Coconut oil: some quick facts

I was watching a cooking segment of Better Homes and Gardens on TV on Friday night, which happened to feature Scott and Luke, a pair of contestants from the current season of Channel 7's My Kitchen Rules. Before I stopped following the show, due to the very obvious new direction that the producers decided to take (dramatisation, rudeness, nasty comments, and bickering between contestants, which sparked a lot of personal attacks and then racial slurs from viewers on the show's social networking sites), i.e. shifting the focus from the food to villain-ising contestants in an attempt to increase ratings, this pair of personal trainers from Bondi was one I was keen to see cook, because they had established themselves as the contestants who cook tasty, healthy food and had said at the outset that they wanted to promote healthy eating to the Australian audience. So imagine my shock when Scott added a generous tablespoonful of solidified coconut oil to the pan to cook his barramundi in, and explained to the show's host, "it's our preferred oil of choice. It's a saturated fat, but it's actually a good fat." I personally think it's a bit irresponsible to start saying something and then not fully explain it, especially when it could be misleading, and viewers are likely to just follow your suggestions blindly, because they are led to believe that you're a healthy-eating guru.

I felt compelled to write a quick post on the matter to clarify this, in case some viewers just take his word for it without doing some research, and proceed to completely substitute their cooking oils at home with coconut oil.

Image taken from Melrosehealth.com.au

I will admit straight off that I am a coconut lover and a big fan of all coconut products - young coconut meat, coconut milk, shredded coconut, desiccated coconut, McKenzie's Moist Coconut Flakes (I was so excited when I first saw this on the supermarket shelves!), coconut water.... you get the gist. And this was even back in the day when we all thought that products made from coconut flesh were all full of the same bad saturated fats as those found in lard. Hence, I, of all people, especially look forward to the day when research shows us that it is actually very good for our health to go a step further and incorporate coconut oil into our family's daily diet. Unfortunately, for the time being, we are still playing the waiting game.

Let's start off with some of the established benefits of using coconut oil, from a culinary perspective:

1. Tastes good;

2. High smoking point, so can be used for cooking things over high heat;

3. Quite stable and less likely than other plant oils to go rancid, since it is mainly comprised of saturated fatty acids. The shelf life is therefore generally longer; about 2 years. 

4. Is solid at room temperature, so it can be used to replace butter and lard in recipes that call for solid fats, e.g. pie pastry.

Now, why are there claims out there that coconut oil is good for you, health-wise?

Coconut oil and other coconut products are traditionally used for culinary purposes in many Asian cultures, but the popularity of this oil in Western countries only arose in recent years, after research revealed coconut oil as a saturated fat that doesn't behave quite like typical saturated fats. The fatty acids in coconut oil are more than 90% saturated1; however, it has been elucidated that a high proportion of these are medium-chain fatty acids (MCFAs), as opposed to the long-chain ones (LCFAs) found in animal fats. Research shows that the shorter-chained fatty acids are more readily oxidised to produce energy, which means that, unlike their longer-chained counterparts, they are generally not retained as body fat.1,2,3 'Their fast metabolism and transit into the body is associated with increased energy expenditure and earlier satiety, which can help to avoid overconsumption'.3 Additionally, unlike the other saturated fats, coconut oil seems to increase HDL-cholesterol (the 'good' cholesterol) levels a lot more, which may theoretically help to somewhat offset the increase in LDL-cholesterol (the 'bad' cholesterol) that it causes. These factors may in part explain why obesity and high cholesterol do not appear to be major problems in countries that traditionally use coconut as a main food source.

In fact, outcomes of a study by Feranil A et al4 indicate that coconut oil may be related to a beneficial lipid profile in pre-menopausal women in the Philippines, where there is a strong coconut presence in the diet of its people. However, the study used the 24-hour recall method, which doesn't really give extremely reliable, accurate data, and contrary to these results, in a study by Tholstrup et al,5 a diet partially substituted with MCFAs yielded totally opposite outcomes, with overall increases in total plasma cholesterol, in the LDL:HDL ratio, as well as in total plasma triglycerides. When looking at correlations between culture and food, we must also think about confounding factors, such as lifestyle and other dietary intake. For example, white rice is a staple in the Chinese diet, but despite what we know today about its high carbohydrate content and its higher glycaemic index compared to unrefined grains, this was not associated with overweight/obesity issues in the Chinese villagers back in the day. This is likely because the people did a lot of manual work in the fields regularly, which helped to offset the energy intake. Nowadays, these health issues are probably not as uncommon, especially in the more developed regions of Asia, where there is an increasing availability of processed foods, growing fast-food industries, influences on eating habits by American media, and, of course, lower physical activity levels due to the conveniences that ever-advancing technology offers. A similar sort of story rings true with the Mediterranean diet.

The health benefit of coconut oil is also suggested by the results of a study by Liau et al2, which examined the effect of ingested MCFAs in the form of virgin coconut oil (the variety containing the highest concentration of these fatty acids) on the anthropometric markers of obesity. There appeared to be a statistically significant decrease in waist circumference in the obese male study participants, averaging 0.97% from baseline; however, there were no significant improvements in the female participants, or significant reductions in any other markers. Nevertheless, this finding, plus the other aforementioned theoretical benefits, imply that coconut oil may have a promising role in weight management strategies.

Moving away from obesity and onto dental health, a team of scientists at the Athlone Institute of Technology in Ireland have also recently identified that enzyme-treated coconut oil inhibits the growth of most strains of Streptococcus bacteria, which commonly reside in the oral cavity and cause tooth decay, including S. mutans, which is known to produce tooth-decaying acids .6 This antimicrobial activity means that modified coconut oil may potentially be a useful additive in oral healthcare products. Don't go gargling coconut oil though - the study also concludes that coconut oil in its natural form has no such antibacterial effect.

On to the negatives.....

There is a protein called haptoglobin, which, when produced by adipose (fat) tissue, is directly related to adiposity (i.e. 'fat-ness'), and the blood level of which is typically elevated in people with diabetes and obesity.7 An animal study by Bueno et al,7 in which mice were given a diet enriched with various dietary fats, shows that both lard and coconut oil independently increases the gene expression of haptoglobin in white adipose tissue in mice, although it is area-specific and depends on duration of treatment. Other studies have shown that both MCFAs and LCFAs may increase serum pro-inflammatory cytokines via direct or indirect pathways, including certain ones that stimulate the expression of haptoglobin in fat depots.7 Collectively, these findings suggest that saturated fats are positively correlated with obesity, and coconut oil, though not definitively, may potentially contribute to it.

Although there are some obvious positive findings in regards to the health benefits of coconut oil, most, if not all, of the studies have been conducted over short periods of time only, so the long-term benefits and the long-term effects on blood lipids remain unclear. Longer term studies are important, since there are already some conflicting trial outcomes. Some studies show, for example, a decline in the enhanced weight loss, energy expenditure and feelings of satiety a few weeks into trials examining MCFA-supplemented diets, with some of the authors speculating that some sort of compensatory mechanism in the body may be responsible for this.7 Moreover, if we are to view coconut oil as a possible weight loss tool, there needs to be more studies based on people with existing weight problems, in order to more accurately assess the effects. Due to its variable effects on the blood lipid profile, more research is required to determine its relationship with heart disease. Without clarifying all these factors first, it is probably not advisable to use coconut oil as part of a weight management plan in those with existing risk factors for cardiovascular (CV) disease.

Another issue is that even if MCFAs prove to be fantastic, the concentration of these vary between different species of coconuts, and different coconut oils may have varied ratios of LCFAs to MCFAs; i.e. you may not get all the theoretical benefits, and may even end up ingesting more 'bad' saturated fats than you expect to. Once determined, it will also be interesting to see the dose required of commercially available coconut oil in order to reap its purported health benefits. One must keep in mind that regardless of if a fat is 'good' or 'bad', there is a limit to how much it should contribute to our diet. The World Health Organisation recommends that total dietary fats should contribute to no more than 30-35% of energy needs, and saturated fats, no more than 10%.1 Excess energy intake may not only lead to weight gain and increased health risks, but may also reduce appetite and therefore consumption of other food groups, which contain many macro- and micronutrients that our body needs to optimally function.

In my humble opinion.....

It is an established fact that coconut oil is healthier than all the other saturated fats and, of course, infinitely better for you than trans-fats. As with many food sources derived from plants, coconut oil may well also contain a whole heap of healthful phytonutrients that we are yet to find out about. But while it has been associated with some evidence of potential weight-loss benefits, albeit short-term data, its effects on cholesterol and CV health are still a bit on the hazy side. Looking at its effect on cholesterol levels alone, even if it may significantly increase HDL-cholesterol levels, it will definitely still increase LDL-cholesterol levels, whereas with the polyunsaturated oils like safflower, sunflower, and corn oils, they will both increase HDLs and decrease LDLs. Thus, at present, the healthiest choice of cooking oil, especially in terms of reducing CV risk, would still be the polyunsaturated oils.

Certainly, it wouldn't harm to occasionally use coconut oil in sensible amounts, and perhaps it may even be beneficial to use it in combination with polyunsaturated oils; but I definitely wouldn't go substituting everything with coconut oil, at least not until there is some solid, long-term evidence to support this.

And that includes for cooking barramundi, too, unless you want to add a lovely subtle coconut flavour to its flesh.

..........................................................................................................................................................

Well, that took me longer than expected to write up! Hopefully you'll now be able to make a bit more of an informed decision about whether or not you want to jump onto the coconut-oil-is-the-latest-and-greatest-health-food-discovery bandwagon ;) If you do decide to try out coconut oil, I would suggest getting the virgin coconut oil variety, since it theoretically contains a higher proportion of MCFAs than the norm. Also, if you're planning on using this oil as part of a weight management plan, please remember that exercise plays a very important role in achieving your weight-loss goals as well, together with a balanced diet.



Disclaimer: I am by no means a nutritional expert. I just happen to like knowing the basic nutritional profile of what I put in my mouth, and have access to certain peer-reviewed research journal articles (there is a great wealth of 'information' out there on the www, but be aware they're not all trustworthy, especially if it's regarding unestablished health benefits of certain products - any random person could have posted it). The above information is only what I have found at the time of posting this (I'm sure there's way more research papers out there with various findings, and more to come in the future); my personal interpretations of them; and the conclusions I have drawn from them. For professional advice, please consult an accredited practising dietitian. 

Reference List: 

1. Wahlqvist M. Food and nutrition: food and health systems in Australia and New Zealand. 3rd ed. Crows Nest, NSW: Allen and Unwin, 2011. p. 289-90, 293, 538. 
2. Liau K, Lee Y, Chen C, Rasool A. An open-label pilot study to assess the efficacy and safety of virgin coconut oil in reducing visceral adiposity. ISRN Pharmacol. 2011;special section:1-6. 

3. Clegg ME. Medium-chain triglycerides are advantageous in promoting weight loss although not beneficial to exercise performance. Int J Food Sci Nutr. 2010;61(7):653-79.

4. Feranil AB, Duazo PL, Kuzawa CW, Adair LS. Coconut oil is associated with a beneficial lipid profile in pre-menopausal women in the Philippines. Asia Pac J Clin Nutr. 2011;20(2):190-5.

5. Tholstrup T, Ehnholm C, Jauhiainen M, Petersen M, Hoy CE, et al. Effects of medium-chain fatty acids and and oleic acid on blood lipids, lipoproteins, glucose, insulin, and lipid transfer protein activities. Am J Clin Nutr. 2004;79(4):564-9.

6. Digested coconut oil could combat tooth decay. Nutr Perspect. 2012;35(4):17.

7. Oller do Nascimento CM, Hunter L, Trayhurn P. Regulation of haptoglobin gene expression in 3TC-L1 adipocytes by cytokines, catecholamines, PPAR-gamma. Biochem Biophys Res Comm. 2004;313:702-8.