There are no legal or scientific definitions of tropical oils. From my own research I found that tropical oil was a term created by the American Soybean Association (ASA) as part of a public relations campaign against the producers of palm oil.  The term is now in common use and refers to palm, palm kernel, and coconut oils.

 I searched the guidelines put forth by the United States Department of Agriculture (USDA), the American Heart Association, the American Dietetic Association and the American Diabetes Association.  The tropical oils, if listed, are found on tables of those fats to avoid.  This is based on the fact that they are all highly saturated fats and saturated fats are associated with health concerns, not least of which is heart disease. The content of these guidelines trickles down to most other websites and blogs that talk about diet and nutrition, and so the tropical fats have come to have a very bad reputation.  My western mindset understands the scientific facts as they are known today but my eastern sensibility cannot fully accept that tropical oils are unhealthy and should not be in my diet.  The tropical oils have been used for thousands of years in traditional cooking and are still very much a part of many traditional societies that not only use the oils for cooking but also as a national economic resource. 

 Let’s look at the quality of tropical oils from three vantage points: 

1. Their content of saturated fat along with how much polyunsaturated and monounsaturated fat is in each oil
2. Their fatty acid profile
3. Any other benefits they may have

Saturated, Monounsaturated and Polyunsaturated Fats in Tropical Oils

The main concern then for the tropical oils, when considered from a nutritional perspective, has to do with the amount of saturated fat that they contain.  Diets high in saturated fat have been linked to chronic disease, specifically, coronary heart disease

Here in this chart we can see that, indeed the tropical oils are highly saturated.  Palm oil though, does contain quite a bit of unsaturated fat along with the saturated fat.  Also, note how similar the palm kernel oil and coconut oil are to each other.  So yes, if we base our total argument on how much saturated fat there is, then the tropical oils are not very healthy.  But I believe there is more to this story then what appears on the surface and that brings me to the second of our vantage points listed above: what is the fatty acid profile for each of these oils.

Ambiguity about Fats versus Fatty Acids

If ever there was a glaring error in the talk on fats, the confusion over fats versus fatty acids is a mistake. Historically, the terms “saturated fats” and “saturated fatty acids” have been used interchangeably and that practice continues today.   But palm oil, coconut oil, and palm kernel oil (as do all fats and oils) do not contain just a group of saturated fats; rather they represent saturated fats rich in certain saturated fatty acids.  Let’s then dig down another level in our composition of these oils and recreate our chart above.

The Fatty Acids in Tropical Oils

The palm kernel oil (blue bar) and coconut oil (green bar) are both rich in Lauric and Myristic fatty acids.  Note the “0” in 12:0 and 14:0.  The 12 and 14 numbers represent the number of carbons and the 0 indicates that these fatty acids are saturated.

 Palm oil (red bar) is rich in Palmitic oil and oleic oils.  These fatty acids have more carbons; oleic is unsaturated with 18:1.  The fact that the tropical oils contain these fatty acids begs the question – do these specific fatty acids make any difference to our assessment about the quality of the tropical oils?

• Myristic and to a lesser extent Lauric acid raise total cholesterol levels but they also are reported to raise HDL as well (HDL is the good cholesterol).  The literature however, is not consistent on how much they raise cholesterol levels.
• Lauric fatty acid has also been recognized for its antiviral and antibacterial functions; and is reported to be effective against the formation of dental caries and plaque.
• Palmitic fatty acid does not increase cholesterol levels as much as Lauric and Myristic; some studies indicate that it does not raise levels at all.
• Palmitic acid is used in commercial baking because Palmitic acid leads to desirable characteristics in food.
• Saturated fatty acids provide oxidative stability (i.e. retards spoilage) to Tropical oils.

 Beyond the Fats and Fatty Acids

The tropical oils are not just about saturated fats.  They also contain other healthy nutrients that we should consider before we judge these oils too harshly.  The table here shows some of those nutrients.

• Palm oil and Palm Kernel oil both contain vitamin E compounds that are potent antioxidants. Antioxidants are agents that help retard spoilage and degradation of fats.  This is especially important in situations where oil is reused for frying, as in commercial operations and in poor areas of the world.
• Crude palm oil is one of the richest known sources of carotenoids (precursor of vitamin A). The carotenoids are destroyed during conventional refining but a refined palm oil is available which retains in excess of 80 percent of the carotenoids.
• Phytosterols (also called plant sterols) are a group of chemicals that naturally occur in plants.  Phytosterols help lower cholesterol by reducing the amount of   cholesterol that is absorbed from the intestines into the blood.

East Meets West

In the latest Yoga⁺ Journal (Summer 2010) there is a provocative article by Dr Timothy McCall that addresses the benefits and differences between a holistic approach (eastern) to health and a reductionist approach (western).  The reductionist model narrows investigations down to one or two elements to study while the holistic model recognizes that all aspects of an individual are interconnected and that working on one aspect improves the function of all.  Dr McCall was talking about holistic versus conventional medicine but this concept also relates to my discussion of tropical fats. By targeting just their content of saturated fat the tropical oils are advertised as being unhealthy.   But a more total picture emerges by inspecting these oils from more of a holistic approach. Then these oils exhibit positive nutritional aspects as well as advantageous functional and economic features for many African and Asian countries.

 I often hear the frustration of many individuals who view nutrition information as a moving target; what the nutrition experts expound as true one day is overturned the next. As western science targets one or two ideas to research we learn about pieces of the whole, much like having lots of pieces of a jigsaw puzzle that we move around trying to fit together to make a whole picture.  Learning how each and every element operates in humans is even more confounded by the fact that human beings are complicated organisms and how we behave, think, function in society, must all be taken into consideration. This exposing of the whole picture via one or two elements at a time is a very long and tedious process. One fact learned may be overturned when the next fact is studied and more is uncovered.

 Saturated fats are reported to be unhealthy based on research that we have conducted to this point in time.  That makes the tropical oils look bad. Take a holistic approach and there is a different picture that emerges.   Some of the fats in the tropical oils have been shown to raise cholesterol; others do not, and some are even neutral (Palmitic).  In addition, there are other nutrients such as vitamin E, A, K that are components of these tropical oils.  There is no pure Yin or pure Yang.  The truth is somewhere between the two.

So consider

Both Lauric acid and Myristic acid are present naturally in human and cow’s milk.  If saturated fatty acids were of no value or were harmful to humans, evolution would probably not have established within the mammary gland the means to produce them as source of nourishment for offspring.

 The mortality rate from CHD is very low in the traditional Mediterranean populations that use olive oil (a major source of oleic acid) as the primary source of fat.  Palm oil also contains a significant amount of oleic acid.  See the chart above.

 Tropical Oils may be a good substitute for Trans fats.  In 2006, the Food and Drug Administration (U.S.) called for mandatory labeling of Trans fatty acids. Now the food industry is scrambling to find alternatives.  Various options are being considered, including the use of naturally occurring saturated fats and oils to provide a more natural source of saturated fatty acids that are needed for products requiring a certain amount of solid fat content. Palm oil is most suitable here as it is 50 percent saturated.

 The impact of tropical oils on nutrition in the developing countries is not to be taken lightly. In some areas of the world (Africa and Asia), there are specific nutritional problems such as low levels of vitamin A.  From a nutritional perspective, it is noteworthy and of public health significance that crude palm oil serves as inexpensive cooking oil in areas of the world where vitamin A deficiency is endemic.  Several reports have shown that red palm oil can be used as an effective medium for delivering Vitamin A without the need for resorting to synthetic Vitamin A.

 Many studies done on Myristic, Lauric and Palmitic fatty acids utilized dairy products and then extrapolated those results to the tropical oils that are all plant derived.  Fatty acids found in plants such as palm or coconut may not act the same as those found in dairy products.

 The impact of tropical oils on diets in the U.S. is minimal. Palm oil exports to the United States constitute only 3% of the world market for palm oil, and a substantial portion of that goes to uses other than food. 

Adverse publicity has caused many countries to question the safety of palm oil, which is the number-one oil of international trade and is second in production in the world. 

 Compelling evidence now indicates that there is greater importance as to the types of fat rather than the total amount of fat with respect to risk of CHD.  However, the optimal mixture of different fatty acids remains unsettled.  In the meantime, we can combine soybean oil, palm oil, and canola oil or palm oil, olive oil and safflower oil to give equal balances of the saturated, polyunsaturated and monounsaturated fats. 

Finally

A healthy diet lifestyle plan should be adequate, balanced, moderate, and contain a variety of foods. 

• Adequate in that it contains enough of the nutrients that we need.
• Balanced in that there is not too much or too little of any one nutrient including caloric balance meaning that we do not include too many high calorie foods that leads to obesity, or the opposite – not having enough calories
• Moderate in that we do not overeat or under-eat.
• Variety in that including many types of foods in our diet plan will ensure that we are getting everything that we need.

 This is a tall order and personal flexibility and readiness to learn with an open mind is required.  But following these guidelines is a holistic approach to eating healthy and includes modifying our eating plans as we learn more about the science behind it all.

So now you decide if the tropical oils deserve their bad reputation.

Next time we will complete our trilogy on fats by looking at what fats and oils are best for cooking purposes.