Can I eat sugar on a low iodine diet?

October 30, 2025 •

3 min read

According to the American Thyroid Association, sugar, maple syrup, honey, and jam are generally allowed on a low iodine diet. This often comes as a relief to those needing to temporarily restrict their iodine intake for medical procedures such as radioactive iodine therapy for thyroid cancer.

Quick Summary

Pure granulated sugar, honey, and maple syrup are safe for consumption while on a low iodine diet. It is essential to avoid sweets containing high-iodine ingredients such as dairy products, egg yolks, and certain red food dyes. Always check product labels to ensure no iodized salt or iodine-containing additives are present.

Key Points

Sugar is Allowed: Pure white sugar, brown sugar, honey, and maple syrup are safe for consumption on a low iodine diet.
Avoid High-Iodine Ingredients: The main concern with sweets is not the sugar but high-iodine additives like dairy, egg yolks, iodized salt, and red food dyes.
Read Labels Carefully: Always check ingredient lists for hidden sources of iodine, including iodized salt, sea salt, and red dye #3 (erythrosine).
Opt for Homemade Sweets: Homemade desserts made with low-iodine ingredients are a safer and more reliable option than commercial baked goods or candies.
Limit Certain Items: Avoid blackstrap molasses and certain red-dyed products like maraschino cherries and some candy.
Consult a Professional: For any specific concerns or dietary questions, always consult with your healthcare provider or a dietitian specializing in low iodine diets.

Understanding the Low Iodine Diet

A low iodine diet is a temporary dietary measure used to prepare the body for specific medical treatments, primarily radioactive iodine (RAI) therapy for thyroid cancer. The goal is to lower the body's baseline iodine levels so that the radioactive iodine can be more effectively absorbed by any remaining thyroid tissue. This diet is not intended to be a long-term nutritional plan but a targeted, short-term preparation. It requires avoiding major sources of iodine, including most seafood, dairy products, and iodized salt.

The Role of Sweeteners

Contrary to some fears, pure sugar and many common sweeteners are low in iodine and are considered safe for consumption on this restrictive diet. This includes granulated white sugar, brown sugar, honey, maple syrup, and unsulfured molasses. However, the safety of a sweet item often depends on its other ingredients, not just the sugar content. For example, a homemade dessert made with allowed ingredients is safe, but a commercially-prepared cake containing dairy or iodized salt is not.

Sweeteners and Iodine Content: A Comparison

To help navigate your options, here is a comparison of various sweeteners and their suitability for a low iodine diet.


Sweetener	Low Iodine Diet Status	Considerations
White Granulated Sugar	Allowed	Pure sugar is safe. Check for added ingredients in packaged sweets.
Brown Sugar	Allowed	A standard low iodine diet allows brown sugar.
Honey	Allowed	Pure, natural honey is a safe sweetener.
Maple Syrup	Allowed	Pure maple syrup is permitted.
Molasses	Allowed	Unsulfured molasses is allowed; blackstrap molasses should be avoided.
High-Fructose Corn Syrup	Depends	Generally low in iodine, but check the final product for other restricted additives.
Artificial Sweeteners	Depends	Most are likely safe, but check for any red food dyes like Red Dye #3 (E127).

What Sweets to Enjoy and What to Avoid

Knowing which treats are safe can make following the diet less daunting. While many baked goods and candies are off-limits, there are still plenty of options. Here is a quick guide to help you differentiate.

Safe Sweets

Homemade sorbet or fruit ice, made with fresh fruit and sugar.
Homemade muffins and bread, prepared with non-iodized salt, egg whites, and no dairy.
Certain dark chocolates (typically >70% cocoa) that contain no milk solids or iodized salt. Always check the label carefully.
Jams, jellies, and fruit preserves (without red food dyes).
Fresh or canned fruits in light syrup.
Hard candies without Red Dye #3 or other iodine-containing ingredients.

Sweets to Avoid

Dairy-based desserts: Ice cream, milk chocolate, yogurt, cheese-based cakes.
Commercial baked goods: Most store-bought cakes, cookies, and pastries are made with iodized salt, dairy, or egg yolks.
Red Dye #3: Found in maraschino cherries, some candies, and certain colored sodas. Always check the ingredient list for 'Red #3' or 'erythrosine.'
Pre-packaged snacks: Many snack foods contain iodized salt or other restricted ingredients.
Blackstrap Molasses: Contains a higher concentration of iodine than unsulfured molasses.

Label Reading is Critical

When buying any packaged food, including sweets, reading the ingredient label is non-negotiable. Look for specific iodine-containing additives, including iodized salt, sea salt, kelp, alginates, agar-agar, or carrageenan. Even products that seem safe might contain these hidden ingredients. It is especially important to avoid foods that contain Red Dye #3 (erythrosine). Some guidelines also recommend limiting consumption of ingredients like soy flour, as high soy intake can interfere with radioactive iodine uptake.

The Short-Term Nature of the Diet

It is important to remember that the low iodine diet is not meant for long-term health management but is a short-term intervention. For most people, it lasts for 1 to 2 weeks before and sometimes a couple of days after RAI therapy. The temporary nature of these restrictions can make managing cravings for sweets more manageable. Focusing on the wide variety of fresh fruits and allowed homemade dessert options can help maintain dietary compliance.

Conclusion

So, can I eat sugar on a low iodine diet? Yes, pure granulated sugar, honey, and maple syrup are generally safe. The key lies not in the sugar itself but in the other ingredients of the sweet product. By carefully reading labels and opting for homemade versions of desserts, individuals can safely satisfy their sweet tooth while adhering to the diet's restrictions. Always consult with your healthcare provider or a registered dietitian for personalized advice regarding your low iodine diet, especially if you have other health conditions.

Resources

For more detailed information on managing your diet, reliable resources like the American Thyroid Association (ATA) provide extensive guides and recipes. American Thyroid Association

Frequently Asked Questions

Pure granulated white sugar, brown sugar, honey, and maple syrup are all considered safe on a low iodine diet. However, it's crucial to check the ingredients of any product containing sugar for other high-iodine additives, such as dairy or certain dyes.

Some candies are safe, but many are not. Hard candies are generally safe if they don't contain Red Dye #3 (erythrosine) or dairy ingredients. It's best to check the label meticulously or opt for homemade sweets to be certain.

Milk chocolate is not allowed due to its high dairy content. Some dark chocolates with a high cocoa percentage (typically 70% or more) and no added dairy or iodized salt may be acceptable. Always read the label to confirm.

Most artificial sweeteners are not a significant source of iodine and are generally considered safe. The main concern is with any added ingredients or dyes, so it is still important to check the product label for Red Dye #3.

Commercially prepared baked goods are often off-limits because they typically contain dairy, egg yolks, or iodized salt. Homemade versions using allowed ingredients, such as non-iodized salt, egg whites, and vegetable oils, are a much safer alternative.

Yes, pure honey is a safe and approved sweetener for a low iodine diet. It can be used as a substitute for sugar in recipes and to sweeten beverages.

Red Dye #3 (erythrosine) is an artificial coloring that contains iodine. It is often found in maraschino cherries, some candy, and other processed foods, and must be avoided to keep iodine intake low.