I read everywhere that palm oil and cocoa butter are a good source of saturated fat which, I think, is true when looking at the fatty acids composition of it, but not when ingested and digested.
Even if palm oil is 50% saturated fat, like pork fat, there is a biological subtlety linked to the distribution of fatty acids in the 1,2 and 3 positions of the glycerol.
The biodisponibility of a fatty acid is maximal when this one is linked to the position 2 of the glycerol.
In Palm oil, like in cocoa butter, the unsaturated fatty acids are in the bioavailable position (position 2) whereas, for example, satured fatty acids occupy that position in lard.
Palm oil has to be considered like an oil which is rich of unsaturated fatty acids, like cocoa butter, and not like a source of saturated fatty acids because, when ingested and after digestion, palm oil’s saturated fatty acids are mostly evacuated via the bowel (the calcium salt of the saturated fatty acids are insoluble and are then excreted) due to their position (1 and 3) of the glycerol and their non-utilisation by the body.
"Differences in the distributions of fatty acids among the positions of the glycerol moiety in triacylglycerols from natural fats and oils were first demonstrated systematically by enzymatic hydrolysis procedures, specifically pancreatic lipase hydrolysis for the analysis of the fatty acids of position sn-2 (regiospecific analysis), before complex stereospecific hydrolysis procedures were developed that permitted the complete positional distributions of the fatty acids to be determined. Because of this historical development of the analytical procedures, there has been a tendency to assume that the composition of fatty acids esterified to the sole secondary hydroxyl group must have greater importance than those of the two primary positions. It is certainly true that the composition of position sn-2 is of great importance when triacylglycerols are consumed and digested by animals, since 2-monoacyl-sn-glycerols are then formed which can be absorbed by the intestines and utilised as such."
- Brockerhoff H., (1967 – Stereospecific analysis of triglycerides: an alternative method – J. Lipid Research, 8, 167-169.
– IUPAC: International Union for Pure and Applied Chemistry.