Thursday, November 21, 2013

The Oiling of the Liver: The Good & Bad Short- & Long-Term Effects of Tocotrienol + Carotenoid Laden Red Palm Olein, Regular Palm-, Corn- and Refined Coconut Oil

I would not expect "red palm olein wonders", but more RPO and less corn oil in the American diet may at least buffer the liver disease burden in the US (the figure is based on data provided by the American Liver Foundation)
On Turesday, November 19, 2013, you've learned from a study by Subermaniam et al. about the "anti-rust" effects of coconut oil (if you missed that, you can catch up here), today, we are going back to Malaysia and the Universiti Kebangsaan Malaysia and the results of another team of researchers to learn about the effects the various oils have on the "oiling of the liver" (Dauqan. 2013).

I guess most of you will remember my previous comments about the critical role of the liver (and its health or disease) in the development of the metabolic syndrome (read it up). It is thus by no means irrelevant, whether the chronic ingestion of a certain type of oil will result in MDA levels of 92µmol/g or  27.3µmol/g.

Boring!? No, rather surprising!

If you think this sounds boring and are by no means surprised that the malondialdehyde levels of the liver samples the researchers harvested after 4 weeks were 27.3µmol/g, 92µmol/g, 54µmol/g, 47.4µmol/g and 72.6µmol/g for the control diet with mixed fats, red palm oloein (RPO), regular palm oil (PO), corn oil (CO) and the previously celebrated coconut oil (COC), respectively, I would suggest you have a closer look at the the "magic" that happened over the following 4 weeks of on 15% RPO, PO, CO and COC diets.
Figure 1: MDA levels (µmol/g) of liver tissue as a marker of lipid oxidation after four and eight weeks on control diet or control diet with 15% of red palm olein, palm oil, corn oil or coconout oil (Dauqan. 2013)
Well, you see, the way the effects of red palm olein came full circle after another months on the 15% RPO diet is hardly "boring", is it? The MDA levels, a relatively reliable indicator of local lipid oxidation, of the rodents on the 15% red palm olein diet is now, 4 weeks after peaking at 92µmol/g down to 25.2µmol/g, indicating that the level of lipid peroxidation in the livers of the RPO group is now significantly lower than that of any other group (43.4µmol/g, 50.1µmol/g and 48.3µmol/g for control, palm oil, corn oil and coconut oil).

Short term detriments, long term benefits!

I know it sounds more than awkward, but eventually every SuppVersity student should be aware of the fact that the extrapolation of long-term effects from short-term data is a 'risky' business. Unfortunately, even 'experts' often disregard this fundamental rule, when they formulate their recommendations on nutrition, supplementation and exercise.
Table 1: Carotenoid  and vitamin E composition (in %) of crude palm oil and red palm olein; the data is from a different study by Bonni & Choo who tested commercially available products (Bonni. 2000)
The statement, "Prefer coconut oil and avoid red palm olein!", for example would have been a reasonable dietary if we did not know about the turn-around in the second part of the study, when the beneficial effects of the saturated fat content of the coconut oil begin to fade and the absence of natural anti-oxidants in refined coconut oil begins to show its ugly face. At this point, the moderate amount of unsaturated fats in red palm olein (13% omega-6, 0% omega-3; see Bonnie. 2000), of which I am honestly not sure if it is the actual reason of the initial increase in lipid peroxidation (remember: corn oil has more PUFAs!), or whatever other underlying cause of the initial rise in inflammation is overriden by the accumulating amounts of vitamins E and carotenoids from the red palm olein, which rendered the liver of the oxidation-proof, or "rustless" if you will - similarly rustless as the hearts of the rogents in the previously cited study by Subermaniam et al. (learn more).
200g of palm fruits have the same amount of tocotrienols as 4kg of oats. Learn more "tocotrienol" and red palm oil facts in "Tocotrienols: What They Are, What They Do & How They Work + Why the RDA of Palm Olein is NOT 1xCup Per Day " | more
Bottom line: I would like to formulate two take home messages for today's SuppVersity article. Firstly, a theoretical one, which shall remind you of the fact that you can do more harm than good, if you (accidentally) terminate a study in a transitional state and formulate long-term dietary recommendations based on short-term observations, because the study at hand clearly indicates that some effects - in this case the antioxidant effects of the tocopherols, -trienols and carotenoids - take their time to become measurable. And seconfly a very practical one, which is eventually only a reminder of the existence of red palm oil (see article referenced on the right) - an excellent source of dietary antioxidants and probably your only chance to get your tocotrienols and high(er) amounts of some of the rarer carotenoids from regular foods.

References: 
  • Bonnie, T. Y. P., & Choo, Y. M. (2000). Valuable minor constituents of commercial red palm olein: carotenoids, vitamin E, ubiquinones and sterols. Journal of Oil Palm Research, 12(1), 14-24.
  • Dauqan, E., Abdullah, A., & Sani, H. A. (2013). LIPID PEROXIDATION IN RAT LIVER USING DIFFERENT VEGETABLE OILS. Malaysian Journal of Analytical Sciences, 17(1), 300-309.
  • Valls, V., Goicoechea, M., Muniz, P., Saez, G. T., & Cabo, J. R. (2003). Effect of corn oil and vitamin E on the oxidative status of adipose tissues and liver in rat. Food Chemistry, 81(2), 281-286.