat-soluble vitamins and minerals.

There are two oil extraction systems:

• dry: mechanical presses are used to crush the plant
• wet: hot water is used to filter the oil

The resulting product is impure, as there are plant residues, cellular debris and fibrous material. Then the hot water is inserted so as to form a barrier in which the solids fall towards the bottom of the container, releasing the oil that will pass through sieves.

The mixture thus obtained and liberated from extraneous substances is boiled for an hour or two and the palm oil, lighter than the water, rises to the surface and is decanted.

Then the oil goes to another stage where it is still heated and skimmed by impurities that will be used either for saponification or for fuel. The ashes have a high potassium content and are therefore useful for fertilizing.

Due to its low cost, this oil is a widespread nutritional source in developing countries.

It contains a high content of saturated fats and palmitic acid.

In the food industry it is used for two reasons:

• it's cheap
• preserves for longer the foods in which it is added

Studies

However, recent studies have shown that a connection has been established between this oil and certain cardiovascular disorders (1) especially when this oil is heated (2).

Since its inception in food, this oil was first challenged for the deforestation it produces as farmers and companies producing it tend to clear forests and woodlands to extract it, given the high demand. Later, however, as early as 1991, attention was paid to the health issue with studies finding it difficult to interpret the evidence for this oil unambiguously with respect to coronary heart disease and cancer (3).

Studies from 2004 drew attention to the risk that this oil could create, if oxidized and that is, not fresh, with the creation of a negative lipid profile, toxicity to kidney, lung, liver and heart, while red palm oil, by virtue of its beta carotene content could protect against vitamin A deficiency and some forms of cancer (4).

There is a strong component of saturated fatty acids in palm oil, particularly palmitic acid, and these ldel 2014 studies confirm this (5).

Another 2015 study reiterates the high saturated fat content and provides not encouraging findings on the increase in harmful LDL cholesterol (6).

At the level of comparison, between palm oil and sunflower oil, it is confirmed that palm oil as a highly saturated vegetable oil can induce dysfunction of liver lipid metabolism before touching serum lipid levels. Sunflower oil, on the other hand, a highly unsaturated vegetable oil, has been shown to be well metabolized in the liver (7).

All these studies agree in attributing to palm oil a high saturated fat content and, in a long and articulate examination of the biological and nutritional properties of this oil by a group of researchers at the University of Naples, controversial results from a health perspective (8).

A study aimed at detecting the mutations produced in palm oil, used as frying oil for potato chips, found that, at temperatures of 150, 165 and 180° thermo-oxidative alterations, changes in fatty acid composition and color alteration are produced. In summary, the higher the temperature, the more the oxidation of palm oil increases (9).

Another problem related to palm oil is the increasing deforestation carried out to plant huge quantities of palm trees.

There is also a "red" palm oil on the market with slightly better physical characteristics and taste.

Palm oil studies

References__________________________________________________________________

(1) Chen BK, Seligman B, Farquhar Multi-Country analysis of palm oil consumption and cardiovascular disease mortality for countries at different stages of economic development: 1980-1997. Global Health. 2011 Dec 16;7(1):45. doi: 10.1186/1744-8603-7-45.

Abstract Background: Cardiovascular diseases represent an increasing share of the global disease burden. There is concern that increased consumption of palm oil could exacerbate mortality from ischemic heart disease (IHD) and stroke, particularly in developing countries where it represents a major nutritional source of saturated fat....Conclusions: Increased palm oil consumption is related to higher IHD mortality rates in developing countries. Palm oil consumption represents a saturated fat source relevant for policies aimed at reducing cardiovascular disease burdens.

(2) Xian TK, Omar NA, Ying LW, Hamzah A, Raj S, Jaarin K, Othman F, Hussan F.  Reheated palm oil consumption and risk of atherosclerosis: evidence at ultrastructural level.  Evid Based Complement Alternat Med. 2012;2012:828170. doi: 10.1155/2012/828170.

Abstract. Background. Palm oil is commonly consumed in Asia. Repeatedly heating the oil is very common during food processing. Aim. This study is aimed to report on the risk of atherosclerosis due to the reheated oil consumption. Material and Methods. Twenty four male Sprague Dawley rats were divided into control, fresh-oil, 5 times heated-oil and 10 times heated-oil feeding groups. Heated palm oil was prepared by frying sweet potato at 180°C for 10 minutes. The ground standard rat chows were fortified with the heated oils and fed it to the rats for six months. Results. Tunica intima thickness in aorta was significantly increased in 10 times heated-oil feeding group (P < 0.05), revealing a huge atherosclerotic plaque with central necrosis projecting into the vessel lumen. Repeatedly heated oil feeding groups also revealed atherosclerotic changes including mononuclear cells infiltration, thickened subendothelial layer, disrupted internal elastic lamina and smooth muscle cells fragmentation in tunica media of the aorta. Conclusion. The usage of repeated heated oil is the predisposing factor of atherosclerosis leading to cardiovascular diseases. It is advisable to avoid the consumption of repeatedly heated palm oil.

(3)  Cottrell RC. Introduction: nutritional aspects of palm oil.  Am J Clin Nutr. 1991 Apr;53(4 Suppl):989S-1009S. Review.

Abstract. The production, composition, and food uses of palm oil are outlined in this introduction to a detailed appraisal of the nutritional and health implications of the use of palm oil in the food supply. The putative role of dietary fats and oils in general, and of palm oil in particular, in the etiology of coronary heart disease and cancer is critically assessed. It is concluded that the evidence available is difficult to interpret unambiguously. Some evidence to suggest that the minor components of palm oil might have useful biological effects is also discussed.

(4)  Edem DO. Palm oil: biochemical, physiological, nutritional, hematological, and toxicological aspects: a review.  Plant Foods Hum Nutr. 2002 Fall;57(3-4):319-41. Review.

Abstract. The link between dietary fats and cardiovascular diseases has necessitated a growing research interest in palm oil, the second largest consumed vegetable oil in the world. Palm oil, obtained from a tropical plant, Elaeis guineensis contains 50% saturated fatty acids, yet it does not promote atherosclerosis and arterial thrombosis. The saturated fatty acid to unsaturated fatty acid ratio of palm oil is close to unity and it contains a high amount of the antioxidants, beta-carotene, and vitamin E. Although palm oil-based diets induce a higher blood cholesterol level than do corn, soybean, safflower seed, and sunflower oils, the consumption of palm oil causes the endogenous cholesterol level to drop. This phenomenon seems to arise from the presence of the tocotrienols and the peculiar isomeric position of its fatty acids. The benefits of palm oil to health include reduction in risk of arterial thrombosis and atherosclerosis, inhibition of endogenous cholesterol biosynthesis, platelet aggregation, and reduction in blood pressure. Palm oil has been used in the fresh state and/or at various levels of oxidation. Oxidation is a result of processing the oil for various culinary purposes. However, a considerable amount of the commonly used palm oil is in the oxidized state, which poses potential dangers to the biochemical and physiological functions of the body. Unlike fresh palm oil, oxidized palm oil induces an adverse lipid profile, reproductive toxicity and toxicity of the kidney, lung, liver, and heart. This may be as a result of the generation of toxicants brought on by oxidation. In contrast to oxidized palm oil, red or refined palm oil at moderate levels in the diet of experimental animals promotes efficient utilization of nutrients, favorable body weight gains, induction of hepatic drug metabolizing enzymes, adequate hemoglobinization of red cells and improvement of immune function. Howerer, high palm oil levels in the diet induce toxicity to the liver as shown by loss of cellular radial architecture and cell size reductions which are corroborated by alanine transaminase to asparate transaminase ratios which are higher than unity. The consumtion of moderate amounts of palm oil and reduction in the level of oxidation may reduce the health risk believed to be associated with the consumption of palm oil. Red palm oil, by virtue of its beta-carotene content, may protect against vitamin A deficiency and certain forms of cancer.

(5) Fattore E, Bosetti C, Brighenti F, Agostoni C, Fattore G. Palm oil and blood lipid-related markers of cardiovascular disease: a systematic review and meta-analysis of dietary intervention trials. Am J Clin Nutr. 2014 Jun;99(6):1331-50. doi: 10.3945/ajcn.113.081190.

(6)  Sun Y, Neelakantan N, Wu Y, Lote-Oke R, Pan A, van Dam RM.  Palm Oil Consumption Increases LDL Cholesterol Compared with Vegetable Oils Low in Saturated Fat in a Meta-Analysis of Clinical Trials. J Nutr. 2015 Jul;145(7):1549-58. doi: 10.3945/jn.115.210575. Epub 2015 May 20. 

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

Abstract. Palm oil is a common cooking ingredient used in the commercial food industry as the second largest consumed vegetable oil in the world. Because of its lower cost and highly saturated nature, it usually maintains a solid form at room temperature and is used as a cheap substitute for butter. However, there has been a growing health concern about palm oil because of the link between dietary fats and coronary heart disease. Palm oil contains ∼49% saturated fat, a relatively high concentration compared with other vegetable oils. Consequently, high intakes of saturated fat from palm oil induce a larger increase in plasma concentrations of total cholesterol and low-density lipoproteins. In the present study, we examined the hyperlipidemia of palm oil and the risk of cardiovascular disease (CVD) using a rat model in comparison with sunflower oil with a relatively low level of saturated fat. On in vivo examination using Sprague-Dawley (SD) rats for 22 days, there were no significant differences in serum lipid levels, suggesting that palm oil may not cause hyperlipidemia and elevate CVD risk. However, liver samples obtained from SD rats fed with palm oil showed a lot of large lipid inclusions stained with the Oil Red O working solution, but not much lipid accumulation was observed in rats treated with sunflower oil. In addition, lipid accumulation in the mixed oil group fed the combination of palm and sunflower (1:1) oil was shown to be at an intermediary level between the palm oil group and sunflower oil group. Taken together, these results indicate that palm oil, a highly saturated form of vegetable oil, may induce dysfunction of the liver lipid metabolism before affecting serum lipid levels. On the other hand, sunflower oil, a highly unsaturated vegetable oil, was shown to be well metabolized in liver.

(8) Biological and Nutritional Properties of Palm Oil and Palmitic Acid: Effects on Health http://www.mdpi.com/1420-3049/20/9/17339

(9) Aniołowska M, Kita A. The effect of frying on glycidyl esters content in palm oil.  Food Chem. 2016 Jul 15;203:95-103. doi: 10.1016/j.foodchem.2016.02.028. Epub 2016 Feb 3.