Until recently, coconut oil was on the list of “bad” foods because it is made up of highly saturated fat, which can raise cholesterol levels and increase the risk of heart disease.¹

Then came the paleo and ketogenic diet trends, both of which advocate greatly limiting the amount of carbohydrates consumed and, in the case of the ketogenic diet, adding more fats like coconut oil to the diet.

The ketogenic diet reduces carbs to less than 10% of the used energy.² This restriction causes the body to go into ketosis, shifting from glucose metabolism to fat metabolism.³ A person on the ketogenic diet gets about 90% of their calories from fat, 6% from protein, and 4% from carbs.²

Nutritional profile of coconut oil

Different dietary fats have different effects on lipid profiles, metabolic markers, and health outcomes depending on whether their main component fatty acids are saturated or unsaturated. They can also vary depending on dietary patterns, processing methods, or the profile of individual fatty acids, as well as the contents of the foods in which they are consumed.⁴

There are two main types of oil extracted from mature coconut kernels: copra oil and virgin coconut oil. Both have similar fatty acid profiles, but virgin coconut oil contains higher amounts of polyphenols and nutrients like vitamin E.⁵

While coconut oil is high in fat, a lot of this fat is made up of medium-chain fatty acids (MCFAs). Because MCFAs are not stored in fat tissue, unlike long-chain fatty acids (LCFAs), some believe coconut oil is an ideal food source for weight reduction. Virgin coconut oil, in particular, is rich in MCFAs, with 70% to 85% being comprised of these easily oxidized lipids.⁶

Coconut oil and weight loss

It is thought that consuming medium-chain triglycerides (MCTs), which break down into MCFAs in the gut, could result in weight loss by helping the body to burn energy more efficiently.⁷ Coconut oil and palm kernel oil are some of the better-known sources of MCTs.^8,9

There have been a number of small studies done on the effect of MCTs on weight loss. In a study of 20 healthy obese Malay volunteers, those who consumed virgin coconut oil experienced a mean reduction of 2.86 centimeters (1.13 inches) in their waistlines without any negative effect on blood lipid levels.⁶

A review of thirteen trials showed the consumption of food containing mostly MCTs lowered body weight and reduced total body fat and waist and hip circumference when compared with long-chain triglycerides. None of these trials showed an adverse change in blood lipid levels.⁷

Coconut oil and the heart

High levels of saturated fat in the diet are linked with higher blood concentrations of LDL-C, a “bad” cholesterol that raises the risk for coronary heart disease. However, in the case of coconut oil, it’s believed that it might have different metabolic effects than other saturated fats.⁴

In a study of 116 patients with coronary artery disease, those who took extra virgin coconut oil as part of their diet not only experienced a reduction in body weight and waist circumference but showed higher levels of HDL-C, the “good” cholesterol.⁸

In another study comparing four weeks consumption of extra virgin coconut oil, butter, and extra virgin olive oil, LDL-C levels were significantly higher in people consuming butter compared with coconut oil and olive oil. By contrast, people consuming coconut oil saw a marked increase in HDL-C compared with butter and olive oil.⁴

There is some evidence that applying coconut oil to the skin is useful for the prevention and treatment of atopic dermatitis. There is also evidence that using coconut oil orally in an “oil pulling” regimen prevents tooth decay.⁵ Oil pulling involves swishing a tablespoon of oil around in the mouth for about 20 minutes before spitting it out.¹⁰

What coconut oil can’t do

Coconut oil products have become increasingly popular because of the perceived health benefits of MCFAs. However, the primary fatty acid found in coconut oil is lauric acid, which has shown an ability to behave as both a MCFA and a LCFA in terms of metabolism.⁵

Because coconut oil includes a wide range of fatty acids, some believe research on pure MCFAs cannot be directly applied to coconut oil products. For instance, when it comes to total and LDL cholesterol, copra oil seems to have less of an impact as compared to butterfat, but a slightly worse impact than other unsaturated vegetable oils. Also, limited studies have shown that coconut oil use cannot be supported for the prevention or treatment of Alzheimer’s disease, bone loss, or glycemic control.⁵

The consensus of many researchers is that while coconut oil has shown some effectiveness in promoting weight loss and increasing HDL-C levels, more investigation is needed. And since many MCFA studies involved the use of purified products not available to consumers, more human clinical and observational studies are needed to confirm the truth of many coconut oil health claims.⁵

References

1. Ghana Med J. 2016 Sep;50(3):189–196.
2. Nutrients. 2019 Oct;11(10):2510.
3. Curr Nutr Rep. 2018 Sep;7(3):97–106.
4. BMJ Open. 2018;8(3):e020167.
5. J Am Coll Nutr. 2019 Feb;38(2):97-107.
6. ISRN Pharmacol. 2011; 2011: 949686.
7. J Acad Nutr Diet. 2015 Feb;115(2):249-63.
8. Nutr Hosp. 2015 Nov 1;32(5):2144-52.
9. Biomolecules. 2019 Feb;9(2):64.
10. J Tradit Complement Med. 2017 Jan;7(1):106–109.