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.

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.

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.