There are certainly a lot of wacky nutrition claims made on various websites. Some of the wackiest claims I have seen may be on one of the most popular nutrition websites run by Joseph Mercola, D.O. Dr. Mercola is opposed to immunizations and fluoridation of water. He also sells and touts numerous food supplements using false and unsubstantiated claims about their efficacy. He also sells some food products. One of the most bizarre claims Dr. Mercola makes on his website at mercola.com is that coconut oil?s benefits include: ?Promoting heart health?.1 He makes this claim despite noting, ??coconut oil contains the most saturated fat of all edible oils.? However, he goes on to claim ??the truth is this: it is unsaturated fats that are primarily involved in heart disease, not the saturated fats, as you have been led to believe.? Of course, this ?truth? conflicts with the vast majority of scientific data, which unequivocally has demonstrated that a diet high in saturated fat raises LDL-C levels, promotes atherosclerosis, and coronary artery disease.2
A recent study compared the impact of feeding a milkshake and carrot cake made with either coconut oil or safflower oil on two separate occasions. The researchers of this study conclude: "Consumption of a saturated fat reduces the anti-inflammatory potential of HDL and impairs endothelial function. In contrast, the anti-inflammatory activity of HDL improves after the consumption of the polyunsaturated fat."3 Simply put even a single saturated fat rich meal with all the saturated fat coming from coconut oil impairs the ability of HDL to protect the artery wall from damage. This led to a reduced flow of blood through the arteries. And while Dr. Mercola claims polyunsaturated fats like safflower oil are actually what damage arteries this study found safflower oil was modestly protective.
Dr. Mercola?s evidence that coconut oil is heart healthy is pretty weak. He sites a study done on two Polynesian islands many years ago. On these two islands a diet high in coconut oil was the norm. On Tokelau Island where the consumption of fat from coconuts was the highest the average total cholesterol levels were well above 200mg/dl. Women age 55-64y had an average total cholesterol level of 245.4mg/dl even though their intake of cholesterol was much lower than that of Americans ? averaging about 129mg per day.4 The authors of this study did state that vascular disease was uncommon on these islands despite their high total cholesterol levels. They used a simple stress test to assess cardiovascular health which we now know is not very accurate. Plus, the relatively low cholesterol and salt content of their diet, coupled with more fiber, plant sterols, and omega-3 fatty acids (from fish) and little tobacco use compared to a modern diet and lifestyle may well mitigate the adverse effects of their high saturated fat intake.
Dr. Mercola also claims coconut oil will ??help stimulate your metabolism? and ??is the dieter?s best friend?. Perhaps Dr. Mercola might want to take a closer look at the data on middle-aged (35-54y) women on Tokelau Island who were consuming the majority of their calories from coconut oil back in the 1970s. It showed their average BMI was over 30. That?s a heck of a lot fatter than middle-aged American were then or even now.
Bottom Line: In 2005 and again in 2006 Dr. Mercola received warning letters from the FDA objecting to the numerous unsubstantiated claims on his website.5 Anyone who switches from unsaturated oils to coconut oil in hopes of improving their blood lipids and preventing heart disease will surely be disappointed.
By James J. Kenney, PhD, RD, FACN
2. Diet and CVD CPE course by J.Kenney at foodandhealth.com
3. J Am Coll Cardiol 2006;48:715-20
4. Am J Clin Nutr 1981;34:1552-61
For more information on diet and cardiovascular disease, visit online at www.foodandhealth.com. Click on CPE courses under Media.
Stephanie Ronco has been editing for Food and Health Communications since 2011. She graduated from Colorado College magna cum laude with distinction in Comparative Literature. She was elected a member of Phi Beta Kappa in 2008.