椰子油

椰子油

椰子油的功能

椰子油是热带油家族中的一员。热带油还包括棕榈油、橄榄油、可可豆、非洲酪脂树籽油。这些油在热带地区如玻利维亚已经食用了数百年。因为这些地区的人们很少患病，所以西方国家认为热带油如椰子油，尤其是它们的天然状态，对人体健康很有益。^{[1 2]}目前，这些油在西方国家已少量应用，尤其是在加工食品的生产中。

热带油富含饱和脂肪酸，目前认为这与血胆固醇增高、动脉粥样硬化和心脏病有关。^{[3 4 5]}但是，饱和脂肪酸并不是单个物质，而是一系列长链分子量的家族，而椰子油比动物脂肪含有更多的饱和脂肪酸中的短链部分（月桂油和肉豆蔻油）^[6]。这就表明椰子油与其他形式的饱和脂肪酸相比，对胆固醇水平和心脏病危险性的作用有所不同。但是，大多数的人类对照试验发现食用月桂油^{[7 8 9]}或肉豆蔻油^{[10 11 12]}后具有明显的升高胆固醇作用。尽管这种升高通常会同时导致低密度脂蛋白（对人体有害）和高密度脂蛋白（对人体有利）的升高。

对于食用椰子油后是否会引起胆固醇的不健康升高，目前还在争论之中。在一项对胆固醇正常的年轻男性的双盲试验中，一组人食用的椰子油中含有较高的月桂油和肉豆蔻油，而另一组则食用普通的长链饱和脂肪酸。结果食用椰子油组总胆固醇和低密度脂蛋白含量升高，而高密度脂蛋白并未明显升高。^[13]其他大多数的对照试验则报道了椰子油与牛油、棕榈油或植物油相比，会同时增加低密度脂蛋白和高密度脂蛋白。^{[14 15 16 17]}一项对玻利维亚人进行的对照试验发现食用椰子油比食用黄油者低密度脂蛋白水平更低而高密度脂蛋白相差不大。^[18]可是，另一项试验则发现椰子油和其他脂肪相比对胆固醇水平的影响相差不大。^[19]目前还需更进一步的试验证实椰子油是否对动脉粥样硬化和心脏病有影响。

动物试验发现椰子油以一定方式作用于能量和脂肪代谢而提高减肥作用。^[20]在一项调查对脂肪代谢作用的双盲试验通过将来源于椰子油的短链饱和脂肪酸和黄油与含有更长链的脂肪酸的牛油相比较，^[21]结果，椰子油和黄油饮食组能更好的控制体重。可是，目前还没有研究椰子油是如何作用与体重变化的试验。

通过试管试验发现，椰子油中含有的一些脂肪酸具有抗菌^{[22 23 24 ]}、抗病毒^{[25 26 27 28]}、提高免疫力^[29]的作用，表明椰子油对于抵抗感染有一定帮助。可是，目前还没有在人类身上研究这一作用。

椰子油中提取的合成脂肪部分发现在动物体内具有抗癌作用，但这些作用在人身上是否同样具有还知之甚少。^{[30 31]}

椰子油的分布

椰子油在许多加工食品中含有，包括油炸食品、薄脆饼干、甜品、糖果、植脂奶油和代奶油。它也在许多食品店中用于烹饪。

哪些人可能会缺乏？

人类并不依赖椰子油及其含有的短链脂肪酸，所以不会缺乏。

一般需要多少椰子油？

各太平洋岛内的传统饮食中每天食用数克的来自于椰子产品的月桂油，因此每天至少需要一茶匙的椰子油。目前还没有关于每天食用多少椰子油的推荐意见。

是否有副作用和药物相互作用？

有报道关于椰子油过敏的副作用，但很少发生。

大剂量食用椰子油者需定期检测血液中的胆固醇水平。

到目前为止，还不清楚椰子油与其他药物间的相互作用。

参考文献

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].