Fluoride Action Network

Fluoride & the Brain: An Interview with Dr. Phyllis Mullenix

Fluoride Action Network | 2000

The following interview with Phyllis Mullenix took place on October 18, 1997.  The interviewer is Paul Connett.


Connett: We’re talking with Dr. Phyllis Mullenix, who in 1995, published a very important work on the neurotoxic effects of fluoride in rat studies. And Phyllis would you begin by telling us your background? What are your qualifications?

Mullenix: Well, I got my PhD in pharmacology from the University of Kansas back in 1975. From University of Kansas Medical Center I went to John Hopkins School of Public Health in Baltimore between 1975 and 1977. And then in 1977 I was hired to come to Boston and work at Harvard with Dr. Herbert Needleman on the lead project. And so, I started then in 1977 and I’ve been in the Boston area for the past 20 years.

I was at the Childrens Hospital in Harvard Medical School in the Psychiatry Departments and Department of Neuropathology at the Harvard Med School between 1977 and 1982. Then [in] 1982 I left and went to the Forsyth Dental Center in Boston. I went first into the Department of Pharmacology and then in 1983 we established the first toxicology department in any dental research institution in the world, in 1983.

Connett: And, if I may interrupt, your task at that point, your brief as you understood it, was to examine the toxicological effects of the kind of materials that we’re using in dentistry?

Mullenix: Yes, Dr. Hein, who was the director of the institute at the time, wrote a nice newspaper article that was in the Forsyth Dental Center news in the spring of 1984 which described who I was and why I was brought in to the department and that I was brought in to head up this department to look at the environmental impact and the toxicity of products that are used by dentists and the dental community. And in particular they specifically mentioned fluoride, mercury, nitrous oxide, and some of those things.


Connett: Ok. Could you briefly summarize your paper, and where was it published first of all?

Mullenix: My paper concerning the neurotoxicity of sodium fluoride in rats was published in the Neurotoxicology and Teratology journal. That’s a peer reviewed journal… And that was published in 1995. It was submitted in 1994, but it was published, it appeared on the shelf, in ’95.

Connett: After extensive peer review?

Mullenix: That’s right. As a matter of fact, it went through extra reviewers because the editor at the time recognized that this was a controversial subject and that to be on the safe side he suggested that they send it to an extra reviewer… and they took a good deal of time with it, and did it right.

Connett: And what did you find?

Mullenix: The study basically found three things. First of all, that if you put sodium fluoride in the drinking water of young animals, that with time – meaning a period of weeks in a rat’s lifetime – they would develop changes in their behavioral patterns. And that pattern change was a hypoactivity pattern. They became slower, ‘couch potatoes’ if you like. But it was definitely a hypoactivity pattern. And it had a specific pattern to it which was very, very strikingly similar to the pattern that I had seen in substances or drugs that they used to treat acute lymphocytic leukemia in children, which clinically cause IQ deficits. And when I saw that specific pattern… that I was getting when I exposed animals to radiation or chemotherapy and steroids… that was very striking.

So, that was one thing – in young animals that were exposed, they became hypoactive.

I also found that if I started the exposure at a little later age, I would get the same pattern, but I would get it at a blood level of fluoride that was lower, even, than the young animals. So it suggested that, in particular females, that the older animal was more susceptible to this fluoride in the drinking water.

And a part of this whole common theme – what’s happening at different ages – we also did a prenatal study. Because I wanted to see if I could do one specific exposure in the prenatal situation giving a subcu[taneous] shot of sodium fluoride at a specific age where a certain part of the brain is developing, if the fetuses of this mother, when they grew up, if they had any type of permanent behavioral damage.

And we gave the subcu[taneous] injections to the mother, we gave no other fluoride exposure, and when those pups were born and when they grew up and we tested them, they had a permanent change. And their pattern was this very distinct changes that are compatible with hyperactivity.

Connett: Hyperactive.

Mullenix: Right.

Connett: So this is above, more active than usual?

Mullenix: That’s right. And some people would say, well, doesn’t it seem a little odd that if you gave the prenatal exposure you get a hyperactivity, and if you give a postnatal exposure you get a hypoactivity? And I say not at all. That’s not unusual at all because the stage of brain development in the prenatal situation is extremely different from that in the postnatal situation. So there are different regions of the brain that are developing, therefore you’ve got different regions of the brain that are going to be susceptible. So it is not at all uncommon to have the long term outcome be strikingly different.

Connett: And you also found that the fluoride accumulated in the brain tissue?

Mullenix: Yes. Besides the prenatal exposures and the postnatal, the third thing that we wanted to look at was – what were the levels of fluoride in the brain? We had gone back in the literature, and it was said, I think it was Gary Whitford’s studies that had said… that fluoride did not get across the blood-brain barrier and get into the brain to any extent. But I had a problem with that study, because what they did was they took fluoride and they gave an IV injection and then 1 hour later they looked at the levels in the brain.

But that’s a far different cry from how people really get fluoride, they get it, you know, orally and day-to-day. And so, looking at fluoride levels in brain tissue 1 hour after injecting an IV does not mimic the real world situation at all…

So we went in with our drinking-water exposure, took out the brains – we dissected the brains in these animals into seven different regions – and then analyzed each region for the fluoride content. Now what we found was that, absolutely no question, there was major accumulations of fluoride in all the regions of the brain, and that some areas looked like there were greater accumulations than others, that were sex-determinant. That was a very interesting piece of information.

Just the fact that we could any level of fluoride at all, when we weren’t expecting the brain to accumulate any fluoride, was a very big surprise and very, very disturbing to some people, of all things, that fluoride was accumulating in the brain.

[Note: At this point in the interview, Connett asked Mullenix questions concerning her relationship with Jack Hein, the Director of Forsyth, & Harold Hodge, a prominent expert on fluoride toxicology who oversaw Mullenix’s work. To read this portion of the interview, scroll down to Section V (“The Manhattan Project Connection”).


Connett: Now, when you got these results, when it became apparent that fluoride, both prenatally and postnatally, effected rat behavior, what kind of responses did you get from your institution and elsewhere?

Mullenix: Well, there was two separate types of responses.

First of all, when I went to Jack Hein [the Director of Forsyth], and I said, look I think there’s a problem with this stuff and I explained the data and everything, Dr. Hein got very excited. He thought this was extremely important. And he said, I want you to fly down to the National Institute of Dental Research and tell them your results. Forsyth paid for my trip down there.

I went there. It was in September of 1990. I’ll never forget it.

Jack Hein also went with me, and he presented this to Harold Loe, who was then the Director of the National Institute of Dental Research, and I was to give this seminar.

Well, just prior to my seminar, I walked over to the main corridor of the National Institutes of Health, and I walked in and all on the walls of this main corridor was this story called “The Miracle of Fluoride”, all over the walls. And it had newspaper articles and artifacts, everything, from back in the 1940s and ’50s, which described and made fun of the anti-fluoridation movement at that time. It called the people crackpots and it made jokes, it had stories about little old ladies in tennis shoes, you know, screaming about communist plots and everything else. And I’m very upset at this point because I knew how they made fun of people, about anti-fluoridationists, and I’m getting ready to walk into the National Institute of Dental Research and tell them that I thought that fluoride was lowering the IQ of children.

And so, I was really very shocked by that. I had no idea that there was that much political controversy.

So when I went in and I gave the seminar, I was amazed. The room was full. It was a small, private room. There were a lot of people from public relations there. There were a lot people from the public health service because they had, what looked like to me, a military uniform on. There was an individual from the Food & Drug Administration. And I proceeded to give my seminar, and I even made a joke about the little old ladies, and I said I’m a little old lady, but I don’t have tennis shoes on. And nobody laughed. I mean there wasn’t a single smile in the entire room. And they proceeded to really grill me on the technique and the technology, and basically, I had to be wrong.

Then, Jack Hein got a letter from the Director, Harold Loe, from the National Institute of Dental Research about two or three weeks later. And basically it was thanking him for the seminar, and he described me as being very enthusiastic, that the technology was extremely innovative, that it was very important that they get in and they look at this. And then he made suggestions of how the National Institute of Dental Research should follow up on this and provide money to do this research in the future.

And then that proceeded to start several tactics on how to get money; and they led me in circles for months, and then into years, of first following this procedure for getting the money through a contract and then I went down that road and then I found out that wasn’t plausible. And…

Connett: And your paper hasn’t been published at this point?

Mullenix: Oh, absolutely not. It was all preliminary data. And, then, at that time, I mean I wasn’t real sure, I only had done a few experiments and so I said, yea, I really need to do more experiments, I need help to go forward. Because the only money to do this is whatever I came up with.

So, we felt obligated. I had this information. I was on the fence. I either had to go forward or I had to bury it. And I wasn’t about to bury it.

I was academically into this because I’d been given a grant from the National Cancer Institute to look at the effects of neurotoxicity on the treatments for childhood leukemia. So, I was being praised on one side of the fence and how great the technique was, how sensitive it was. I’d been given a big grant to do that. And yet when I found the very same problem with this fluoride in drinking water, there all of a sudden they were questioning the technique, they were questioning me, and you know it was a completely different acceptance; that something had to be wrong with me. So here I was being applauded on one side and defamed on the other.

So at that time then at [Forsyth], the first time I really came out of the closet, so to speak, at the institution, other than Jack Hein – and I got the impression that Dr. Hein really didn’t talk to very many faculty members about my work and fluoride research and what the results were, he kept that somewhat quiet – and I didn’t talk about it until February of 1992.

And then when I stood up in the institution and I gave a seminar which told my results, the looks on the faces I’ll never forget. It was almost complete horror. And I told them the dilemma I was in. I thought I was studying a control group and I wasn’t expecting the answers I was getting [that fluoride was affecting the behavior of rats], and I was basically asking help.

What happened though was… 24 hours after that seminar, the Director of Research came up and talked to the second author on the paper that I was working with, Dr. Pam Den Besten, and basically said that, what would you think if we were not going to, as an institution, not going to allow you to publish this information?

Well, Dr. Den Besten got very upset that, you know, they started talking about ways of keeping us from publishing this information. That all of a sudden they were going to make these papers go through an approval system before they could be going into print.

Well, she came and told me and I got very upset about this because we’d never done this kind of thing. You write the paper, you send it out for peer review. You don’t go through the institution. We’re not like a government agency or something like that where you have to have approval by your institution before you can publish this information.

So I got very upset. This was on Friday. And, the Director of Research then started working on Dr. Den Besten, and finally she got very exasperated with the whole situation and said you go talk with Dr. Mullenix yourself.

So the seminar was on a Thursday, this on Friday – they were talking about not allowing me to publish it – and then on Monday, finally, the Director of Research came to me personally and sat down in my office. And said to me things, such as, first of all he said you have to do more studies because this can’t be correct.

I said, I would love to do more studies. Help me do more studies. You know, maybe there was something we’ve done wrong. We need to do further studies. So help me.

The institution, he says, well, we don’t have, we can’t give you support for doing this. He also said that you are jeopardizing the funds to our institution from the National Institute of Dental Research if you go forward and come out with this.

He said that I was going to cause hysteria on the part of the public and that they just didn’t want me to go into this controversial area.

And there were some other remarks that these types of results and the way I was presenting it was an ‘hysterical response.’

So I got very upset with this because I didn’t exactly like being portrayed as an hysterical female all of a sudden when for ten years I’d been the Head of the Department and encouraged by the Director to even do these studies in the first place.

But unfortunately, at that time what happened was, my supporter and the reason that I did these studies – Dr. Hodge had died – and then Jack Hein went into retirement in 1991. And then what happened was the successors, the people, the Assistant Directors and Director of Research, then they became the Director. And at that time they had some consortium money from groups like Colgate, and whatever, and they were not in favor of the fluoride research at all.

Connett: Well, never the less, you went ahead and you submitted this thing for publication?

Mullenix: Yes.

Connett: It got extensive peer review?

Mullenix: Yes.

Connett: And tell us what happened when it became known that it had been accepted for publication?

Mullenix: I first got the acceptance over the telephone. I walked down to the administrators’ office at Forsyth and told them that the paper was going to be published. The assistant to the administrator said well, we should notify the National Institute of Dental Research. Do you mind if we tell them? And I said, well, do you whatever you want, you know, I don’t care.

And so they called Pat Bryant at the National Institute of Dental Research. Pat Bryant then proceeded to call me. And in several telephone conversations she basically asked me, she says, will you fly down to Washington and tell us what you found? And will you give us a copy of your paper before it had actually been finished with the peer review process? I said no, I won’t give you a copy of the paper. I will be glad to talk about it however and tell you what the results are going to be. But before it had finished the peer review process and editing and everything, I didn’t think it was appropriate to give this paper out…

So from the time that they had found out that this was accepted for publication to the time that they set up that television conference – which took place over at Harvard – was about three weeks all total. They paid for the television conference, they set it up, they had their people at their end and I think it was in Arlington, or some place in Virginia. And then we were at the Harvard campus at this end, and we had several people there. And we proceeded with about a two to three hour television conference where I explained the data.

Connett: And you overheard something whilst they were setting these cameras up?

Mullenix: Oh yes that was a funny part.

They didn’t know that we could hear what they were saying, [since] they couldn’t see or hear us. And we heard Pat Bryant, in fact several people heard on this end, heard Pat Bryant instructing the people at NIDR and other government people, she said don’t make this an inquisition. We’re trying to find out what she’s going to say to the public so that we know what is about to be presented. And so she was really asking them several times not to make this an inquisition.

Well, it was an inquisition.

And, in fact, it was so much so that it was noticed on both sides, that about a week after the television conference [Pat Bryant] called up and she apologized to me, that it was an inquisition and that they were, you know, not very receptive. Which was odd because the group that they had collected down in Washington were, yeah there were some scientists that I recognized, but more important, the room was full of public relations people.

So I couldn’t understand why, if you’re going to listen to scientific data and this kind of thing, you’ve got public relations people there. I also did recognize one person from the Food & Drug Administration that was there, it was Dr. Tom [Zavotkin – sp?] and he asked a few questions and everything. And I talked with him subsequent to that and he thought it was because it was some kind of grant review and he thought that they were going to give me money, or I was asking for money to do research. And when he found out then that it was just because I was about to publish a paper, he was amazed, he was totally shocked. That they did this kind of thing.

As a matter of fact, even the people at Harvard said we’re always trying to get Washington to pay attention to some of our works, where we have to pay for the television conference, we have to pay for it. How did you get the NIDR and NIH to pay for a television conference where [they are] coming to us?…


Connett: But despite this enormous interest in your work, which prompted the teleconference and so on, they still would not give you funding to continue this work?

Mullenix: No. What was funny was after this presentation Pat Bryant on the phone said well, the way to go forward here is a program project. And I said, yes, that would be nice, I think that would be a way to go forward. I said, however, I’ve got a bit of a problem – I’ve just been fired by Forsyth. And at the same time I’m doing the television conference in Harvard, they’re moving my stuff out at Forsyth as fast as possible. In fact, I had to negotiate with the lawyers to delay moving my equipment out at least a month to give me some time.

Connett: And what reason did they give you for sacking you from Forysth?

Mullenix: Well, let’s just say that the reasons changed over a period of time through a lawsuit. Basically they said that I didn’t get enough funds to do my research, number one, And, number two, the projects I worked on were not ‘dentally related.’ And that fluoride, they also that they weren’t interested in that kind of science, to look into the safety of fluoride. They didn’t consider that, well, as they put it, that’s not ‘their idea of science.’

Connett: But since that time, two or three members, or at least two members of the Forsyth Center have got some very large grants from, from where? Tell us about that.

Mullenix: Well, actually I’ve heard that they have got some large grants from NIDR, yes. And… at the time, there was consortium money that went in from industries into Forsyth. I think they had one that was even in their newsletter about $250,000 from a couple of the industries and it was noteworthy that this money went to the individuals that actually were giving me a hard time about my fluoride research in the first place. So it was an unusual situation.

And when Pat Bryant at NIDR said oh you’ve got to do a program project, and then I said well, that’s going to be difficult because I’ve been fired and I have to move out, she basically said oh well then when you get an institution then we’ll talk. Well I subsequently moved over to Childrens Hospital. I did get an institution. I did put a grant in. And submitted it three times. And basically it went nowhere. Absolutely nowhere.


Connett: Ok, what I’d like to do now is to ask about the two people you were associated with at Forsyth Dental Center. There was Harold Hodge and Jack Hein.

Mullenix: Yes.

Connett: Could you tell me the background on these two people?

Mullenix: Jack Hein was the director of Forsyth and he’d been the director for many, many years. But prior to being the director of the Forsyth Dental Center he was actually head of the dental laboratories I believe for Colgate. And he maintained the status of a consultant for Colgate for many years. But most importantly Jack Hein was the individual that was responsible for MFP.

Connett: Monofluorophosphate.

Mullenix: Right. And really the individual responsible for fluoride being put in toothpaste in the first place. So he had a very long history in the study of fluoride.

But more than that, Jack Hein was the student of Harold C. Hodge. And Harold Hodge was one of the founders of the Society of Toxicology. He was also one of the chief pharmacologists of the Manhattan Project, and in that Manhattan Project he had done a lot of the studies on toxicology of fluorides, in looking at the adverse effects that you could expect from fluoride exposures extending from the exposures to uranium hexafluoride.

So Jack Hein as a student of Harold Hodge’s, and at the University of Rochester at the time when this is going on, he actually did experiments under Harold Hodge’s supervision.

And, then when I came into Forsyth, Jack Hein wanted this toxicology department to be set up – and I felt it was a great thing to do – Jack Hein suggested that Harold Hodge was retiring from his current professor position, and that it would be a great thing if we could get Harold Hodge to retire and come to Forsyth and join in our department and become a part of the toxicology department.

So Harold Hodge came in 1983 to the Forsyth Dental Center and became a member of the toxicology department that I was made the head of.

Connett: And he was pretty famous at that time as being one of the gurus of fluoride. He’s written books on fluoride.

Mullenix: Oh, Dr. Hodge did all of the research during the Manhattan Project, was responsible for directing all of the studies, he’s published major works, is known internationally… [and] was responsible for the data that was used as the basis for all of the fluoridation projects in this country. He’s written a book on Fluorine Chemistry. You will see his works through a lot of publications through the Atomic Energy Commission. So, yes, he was very much connected with the fluoride issue.

Connett: But it’s only much, much later that you have discovered that he had, in fact, proposed looking at fluoride’s impact on rat brain, or rat behavior, many years before.

Mullenix: Yes, now that was a real shock to me. Because, when I was at Forsyth in 1983, and one of the reasons I was brought over from Childrens Hospital to Forsyth was because they knew what I was doing – I was working on developing a computer pattern recognition system with Dr. William Kernan, a physicist, and we were trying to develop this system and we had explained what we were going to use it for – how it was an objective measurement, how it could be applied – and Dr. Hein thought this was a fabulous thing, and the institution really supported and pushed this.

And so, as we were working on this computer system, Dr. Hodge would come up every day, and see how we were doing, see how we were progressing. He would ask multiple questions about how we did this and how we did that…

But he didn’t say anything about any particular knowledge about fluoride and the effects on the central nervous system. The only thing he talked about, at that time, was about how weird it was during the Manhattan Project, how one scientist couldn’t talk to another scientist and go from one laboratory to the next. But he never said anything that he knew that fluoride would affect the central nervous system. Not in those seven years between 1983 and 1990 when he died.

So I was shocked then in 1996, after Dr. Hodge’s death, that some investigative reporters, Joel Griffiths and Cliff Honicker, presented to me various documents, declassified documents. And of the documents in this whole series of papers was a request from Harold Hodge to the military, or Colonel Stafford Warren, saying something to the effect that they wanted money to do studies to look at the effects of fluoride on the central nervous system in an animal model.

And they specifically stated that they had evidence, clinical evidence, that fluoride would cause confusion, drowsiness, lassitude, and that they were afraid that workers who worked with uranium hexafluoride were going to become a danger, either to themselves or to other people that they were working with, if they should have their brains effected by fluoride, and that they thought that this is something that should be examined.

So they asked for money to set this up. The military gave them money to do this project, they set up a budget. And then there was another document, not six months later, saying to stop these studies, or if they’ve started them, or haven’t started them, not to start them.

And so I saw this series of documents. I was totally shocked. Because that told me for the first time that Harold Hodge knew that fluoride affected the central nervous system. And yet, I thought, and he led me to believe, or they let me believe, that I was doing something that had never been done before, that there was no connection between fluoride and the central nervous system, that it all went into the bone, and it [didn’t] affect the central nervous system.

So when I saw those documents I called up Dr. Hein. I asked him, I said did Harold Hodge ever tell you that he’s done studies on the effects of fluoride on the central nervous system, and that he tried to do a study in animals like I did, published in ’95, that he tried to do that fifty years ago, and that it was stopped?

And Dr. Hein told me no, that he didn’t know anything about that. I asked him if he knew anything about the existence of these documents, and he said no, that Dr. Hodge never mentioned anything.

Connett: That’s an amazing story. So he had to wait fifty years to see the outcome of an idea…

Mullenix: Of an idea that was from fifty years ago.

And I don’t know why, I mean I have no idea if that was the reason that they brought a neurotox person in to study in a dental institution, and let them develop a computer pattern recognition system that was really quite risky at the time, and very expensive to do, to let me take the time, to let me put resources into that, and then study fluoride? I mean, it kind of boggles the imagination, how this connection was made.


Connett: Well, Phyllis, to wrap up, how do you see… explain all of these strange things happening to you?

Mullenix: I wish I understood it. I really don’t.

I feel like, number one, I was betrayed. That Dr. Hodge never explained to me that he knew that fluoride affected the central nervous system. Perhaps he was signed to secrecy because it was the Manhattan Project. Perhaps not. I don’t know. I will never know. No one will know…

Why they would say that I didn’t work on anything dentally related when I published studies on nitrous oxide – laughing gas – it’s used by dentists. Why they said fluoride wasn’t a dental related issue. Why safety of fluoride didn’t make my research relevant at a dental institution. There’s no explanation for this. And the explanations went all around.

And then they said well, I didn’t get enough funds for my research. Except that, when I went to file another grant application, the then director, acting director of the institution refused to sign the grant. So, on one hand, they criticized me for not having money, but then they wouldn’t sign my grant, you know, to go and get another grant money. And it was all very bizarre.

So I couldn’t tell you, really, what the reasons are why I was fired.

Connett: But clearly, clearly the National Institute of Dental Research and others in Washington were very, very concerned of the ramifications of…

Mullenix: Oh, absolutely. Even after [the television conference], there were phone calls from the ADA; there were phone calls from Pat Bryant, will you please give us a copy of the paper? And I still wouldn’t do it until all of the editorials, and all of the peer review, was totally done. And that television conference took place in early June [1994], and I was still getting phone calls into the fall of that year trying to get their hands on the paper. And I didn’t actually put the paper in their hands until like January, when it was already committed that it was going to come out in a journal.

Connett: Obviously you sensed that they were going to try sabotage that in some way?

Mullenix: I was nervous. It was inappropriate to be demanding copies of a paper before it was finished with a peer review system. I wasn’t about to have that happen. Both the NIDR and the ADA wanted copies of this paper before.

Also, right after that television conference, they asked for a copy of every thing I’d written on this technique, all the substances that I studied. And I sent down a whole packet, almost my entire publishing career to them for their review and they looked through it.

Connett: And, finally Phyllis, before this happened, would you have described yourself as an environmentalist?

Mullenix: Oh my, no. [laughs]

Connett: Ok, would you have…

Mullenix: As a matter of fact, I mean, I did a lot of consulting for industry. I was a laboratory scientist and I really didn’t get into any political…

Connett: An activist, would you have described yourself as an activist?

Mullenix: Oh my word no. I was a bench scientist. I liked working with my rats. I still like working with my rats. I prefer them, they make more sense some times than people. [laughs] And I would like to go back to doing the rat [studies], because this whole thing has been totally destructive.

So I wouldn’t consider myself an activist at all. Even today, after what I’ve gone through. I wouldn’t consider myself an activist. I just simply want to do the research that obviously needs to be done in this situation. And I’d like to go back in. But I cannot get the approvals. I cannot get the support or the funding, or even the approval by institutions that this research can go forward. Because there’s simply no money to do it. And no help from the government to go forward with this issue.

Connett: Phyllis Mullenix, thank you very much.

Mullenix: Thank you.