I recently interviewed Dr. Alan Christianson, widely regarded as a premier expert on thyroid issues, and Ashley Armstrong, a regenerative farmer and founder of Angel Acres. Our discussion explored the intricate relationship between iodine intake and thyroid health, uncovering a paradox that has significant implications for your health.
To understand the current iodine dilemma, we must rewind to the early 20th century. In the 1920s, iodine was added to table salt as a public health measure to prevent goiters — a swelling of the thyroid gland. Christianson explained that before iodine fortification, autoimmune thyroid disease was a rarity in medicine. However, within a decade of adding iodine to foods, rates among adult women skyrocketed, increasing up to 26-fold.
This historical intervention, intended to correct deficiencies, inadvertently set the stage for widespread thyroid issues. Armstrong emphasized the interconnectedness of iodine fortification across the food chain, including the mistaken belief that “if humans are deficient in iodine, then animals must be deficient too.”1 So, iodine was added not just to human salt but also to animal feed, resulting in significantly higher iodine levels in animal products and processed foods.
Iodine Overload Is a Modern Epidemic
Fast forward to today, and the narrative around iodine has taken a troubling turn. While there was once a legitimate concern about iodine deficiency, modern food production systems have transformed iodine into a stealthy toxin.
Armstrong highlighted, “The iodine content, which impacts thyroid health, has significantly increased in our food production system over the last 20 to 30 years.” This over-supplementation has led to an epidemic of thyroid dysfunction, including autoimmune thyroid disease, where your body attacks its own thyroid gland.
Christianson added, “Iodine accumulation is a really big problem that our nation is facing. It’s one of those government interventions — oops — that have unintended consequences.”2 The excessive iodine intake is pervasive, stemming from various sources beyond fortified salt, making it difficult for individuals to control their iodine levels.
Sources of Excess Iodine Beyond Table Salt
The underlying sources of modern iodine overload isn’t limited to fortified table salt. Christianson and Armstrong shed light on various sources contributing to excessive iodine intake:
1. Animal feed — Conventionally raised livestock are routinely supplemented with iodine, significantly increasing iodine levels in animal products. Armstrong emphasized that if animals are supplemented with iodine, the iodine levels in products like eggs increase five to 10-fold.
2. Dairy cleaning practices — The dairy industry commonly uses iodine-based disinfectants to clean teats and equipment. Although a hot water rinse helps mitigate iodine residues, the pervasive use of iodine teat dips introduces an additional, often unnoticed source of iodine into dairy products.
3. Processed foods — Iodine additives in processed grains and salt heavily fortify the food supply, making it challenging to control individual iodine intake if you consume processed foods. Christianson noted that many processed grains contain iodized dough conditioners. Even those that don’t explicitly list iodine often have significant levels when tested.
4. Personal care products — Iodine is prevalent in numerous personal care products, including some acne treatments, contributing to daily iodine exposure without consumers’ awareness. Armstrong pointed out, “Many common acne treatments contain a lot of iodine because of its antifungal and antimicrobial properties.”
5. Seafood and kelp supplements — While ocean-based seafood is a natural iodine source, fishmeal is also a common protein source for cattle feed, which increases iodine levels in eggs and dairy products.
Balancing the Benefits and Risks of Thyroid Hormone Supplementation
The conversation naturally transitioned to thyroid hormone supplementation, a common treatment for hypothyroidism. Christianson provided an important perspective that taking thyroid hormones from outside your body, even in bioidentical forms, isn’t the same as your body producing them naturally. As a result, this often leads to long-term complications.
He distinguished between T4-only medications and combination therapies (T4 plus T3), noting that the latter often yield better patient outcomes. However, both forms present challenges, especially given the variability in iodine content of natural desiccated thyroid products. Armstrong raised concerns about historical and modern practices, including the fact that in the early 1900s, cattle weren’t supplemented with iodine, so their thyroids had low levels.
Today, livestock are overloaded with iodine, making natural desiccated thyroid supplements likely much higher in iodine than historical counterparts. Christianson explained the regulatory landscape, in that prescription forms of natural desiccated thyroid are standardized for iodine content, but over-the-counter versions often lack this quality control, leading to unpredictable iodine levels.
Unraveling the Connection Between Iodine and Breast Health
Our discussion also touched upon the role of iodine in breast tissue health. Christianson elaborated on studies linking high iodine intake to increased breast cancer risk, particularly in populations with overexpressed sodium iodide symporters in breast tissue. He explained that in pathologic breast tissue, the sodium iodide symporter is overexpressed, leading to heightened iodine uptake and cellular damage.
This overexpression correlates with higher breast cancer rates, debunking earlier theories that iodine supplementation might be protective. Therefore, recommendations that promote iodine supplementation as a protective measure against breast conditions are misguided.
Christianson clarified that while high-dose iodine temporarily reduces iodine uptake in fibroadenomatous breast disease, population studies indicate that higher iodine intake is associated with increased breast cancer risk. Thus, iodine is not a protective factor for breast tissue. He explains:
“In the case of breast cancers, there have been assays looking at Japanese women and contrasting their iodine excretion, their urinary iodine in groups with their overall breast cancer risk. And those in the highest quintiles and quartiles have proportionately higher risks for breast cancer. And there’s a linear relationship. So, the more they’re consuming, the greater their risks are.”
Exploring Thyroid Health from Antibodies and Autoimmunity to Epigenetics
Our conversation also focused on the role of thyroid antibodies in autoimmune thyroid disease. Christianson emphasized that thyroid antibodies, such as antithyroid peroxidase and antithyroglobulin, are more predictive of thyroid symptoms and risks than T4 or thyroid-stimulating hormone (TSH) levels alone.
Elevated thyroid antibodies indicate an autoimmune response, which is the primary driver of thyroid dysfunction today. Epigenetics are also involved, as early iodine exposure affects thyroid health across generations. Armstrong noted, imagine being born into a womb with higher iodine levels, then supplementing with iodine throughout life and consuming a high-iodine diet. This exposure leads to accumulated iodine generation over generation.
Christianson agreed, explaining that genetic variations significantly influence how individuals metabolize iodine. Those adapted to lower iodine environments are particularly susceptible to thyroid dysfunction when exposed to excess iodine. This epigenetic and genetic interplay complicates the iodine-thyroid relationship.
Further, basal body temperature is sometimes used as a metric for thyroid health, a practice championed by Dr. Broda Barnes. However, Christianson pointed out that the development of high-sensitive TSH assays and understanding of T3 metabolism shifted thyroid assessment away from basal body temperature. While it’s true that many overtly hypothyroid individuals have lower body temperatures, the relationship isn’t as linear or reliable as once thought. Christianson noted:3
“Since Barnes’ time, we’ve learned that the thyroid basal body temperature connections are very real, but they’re not as linear, they’re not as tight as one might think. So many who are overtly hypothyroid will have a lower basal body temperature.
And during hyperthyroid storm, people often elicit a febrile response, but there’s not a linear increase in basal body temperature as one moves further into hyperthyroidism. That wasn’t understood during Barnes’ time.”
Cellular Energy and Thyroid Function
Armstrong emphasized a holistic view of thyroid health, highlighting the multiple steps involved in cellular energy production:
“Metabolic health and cellular energy aren’t just about the thyroid gland. There are four different steps after the thyroid produces thyroid hormones — T4 is produced. Then there’s transporter proteins that have to take those thyroid hormones throughout the body.
That T4 must be converted to T3, cells must be able to accept that T3 and utilize it as the spark plug for energy production. So, there are a number of things that get in the way of cellular utilization of active thyroid hormone. Even if your thyroid is functioning well, using active thyroid hormone at various other parts of your body can be hindered.”
Christianson expanded on this, explaining that different body tissues have their own thyroid hormone ecosystem with different balances of thyronamines. This means that thyroid function at the cellular level is highly individualized and influenced by various factors like insulin levels, stress and nutrient intake.
Armstrong connected this to modern dietary practices, explaining that low-carb diets downregulate thyroid hormones, increasing reverse T3 and impairing cellular utilization of T3. High omega-6 polyunsaturated fatty acid (PUFA) consumption and stress further complicate this picture, reducing your body’s ability to use thyroid hormones effectively.
Thyroid hormone metabolism is influenced by many factors, including insulin levels, nutrient availability and overall metabolic health. So, addressing thyroid issues requires a comprehensive approach that considers these interconnected systems.
In a personal revelation, I also discussed my use of photobiomodulation (previously known as low-level laser therapy) to support thyroid health during my transition off thyroid medication. Christianson acknowledged the benefits, explaining that photobiomodulation helps improve antioxidant status in your thyroid, which is necessary for processing iodine without cellular damage.
Practical Tips to Avoid Excess Iodine
The interplay between iodine intake and thyroid function is complex and often misunderstood. Excess iodine, a byproduct of historical fortification efforts and modern agricultural practices, poses a significant threat to thyroid health, contributing to autoimmune diseases and other dysfunctions.
By implementing strategic dietary changes, choosing high-quality food sources and staying informed about iodine’s role in your body, you reclaim your ability to reach optimal thyroid health.
Christianson wrote “The Thyroid Reset Diet,” emphasizing a low-iodine regimen for one to three months to detoxify your body. While Armstrong shared her concerns about maintaining nutritional balance during this phase, particularly regarding nutrients like choline, biotin and calcium, Christianson suggested that selecting high-quality eggs and dairy that are low in iodine helps meet these nutritional needs without introducing excess iodine.
Armstrong elaborated on practical strategies to reduce your iodine intake, including: “Don’t eat out as much, don’t eat food with an ingredient list, prioritize home-cooked meals … assess your supplements, stop iodine supplementation and evaluate your personal care products.” Here are additional practical strategies to avoid excess iodine and protect your thyroid health:
1. Limit processed foods — Processed grains and packaged foods often contain high levels of iodine due to salt iodization and iodine-based additives. Prioritize whole, unprocessed foods to better control iodine intake. Further, a balanced diet rich in the right carbohydrates — and free of processed foods — supports cellular energy production, which is necessary for thyroid health.
Excess PUFA intake, including linoleic acid in seed oils, is a major culprit, as PUFAs interfere with your cell’s ability to use active thyroid hormone.
2. Choose high-quality dairy and eggs — Source dairy and eggs from farmers who do not supplement livestock with iodine or use iodine-based disinfectants. Pasture-raised and organic options are more likely to have lower iodine levels.
Armstrong noted that eggs from pasture-raised chickens without iodine in their diet have as low as 5 micrograms per egg, compared to eggs from chickens supplemented with iodine, which have up to 100 micrograms per egg.
3. Assess personal care products, supplements and medications — Review all supplements and medications for iodine content. Avoid iodine-rich supplements unless medically necessary. Many personal care items, such as acne treatments, contain iodine. Opt for iodine-free alternatives to reduce iodine exposure.
4. Conduct an iodine inventory — Utilize tools like Christianson’s iodineinventory.com to track your iodine intake from all sources, including diet, supplements and personal care products.
5. Explore additional therapies — Consider therapies like photobiomodulation to support thyroid health in conjunction with dietary adjustments.
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