I have no scientific study to back this up but I feel that ingesting dark seaweeds (kelps) with the strongest tastes do reduce iron absorption.
Ironically, I am a large eater of seaweeds - and I have a history of low iron levels - so I tend to find I need to eat more of the green chlorophyll rich weeds, by proportion to the iodine heavier kelps.
In addition - and you are probably aware of this anyway - but bitter tastes in the skin of fruit, such as plums, blackberries, kiwi fruit skin, pomegranate, red grape skins, and quite a number of others, are high in tannic acid, which also reduces iron absorption. (Also bitter taste in walnuts.)
Individuals with blood sugar issues can eat the skin and leave the fleshy inner part of the fruit.
With a keen taste, the bitter skin is quite easily differentiated from the sweeter inner.
Kind wishes, J