Does coconut oil harm endothelial cells?

– James B.


What a curious question!

The endothelial cells lining your blood vessels work to relax and contract the diameter in response to stimuli. They produce nitric oxide, a vasodilator. Stiff or narrow arteries are risk factors for cardiovascular events because they don’t allow the blood to flow through adequately. When the endothelium isn’t working properly, it’s called dysfunction. This can lead to the development of atherosclerosis (plaque deposition).

Coconut oil is 100% cholesterol-free (as are all plant oils), but contains mostly saturated fatty acids. These differ chemically from, and are not as harmful to the vascular system as, animal saturated fats.

In searching the US National Library of Medicine’s database of published research for “coconut” and “endothelial” in human subjects, the search results showed only 3 related articles. One suggested that saturated fats did not affect endothelial function as compared with trans fats1. Another showed no difference between coconut oil and sunflower oil (high in polyunsaturated fatty acids) in cardiovascular risk2. The third showed similar impairment in endothelium-dependent artery dilation from both coconut milk and a Western high-fat meal3.

Leaving no stone unturned, I looked for other studies not in this database. One that compared coconut oil to safflower oil (high in polyunsaturated fatty acids) in a single high fat meal found a “non-significant trend toward impairment of endothelium-dependent vascular reactivity in conduit arteries… after the saturated fat meal.4

All together, the body of research shows that there is not enough evidence to say there is a definitive correlation between consumption of coconut oil and epithelium health. So James, I would say to keep your fat intake at a low to moderate level and from primarily plant sources of unsaturated fat.

– Debbie J., MS, RD



  1. High trans but not saturated fat beverage causes an acute reduction in postprandial vascular endothelial function but not arterial stiffness in humans. Lane-Cordova AD, et al.  Vascular Medicine 2016 Oct; 21(5): 429-436.
  2. A randomized study of coconut oil versus sunflower oil on cardiovascular risk factors in patients with stable coronary heart disease. Vijayakumar M, et al. Indian Heart Journal. 2016 Jul-Aug; 68(4): 498-506.
  3. Impairment of endothelial function–a possible mechanism for atherosclerosis of a high-fat meal intake. Ng CK, Chan AP, Cheng A.  Annals of the Academy of Medicine, Singapore. 2001 Sep; 30(5): 499-502.
  4. Consumption of Saturated Fat Impairs the Anti-Inflammatory Properties of High-Density Lipoproteins and Endothelial Function. Stephen JN, et al.

Journal of the American College of Cardiology

Volume 48, Issue 4, August 2006

This article should not replace any exercise program or restrictions, any dietary supplements or restrictions, or any other medical recommendations from your primary care physician. Before starting any exercise program or diet, make sure it is approved by your doctor.

Some questions have been edited for length and/or clarity.

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