Perchlorate in Breastmilk: Responses to Concerns

by Purnendu K Dasgupta. Reprinted with permission from the author.

March 3, 2005

Dear Kellymom:

I am the senior author of the Texas Tech Breast Milk Study that has been much publicized and much misinterpreted. Since many women who breast feed visit your site, I would appreciate it if you could bring my viewpoint to your readers:

As you obviously know, the topic in general and the paper in particular have received wide press coverage. Some of them report what I said accurately, others wrote what was in their mind. I cannot be responsible for them even when sometimes they put things in quote marks.

  1. First, I would like to assure you that even in my wildest imagination it did not cross my mind to advise someone to stop breast feeding just because perchlorate is detectable in breast milk. There are so many physiologic and psychological benefits of breast feeding, I truly regret if our paper has caused any one to stop breast feeding even for a day. Also, one needs to recognize that with improved detection technologies, we can detect almost anything at some level in almost anything.
  2. Our study was funded out of our pockets and internal funds – it is too small – it is preliminary – and it is far from perfect. No sweeping generalizations are in order and were not intended. We are hoping that a grant we have applied for will be funded and allow us to conduct a broader study.
  3. Aside from any issues on perchlorate, some of the women (even some with low perchlorate) we studied had very low levels of iodide. In a study on 100 pregnant women published in 2004 in Thyroid, scientists from the Boston Medical Center found 49 to be taking iodine below the recommended daily allowance (RDA, and Boston is not exactly seafood-deprived: after iodized salt, seafood is the second most important source of iodine). The median urinary iodine (UI) concentration in this study was 149 ug/L, just below the 150 ug/L UI value that is considered to correspond to adequate iodine intake (220 ug/day for a pregnant woman).Completely independent of our study, several experts have been saying for some time that this country is becoming iodine deficient. The effect of perchlorate (as far as presently known, the only effect) is to further aggravate iodine deficiency by inhibiting iodide transport. I am not expert on what levels of perchlorate will present a real problem; the venerable panel appointed by the National Academy of Sciences have already done that. However, one needs to be aware that any effect of perchlorate will depend on the iodine nutrition level; if the iodine nutrition level is poor, any effect of perchlorate will be magnified.
  4. Be concerned about your iodine nutrition. Contrary to what many believe, the majority of salted processed food does not contain iodized salt. It is the increased consumption of prepackaged and preprocessed food that is at least in part responsible for the reduced iodine intake.Unless you are into eating Sushi (specifically the seaweed wrappers), make sure that your vitamin contains the level of iodine recommended for a lactating mother (290 ug/day). At least up to 1100 ug/day is believed to safe but one should not attempt to overdose on iodine, either.
  5. What I have stated, not in the paper, but in a few interviews, is that health food stores sell dried Kelp capsules (that typically contain 300-400 ug organic iodine, which is only partly absorbed, and which is equivalent to 2-3 wrappers of typical Sushi offerings). One a day and not more than one a day should be fine. Although many “real doctors” have taken real issue with my suggestion about “iodine supplements”, one is not talking about radiation sickness pills here containing many milligrams of iodide. Japanese women on the average take twice our RDA and the average pediatric and maternal health in Japan are both much better (although admittedly there are far too many confounding covariates to make much of such a simplistic statement: they also walk much longer distances everyday….).
  6. It was not our intention to cause alarm. However, we feel that even though we had a woefully small number of samples (36), American breast feeding mothers are better off knowing that many of the women had appallingly low concentration of iodide in their breast milk – whereas 100-200 ug/L is normal and nutritionally recommended, in a third of the samples in which iodide was measured, it was below 20 ug/L. Note also that what we measured was iodide, which is only one form of iodine. There is some evidence that other forms of iodine make up to half of total iodine in breast milk.
  7. It may be disconcerting, but I believe that we are ultimately better off knowing that all of the women tested had easily measured values of perchlorate in their breast milk, some at levels that nature surely did not intend.I would hasten to add that in a paper we published a month ago, we showed that some perchlorate is formed naturally, for example, every time sea salt particles go through lightning. We can detect perchlorate in the majority of rain samples in trace quantities.
  8. I am too old to be an activist. If I were, I would write my congressperson to legislate that FDA make iodization of all food grade salt mandatory, as for example Austria has recently done. It costs nothing, especially when you think iodine deficiency causes mental retardation. As a nation, we cannot afford to fall any further behind. I would also urge my congressperson to pass legislation to clean up at least the more grievous acts of perchlorate contamination.

There is nothing more beautiful than a mother breast feeding a child. I sincerely wish all your readers and their babies well.

Thank you,

Purnendu K Dasgupta
Paul Whitfield Horn Professor
Department of Chemistry and Biochemistry
Texas Tech University
Lubbock TX

(revised per Dr. Dasgupta’s comments at 4:05 pm EST, March 3, 2005)

Additional Information

Iodine Nutrition in Industrialized Nations from the Network for Sustained Elimination of Iodine Deficiency. Per Dr. Dasgupta, this information is not very new any more and the actual situation is worse.

Perchlorate in Breastmilk by Kelly Bonyata, IBCLC @

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