A New Look at Coconut Oil, Part II

by Mary G. Enig, Ph.D.

From: A New Look at Coconut Oil Part II

IV. Coconut Oil and Cancer

Lim-Sylianco (1987) has reviewed 50 years of literature showing anticarcinogenic effects from dietary coconut oil. These animal studies show quite clearly the nonpromotional effect of feeding coconut oil.

In a study by Reddy et al (1984) straight coconut oil was more inhibitory than MCT oil to induction of colon tumors by azoxymethane. Chemically induced adenocarcinomas differed 10-fold between corn oil (32%) and coconut oil (3%) in the colon.

Both olive oil and coconut oil developed the low levels (3%) of the adenocarcinomas in the colon, but in the small intestine animals fed coconut oil did not develop any tumors while 7% of animals fed olive oil did.

Studies by Cohen et al (1986) showed that the nonpromotional effects of coconut oil were also seen in chemically induced breast cancer. In this model, the slight elevation of serum cholesterol in the animals fed coconut oil was protective as the animals fed the more polyunsaturated oil had reduced serum cholesterol and more tumors.

The authors noted that "...an overall inverse trend was observed between total serum lipids and tumor incidence for the 4 [high fat] groups."

This is an area that needs to be pursued.

V. Coconut Oil Antimicrobial Benefits

I would now like to review for you some of the rationale for the use of coconut oil as a food that will serve as the raw material to provide potentially useful levels of antimicrobial activity in the individual.

The lauric acid in coconut oil is used by the body to make the same disease-fighting fatty acid derivative monolaurin that babies make from the lauric acid they get from their mothers= milk.

The monoglyceride monolaurin is the substance that keeps infants from getting viral or bacterial or protozoal infections. Until just recently, this important benefit has been largely overlooked by the medical and nutrition community.

Recognition of the antimicrobial activity of the monoglyceride of lauric acid (monolaurin) has been reported since 1966. The seminal work can be credited to Jon Kabara. This early research was directed at the virucidal effects because of possible problems related to food preservation.

Some of the early work by Hierholzer and Kabara (1982) that showed virucidal effects of monolaurin on enveloped RNA and DNA viruses was done in conjunction with the Center for Disease Control of the US Public Health Service with selected prototypes or recognized representative strains of enveloped human viruses. The envelope of these viruses is a lipid membrane.

Kabara (1978) and others have reported that certain fatty acids (e.g., medium-chain saturates) and their derivatives (e.g., monoglycerides) can have adverse effects on various microorganisms: those microorganisms that are inactivated include bacteria, yeast, fungi, and enveloped viruses.

The medium-chain saturated fatty acids and their derivatives act by disrupting the lipid membranes of the organisms (Isaacs and Thormar 1991) (Isaacs et al 1992). In particular, enveloped viruses are inactivated in both human and bovine milk by added fatty acids (FAs) and monoglycerides (MGs) (Isaacs et al 1991) as well as by endogenous FAs and MGs (Isaacs et al 1986, 1990, 1991, 1992; Thormar et al 1987).

All three monoesters of lauric acid are shown to be active antimicrobials, i.e., alpha-, alpha'-, and beta-MG. Additionally, it is reported that the antimicrobial effects of the FAs and MGs are additive and total concentration is critical for inactivating viruses (Isaacs and Thormar 1990).

The properties that determine the anti-infective action of lipids are related to their structure; e.g., monoglycerides, free fatty acids. The monoglycerides are active, diglycerides and triglycerides are inactive. Of the saturated fatty acids, lauric acid has greater antiviral activity than either caprylic acid (C-10) or myristic acid (C-14).

The action attributed to monolaurin is that of solubilizing the lipids and phospholipids in the envelope of the virus causing the disintegration of the virus envelope. In effect, it is reported that the fatty acids and monoglycerides produce their killing/inactivating effect by lysing the (lipid bilayer) plasma membrane.

However, there is evidence from recent studies that one antimicrobial effect is related to its interference with signal transduction (Projan et al 1994).

Some of the viruses inactivated by these lipids, in addition to HIV, are the measles virus, herpes simplex virus-1 (HSV-1), vesicular stomatitis virus (VSV), visna virus, and cytomegalovirus (CMV).

Many of the pathogenic organisms reported to be inactivated by these antimicrobial lipids are those known to be responsible for opportunistic infections in HIV-positive individuals. For example, concurrent infection with cytomegalovirus is recognized as a serious complication for HIV+ individuals (Macallan et al 1993).

Thus, it would appear to be important to investigate the practical aspects and the potential benefit of an adjunct nutritional support regimen for HIV-infected individuals, which will utilize those dietary fats that are sources of known anti-viral, anti-microbial, and anti-protozoal monoglycerides and fatty acids such as monolaurin and its precursor lauric acid.

No one in the mainstream nutrition community seems to have recognized the added potential of antimicrobial lipids in the treatment of HIV-infected or AIDS patients.

These antimicrobial fatty acids and their derivatives are essentially non-toxic to man; they are produced in vivo by humans when they ingest those commonly available foods that contain adequate levels of medium-chain fatty acids such as lauric acid.

According to the published research, lauric acid is one of the best "inactivating" fatty acids, and its monoglyceride is even more effective than the fatty acid alone (Kabara 1978, Sands et al 1978, Fletcher et al 1985, Kabara 1985).

The lipid coated (envelop) viruses are dependent on host lipids for their lipid constituents. The variability of fatty acids in the foods of individuals accounts for the variability of fatty acids in the virus envelop and also explains the variability of glycoprotein expression.

Loss of lauric acid from the American diet

Increasingly, over the past 40 years, the American diet has undergone major changes. Many of these changes involve changes of fats and oils. There has been an increasing supply of the partially hydrogenated trans-containing vegetable oils and a decreasing amount of the lauric acid-containing oils.

As a result, there has been an increased consumption of trans fatty acids and linoleic acid and a decrease in the consumption of lauric acid. This type of change in diet has an effect on the fatty acids the body has available for metabolic activities.

VI. Lauric Acid In Foods

The coconut producing countries

Whole coconut as well as extracted coconut oil has been a mainstay in the food supply in many countries in parts of Asia and the Pacific Rim throughout the centuries. Recently though, there has been some replacement of coconut oil by other seed oils. This is unfortunate since the benefits gained from consuming an adequate amount of coconut oil are being lost.

Based on the per capita intake of coconut oil in 1985 as reported by Kaunitz (1992), the per capita daily intake of lauric acid can be approximated. For those major producing countries such as the Philippines, Indonesia, and Sri Lanka, and consuming countries such as Singapore, the daily intakes of lauric acid were approximately 7.3 grams (Philippines), 4.9 grams (Sri Lanka), 4.7 grams (Indonesia), and 2.8 grams (Singapore).

In India, intake of lauric acid from coconut oil in the coconut growing areas (e.g., Kerala) range from about 12 to 20 grams per day (Eraly 1995), whereas the average for the rest of the country is less than half a gram.

An average high of approximately 68 grams of lauric acid is calculated from the coconut oil intake previously reported by Prior et al (1981) for the Tokelau Islands. Other coconut producing countries may also have intakes of lauric acid in the same range.

The US experience

In the United States today, there is very little lauric acid in most of the foods. During the early part of the 20th Century and up until the late 1950s many people consumed heavy cream and high fat milk. These foods could have provided approximately 3 grams of lauric acid per day to many individuals.

In addition, desiccated coconut was a popular food in homemade cakes, pies and cookies, as well as in commercial baked goods, and 1-2 tablespoons of desiccated coconut would have supplied 1-2 grams of lauric acid. Those foods made with the coconut oil based shortenings would have provided additional amounts.

Until two years ago, some of the commercially sold popcorn, at least in movie theaters, had coconut oil as the oil. This means that for those people lucky enough to consume this type of popcorn the possible lauric acid intake was 6 grams or more in a three (3) cup order.

Some infant formulas (but not all) have been good sources of lauric acid for infants. However, in the past 3-4 years there has been reformulation with a loss of a portion of coconut oil in these formulas, and a subsequent lowering of the lauric acid levels.

Only one US manufactured enteral formula contains lauric acid (e.g., Impact7); this is normally used in hospitals for tube feeding; it is reported to be very effective in reversing severe weight loss in AIDS patients, but it is discontinued when the patients leave the hospital because it is not sufficiently palatable for oral use.

The more widely promoted enteral formulas (e.g., Ensure7, Nutren7) are not made with lauric oils, and, in fact, many are made with partially hydrogenated oils.

There are currently some candies sold in the US that are made with palm kernel oil, and a few specialty candies made with coconut oil and desiccated coconut. These can supply small amounts of lauric acid.

Cookies such as macaroons, if made with desiccated coconut, are good sources of lauric acid, supplying as much as 6 grams of lauric acid per macaroon (Red Mill). However, these cookies make up a small portion of the cookie market.

Most cookies in the United States are no longer made with coconut oil shortenings; however, there was a time when many US cookies (e.g., Pepperidge Farm) were about 25% lauric acid.

Originally, one of the largest manufacturers of cream soups used coconut oil in the formulations. Many popular cracker manufacturers also used coconut oil as a spray coating. These products supplied a small amount of lauric acid on a daily basis for some people.

How much lauric acid is needed?

It is not known exactly how much food made with lauric oils is needed in order to have a protective level of lauric acid in the diet. Infants probably consume between 0.3 and 1 gram per kilogram of body weight if they are fed human milk or an enriched infant formula that contains coconut oil.

This amount appears to have always been protective. Adults could probably benefit from the consumption of 10 to 20 grams of lauric acid per day. Growing children probably need about the same amounts as adults.

VII. Recommendations

The coconut oil industry needs to make the case for lauric acid now. It should not wait for the rapeseed industry to promote the argument for including lauric acid because of the increased demand for laurate.

In fact lauric acid may prove to be a conditionally essential saturated fatty acid, and the research to establish this fact around the world needs to be vigorously promoted.

Although private sectors need to fight for their commodity through the offices of their trade associations, the various governments of coconut producing countries need to put pressure on WHO, FAO, and UNDP to recognizes the health importance of coconut oil and the other coconut products.

Moreover, those representatives who are going to do the persuading need to believe that their message is scientifically correct -- because it is.

Among the critical foods and nutrition "buzz words" for the 21st Century is the term "functional foods." Clearly coconut oil fits the designation of a very important functional food.

About the Author: Mary G. Enig, PhD is the author of Know Your Fats: The Complete Primer for Understanding the Nutrition of Fats, Oils, and Cholesterol, Bethesda Press, May 2000. Order your copy here: www.enig.com/trans.html.