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Coconut Oil: The Great Debate

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Coconut Oil: The Great Debate

People have avoided coconut oil for years because of its high saturated fat content (85%+ of calories), which is linked with high cholesterol and triglycerides. However, recent studies and articles have argued that not all saturated fat is created equal. The primary saturated fat component in coconut oil, lauric acid, is absorbed by the body differently than the other common saturated fat, stearic acid. This article looks at both sides of the coconut oil issue and provides a primer on fats.

Fat: Chains and bonds
Most dietary fats are called triglycerides, which are three fatty-acid chains attached to a compound called glycerol. Most dietary fats discussed by the media are described based on the length and types of bonds on each fatty-acid chain.

Length: If the fatty acids have less than six carbons, it is considered a short-chain triglyceride (SCT). If the fatty acid has between 6−12 carbons, it is a medium-chain triglyceride (MCT). If it has more than 12 carbons, it is a long-chain triglyceride (LCT).

Bonds: A fatty-acid chain is considered “saturated” if all of the carbons on the chain are “saturated” with hydrogen molecules—like a restaurant that is filled to maximum capacity with no more people allowed in (or in this case hydrogen). A fatty acid is “monounsaturated” if one space is available (a “double bond”) for a hydrogen on the chain—like having 39 people in a 40-person maximum capacity restaurant. A fatty acid is “polyunsaturated” if more than one space is available for hydrogen on the chain (multiple “double bonds”)—like having 38 or fewer people in the restaurant.

Omega: The term “omega” often is used to describe the essential fatty acids. Omega-3 and omega-6 simply describes where on the chain the first double bond occurs. An omega-3 monounsaturated fatty acid (the main fatty acid found in olive oil) has its one double bond at the third bond from the end of the chain. The higher the number, the higher up the chain the double bond occurs.

So, what does this all mean? Coconut oil is mainly saturated fat, which is linked with increased cholesterol, triglycerides, and consequently heart disease.

However, coconut’s primary saturated fatty acid, lauric acid, has a shorter fatty-acid chain (12 carbons) than the fatty-acid chain found in most other saturated fat foods—stearic acid (18 carbons). As a result the body absorbs lauric acid differently and burns it more readily for energy. Proponents of coconut oil argue that this feature of coconut oil can help promote weight loss and improve health risks when compared to a number of other frequently used oils. However many others are quick to warn that overconsumption of foods high in saturated fat, such as coconut oil, still will have negative effects on the body.

In favor of coconut oil
A 2009 study by Assunção et al found that obese women who supplemented 30 milliliters (mL) of coconut oil (about 2 tablespoons [Tbsp]) every day, while trying to exercise and diet over 12 weeks, had better improvement in high-density lipoprotein (HDL), low-density lipoprotein (LDL):HDL ratio, and waist circumference levels compared to similar women who supplemented 30 mL of soybean oil. Liau et al found that men who supplemented 30 mL of virgin coconut oil for 4 weeks, while maintaining their “usual” dietary and physical activity regimens, had a significant 1ʺwaist circumference reduction. However, a number of other anthropometric and lipid variables did not change significantly.

Other studies have pointed to the benefits of MCT supplementation when compared to intake of other fatty acids, including greater upper body fat reduction, limited-time increased energy expenditure, and fat oxidation, and similar beneficial impact on fasting blood glucose, total cholesterol, and diastolic blood pressure. Coconut oil also is shown to potentially have antimicrobial properties.

Another benefit touted by proponents of coconut oil is its higher smoking point in cooking when compared to extra virgin olive oil. When oil begins to smoke, it indicates a degradation of the carbon bonds in the fatty acids, which can lead to rancidity and increased free radicals. While it is true that unrefined oils, including extra virgin olive oil, have lower smoke points than coconut oil, it is not always by much. Extra virgin olive oil’s smoke point is 320° F, while coconut oil’s is 350° F. However, a number of other oils, including other olive oil (not extra virgin olive oil), sesame oil, peanut oil, sunflower oil, and almond oil, have smoke points significantly greater (400+° F). Visit Cooking for Engineers to find a compilation of the smoke points of many different oils/fats. Cooking with extra virgin olive oil is maybe not  ideal, but luckily many other options are available.

Against coconut oil
The proponents against coconut oil primarily cite its high saturated-fat content (over 85% of the fat content) and its link to high cholesterol and heart disease as the reasons why coconut oil is not widely recommended. Saturated oil, in general, is shown to increase both types of cholesterol, LDL (bad) and HDL (good). Coconut oil, because of its MCTs, tends to increase HDL better than many other saturated fats, such as lard and butter. However, many unsaturated oils, such as olive oil, are shown to lower LDL cholesterol, improve the total cholesterol/HDL ratio, and potentially increase HDL, all at the same time.

Another source of criticism is pointed at the methodologies of the studies that demonstrate coconut oil’s health and weight-loss benefits. For example, many of the coconut oil studies are performed for short periods of time (4−12 weeks), sample sizes are relatively small (20−40 participants), and many of the target variables have insignificant changes. In comparison, the research backing up the benefits of unsaturated fatty acids, particularly monounsaturated and omega-3 fatty acids, is better established.

In addition, regardless of type, all fat has 9 calories/gram, which is more than double the number of calories per gram of carbohydrate or protein. Too many calories in any form can lead to reduced weight loss or increased weight gain. Many of the coconut oil studies involved supplementation of about 30 mL of coconut oil, which equals 232 calories. For those people looking to lose weight on caloric intakes of 1500−2000 calories/day, 232 calories is quite significant!

While some benefits of coconut oil may exist when replacing other types of fats, including additional coconut oil into the diet is perhaps not as beneficial. In fact, a study feeding high-fat diets (45% of total calories) to rats for 8 weeks found that consuming greater amounts of fat, regardless of whether they were MCTs or LCTs, led to weight gain and greater insulin resistance compared to more moderate-fat diets. Interestingly, the MCT oil-fed rats had less weight gain and greater fat oxidation, but had greater insulin resistance when compared to the LCT-fed rats. It appears that too much oil, in any form, is not very healthy.

Conclusions
Both sides provide compelling arguments, which is why many consumers are confused about which fat and oil options are the healthiest. Overall, it appears that coconut oil can play a role in raising HDL (the good cholesterol), increasing fat oxidation, and providing a flavorful cooking/baking option (up to 350° F). However, coconut oil is still a significant source of calories (115−120 calories/Tbsp) and does promote increased total cholesterol levels, especially compared to unsaturated fats, such as olive and peanut oil, avocados, nuts, and salmon. Coconut oil’s best role is possibly replacing trans fats, other saturated fats, and over-consumed omega-6 polyunsaturated fats (vegetable oils frequently used in commercial cooking and foods), which are found in the typical Western diet. The proverb remains true—enjoy everything in moderation.

 

References and optional reading

Assunção ML, Ferreira HS, dos Santos AF, Cabral CR Jr, Florêncio TM. Effects of dietary coconut oil on the biochemical and anthropometric profiles of women presenting abdominal obesity. Lipids [serial online]. 2009;44:593-601. Available at: http://www.springerlink.com/content/02ngg2413wm2w630/. Accessed July 20,2011.

Bhatnagar AS, Prasanth Kumar PK, Hemavathy J, Gopala Krishna AG. Fatty acid composition, oxidative stability, and radical scavenging activity of vegetable oil blends with coconut oil.  Journal of the American Oil Chemists’ Society [serial online]. 2009;86:991-999. Available at: http://www.springerlink.com/content/mk0876j862476v65/. Accessed July 20, 2011.

Chu M. Smoke points of various fats. Available at: http://www.cookingforengineers.com/article/50/Smoke-Points-of-Various-Fats. Accessed July 20, 2011.

De Vogel-van den Bosch J, van den Berg SA, Bijland S, et al. High-fat diets rich in medium- versus long-chain fatty acids induce distinct patterns of tissue specific insulin resistance. J Nutr Biochem [serial online]. 2011;22:366-371. Available at: http://www.jnutbio.com/article/S0955-2863%2810%2900077-X/abstract. Accessed July 20, 2011.

Enig MG. In the land of Oz: the latest attack on coconut oil. Available at: http://www.westonaprice.org/know-your-fats/land-of-oz-attack-on-coconut-oil. Accessed October 3, 2011.

Fife BF. Coconut oil and health. In: Adkins SW, Foale M, Samosir YM, eds. Coconut revival—new possibilities for the ‘tree of life.’ Proceedings of the International Coconut Forum; November 22–24, 2005; Cairns, Australia. ACIAR Proceedings 125. Available at: http://aciar.gov.au/files/node/748/PR125%20full%20text.pdf#page=49. Accessed July 20, 2011.

Foster R, Williamson CS, Lunn J. Culinary oils and their health effects. British Nutrition Foundation Nutrition Bulletin [serial online]. 2009;34:4-47. Available at: http://onlinelibrary.wiley.com/doi/10.1111/j.1467-3010.2008.01738.x/pdf. Accessed July 20, 2011.

Liau KM, Lee YY, Chen CK, Rasool AH. An open-label pilot study to assess the efficacy and safety of virgin coconut oil in reducing visceral adiposity. International Scholarly Research Network: Pharmacology [serial online]. 2011;2011:1-7. Available at: http://downloads.hindawi.com/isrn/pharmacology/2011/949686.pdf. Accessed July 20, 2011.

Mensink RP, Zock PL, Kester AD, Katan MB. Effects of dietary fatty acids and carbohydrates on the ratio of serum total to HDL cholesterol and on serum lipids and apolipoproteins: a meta-analysis of 60 controlled trials. Am J Clin Nutr [serial online]. 2003;77:1146-1155. Available at: http://www.ajcn.org/content/77/5/1146.short. Accessed July 20, 2011.

SelfNutritionData. Nutrition facts: coconut oil. Available at: http://nutritiondata.self.com/facts/fats-and-oils/508/2. Accessed July 20, 2011.

St-Onge MP, Bosarge A, Goree LL, Darnell B. Medium chain triglyceride oil consumption as part of a weight loss diet does not lead to an adverse metabolic profile when compared to olive oil. J Am Coll Nutr [serial online]. 2008;27:547-552. Available at: http://www.jacn.org/content/27/5/547.short. Accessed July 20, 2011.

St-Onge MP, Ross R, Parsons WD, Jones PJ. Medium-chain triglycerides increase energy expenditure and decrease adiposity in overweight men. Obes Res [serial online]. 2003;11:395-402. Available at: http://www.nature.com/oby/journal/v11/n3/abs/oby200353a.html. Accessed July 20, 2011.

University of Maryland Medical Center. Omega-6 fatty acids. Available at: http://www.umm.edu/altmed/articles/omega-6-000317.htm. Accessed July 20, 2011.

Weil A. Q & A Library: balancing omega-3 and omega-6? Available at: http://www.drweil.com/drw/u/QAA400149/balancing-omega-3-and-omega-6.html. Accessed July 20, 2011.

Willett WC. Ask the doctor: coconut oil. Harvard Health Letter [serial online]. May 2011.  Available at: http://www.health.harvard.edu/newsletters/Harvard_Health_Letter/2011/May/coconut-oil. Accessed July 20, 2011.

Zeratsky K. Coconut oil and weight loss: does it work? Can coconut oil help me lose weight? Available at: http://www.mayoclinic.com/health/coconut-oil-and-weight-loss/AN01899. Accessed July 20, 2011.

 

Contributed by Jason Machowsky, MS, RD, CSCS

Review Date 10/11
G-1705

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