1. What is the difference between palm oil and palm kernel oil?
Palm oil is found in the fleshy portion of the fruit (mesocarp), whereas palm kernel oil is found in the kernel or the seed of the fruit. These two oils have very different fatty acid compositions. Palm oil is 50% saturated fat and 50% unsaturated fat. More specifically palm oil contains approximately 44% palmitic acid, 5% stearic acid, 39% oleic acid (monounsaturates), and 10% linoleic acid (polyunsaturates). Myristic acid and lauric acid are negligible.
Conversely, the fatty acid composition of palm kernel oil resembles coconut oil, or what one generally thinks of when the term 'saturated fat' is used. Approximately 82% of palm kernel oil is saturated fat with the main contributors being 48% lauric acid, 16% myristic acid, and 8% palmitic acid. Approximately 18% of palm kernel oil is unsaturated fat with 15% oleic acid (monounsaturates) and 3% linoleic acid (polyunsaturates).
The specific fatty acids were provided as current research suggests that one cannot simply classify all saturated fat as being 'bad' when pertaining to blood cholesterol levels. Each individual fatty acid demonstrates its unique characteristic on cholesterol regulation. Please refer to the question 'Are all saturated fats bad?' for more detail. (top)
2. What are saturated fats?
The scientific definition of saturated fat is having every carbon bound to as many hydrogens as possible, thus the molecule is absent of double bonds. Saturated fat and saturated fatty acids may be used interchangeably. Often saturated fat is used when generalizing common characteristics of saturated fatty acids. The length of the carbon chain differentiates saturated fatty acids. The saturated fatty acids commonly found in a typical American diet are lauric acid, myristic acid, palmitic acid, and stearic acid. As a rule of thumb, the greater the saturated fat in a food item, the more solid it will be at room temperature. The reverse is also true, the greater the unsaturated fat in a food item, the more liquid it will be at room temperature. (top)
3. Are all saturated fats equally cholesterol elevating?
There is scientific evidence that not all saturated fats are equally cholesterol elevating. Studies have found that, compared to other long chain saturated fatty acids, stearic acid appears to have a neutral effect on total cholesterol and low-density lipoprotein (LDL), otherwise known as the 'bad' cholesterol1, 2.
Studies have found that, compared to palmitic acid, lauric acid and myristic acid increase total blood cholesterol, LDL cholesterol (the 'bad' cholesterol), high-density lipoprotein (HDL), the 'good' cholesterol, and the LDL/HDL ratio in both nonhuman primates, and normo-cholesterolemic men and women who consumed a typical western diet3,4. The myristic acid and lauric acid from coconut oil increased total blood cholesterol, LDL, HDL, and triglycerides5.
Another study found that, in normocholesterolemic primates, dietary palmitic acid and oleic acid produced similar effects on LDL and HDL metabolism6. These findings were confirmed in studies with normolipidemic humans who consumed a moderate fat diet low in myristic acid and dietary cholesterol, which found the effect of palmitic acid on total blood cholesterol and LDL/HDL ratio to be comparable to that of oleic acid7,8. Oleic acid is a monounsaturated fatty acid which studies have found to have beneficial effects on total blood cholesterol, LDL, and HDL, in comparison with saturated fats.
In summary, the literature suggests that both stearic acid and palmitic acid, which comprise virtually all the saturated fats in palm oil, have neutral to favorable impact on serum lipid profiles compared to lauric and myristic acid.
Bonanome, A. & Grundy S.M. (1988) Effect of dietary stearic acid on plasma cholesterol and lipoprotein levels. N. Engl. J. Med. 318:1244-1248.
Yu, S., Derr, J., Etherton, T. D. and Kris-Etherton, P. M. (1995) Plasma cholesterol-predictive equations demonstrate that stearic acid is neutral and monounsaturated fatty acids are hypocholesterolemic. Am. J. Clin. Nutr., 61:1129-1139.
Hayes, K.C., Pronczuk, A., Lindsey, S. and Diersen-Schade, D. (1991) Dietary saturated fatty acids (12:0, 14:0, 16:0) differ in their impact on plasma cholesterol and lipoproteins in nonhuman primates. Am .J. Clin. Nutr. 53:491-498.
Zock, P. L. de Vries, J. H. M. and Katan, M. B. (1994) Impact of myristic versus palmitic acid on serum lipid and lipoprotein levels in healthy women & men. Arterioscler. Thromb. 14:567-575.
Ng, T. K.W., Hayes, K. C., de Witt, G. F., Jegathesan, M., Satgunasingham, N., Ong, A. S. H. and Tan, D. T. (1992) Dietary palmitic and oleic acids exert similar effects on serum cholesterol and lipoprotein profiles in normocholesterolemic men & women. J. Am. Coll. Nutr., 11:383-390.
Khosla, P. & Hayes, K.C. (1992) Comparison between dietary saturated (16:0), monounsaturated (18:1) and polyunsaturated (18:2) fatty acids on plasma lipoprotein metabolism in cebus and rhesus monkeys fed cholesterol-free diets. Am. J. Clin. Nutr. 55:51-62.
Sundram, K., Hayes, K. C. and Siru, O. H. (1995) Both dietary 18:2 and 16:0 may be required to improve the serum LDL/HDL ratio in normocholesterolemic men. J. Nutr. Biochem. 6:179-187.
Choudhury, N., Tan, L. and Truswell, A. S. (1995) Comparison of palmolein and olive oil: effects on plasma lipids and vitamin E in young adults. Am. J. Clin. Nutr. 61:1043-1051.
4. What are trans fats?
The majority of unsaturated fat molecules are in the cis configuration thus having the carbons on the same side of the double bond. Most unsaturated fats are cis except for some naturally occurring trans in meats and milk. However when hydrogenation, taking a liquid fat and making into a solid fat by the addition of hydrogens, is performed trans fats are created. Trans fats have the carbons on the opposite side of the double bond. Hydrogenation is used to remove the unsaturation of fatty acids in order to increase the oxidative stability of oils and to raise their melting points, which allows for the modification of their physical properties allowing for a broader range of usage in the food industry. Hydrogenated oils are often used in processed foods due to their stability. Trans fats have not been required on the food label, but will be as of 2006. A product contains trans fatty acids if a hydrogenated oil is listed under the 'ingredient' section of the food label. Research within the last decade has shown a detrimental effect of trans fat on cholesterol (see 'Which is better trans fats or saturated fats'). (top)
5. What are the uses of Palm oil?
Palm oil may be used in a variety of ways. Trans free uses of palm oil are shortenings, margarine, puff pastry margarine, frying, and vanspati.
There are also a variety of non-food uses of palm oil and palm kernel oil such as soaps, candles, rubber processing, cosmetic products, fuel for cars with modified engines, and as a substitute for diesel oil for drilling mud. (top)
6. How do the physiological effects of trans fat compare to saturated fats?
Extensive research on trans fats (see 'What are trans fats?') has occurred in the past decade. Numerous studies have suggested that trans fat consumption elevates LDL cholesterol (the 'bad' cholesterol) 1,2,3,4,5 and decreases the ratio of HDL cholesterol (the 'good' cholesterol) to LDL cholesterol resulting in a less desirablecholesterol profile.6 In 1999, a meta-analysis of comparative effects of trans fats versus saturated fats on cholesterol was performed. This study found that as the fat intake increased the LDL: HDL cholesterol ratio (a low value is desired) also increased in a dose-dependent manner, and that trans fat consumption increased this ratio by more thatn saturated fat consumption.
Aro A., Jauhianen M., Partanen R., Salminen I., Mutanen M. (1997) Stearic acid, trans fatty acids, and dairy fat: Effects on serum and lipoprotein lipids, apolipoproteins, lipoprotein(a), and lipid transfer proteins in healthy subjects. Am. J. Clin. Nutr. 65:1419-1426.
Judd J.T., Clevidence B.A., Muesing R.A., Wittes J., Sunkin M.E., Podczasy J.J. (1994) Dietary trans fatty acids: Effects on plasma lipids and lipoproteins of healthy men and women. Am. J. Clin. Nutr. 59:861-868.
Judd J.T., Baer D.J., Clevidence B.A., Muesing R.A., Chen S.C., Weststrate J.A., Meijer G.W., Wittes J., Lichtenstein A.H., Vilella-Bach M., Schaefer E.J. (1998) Effects of margarine compared with those of butter on blood lipid profiles related to cardiovascular disease risk factors in normolipemic adults fed controlled diets. Am. J. Clin. Nutr. 68:768-777.
Louheranta A.M., Turpeinen A.K., Vidgren H.M, Schwab U.S., Uusitupa M.I.J. (1999) A high-trans fatty acid diet and insulin sensitivity in young healthy women. Metabolism. 48:870-875.
Müeller H., Jordal O., Seljeflot I., Kierulf P., Kirkhus B., Ledsaak O., Pedersen J.I. (1998) Effect on plasma lipids and lipoproteins of replacing partially hydrogenated fish oil with vegetable fat in margarine. Br. J. Nutr. 80:243-251.
Sundram K., Ismail A., Hayes K.C., Jeyamalar R., Pathmanathan R. (1997) Trans (elaidic) fatty acids adversely affect the lipoprotein profile relative to specific saturated fatty acids in humans. J. Nutr. 127:514S-520S.
Mensink R.P. & Katan M.B. (1990) Effect of dietary trans fatty acids on high-density and low-density lipoprotein cholesterol levels in healthy subjects. N. Engl. J., Med. 323:439-445.
Ascherio A., Katan M.B., Zock P.L., Stampfer M.J., Willett W.C. (1999) Trans fatty acids and coronary heart disease. N. Eng. J. Med. 340:1994-1998.
7. Can Palm oil be used to make trans free products?
Yes, palm oil may be used to make trans free products. Palm oil is approximately 50% saturated fat and 50% unsaturated fat. Due to such a unique characteristic palm oil may be separated under controlled thermal conditions into two components, a solid form (palm stearin) and a liquid form (palm olein). This is a type of fractionation (see 'What is fractionation') process and may occur in either a dry form or in the presence of a detergent or solvent. Palm stearin is then utilized to form more solid fats, such as margarines, without the need of hydrogenation, and thus being trans free. (top)
8. What is fractionation?
Fractionation is a physical method using the crystallization properties of triglycerides to separate a mixture into a low melting liquid fraction and a high melting liquid fraction. There are three different types of fractionation: dry fractionation, detergent fractionation, and solvent fractionation. The two components resulting from the fractionation of palm oil is palm olein (liquid oil) and palm stearin (solid form). (top)
9. Is palm oil that is used for frying trans-free?
Frying is usually performed at 180°C and thus a fat used for frying must be able to withstand high temperatures without adverse chemical changes. Oils high in unsaturated fatty acids as well as those containing large amounts of linoleic and linolenic acid are not suitable for frying due to their tendency to oxidize and break down or polymerize. In the USA, hydrogenated vegetable oils have been the oil of choice for frying. However, these fats contain trans-fatty acids that pose a health concern. Palm oil may be used for frying without the need of hydrogenation, and thus creating trans-free oil for frying. Palm oil is a good frying oil as it contains a moderate level of linoleic acid, negligible amounts of linolenic acid and natural antioxidants. (top)
10. What are tocotrienols?
Vitamin E is a general term used with two subclasses: tocopherols and tocotrienols. Among vegetable oils, palm oil is one of the richest sources of tocotrienols. Tocotrienols are also found in rice bran oil, germ protein of barley, wheat, and rye, and grapeseed oil. Tocotrienols are potent antioxidants and have been found in some cell culture and animal studies to exhibit anti-cancer properties. (top)
11. Isn't palm oil a tropical oil, which is high in saturated fats and should be avoided?
Tropical oils are generally thought of as having a high saturated fat content and should be avoided. Although, palm oil is grown in the tropical regions, compared to other tropical oils, its saturated fat content is approximately 30% less. Palm oil is often confused with the more highly saturated palm kernel oil and coconut oil. Studies have found that, unlike coconut oil, palm oil's impact on serum lipid and lipoprotein profiles compares favorably to corn oil, hydrogenated soybean oil, and olive oil. A 1995 study comparing the effect of palm olein and olive oil diets on twenty-one healthy, free-living normocholesterolemic subjects found no difference in total and LDL-cholesterol levels. In sum, palm oil appears to affect serum lipids more like a monounsaturated than a saturated oil. (top)
12. What are the effects of palm oil on blood cholesterol?
Recent studies have compared palm oil with other oils to understand the effect it has on blood cholesterol. An Australian study of twenty-one normocholesterolemic young adults (both men and women) compared the effects of palmolein and olive oil on plasma lipids. The total cholesterol and LDL cholesterol ('bad' cholesterol) were nearly identical between palm olein and olive oil1. A double-blind crossover trial with thirty-eight Dutch males examined the effect replacing their usual saturated fat (animal fats and hydrogenated oils) consumption with palm oil and found no change in total cholesterol, but a 11% increase in HDL cholesterol (the 'good' cholesterol) compared to the control group2. Another crossover study consisted of 33 normocholesterolemic subjects who were challenge fed with a coconut oil-rich diet for 4 weeks and then provided with that test diet, either a palm olein-rich diet or an olive oil-rich diet. The results showed identical total cholesterol, LDL cholesterol, HDL cholesterol, and triglyceride levels3.
In summary, there is evidence that palm oil has similar effects as olive oil on total cholesterol, LDL cholesterol, and HDL cholesterol.
Choudhury N., Tan L., Truswell A.S. (1995) Comparison of palmolein and olive oil: effects on plasma lipids and vitamin E in young adults. American Journal of Clinical Nutrition. 61:1043-1051.
Sundram K., Hornstra G., von Houwelingen A.C., Kester A.D. (1992) Replacement of dietary fat with palm oil: effect on human serum lipids, lipoproteins and apolipoproteins. Br. J. Nutr. 68:677-692.
Ng T.K., Hayes K.C., DeWitt G.F., Jegathesan M., Satgunasingam N., Ong A.S., Tan D. (1992) Dietary palmitic and oleic acids exert similar effects on serum cholesterol and lipoprotein profiles in normocholesterolemic men and women. Journal of the American College of Nutrition. 11:383-390.
13. What is hydrogenation?
Hydrogenation of fats is the addition of hydrogen to the double bonds in the fatty acid chains. This process is very important in the food industry. Two major objectives are accomplished through hydrogenation of fats, (1) the allowance of the conversion of a liquid oil to a semisolid fat that is more suitable for specific food applications such as margarines and shortenings, and (2) the improvement of oxidative stability of the oil. A major disadvantage of the hydrogenation process is the formation of trans fats (see 'Which is better trans fats or saturated fats?'). (top)
14. What are unsaturated fats?
The scientific definition of an unsaturated fat is having one or more double bond(s) in the fatty acid chain. There are two types of unsaturated fatty acids:
Monounsaturated fats have only one double bond in the fatty acid chain. The common fatty acid is known as oleic acid.
Polyunsaturated fats have two or more double bonds in the fatty acid chain. Some common fatty acids are linoleic acid and linolenic acid, which are essential fatty acids. In general, the greater the unsaturation of a fat, the more liquid it is.
15. Why is palm kernel oil hydrogenated in chocolates?
In cases where hydrogenated oils are necessary, palm kernel oil may be partially hydrogenated. Since palm kernel oil is already highly saturated (~82%) minimal hydrogenation is needed, thus limiting the trans fat formation compared to a primarily unsaturated fat, such as soybean oil where much hydrogenation is needed. (top)
16. What does palm fruit mean under the ingredient section of the food label?
Occasionally, palm fruit may be listed under the ingredient section of the food label. This is sometimes used in substitution for palm oil. (top)
17. What is the fatty acid composition of palm olein versus palm stearin post fractionation?
The resulting two components of the palm oil fractionation (see 'What is fractionation') is palm olein (liquid) and palm stearin (solid). The fatty acid composition of palm olein is approximately 45% saturated fat and 55% unsaturated fat. The main saturated fatty acids are 40% palmitic acid and 5% stearic acid. The unsaturated fatty acids are 43% oleic acid (monunsaturates) and 12% linoleic acid (polyunsaturates).
The fatty acid composition of palm stearin is approximately 60% saturated fat and 40% unsaturated fat. The main saturated fatty acids are 54% palmitic acid, 5% stearic acid, and 1% myristic acid. The main unsaturated fatty acids are 33% oleic acid (monounsaturates) and 7% linoleic acid (polyunsaturates).
The main saturated fats in both palm olein and palm stearin are palmitic acid and stearic acid which may be neutral fats on cholesterol (see 'Which is better trans fats or saturated fats?'). (top)
18. What gives palm oil its red color?
Palm oil naturally contains carotenes (pro-vitamin A) which gives it its red color. Palm oil carotenoids have comparative alpha-carotene and beta-carotene distribution as carrots. (The refined red palm oil that is available in some food stores in the US has 15 times the amounts of carotenes compared to carrots and 300 times more than tomatoes!). Approximately 1 tablespoon of red palm oil meets 100% of the adult reference dietary intake (RDI). Furthermore, some animal studies have found that carotenoids may have beneficial effects on cancer and coronary heart disease. (top)
19. Are carotenoids lost during the refining process?
During the conventional refining process 100% of the natural carotenes (pro-Vitamin A) and a substantial portion of vitamin E were destroyed. However, with the new refining technology, greater than 90% of the natural carotenes and vitamin E may be retained. (top)
20. Is palm oil, palm kernel oil safe for people whom are allergic to nut/tree nut?
Allergies are caused by a protein called allergen which initiate inflamatory reactions in the body. It is safe for those whom are allergic to nut/tree nut simply beacause palm oil or palm kernel does not contain any proteins.