"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.