"Iodine Number" or "Iodine Value" refers to how much Iodine an oil is capable of sucking up by addition to the double bonds present in the molecular structure of the oil. Walnut oil, a glycerol tri-ester, contains typically ovre 80% of unsaturated chains.
We measure how much Iodine that oil is capable of reacting with, and then use the result as a reflection of the unsaturation (or "double bond") content of the oil.
When an oil or substance is said to have an Iodine Value, or Iodine Number of 184, that does not mean the oil contains any iodine. It only means that 100 grams of the oil under consideration contained enough unsaturation that it is capable of reacting (absorbing) 184 grams of iodine. In fact, if the substance contained iodine it would likely cause an interference. For this reason, Iodine Number (An ASTM standardized method) is only used on substances which are free from iodine, including walnut oil.
We also run bromine numbers for cases where the material does not react readily with iodine. Similarly, just because a bromine number is given for a substance, does not mean that substance contains any bromine.
It goes to show that just because something says Iodine Value in a study, the results are meaningless unless one understands what the terms mean. One might be tempted to conclude that it contains iodine because it has an Iodine Value, but please read with precision. If it had an iodine content, it would say so, and give an amount expressed as a percentage or parts per million.
Otherwise, some would go around thinking they are getting iodine from walnut oil, when it is not present. Placebo effect would predict that about 1/3 of them would report feeling better, and many might attribute it to the iodine alleged to be in walnut, when in fact there is none !!!!!!
These misinterpretations and conclusion-jumping are not uncommon, so go slow about concluding anything.
I can see where some might misinterpret Iodine Number as wrongfully meaning the substance has Iodine in it.
Maybe that's where all those rumors about walnut containing Iodine derive. The only ones I've seen author articles alleging iodine in walnut are ones without any degree or background info concerning analytical chemistry knowledge, which could easily cause them to wrongfully conclude the stuff contains iodine.
It's another aspect of that typical human error your species is so prone to. We Vulcans have a different set of challenges to manage, especially the green monster within all of us, but I take refuge often in the fact that it is a quite logical battle.
good point, crosses well with my earlier mental question about whether the dissappearance of Iodine color on the skin of those who paint is merely a reflection of the unsaturated fatty acid content of their skin. quite logical, no ?