Fluoride lowers ceruloplasmin, the key copper transport protein in the blood, thus blocking copper. Serum sialic acid and ceruloplasmin levels in experimental fluorosis (Y D Sharma, 1983) https://pubmed.ncbi.nlm.nih.gov/6836584/ Published way back in 1983, fluoride lowers ceruloplasmin.  Fluoride lowers copper: Effect of excessive dietary fluoride on nutrient digestibility and retention of iron, copper, zinc, and manganese … Continue reading Chapter 33: Effects of Fluoride on the body and copper