One of the universal truths we were taught years ago was that saturated fats are unhealthy and should be avoided/minimized. The first crack in my blind acceptance of this belief was due to a flippant remark by one of my nutrition profs, who specialized in lipid research. He commented that not all saturated fats react the same way in the body and the simplification of the message by certain fellow academics were not beneficial for the profession or the public. Ah the nature of academia.
Nutrition is a notoriously difficult science to research. It isn't like pharmaceutical drugs where you can compare one pill to another. Nutrients interact, work together, and compete with each other in a myriad of different ways. Often findings indicate the reduction of a certain nutrient (such as saturated fat from animal products) is beneficial if it is replaced by a more beneficial one (such as omega-3 fatty acids), but the benefit is lost when the replacement is in the form of an equally or more detrimental nutrient (such as sugar or trans fats). Unfortunately in the simplification of our messaging these nuances may be lost and all we hear is fat is bad and as the expression goes we throw the baby out with the bathwater. Based on our obesity/diabetes epidemic, the low fat, high carbohydrate message from the 1980s/1990s has proven to be ineffective and possibly even harmful. The replacement of saturated fats in our diet with refined carbohydrates (high glycemic index) is actually more detrimental for cardiovascular health. http://www.ajcn.org/content/93/4/684.full
Saturated fat came onto our radar with the 1953 Seven Countries epidemiological study by Ancel Keys that linked a high saturated fat intake with high coronary heart disease. As I mentioned in my post about fish, these types of studies only give us clues (correlations) and not definitive causes. It could be that those countries exercised less, or ate more processed meats etc.
With the popularity of the paleo diet exploding and people beginning to question the black and white stance regarding saturated fat, cholesterol and total fat. I thought I would look at one dietary fat source that appears to be gaining a popular following. Coconut oil.
Virgin coconut oil is high in saturated fat. Just as with polyunsaturated fats (omega-6 and omega-3) there are different saturated fatty acids and they don't all work the same way in our body. The main saturated fatty acid in non-hydrogenated coconut oil is lauric acid, the same we find in breast milk. It is a smaller saturated fatty acid (less carbons) than those found in meat. Shorter fatty acids make up something called medium-chained triglycerides (MCTs). Coconut oil is comprised of over 50% MCTs.
MCTs are digested, absorbed and utilized in a different manner than longer chain fatty acids. They are more readily used as energy rather than fat storage. They also are believed to contribute to a feeling of fullness, although the research at this point is not strong.
Coconut oil does increase cholesterol the most of all oils, but it does so by increasing HDL (high density lipoprotein), the so-called good cholesterol. When looking at the relationship between blood cholesterol and heart disease it is the ratio of the good cholesterol HDL to the less desirable cholesterol LDL or total cholesterol that is important. Therefore an increase in HDL (and resulting change in the ratio) can be viewed as positive.
A small study in women with abdominal obesity found after 12 weeks of supplementation of 2 Tbsp coconut oil vs 2 Tbsp soy oil that there was an increase in HDL (better LDL/HDL ratio) in the coconut group. The study also asked the participants to walk 50 minutes per day and there was weight loss in both groups but only the coconut oil group had a decrease in waist circumference (measure of abdominal fat). This is a small study but if it is replicable it could have important implications as the fat we store in our abdomen is the nasty fat that sends out many inflammatory hormones and messengers that wreck havoc on our bodies.
This obviously is not a doctoral thesis...just a blog. What I have read so far has whet my appetite to dig into the research a little more. How well designed were the studies etc. In the meantime adding a little virgin coconut oil in my baking or on a batch of popcorn in moderation doesn't seem like a bad idea. I won't be using it on my stove top cooking though as it has a relatively low smoke point (similar to extra virgin olive oil).
The refined version (labeled coconut oil rather than virgin coconut oil) has a much higher smoke point. I haven't been able to find the fatty acid breakdown of this one yet - so I will stick with the virgin coconut oil until I am able to read more.
As for the paleo diet. I plan to read more about it in the future, at the moment I won't start eating red meat three times a day, even if it is pasture-fed (better lipid profile). Even if the saturated fatty acids found in animal products earn a reprieve, for me the evidence that a plant-based low-glycemic index diet is a healthy choice continues to dominate.
How about you? What do you think about coconut oil?