Coconut Oil

Also indexed as: Palm Kernel Oil, Palm Oil, Tropical Oils

What does it do?

Coconut oil is a member of the family of tropical oils, which also include palm, palm kernel, cocoa, and shea nut oils. These oils have been used for centuries in the traditional diets of people living in tropical regions such as the Polynesian islands. Because these populations experience less of the diseases, such as heart disease, that are common in Western countries, some people believe that tropical oils such as coconut oil, especially in their natural state, can be part of a healthful diet.1 2 Currently, these oils are used in Western countries in small amounts, primarily in the production of processed foods.

Tropical oils are high in saturated fat, which has been associated with increased risk of high blood cholesterol, atherosclerosis, and heart disease.3 4 5 However, saturated fat is not a single substance but rather a family of molecules having varying lengths, and coconut oil has more of the shorter-length type of saturated fat molecules (known as lauric acid and myristic acid) compared with most animal fats.6 This has led to speculation that coconut oil might have different effects on cholesterol levels and heart disease risk compared with other sources of saturated fats. Most controlled human studies, however, find significant cholesterol-raising effects of diets high in either myristic acid,7 8 9 lauric acid,10 11 or a combination of these two fatty acids,12 although this increase is usually a combination of both higher low-density lipoprotein (LDL; “bad”) and high-density lipoprotein (HDL; “good”) cholesterol.

Whether consuming coconut oil will result in unhealthy changes to blood cholesterol levels is controversial. In a double-blind study of young men with normal cholesterol levels, coconut oil was used to create a diet higher in both myristic and lauric acids, and this diet was compared with a similar diet with longer-chain saturated fatty acids. The coconut oil diet resulted in higher levels of both total and LDL cholesterol, whereas HDL levels were not significantly different.13 Most other controlled studies of healthy young adults have reported that coconut oil increases both LDL and HDL compared with either beef fat, palm oil, or vegetable oils high in unsaturated fats.14 15 16 17 A controlled study of Polynesians found that a diet with coconut oil resulted in lower LDL levels compared with butter, while HDL was not different between the two diets.18 However, one trial found no difference in the effects on cholesterol levels of a diet containing small amounts (4% of total calorie intake) of coconut oil compared with similar diets containing other fat sources.19 More research is needed to determine whether consuming coconut oil will affect the risk of atherosclerosis and heart disease.

Animal studies suggest that coconut oil can affect energy and fat metabolism in a way that could improve the results of a weight-loss diet.20 In a two-week double-blind trial investigating the effect of dietary fat on fat metabolism, a diet containing shorter-chain saturated fatty acids from coconut oil and butter was compared with one containing longer-chain saturated fatty acids from beef fat.21 The coconut oil-butter diet led to changes in fat metabolism that suggested that eating these fats might result in better control of body weight. However, no studies have investigated whether consuming coconut oil actually affects body weight.

According to test tube studies, some of the fatty acids present in coconut oil have antibacterial,22 23 24 antiviral,25 26 27 28 and immune system-stimulating effects,29 suggesting that coconut oil might be helpful in fighting infections. However, no research has investigated these possible effects in humans.

Synthetic fats resembling those found in coconut oil have been found to have anticancer effects in animals but whether these effects would be possible in humans consuming coconut oil is unknown.30 31

Where is it found?

Coconut oil may be found in many types of processed foods, including fried foods, crackers, desserts, candies, whipped topping, and non-dairy creamers. It is also available in some grocery stores for use in cooking.

Who is likely to be deficient?

There is no human requirement for coconut oil or the shorter-length fatty acids it contains, so no deficiency is possible.

How much is usually taken?

The traditional diets of Pacific Islanders contains several grams per day or more of lauric acid from coconut products, which would require at least one tablespoon per day of coconut oil. Research has not established a recommended intake for coconut oil.

Are there any side effects or interactions?

Serious allergic reactions to coconut or coconut oil have been reported but are considered rare.32 33 34

People using large amounts of coconut oil in their diet should have their blood cholesterol levels checked regularly.

At the time of writing, there were no well-known drug interactions with coconut oil.

References

1. Prior IA, Davidson F, Salmond CE, Czochanska Z. Cholesterol, coconuts, and diet on Polynesian atolls: a natural experiment: the Pukapuka and Tokelau island studies. Am J Clin Nutr 1981;34:1552–61.

2. Kaunitz H, Dayrit CS. Coconut oil consumption and coronary heart disease. Philippine J Intern Med 1992;30:165–71 [review].

3. Hu FB, Stampfer MJ, Manson JE, et al. Dietary fat intake and the risk of coronary heart disease in women. N Engl J Med 1997;337:1491–9.

4. Kromhout D, Menotti A, Bloemberg B, et al. Dietary saturated and trans fatty acids and cholesterol and 25-year mortality from coronary heart disease: the Seven Countries Study. Prev Med 1995;24:308–15.

5. Tell GS, Evans GW, Folsom AR, et al. Dietary fat intake and carotid artery wall thickness: the Atherosclerosis Risk in Communities (ARIC) study. Am J Epidemiol 1994;139:979–89.

6. Grundy SM, Denke MA. Dietary influences on serum lipids and lipoproteins. J Lipid Res 1990;31:1149–72 [review].

7. Zock PL, de Vries JHM, Katan MB. Impact of myristic acid versus palmitic acid on serum lipid and lipoprotein levels in healthy women and men. Arterioscler Thromb 1994;14:567–75.

8. Temme EH, Mensink RP, Hornstra G. Effects of medium chain fatty acids (MCFA), myristic acid, and oleic acid on serum lipoproteins in healthy subjects. J Lipid Res 1997;38:1746–54.

9. Tholstrup T, Marckmann P, Jespersen J, et al. Effect on blood lipids, coagulation, and fibrinolysis of a fat high in myristic acid and a fat high in palmitic acid. Am J Clin Nutr 1994;60:919–25.

10. Denke MA, Grundy SM. Comparison of effects of lauric acid and palmitic acid on plasma lipids and lipoproteins. Am J Clin Nutr 1992;56:895–8.

11. Temme EH, Mensink RP, Hornstra G. Comparison of the effects of diets enriched in lauric, palmitic, or oleic acids on serum lipids and lipoproteins in healthy women and men. Am J Clin Nutr 1996;63:897–903.

12. Sundram K, Hayes KC, Siru OH. Dietary palmitic acid results in lower serum cholesterol than does a lauric-myristic acid combination in normolipemic humans. Am J Clin Nutr 1994;59:841–6.

13. Sundram K, Hayes KC, Siru OH. Dietary palmitic acid results in lower serum cholesterol than does a lauric-myristic acid combination in normolipemic humans. Am J Clin Nutr 1994;59:841–6.

14. Ng TK, Hassan K, Lim JB, et al. Nonhypercholesterolemic effects of a palm-oil diet in Malaysian volunteers. Am J Clin Nutr 1991;53:1015S–1020S.

15. Mendis S, Kumarasunderam R. The effect of daily consumption of coconut fat and soya-bean fat on plasma lipids and lipoproteins of young normolipidaemic men. Br J Nutr 1990;63:547–52.

16. Reiser R, Probstfield JL, Silvers A, Plasma lipid and lipoprotein response of humans to beef fat, coconut oil and safflower oil. Am J Clin Nutr 1985;42:190–7.

17. Muller H, Lindman AS, Brantsaeter AL, Pedersen JI. The serum LDL/HDL cholesterol ratio is influenced more favorably by exchanging saturated with unsaturated fat than by reducing saturated fat in the diet of women. J Nutr 2003;133:78–83.

18. Cox C, Sutherland W, Mann J, et al. Effects of dietary coconut oil, butter and safflower oil on plasma lipids, lipoproteins and lathosterol levels. Eur J Clin Nutr 1998;52:650–4.

19. Schwab US, Niskanen LK, Maliranta HM, et al. Lauric and palmitic acid-enriched diets have minimal impact on serum lipid and lipoprotein concentrations and glucose metabolism in healthy young women. J Nutr 1995;125:466–73.

20. Portillo MP, Serra F, Simon E, et al. Energy restriction with high-fat diet enriched with coconut oil gives higher UCP1 and lower white fat in rats. Int J Obes Relat Metab Disord 1998;22:974–9.

21. Papamandjaris AA, White MD, Raeini-Sarjaz M, Jones PJ. Endogenous fat oxidation during medium chain versus long chain triglyceride feeding in healthy women. Int J Obes Relat Metab Disord 2000;24:1158–66.

22. Sun CQ, O'Connor CJ, Roberton AM. Antibacterial actions of fatty acids and monoglycerides against Helicobacter pylori. FEMS Immunol Med Microbiol 2003;36:9–17.

23. Ruzin A, Novick RP. Equivalence of lauric acid and glycerol monolaurate as inhibitors of signal transduction in Staphylococcus aureus. J Bacteriol 2000;182:2668–71.

24. Bergsson G, Arnfinnsson J, Karlsson SM, et al. In vitro inactivation of Chlamydia trachomatis by fatty acids and monoglycerides. Antimicrob Agents Chemother 1998;42:2290–4.

25. Bartolotta S, Garcia CC, Candurra NA, Damonte EB. Effect of fatty acids on arenavirus replication: inhibition of virus production by lauric acid. Arch Virol 2001;146:777–90.

26. Kristmundsdottir T, Arnadottir SG, Bergsson G, Thormar H. Development and evaluation of microbicidal hydrogels containing monoglyceride as the active ingredient. J Pharm Sci 1999;88:1011–5.

27. Hornung B, Amtmann E, Sauer G. Lauric acid inhibits the maturation of vesicular stomatitis virus. J Gen Virol 1994;75:353–61.

28. Ismail-Cassim N, Chezzi C, Newman JF. Inhibition of the uncoating of bovine enterovirus by short chain fatty acids. J Gen Virol 1990;71:2283–9.

29. Witcher KJ, Novick RP, Schlievert PM. Modulation of immune cell proliferation by glycerol monolaurate. Clin Diagn Lab Immunol 1996;3:10–3.

30. Ngwenya BZ, Fiavey NP, Mogashoa MM. Anti-neoplastic action of peritoneal macrophages following oral administration of ether analogues of lysophospholipids. Eur J Cancer 1992;28A:1637–42.

31. Ngwenya BZ, Fiavey NP, Mogashoa MM. Activation of peritoneal macrophages by orally administered ether analogues of lysophospholipids. Proc Soc Exp Biol Med 1991;197:91–7.

32. Rosado A, Fernandez-Rivas M, Gonzalez-Mancebo E, et al. Anaphylaxis to coconut. Allergy 2002;57:182–3.

33. Teuber SS, Peterson WR. Systemic allergic reaction to coconut (Cocos nucifera) in 2 subjects with hypersensitivity to tree nut and demonstration of cross-reactivity to legumin-like seed storage proteins: new coconut and walnut food allergens. J Allergy Clin Immunol 1999;103:1180–5.

34. Couturier P, Basset-Stheme D, Navette N, Sainte-Laudy J. A case of coconut oil allergy in an infant: responsibility of "maternalized" infant formulas. Allerg Immunol (Paris) 1994;26:386–7 [in French].