Sean Plunket interviewed Dr Robin Whyman 13 February 2025
Babies bottle-fed with fluoridated water receive 212.5 times more fluoride than babies who are breast-fed when water is fluoridated. The New Zealand Ministry of Health recommends a range from 0.7ppm to 1ppm, with a target of 0.85ppm.
Breast milk is very low in fluoride, containing only 0.004ppm, no matter how much fluoride the mother is consuming. This means that for every litre of water a baby consumes, they will get 0.85mg if bottle-fed fluoridated water, or 0.004mg if breast fed.
Considering fluoride is not an essential nutrient in any way whatsoever, it only requires common sense to know that feeding a baby over 200 times more of something that is not an essential nutrient, in fact is a poison, is a dumb thing to do.
A big review from the U.S. National Research Council (NRC) in 2006, Fluoride in Drinking Water, determined the amount of fluoride that is likely to affect the thyroid. (See chapter 8, Effects on the Endocrine System). The NRC found that in humans, effects on thyroid function were associated with fluoride exposures of 0.05-0.13 mg/kg/day when iodine intake was adequate and 0.01-0.03 mg/kg/day when iodine intake was inadequate.
The below chart shows bottle fed babies are getting a dose that is associated with an effect on the thyroid, even when iodine intake is adequate. At birth they are getting 0.145 mg/kg/day and at six months 0.106 mg/kg/day. Both of these dosages are well above 0.05 mg/kg/day, the dosage known to affect thyroid.
| Age | Weight | Bottle/breast fed | Fluoride per litre of liquid | Daily milk consumption | Total fluoride intake | Mg fluoride/kg body weight per day |
| Birth | 3.5kgs | Bottle | 0.85mg | 600 ml | 0.51mg (0.6 x 0.85) | 0.145mg/kg/day (0.51/3.5) |
| Birth | 3.5kgs | Breast | 0.004mg | 600 ml | 0.0024mg (0.6 x 0.004) | 0.0006mg/kg/day (0.0024/3.5) |
| 6 mths | 8 kg | Bottle | 0.85mg | 1 litre | 0.85mg (1 x 0.85) | 0.106mg/kg/day (0.85/8) |
| 6 mths | 8 kg | Breast | 0.004mg | 1 litre | 0.004mg (1 x 0.004) | 0.0005mg/kg/day (0.004/8) |
The above estimates are based on the average size and intake of a baby according to Plunket New Zealand.
A 2020 Canadian study that looked at fluoride exposure from infant formula found that bottle-fed babies had an average 9 point decrease in IQ. Water in Canada is fluoridated to a maximum of 0.7ppm.
A large study in the UK, published in the British Medical Journal, which took data from all GP practices found women living in fluoridated areas had a 60% increased chance of developing hypothyroidism. Hypothyroidism causes lethargy, weight gain and depression. Hypothyroidism in pregnancy is also known to cause a lowering of IQ in the child.
See this presentation by Fetal Pathologist, Dr Vyvyan Howard, explaining how lowered thyroid function is most probably the mechanism by which fluoride is lowering children’s IQ.
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