Your thyroid is a small gland that controls how your body uses energy, and sometimes it attacks itself, causing disease. Scientists have discovered that tiny minerals in your food—like selenium, zinc, and iron—play important roles in keeping your thyroid and immune system healthy. When you don’t get enough of these minerals, or sometimes when you get too much, your body’s defense system can go wrong and start attacking your thyroid. This review looks at what we know about seven key minerals and how they affect thyroid disease, showing that eating the right amounts of these nutrients might help prevent or manage thyroid problems.

The Quick Take

  • What they studied: How seven different minerals (iodine, selenium, vitamin D, zinc, iron, copper, and magnesium) affect thyroid disease where the body’s immune system attacks the thyroid gland
  • Who participated: This was a review of existing research, not a new study with participants. Scientists looked at many previous studies to understand what we know about minerals and thyroid disease
  • Key finding: Getting the right amount of certain minerals—especially selenium and vitamin D—appears to protect against thyroid disease by reducing inflammation and helping the immune system work properly. However, too much or too little of some minerals like iodine can actually increase disease risk
  • What it means for you: Eating foods rich in these minerals or taking supplements might help prevent or manage thyroid disease, but you should talk to your doctor before making changes, especially if you already have thyroid problems

The Research Details

This is a narrative review, which means scientists read through many published studies about minerals and thyroid disease, then summarized what they learned. Instead of doing a new experiment with people, the researchers looked at the evidence that already exists to understand how different minerals affect the thyroid and immune system.

The scientists focused on seven specific minerals that seem most important: iodine (which your thyroid needs to make hormones), selenium (which protects cells from damage), vitamin D (which helps control immunity), zinc (which helps immune cells work), iron (which carries oxygen), copper (which helps with energy), and magnesium (which helps muscles and nerves). They looked at how each mineral works in your body and what happens when you don’t have enough or have too much.

The review examined both how these minerals help your thyroid work normally and how imbalances can trigger your immune system to attack your own thyroid. The scientists also looked at the complicated relationships between minerals and disease—for example, with iodine, a little bit is good, but too much can be bad (called a U-shaped curve).

This type of review is important because it brings together information from many different studies to see the big picture. Instead of relying on one small study, scientists can identify patterns across lots of research. This helps doctors and patients understand which minerals are most important for thyroid health and where we need more research. The review also highlights that we don’t fully understand how all these minerals work together, which helps scientists know what to study next.

This review was published in a well-respected scientific journal (Frontiers in Immunology), which means it went through quality checks before publication. However, because it’s a review of other studies rather than a new experiment, the strength of the findings depends on the quality of the studies it reviewed. The authors were honest about what we know well (like selenium’s protective effects) versus what we still need to learn (like how copper and magnesium affect thyroid disease). The review focuses on evidence-based information rather than speculation.

What the Results Show

The research shows that selenium and vitamin D have the strongest protective effects against thyroid disease. Selenium works by reducing oxidative stress (damage from harmful molecules) and helping special immune cells called regulatory T cells function properly—these cells tell the immune system to stop attacking the body’s own tissues. Vitamin D works similarly by controlling how immune cells develop and helping maintain the balance between different types of immune responses.

Iodine has a complicated relationship with thyroid disease. A small amount is absolutely necessary because your thyroid uses it to make thyroid hormones. However, too much iodine can trigger thyroid disease in people who are at risk. This is why the relationship looks like a U-shape on a graph—too little is bad, too much is bad, but the right amount in the middle is good.

Zinc, iron, copper, and magnesium all appear to play roles in thyroid disease, but scientists don’t yet fully understand exactly how. These minerals are involved in immune function and protecting cells from damage, but more research is needed to know the best amounts and how they interact with each other.

The review found that these minerals don’t work in isolation—they interact with each other in complex ways. For example, selenium needs adequate iodine to work properly, and vitamin D helps the body absorb and use other minerals. The research also shows that imbalances in these minerals can cause oxidative stress (cellular damage) and allow immune cells to develop abnormally, both of which can trigger thyroid disease. Additionally, the review notes that genetic factors determine who is at risk for thyroid disease, but environmental factors like mineral imbalances can trigger the disease in susceptible people.

This review builds on decades of research showing that nutrition affects immune function and thyroid health. Previous studies have established that selenium and iodine are critical for thyroid hormone production, and newer research has expanded our understanding of how vitamin D controls immunity. This review goes further by examining all these minerals together and explaining the mechanisms—the actual biological processes—by which they affect thyroid disease. It also highlights that while we know a lot about selenium and vitamin D, we have significant gaps in understanding the roles of zinc, iron, copper, and magnesium.

Because this is a review of other studies rather than a new experiment, the findings are only as strong as the studies reviewed. Many studies on this topic are small or done in animals rather than humans. The review also notes that most research has focused on deficiency (not enough minerals) rather than excess, so we know less about what happens when people get too much. Additionally, most studies look at one mineral at a time, but in real life, people consume many minerals together, so we don’t fully understand how they interact. The review also points out that genetic differences between people mean that mineral needs may vary, and what works for one person might not work for another.

The Bottom Line

Based on moderate evidence: Ensure adequate intake of selenium and vitamin D through diet or supplements, as these appear to have the strongest protective effects against thyroid disease. Based on weaker evidence: Maintain adequate but not excessive iodine intake—follow standard dietary guidelines rather than supplementing unless directed by a doctor. Based on emerging evidence: Ensure adequate zinc, iron, copper, and magnesium through a balanced diet, though more research is needed to determine optimal amounts for thyroid health. Important: Talk to your doctor before starting any supplements, especially if you have thyroid disease or a family history of it.

People with a family history of thyroid disease should pay attention to these findings, as should anyone with diagnosed thyroid disease. Women are more likely to develop thyroid disease than men, so this information is particularly relevant for women. People in areas with very low or very high iodine in the water and soil should be especially careful about iodine intake. However, if you have normal thyroid function and no family history, eating a balanced diet with a variety of foods should provide adequate minerals without special supplementation.

If you start adjusting your mineral intake, it may take several weeks to months to see changes in thyroid function, as the thyroid works slowly. If you’re trying to prevent thyroid disease, consistent good nutrition over years is more important than short-term changes. If you already have thyroid disease, mineral adjustments work best alongside medical treatment, not as a replacement for it.

Want to Apply This Research?

  • Track weekly intake of selenium-rich foods (Brazil nuts, fish, eggs), vitamin D sources (fatty fish, egg yolks, sunlight exposure), and iodine-containing foods (seaweed, dairy, eggs). Use a simple checklist: Did you eat selenium sources 3+ times this week? Did you get vitamin D 4+ times? Did you include iodine sources 5+ times?
  • Add one selenium or vitamin D rich food to your daily routine—for example, eat one Brazil nut daily for selenium, or add an egg to breakfast for both selenium and iodine. If using the app, set a daily reminder to log these foods and track consistency over 8-12 weeks to see if you notice improvements in energy or thyroid symptoms.
  • Every 3 months, review your mineral intake patterns and note any changes in energy, mood, or thyroid-related symptoms. If you’re taking supplements, get thyroid function tests (TSH, free T4) done annually with your doctor to ensure your mineral intake is supporting healthy thyroid function. Use the app to identify any mineral gaps in your diet and adjust accordingly.

This review summarizes scientific research about minerals and thyroid disease but is not medical advice. Thyroid disease is a serious condition that requires professional medical care. Do not start, stop, or change any supplements or medications without talking to your doctor first. If you have thyroid disease or symptoms like fatigue, weight changes, or temperature sensitivity, see a healthcare provider for proper testing and treatment. This information is especially important if you’re pregnant, breastfeeding, or have other health conditions, as mineral needs change in these situations.