Coconut Oil — Learn More About This Superfood That Contains Healthful Saturated Fats
By Aglaée Jacob, MS, RD, CDE, Today’s Dietitian, Vol. 15 No. 10 P. 56
Coconut oil’s popularity appears to be a new trend, but the truth is coconut oil has been a staple in tropical regions of the world for thousands of years. Read on to learn about the history of the coconut, the traditional uses of coconut oil, its biochemical properties, and how it can aid in weight loss and play a positive role in preventing cardiovascular and neurological diseases.
History
Ayurvedic medicine texts written in Sanskrit about 4,000 years ago report the health benefits of coconut oil. Filipino people call the coconut palm tree (cocos nucifera L)—which grows mostly in Indonesia, the Philippines, India, and other Southeast Asian countries—the “tree of life” because of its highly valued and respected source of plant-based fats that have been used both as an energy-dense food and as folk medicine. Each mature and productive tree between the ages of 6 and 10 years, and until it reaches between the ages of 80 and 120, can yield 12 to 16 bunches of coconuts yearly, each holding eight to 10 coconuts.1 Despite its name, the coconut isn’t a nut but rather a drupe like olives, mangoes, and dates.
During World War II, coconut water was administered to soldiers intravenously to provide sterile hydration. Individuals pierced a young coconut with an IV tube and placed it directly into the soldier’s vein. It’s still used this way today in remote areas of the world. The unique composition of coconut water—the liquid found inside young coconuts—contains electrolytes, natural sugars, and essential amino acids, giving it a composition similar to that of intracellular and extracellular fluids.
In the last century, coconut oil became one of the preferred sources of plant fats for food manufacturers in North America because of its taste, texture, and stability. In the 1940s, vegetable oils and seed oils from corn, soybeans, and cottonseeds started replacing coconut oil because of the diet-heart hypothesis of Ancel Keys, PhD, which stated that saturated fat contributes to the development of heart diseases.3 This hypothesis, along with the nutritional guidelines encouraging Americans to adopt low-fat diets, unfortunately made coconut oil disappear from our plates for many decades.
Traditional Medical Uses
Even though most Americans weren’t consuming coconut oil during the second half of the 20th century, some of the unique properties of coconut oil were too good for the health care community to ignore. “As RDs, we’re familiar with the use of MCT [medium-chain triglyceride] oil for critically ill patients,” says Lily Nichols, RD, CLT, owner of a private nutrition business in Los Angeles. “Turns out, coconut oil is a great natural source of MCTs, making it a perfect choice for patients with compromised fat digestion [eg, gallbladder issues] or sensitive GI [gastrointestinal] tracts,” she says.
MCT oil is extracted from coconut oil. Traditionally, it has been used to treat various GI disorders associated with malabsorption syndrome because of its ability to bypass the normal fat digestion and absorption route.4 The biochemical properties of this MCT oil also have been used to promote ketosis in patients following a ketogenic diet to help treat refractory epilepsy.
Biochemical Properties
Like other oils, coconut oil is 100% fat. But the type of fat it contains makes it unique. Dietitians are aware of coconut oil’s high saturated fat content; it represents more than 85% of its fatty acids. One of the oil’s most interesting characteristics is that 65% of its fats are present in the form of medium-chain fatty acids (MCFAs), as opposed to long-chain fatty acids (LCFAs) commonly found in other food sources of fats. MCFAs have only eight to 14 carbons in length. Unlike other fats, MCFAs don’t need to break down into single fatty acids for the body to absorb them. Rather, MCTs make their way directly to the liver through the portal vein and can bypass the carnitine transport system for mitochondrial entry.
About 49% of the MCFAs in coconut oil is lauric acid (12:0) while the rest of the fats include 8% caprylic acid (8:0), 7% capric acid (10:0), 2% stearic acid (18:0), 6% oleic acid (18:1), and 2% linoleic acid (18:2).2 Coconut oil’s fatty acid profile makes it highly stable, protecting it from oxidative and heat damage. “Being mostly saturated, it’s an optimal fat for cooking, since the fats aren’t easily damaged by heat,” Nichols says. “I recommend it frequently to my clients, and the flavor is incredible.”
Lauric acid is recognized for its antimicrobial properties. When lauric acid infiltrates the membranes of lipid-coated bacteria or other microbes such as fungi, protozoa, and even viruses—which it can do because of high MCT blood levels—it destabilizes their membranes, causing them to disintegrate, and kills the microbes as a result. However, this process can occur only in the presence of sufficient blood concentrations of lauric acid.
Weight Loss
Although it may seem counterintuitive that fat intake can produce fat loss, coconut oil can be part of a balanced weight-loss plan. The first explanation supporting the use of coconut oil for weight loss is that it contains 2.6% fewer calories per gram than other fats.6 This difference of about 100 kcal per pound of fat may appear small but can become significant over time.
In a study published in the March 2008 issue of the American Journal of Clinical Nutrition, researchers had a group of 49 overweight men and women adopt a calorie-restricted diet (1,500 kcal for women and 1,800 kcal for men), including a daily dose of either MCT oil or olive oil (18 g for women or 24 g for men), representing 12% of their energy intake for 16 weeks. Both groups lost weight but the weight loss was more significant in the MCT group. The group that consumed MCT oil lost 7 lbs, while the olive oil group lost only 3 lbs. These results are in line with other studies showing a reduction in weight and body fat in overweight participants who consumed MCT oil as part of their diet.
The unique structure of the MCT fats in coconut oil make them easier to burn and harder to store in adipose tissues compared with the LCFAs found in most other fats, including olive oil. Increased postprandial thermogenesis and energy expenditure have been observed in both lean and obese subjects following the ingestion of as little as 5 to 10 g to as much as 30 g of MCT oil within a meal compared with the same amount of LCFAs.
Some of these studies hid the coconut or MCT oil in foods to keep the study double-blinded, but it’s possible that simply substituting the more common cooking fats and oils clients typically use, such as vegetable oils and margarines, may be even more effective to facilitate weight loss. Many participants involved in some of the weight-loss studies using coconut or MCT oil also have reported higher satiety and more stable energy levels, which can facilitate weight loss.
Cardiovascular Disease
Despite the research, however, most dietitians don’t feel comfortable recommending that clients consume coconut oil because of its high saturated fat content. But it’s important to remember that dietary saturated fats aren’t associated with heart diseases and stroke, according to a meta-analysis published in the January 2010 issue of the American Journal of Clinical Nutrition. (The researchers examined data from almost 350,000 people who were followed up to 23 years. The study showed there was no relationship between saturated fat intake and the risk of cardiovascular diseases and stroke.)
In addition, the types of saturated fats found in coconut oil have a different structure, making it impossible to draw conclusions by directly comparing them with LCFAs.
To further support the safety of coconut oil, researchers in a randomized clinical trial gave 40 middle-aged Brazilian women with abdominal obesity 2 T of soybean or coconut oil daily for 12 weeks. At the end of the study, both groups lost weight, but only the coconut oil group saw a significant decrease in waist circumference. In the soybean oil group, levels of total and LDL cholesterol significantly increased, while HDL levels decreased, worsening their cardiovascular risk profile.
The blood lipid profile of the women in the coconut oil group didn’t change significantly, although they tended to have higher HDL cholesterol levels, indicating improved cardiovascular health.7 These results may be explained by the fact that MCTs aren’t incorporated into chylomicrons and are more inclined to be used quickly for energy.
Other studies have reported a decrease in inflammatory cytokines, such as tumor necrosis factor alpha and interleukin-6 (IL-6), and increased production of the anti-inflammatory IL-1 with consumption of coconut oil and MCT oil.5 Moreover, some researchers have observed improved insulin sensitivity in patients diagnosed with type 2 diabetes who consumed coconut oil. In one study, participants followed a diet for five days deriving 40% of calories from fat, 77.5% of which came from either MCTs or LCFAs. The results showed that healthy subjects and those with type 2 diabetes increased their insulin sensitivity by 17% and 30%, respectively, as measured by the euglycemic clamp technique.
Neurological Conditions
Research shows that MCT oil also can improve glucose metabolism in the brain in Alzheimer’s disease, which is sometimes referred to as type 3 diabetes because it’s associated with a decline in glucose metabolism in the brain. This is why dietary strategies that promote ketosis can help the brain obtain an alternative source of energy. While glucose tends to be the brain’s primary energy source on a standard high-carb American diet, ketone bodies can supply more than one-half of the brain’s energy needs when carbohydrates and glucose become scarce.
Some Alzheimer’s disease studies show that ketone bodies enhance mitochondrial efficiency and make the brain less reliant on glucose.8 Besides epilepsy, similarly promising neuroprotective properties of ketone bodies have been observed in malignant brain cancer and Parkinson’s disease.9,10
Dietitians can help clients achieve higher levels of ketone bodies by suggesting they adopt a higher-fat and lower-carbohydrate diet if their condition warrants it. Moreover, the use of coconut oil or MCT oil can help boost the ketogenic potential of any dietary intervention, considering that MCFAs produce more ketone bodies gram for gram than fats rich in long-chain triglycerides.
Dietitian’s Perspective
Considering the evidence that refutes the association between excess saturated fat intake and cardiovascular disease, in addition to the unique structure of the saturated fats found in coconut oil and the many studies supporting its safety in human health, dietitians should feel confident suggesting clients incorporate coconut oil into their diets, either as a substitute for other fats or as a supplemental source of healthful fats to encourage energy balance.
Some dietitians consider coconut oil both food and medicine. “As RDs, we often support the health benefits [of coconut oil] without really even knowing it,” says Mary Trenda, MS, RD, LDN, a nutrition coach and long-term care specialist at National Healthcare Corporation Johnson City in eastern Tennessee. “We know that MCT oils are extremely beneficial in our tube-feeding patients, as these oils are absorbed directly into the portal system without the use of bile. This means it would be just as easy to absorb for our average Joe as well.
“I like to think of coconut oil as an instant energy boost because it produces energy, not fat,” she adds. “It has been shown to increase metabolism, protect against diseases, increase immunity, and aid in killing bacteria and viruses. Coconut oil is a superfood, and RDs need to be recommending it to patients.”
Other RDs agree that since MCFAs can be absorbed directly into the bloodstream and preferentially burned as fat, they serve as a good energy source. Ryah Nabielski, MS, RDN, owner of Eco Nutrition, specializing in women’s health in Littleton, Colorado, recommends clients consume one spoonful of coconut oil or coconut butter whenever blood sugar levels drop between meals or when a sugar craving develops.
Based on the research, coconut oil should be considered a functional food. Not only does it provide a safe source of stable and easy-to-utilize fats, but it also can precipitate weight loss and improve cardiovascular health and certain neurological conditions. The easy digestibility of coconut oil makes it well suited to help treat various digestive disorders, such as irritable bowel syndrome, gastroesophageal reflux disease, heartburn, and cholecystectomy, so it has its place as part of a healthful diet.
