Fact check: Does fluoride lower iq

1. Summary of the results

The relationship between fluoride and IQ is complex and not definitively established. While some research suggests a potential association between high fluoride exposure (above 1.5 mg/L) and lower IQ scores in children, with a decrease of 1.63 IQ points per 1 mg/L increase in urinary fluoride ^[1], this does not prove causation. The National Toxicology Program found a potential association with only a small IQ reduction of 2-5 points at high fluoride levels ^[2].

2. Missing context/alternative viewpoints

Several crucial pieces of context are missing from the original question:

• The studies showing correlation were not conducted in the United States ^[1]
• There is insufficient data regarding effects at the current U.S. recommended level of 0.7 mg/L ^[1]
• The research base is limited, with only 3 out of 19 studies being prospective cohort studies, which significantly limits causal inference ^[2]
• Harvard's Dr. Brittany Seymour has explicitly rejected claims about fluoride lowering IQ ^[3]
• The American Dental Association has raised significant concerns about the methodology and potential biases in the studies ^[2]

3. Potential misinformation/bias in the original statement

The original question oversimplifies a complex scientific issue. Several groups have stakes in this debate:

• Anti-fluoridation activists benefit from promoting fear about fluoride's effects
• Dental and public health organizations benefit from maintaining public trust in water fluoridation
• The question fails to distinguish between regulated fluoride levels in water treatment (0.7 mg/L in the US) and the higher levels (>1.5 mg/L) where potential effects were observed ^[1]
• The research community itself acknowledges that while there is "moderate scientific evidence" for an association, this does not prove causation, and more research is needed ^[1]