Selecting an iodine supplement may seem anything but straightforward. Some contain iodine, while others have iodide or a combination of the two. And the dosages can be vastly different.
Yet one thing is certain — iodine is vital to your body. Its best-known role is in thyroid health. But, the mineral is found in every tissue of your body. (1)
Many people don’t get enough of this essential mineral. In fact, iodine intake in the United States has significantly decreased since the 1970s. (2)
On top of that, toxins may interfere with your cells’ ability to take in or use iodine. These toxins include bromide and fluoride found in food, water, and the environment.
This article explains what to look for in an iodine supplement. That includes the difference between iodine and iodide. Plus, discover an ingredient that helps counteract toxins that interfere with iodine.
What Is Iodine?
Iodine is a naturally-occurring trace mineral. It is vital to your health. But you need relatively small amounts compared to major minerals like magnesium and calcium. That’s why iodine is called a trace mineral. (3, 4)
Iodine is sometimes referred to as a halogen. That’s a non-metallic element in the same group as bromine, chlorine, and fluorine.
Some everyday places you encounter halogens include water, light bulbs, and salt. (In a bit, you’ll read more details about this and how some common halogens interfere with iodine.)
Halogens can join with certain elements to form a halide, which is a salt. For example, when iodine joins with potassium, it forms potassium iodide. The “ide” ending indicates the salt form. Potassium iodide is a salt commonly used to fortify table salt with iodine.
Do you think you’re getting plenty of iodine from salt in your diet? Quite possibly, you’re not.
Only 15% of daily salt intake is from table salt. The rest comes from processed foods and restaurant foods. This salt is often non-iodized. Why? Some food producers don’t like the way iodine makes food taste. (2)
On top of that, the mineral isn’t abundant in many foods.
You can get iodine from eggs, milk, seafood, and seaweed. But you may be restricting these items due to food allergies or intolerances. And seafood carries concerns of heavy metal contamination. (2)
So, it’s time you give iodine and supplementation a closer look.
What Does Iodine Do for the Body?
Many roles of iodine are intertwined with your thyroid gland. That’s because you need the mineral to make thyroid hormones. About 70–80% of iodine is stored in your thyroid gland. (4)
Your thyroid is a butterfly-shaped structure in your neck. It helps regulate many body functions, including calorie-burning and body temperature. (5)
Have you heard of T3 (triiodothyronine) and T4 (thyroxine)? These are thyroid hormones. The numbers indicate the atoms of iodine. In other words, T3 has three iodine atoms, and T4 has four iodine atoms. T3 is the active form made by removing an iodine atom from T4. (6, 7)
Thyroid hormones help regulate cells and tissues throughout your body. For example, they can affect the function of your liver, kidneys, brain, heart, gut, and muscles. They’re also involved in regulating your mitochondria, the tiny “power plants” in your cells. (8)
In short, most organ systems in your body are influenced by thyroid hormones — either directly or indirectly.
Because thyroid hormones help regulate so many vital processes, a variety of symptoms can appear if you’re low in iodine. These include: (5, 8, 9, 10, 11)
- Hypothyroidism (low thyroid function)
- Goiter (enlarged thyroid gland)
- Impaired development in infants
- Poor concentration and learning
- Intolerance to cold temperatures
- Weight gain, despite efforts to control it
- Heart disease, abnormal heart rate
Poor mitochondrial function
- Skin dryness
Excessive hair loss
Clearly, iodine deficiency and thyroid dysfunction could have far-reaching effects. And scientists are continuing to study other ways iodine could benefit your health.
Iodine also has antioxidant, anti-inflammatory, and immune-supportive properties. This may be particularly true when you take daily doses of at least 3 milligrams (mg). (12, 13)
And, it’s not just your thyroid gland that takes up iodine. The mineral is also found in your eyes, salivary glands, stomach lining, and mammary (milk-producing) glands, among other organs and tissues. Plus, animal research suggests iodine may help your immune system guard against parasites. (4, 12)
Lastly, taking supplemental iodine (as potassium iodide) is considered protective in nuclear accidents. Filling your thyroid gland with iodide limits how much radioactive iodine the gland can absorb from the atmosphere. (14, 15)
For these reasons, this often-overlooked mineral should be a cornerstone of your wellness protocol.
How Much Iodine Do You Need?
Dosages listed on iodine supplement labels tend to cluster around either 150 micrograms (mcg) or 12.5 mg. That’s a big range, considering that 1 mg = 1,000 mcg.
So, how much do you need?
The Reference Daily Intake (RDI) for iodine is set at 150 mcg. But it’s important to understand what the RDI represents. (16)
In short, the RDI is the amount needed to avoid overt disease — like a goiter. But the RDI is not the amount needed to support optimal health throughout your body. (2)
Scientists have also set a Tolerable Upper Intake Level (UL) for iodine. The UL for iodine is 1,100 mcg, which is equivalent to 1.1 mg.
By definition, the UL is: “The highest average daily nutrient intake level that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the potential risk of adverse effects may increase.” (17)
That said, people exceed the UL for iodine in moderately high doses without harm. Your thyroid gland has regulatory mechanisms that control thyroid hormone production. This helps it adapt to wide variances in how much iodine is available. (13, 18)
And taking in amounts beyond the bare-bones RDI could provide additional benefits.
For example, in one study, women with normal thyroid health but monthly breast pain took 6 mg of iodine daily for six months. About 50% of them had a significant reduction in breast pain related to their monthly cycles. (19)
And in Japan, iodine intake from seaweed is estimated to be as high as 20 mg daily. Seaweed intake has been linked with a lower risk of premature death from any cause. Also, people in Japan have a lower cancer rate and a low rate of fibrocystic breast disease. Though this research can’t prove cause and effect, it’s intriguing. (20, 21)
The work of the French physician Jean Lugol nearly two centuries ago is also key. He developed a liquid supplement with 5 mg of iodine and 7.5 mg of iodide. That provided a total of 12.5 mg of iodine per dose. This was commonly recommended in pharmacy reference books. (22)
Today, the amount of iodine and the ratio of different forms of iodine in Lugol’s formulation are guides used by some functional medicine practitioners.
Keep reading to find out how iodine and iodide may support your health in different ways.
Is There a Difference Between Iodine and Iodide?
The terms “iodide” and “iodine” are often used interchangeably, but they’re not quite the same.
As mentioned earlier, iodide is the salt form of iodine. Commonly, this is an iodine atom bound to a potassium atom to form potassium iodide. (By the way, you may also see the term nascent iodine, which just means a single iodine atom.) (23, 24)
Another difference between iodine and iodide is how they enter cells. Iodine can diffuse into your cells. But iodide needs help to be transported into cells. This help comes from symporters. These are like tiny taxi cabs that help the iodide move through cell membranes. (25)
Also, some tissues of your body may preferentially store different forms of iodine. So, iodine versus iodide (and vice versa) may be more effective for supporting particular tissues and organs.
Studies suggest the following preferences for different forms of iodine:
Thyroid gland: Iodide may be the preferred form. In a study of iodine-deficient rodents, iodide was more effective at restoring thyroid health than iodine. (22, 25, 26)
Breasts: Human research suggests iodine may be superior to iodide for helping fibrocystic breasts and breast pain during women’s monthly cycles. And animal research suggests iodine may support breast cancer prevention. More studies are needed in this area. (19, 27, 28, 29)
Pituitary gland: Iodine may be the preferred form. Still, the pituitary gland will take up some iodide. Your pituitary gland releases hormones into your bloodstream, including thyroid stimulating hormone (TSH). That signals your thyroid gland to release thyroid hormones. (28)
Prostate gland: The best form of iodine might depend on the health of the cells. A lab study found that healthy prostate cells responded well to iodide. But cancerous prostate cells responded best to iodine. Further research is needed to clarify potential benefits in this area. (30)
Given the evidence at this time, you’ll get broader support when you supplement with both forms of iodine. Just keep in mind that sometimes the term “iodine” is used as a blanket term for both forms of the mineral. But a distinction between the two is often made on supplement labels.
Getting both forms of iodine isn’t all that you should consider when supplementing with the nutrient. Other factors can support the effectiveness of iodine supplements, as explained next.
Maximizing the Effectiveness of Iodine Supplements
It’s not hard to find supplements with both iodine and iodide in them. Still, some experts say the distinction between the two forms is unnecessary. They explain that the iodine you take is mostly converted to iodide in your gut. (31)
But here’s the clincher: Whether iodine is converted into iodide can depend on how the supplement is formulated.
There’s a way to protect the iodine in your gut and keep it from being converted to iodide. That’s by using specialized extracts of fulvic acid.
Iodine can be folded into these extracts to shield it in your gut. Think of it as protective armor for the iodine. This way, iodine can be absorbed into your bloodstream and routed to organs and tissues that prefer that form of the mineral. (32, 33, 34)
The effectiveness of an iodine supplement also depends on whether your cells can take in the iodine. What would stand in their way? Toxins.
Your thyroid gland is like a pegboard. It has binding sites for iodine. But toxins often occupy the binding sites. So, you need to be able to remove the toxins and put iodine in their place before other toxins “sneak” into the binding sites.
What’s the solution to this challenge? Nature's carbons.
Humic and fulvic acids can bind toxins and hold on tight to them, carrying them all the way out of your body. This enables iodine to fill the binding sites on the pegboard that is your thyroid. The same scenario is true for other tissues and organs of your body. (35)
But, what are these toxins that hog the binding sites for iodine in your thyroid gland? One significant type of toxin is other halogens. Read more about those next.
Toxic Halogens and Your Iodine Status
Some halogens compete with iodine (or iodide) for the same receptors in your cells or the same “slots in your pegboard.” And some halogen compounds can interfere with iodine transport across cell membranes.
Here’s a closer look at halogens that could interfere with your iodine levels.
Bromine or bromide can displace iodide in your thyroid gland and increase its excretion via your kidneys. This is particularly true if you don’t consume enough iodine and are exposed to a lot of bromine. (35, 36, 37)
You can be exposed to bromine by touching, breathing, or ingesting it. This happens more often than you might think. The chemical is present in many everyday places. (38)
Some ways you could be exposed to bromine include:
Bromated flour, commonly used in foodservice baking (39)
Citrus-flavored soda, to keep ingredients suspended (40)
Dyes, such as cosmetics and tattoo ink (41)
Farming chemicals, such as fertilizers (38, 42)
Flame retardants, such as on upholstered furniture and mattresses (43, 44)
New electronics, such as computer equipment and televisions (38, 45)
Rubber products, such as tires (38)
Seawater and seafood (43)
Some prescription nasal sprays and inhalers (43)
Water disinfectants, such as for pools and hot tubs (38, 46)
Bromine is being phased out of some uses because it depletes the earth’s ozone layer. For example, methyl bromide has long been used on strawberry crops to control fungi and pests. But newer rules are limiting its use. That said, you’re still exposed to a lot of bromine. (42)
This halogen probably needs no introduction since it’s commonly promoted in dental products. But you may not know that fluoride can interfere with your body’s uptake of iodine. As with bromine, this interference is more likely if your iodine intake is low. (47, 48)
Some ways you could be exposed to fluorine or fluoride include:
Toothpaste, mouthwashes, and other dental products (49)
Drinking water, including public water and bottled water (49)
Processed foods and beverages made with fluoridated water (47)
Black tea and other teas from the Camellia sinensis plant (50)
Many medications, including some antifungal and anti-malarial drugs (47, 51)
Pesticides such as cryolite, used on some fruits and vegetables (52)
Chloride is an essential electrolyte in your body. But chlorine competes with iodine for absorption. Public water supplies and swimming pools are commonly treated with chlorine. (2, 53)
Perchlorate is another form of chlorine that is problematic. Perchlorate inhibits the symporters that would transport iodide into your thyroid cells. That could result in reduced production of thyroid hormones. (44)
You don’t need to look far to find perchlorate. It is found in cars’ airbag systems, rocket fuel, leather treatment chemicals, fireworks, and drinking water. It’s also in some fertilizers and crops irrigated with contaminated water. (44, 54)
And unfortunately, perchlorate is allowed in plastic packaging that touches food and beverages. The compound is used to control static electricity. But the chemical can transfer into your food. (44, 54)
Food and Drug Administration studies have found perchlorate in the majority of foods tested. That includes baby food, dairy products, meats, poultry, fish, fruits, vegetables, cooking oil, sweets, legumes, grain products, eggs, bottled water, and juice. (55)
Perchlorate also comes from the breakdown of hypochlorite. That’s used in household bleach. Hypochlorite is also used as a disinfectant in food processing plants. (55)
As you’re likely realizing, it would be nearly impossible to avoid all these exposures to toxic halogens.
That makes it essential that you get enough iodine. And it’s best if the iodine is formulated with carbons to help “kick out” unwanted halogens and other toxic compounds.
Supportive Nutrients and Iodine Tolerance
As crucial as iodine is, it doesn’t act alone. Other nutrients — including selenium, iron, and zinc — support the work of iodine. (56, 57)
Still, this doesn’t mean you need an iodine supplement that contains all these nutrients. You should be getting them as part of a healthy diet. And mineral-rich humic and fulvic acids can help fill in dietary gaps. (58)
Here’s a look at these nutrients’ roles in supporting your iodine status and thyroid health, along with top food sources:
Selenium: Is a vital part of an enzyme that converts the inactive T4 thyroid hormone into the active T3 form. You can get selenium in Brazil nuts, meat, poultry, eggs, oatmeal, and brown rice. (57, 59)
Iron: Is required to initiate the production of thyroid hormones. Common sources of iron include beef, dark chocolate, legumes, spinach, and cashews. (56, 60)
Zinc: Helps regulate both the production and action of thyroid hormones. Some foods that will help you get more zinc in your diet include meat, poultry, yogurt, and pumpkin seeds. (61, 62, 63)
Deficiencies of these nutrients can limit the effectiveness of iodine supplements. So, make sure you’re getting enough. Taking supportive minerals for a month or two before starting iodine supplementation may also help with your tolerance of iodine. (56)
And if you have a thyroid condition, it’s important to start with a low dose of iodine and increase it slowly. It’s also wise to track your symptoms and have a functional medicine practitioner monitor your thyroid markers.
Lastly, realize that replenishing your body’s iodine stores takes time. It’s like a marathon, not a quick sprint.
Iodine and Iodide for Whole-Body Health
At best, your diet likely only supplies enough iodine to avoid developing a goiter. But every tissue in your body utilizes iodine, so it’s time to think much bigger.
To get the iodine you need to support the health of your body from head to toe, you generally need to supplement the mineral.
That’s because few foods supply much iodine. Plus, bromide, fluoride, and perchlorate interfere with your cells’ iodine uptake.
Some tissues of your body may respond better to iodine versus iodide and vice versa. So, choose a supplement that supplies both.
Also, look for humic and fulvic acids in an iodine supplement. This functions to protect iodine, so it’s absorbed in the needed form. These carbons also vigilantly removes toxins from iodine receptors and enables your cells to take in the iodine.
How are you going to make sure your body gets enough iodine and iodide?