Thyroid Health and Environmental Stress: Expert Insights

What is the primary function of the thyroid? What effect does iodine or fluoride have on the thyroid? These are some of the interesting things that Dr David Brownstein and I discussed in the podcast and which I will be pondering on today.

15 years ago, I encountered a holistic and integrative medical practitioner when I read his book about Iodine, and this week I am delighted to have him as a guest. Join me as I talk about some of the highlights of our conversation.

Thyroid Health: Nutritional and Environmental Stress

Now, this week had the pleasure of speaking to Dr David Brownstein, a holistic, integrative medical practitioner with over 30 years of experience from Michigan in the United States. He is the author of 16 books. We have links to them in our show notes.

The books are accessible to patients. The first time I ever encountered David was when I got his book on Iodine, 15 or more years ago. I have been impressed that he now has over 16 books on thyroid function, holistic medicine, what supplements work, what medicines don’t, what is holistic medicine, and how to deal with viruses.

Thyroid Function

We covered a lot of these topics in the podcast this week, but I thought I would focus a little bit on thyroid function because the thyroid gland is a really important gland in terms of regulating the body. The thyroid hormone controls the way your body uses energy. They affect nearly every organ in the body. 

Vitamin D, I think there is a hormone receptor on almost every cell in the body for thyroid hormone and Vitamin D. So they are incredibly important. How common is it? Well, some estimates put it as high as 5% of the population and estimate that even the 5%, at least are undiagnosed. 

Women are ten times more likely to have it than men. Underactive or overactive thyroid. Underactive I think is called Hashimoto’s and overactive is called Graves’ Disease. It is often a form of an autoimmune condition. Now there are over 100 autoimmune conditions. Now that is the body attacking itself

Now if your predisposition, family predisposition was thyroid, particularly if you are low in iodine, which is what we talk about in this podcast, then you would be more susceptible to the autoimmune condition manifesting itself as an underactive or overactive thyroid. If your predisposition was neurological, you might be predisposed to multiple sclerosis or Parkinson’s disease. 

If your autoimmune condition or family predisposition with the joints in your body, then rheumatoid arthritis might be the problem. If it was the gut, it might be Crohn’s disease or Coeliac disease. It goes on, but there are some interesting correlations between all of these autoimmune conditions, and it’s often overlooked actually.


Well, iodine was one. This was an important one to draw to your attention because I had the privilege in my original podcast, The Good Doctors Healthcare Unplugged, in which I did over 180 episodes from 2013 to 2016.

I had the pleasure once of speaking with a Professor of Medicine at Sydney University, Professor Creswell Eastman, and the ABC Health Programme Catalyst once did a programme on him and the title was The Man Who Saved a Million Lives. 

The reason was he went to China, identified a whole area that was deficient in iodine, and started a public health programme to ensure that the diet supplementation was adequate. Therein inlay the man who saved a million lives.

I remember asking Professor Cresswell Eastman this question: Does fluoride have the potential to displace iodine from the thyroid gland? He mentioned to me that in fact in the first part of the 20th century, fluoride was used to treat overactive thyroid. If your thyroid was overactive, then you would be given a fluoride supplement to displace some of the iodine in your thyroid gland and that would downregulate thyroid function. 

This is going back to high school chemistry. This is interesting because remember the periodic table, you would have studied it in chemistry or in physics, and you may recall a group of elements in the periodic table called halogens. Halogens included iodine, fluorine, chlorine, and bromine. 

Why is that important? Well, in Australia our water supply is supplemented with fluoride and as a dentist, I was very impressed with what I thought I was seeing in my practise, which was a significant reduction in tooth decay. 

There’s no question the rate of tooth decay in Australia has gone down dramatically in the last 40 or 50 years. And so to an unsuspecting dentist you might just go, “Well, there’s the fluoride, it’s just doing its job.”. 

Until I engaged in this topic about 15 or 20 years ago and read a little bit more than what the Australian Dental Association, a newsletter, or journals were publishing because when you look at the WHO incidence of decay and you look at the incidence of decay in countries like Australia, New Zealand, the UK, and the US, you see the decay rates have gone down quite dramatically and you think, “well there it is, it’s so obvious. 

That’s why we supplement the water supply with fluoride.” Except when you look at the other 10 or 15 countries in Europe, Scandinavia, and Japan that haven’t fluoridated the water, and you realise that the trend lines are almost indistinguishable from those that have, you start to think, “Okay, maybe something else is going on here besides fluoride.”.

Oral Hygiene

Something else I believe is indeed going on because when I was growing up, oral hygiene was not even talked about really. It is now almost everybody, I believe, would at least be brushing twice a day, and for those people that are very diligent and aware of their oral health, they would also be flossing once a day as well. Brushing twice a day is an important thing.

I don’t think people did that as much prior to the last 40 or 50 years. Fluoride is used to supplement the water to reduce tooth decay, well, when you put countries that have been fluoridated and haven’t been fluoridated together, they’re almost indistinguishable. 

When you study biochemistry and you learn about all the biochemical pathways and you learn how the 30, 40, or 50 elements of the periodic table, as well as essential fatty acids and vitamins and minerals, are all used in those pathways, you realise that fluoride is not used in any biochemical pathway, therefore, it is an additive, a medicine which is added to our water supply and I have serious concerns about that. 

I remember asking Professor Eastman, “If you had a choice really, and remember iodine deficiency affects 2 billion people globally. It is the biggest deficiency in the world. If you had a choice of supplementing the water supply with iodine or with fluoride, what would you choose?” I think he may have mentioned that iodine would have been his preference.

Chlorine is another halogen

What is another halogen? Chlorine is another halogen and we have chlorine in our water supply to reduce the bacterial load and bring clean water, and safe drinking water to our tap. I’m very grateful for that. 

I think what I have done in my own home is have a reverse osmosis water filter, which takes everything out, including the chlorine, the fluoride, and any other pollutants that may have been picked up along the way. There are many in our water supply and gives me almost well, I think it’s like distilled water almost, and that’s not necessarily a good thing. 

I also add some Himalayan rock salt or the Celtic Sea Salt to my water and bingo, I’ve got clean water from my own tap with some minerals put into it because Himalayan rock salt and the Celtic Sea Salt have between 40, 50, or 60 elements which we require for healthy for biochemistry to function optimally.

Iodine Deficiency

We talked about iodine deficiency. We are aware that some of these other halogens and other halogens. Now, bromine, you might think, where would I ever get bromine from? 

If you have any fire retardants in your furniture, in your clothing, particularly in your pajamas, in embedding, in mattresses, or in pillows, then you are exposed to bromine. That has the potential also to displace iodine and cause potential problems with the thyroid gland. 

Now, it’s worth mentioning that the thyroid gland is part of the endocrine system. We have from top to bottom the pineal gland, the pituitary gland, the thyroid gland, the pancreas, and the adrenal glands. 

Now the adrenals are interesting because the thyroid actually regulates our metabolism. If you liken it to a car when we’re idling along just humming along nicely, the thyroid is working optimally. When we’re wanting to put our foot on the accelerator, when we’re under stress, the adrenals kick in. 

This is when there is an overload of stress and an overload of adrenal function. People sometimes refer to it as adrenal fatigue. It is an overactive stress response.

The testes and the ovaries are other examples of endocrine of the endocrine system. The reason I mention it is because another problem, apart from iodine deficiency that causes a problem with the thyroid is what are called endocrine disrupting chemicals. Where would they be? 

If you go back and have a listen to Marc Cohen, the podcast I did with Mark Cohen on his Ten Toxic Truths, you will know that there are many chemicals. In fact, I think Marc estimated that we are exposed in our modern world to over 100,000 chemicals. You might be excused for thinking that each and every one of those chemicals have gone through some rigorous testing. 

In fact, only a small percentage, less than 5%, have gone through rigorous testing. By rigorous testing, I mean testing of one chemical at a time for a period of two or three months, usually on a healthy volunteer, and then it is deemed to be safe.


Well, you look at any packet in any supermarket and you will recognise more than one chemical. So one chemical is not how we are exposed to chemicals. We were exposed to multiple chemicals that have synergistic effects and accumulative effects and many of those chemicals are endocrine disruptors. In food preservatives, we have parabens. 

In personal care products, we have parabens and phthalates. Plastics are ubiquitous. There are phthalates and bisphenols. In food packaging, also ubiquitous bisphenols. In clothing and furniture, perfluoroalkyl substances, which also include chlorinated products. 

Pesticides, herbicides, and fungicides are ubiquitous in commercially grown food and non-organic food. We have polychlorinated biphenyls. In pharmaceuticals and synthetic hormones, we have solvents. They are everywhere.

Endocrine disrupting chemicals together with chlorine, fluoride, and bromine, kind of make you feel like, “Oh my God, what do I do?” Well, the good news is this: By making informed decisions about these environmental toxins, you can reduce your environmental toxic load or what we refer to as environmental stress or nutritional stress. 

There’s a lot of overlap there by up to 80 or 90%. So please don’t feel like you are a victim. You are not. You are certainly posed with some challenges. We all are. But we can make a significant impact by making informed choices, which is ultimately what this programme is about. 

Autoimmune disease 

Back to thyroid function, an example in many cases of autoimmune and autoimmune disease is the body attacking itself. I made the point that depending on your genetic predisposition, your autoimmune condition may manifest in different ways. There are similarities to these autoimmune conditions and one is nutritional stress. 

That refers to intestinal permeability. Now the lining of the gut is made up of endothelial cells which are tightly joined together. If my hands represent two cells in the gut, they should be tightly joined together and my fingers represent the little villi that increase the surface area of the gut to improve absorption and digestion.

When you have a leaky gut or more recently referred to as intestinal permeability, what happens is you eat something that you may be sensitive to. When we talked to Professor Pete Smith about allergies and food sensitivities, and chemical sensitivities, he outlined many of those. 

When we have a food allergy or sensitivity, our body reacts by producing a chemical called Zonulin, which results in those tight junctions of the cells, of the gastrointestinal tract opening up. We now have a leaky gut, which means undigested proteins can enter the bloodstream and the body mounts an auto-immune response, which depending on your genetic predisposition, will manifest itself in different ways.

Food Sensitivity

Now that food sensitivity, that intestinal permeability could be triggered by a whole range of things. Now vegetables, for example, are often placed as the foundation of a good diet, and I’ve often mentioned that as well. I think, you know, we need to be aware of the potential problems with vegetables. 

Vegetables are not everything they’re cracked up to be. They are stationary living things. They cannot run away from their prey. Those that want to consume them that would be insects or animals or even us. And so they put out various protective chemicals like oxalate, phytates, salicylate, fodmaps. 

The list of nightshades. A lot of vegetables have a lot of protective chemicals built into them to protect themselves from predators like insects, animals, and us. Those protective chemicals are potential triggers for causing a leaky gut to occur.

Some people who have had long-lasting autoimmune conditions choose to go on a carnivore diet. Yes, an animal-based diet. I draw that distinction here. Not all animals are the same, and that is important. We’ve often talked about ethically grown animals, grown in an ethical way. 

So then, they have a happy, healthy, natural life and they only have one bad day in their life, and that’s the day they die. That is the kind of animal-based food that we are wanting to consume. Many people who have long, protracted, frustrating autoimmune conditions go on an animal-based carnivore diet, eliminating yes, eliminating vegetables from their diet, including grains, of course. 

That’s another story because the modern grains are short, the semi dwarfed high yield grains and they are very high in gluten. Gluten intolerance, which is manifest as another autoimmune condition called Coeliac, is one thing where all those villi that I referred to have been denuded. So they’re not there anymore. But you can be intolerant to gluten without being a coeliac and guess what that’s called non-celiac gluten intolerance.

These kinds of vegetables, be they vegetables or be they grains, have the potential to cause leaky gut or intestinal permeability. In turn, will result in an autoimmune condition of which underactive or overactive thyroid is an example. 

Look, I thought I would just highlight a couple of things. In addition to the thyroid issue, which we touched on in the podcast with Dr David Brownstein, I thought it was a great conversation. I’ve known him for over 20 years and I was really excited to have him on the programme.

It was great to connect and I am looking forward to staying in contact with him and maybe even bringing him out to Australia to do some courses. I’d recommend you have a look at it, and certainly have a look at his brilliant books. We’ll have links to those in his show notes. I hope this finds you well. Until next time.



This podcast provides general information and discussion about medicine, health, and related subjects. The content is not intended and should not be construed as medical advice or as a substitute for care by a qualified medical practitioner. If you or any other person has a medical concern, he or she should consult with an appropriately qualified medical practitioner. Guests who speak in this podcast express their own opinions, experiences, and conclusions.