What Replaced Iodine in Bread and Why?

December 15, 2025 •

4 min read

In the 1960s, a slice of commercial bread provided a significant portion of the recommended daily iodine intake, but by 1980, this practice was largely abandoned in the United States and elsewhere. This shift begs the question: what replaced iodine in bread, and what are bakers using today to achieve consistent results in modern, high-speed production?

Quick Summary

After health concerns prompted a move away from iodine fortification in bread, bakers replaced it with chemical dough conditioners like potassium bromate. Concerns over bromate's safety later led the industry to adopt modern, safer alternatives such as ascorbic acid and a suite of specialized enzymes.

Key Points

Iodine's Decline: Around 1980, iodine was largely removed from bread dough as a flour additive due to concerns about potentially excessive iodine intake, though it is still used in other countries.
Bromate's Replacement: The initial replacement for iodine in many commercial bread products was potassium bromate, a potent oxidizing agent that strengthened dough.
Bromate's Ban: Potassium bromate was subsequently banned in Europe, Canada, and many other countries due to evidence suggesting it is a possible carcinogen, though it is still technically legal but rarely used in the U.S..
Ascorbic Acid's Rise: Today, a primary and safe replacement is ascorbic acid (Vitamin C), which acts as a dough conditioner by strengthening the gluten network for better loaf volume and crumb structure.
Enzymes' Role: A variety of specialized enzymes, including amylases, xylanases, and lipases, are also used to improve dough handling, gas retention, softness, and overall bread quality.
Clean Label Focus: The modern baking industry, especially in Europe, prioritizes less-processed ingredients, moving toward alternatives like enzymes that are heat-deactivated and considered processing aids rather than additives.

The Era of Iodine in Bread

From the 1960s until approximately 1980, potassium iodate was a common additive in bread dough, serving as both a dough conditioner and a source of dietary iodine. The practice was a response to widespread iodine deficiency, particularly in inland regions where food was grown in iodine-poor soil. The addition of iodine to a staple like bread effectively boosted public iodine levels. However, as dietary sources of iodine increased and the prevalence of iodine deficiency disorders decreased, concerns about excessive iodine intake began to rise.

Around 1980, the baking industry began phasing out iodine-based dough conditioners in the United States, in part due to perceived health risks associated with over-consumption and concerns about its effect on sensitive individuals with thyroid conditions. This created a need for a new additive to provide the necessary dough-strengthening effects in industrial, high-speed baking processes.

The Rise and Fall of Potassium Bromate

In the transition away from iodine, many bakers turned to potassium bromate, a powerful and cost-effective oxidizing agent. It was first patented for use in baking in 1914 and became a popular choice for its ability to strengthen the gluten network in dough, leading to greater loaf volume, a finer crumb, and higher rising. Bromate was a reliable flour improver for decades.

However, its reign was short-lived in much of the world due to serious health concerns. In the late 20th century, research revealed that potassium bromate was a possible carcinogen.

1990: The European Union banned its use as a food additive.
1994: Canada followed suit with a ban.
1999: The International Agency for Research on Cancer (IARC) classified it as "possibly carcinogenic to humans".

While the U.S. Food and Drug Administration (FDA) urged bakers to voluntarily stop using it in 1991, they did not issue a mandatory ban. As a result, bromate-treated flour remains legal for use in many parts of the U.S., though most major bakers have voluntarily transitioned to safer alternatives due to consumer demand and regulatory pressure, including recent state-level bans.

The Modern Replacements: Ascorbic Acid and Enzymes

Today, the baking industry relies on a suite of different dough conditioners to achieve the volume, texture, and consistency that iodine and bromate once provided. The most prominent of these alternatives are ascorbic acid and various enzymes.

Ascorbic Acid (Vitamin C) Ascorbic acid acts as a powerful, yet safe, dough conditioner. When mixed into dough, an enzyme naturally present in flour converts the ascorbic acid into an oxidizing agent. This strengthens the gluten protein network, improving the dough's elasticity and its ability to trap the carbon dioxide produced by yeast. This leads to:

Improved loaf volume
Finer crumb structure
Better handling properties for the dough

Unlike potassium bromate, ascorbic acid is converted during the baking process and is generally not present in the final product. It is a very effective and widely accepted alternative used globally.

Enzymes Alongside ascorbic acid, bakeries use specific enzyme blends to fine-tune the characteristics of bread dough. Enzymes are biological catalysts that speed up chemical reactions, and in baking, they perform specialized functions that enhance the dough's properties. Common examples include:

Amylases: Break down starches into simpler sugars, providing more food for the yeast and improving crust color and fermentation.
Xylanases: Target non-starch polysaccharides in flour, improving water absorption and enhancing the dough's ability to retain gas, which leads to better volume and a softer crumb.
Proteases: Relax the dough by breaking down proteins, which can be useful when working with high-protein flours.
Lipases: Breakdown lipids to act as natural emulsifiers, improving dough stability and crumb texture while also extending shelf life.

These enzymes are often considered 'processing aids' rather than additives in the final product, as they are deactivated by heat during baking. This supports the trend towards 'clean-label' foods with fewer listed ingredients.

Comparison of Bread Additives


Additive	Function	Safety & Status (USA)	Safety & Status (EU)
Potassium Iodate	Strengthens gluten, provides iodine.	Used historically, largely phased out around 1980 due to overconsumption concerns.	Used historically, largely phased out for similar reasons.
Potassium Bromate	Strong oxidizing agent for gluten strengthening.	Permitted by FDA but most bakers have voluntarily stopped using it. Some states have banned it.	Banned as a food additive since 1990.
Ascorbic Acid (Vitamin C)	Oxidizes gluten, improving elasticity and volume.	Widely used and accepted as safe.	Approved and widely used (E300).
Enzymes (Amylases, Xylanases, etc.)	Improve gas retention, softness, and dough handling.	Widely used as processing aids, often not listed on labels.	Widely used as processing aids.
Emulsifiers (e.g., DATEM)	Strengthen dough, soften crumb, extend shelf life.	Permitted and commonly used.	Permitted (e.g., E472(e)).

Global Variations in Baking Practices

While the evolution away from iodine and bromate is a global trend, differences remain in common baking practices and regulations. European bakeries, for instance, are known for using fewer additives overall, often relying on traditional, slower fermentation methods to achieve desirable bread characteristics. In contrast, American commercial baking has historically relied more on additives to speed up the process and ensure consistency. The increasing consumer demand for 'clean-label' and less-processed foods, however, is influencing both markets, leading to greater adoption of ingredients like ascorbic acid and naturally-derived enzymes over harsher chemical alternatives. For more on the health impacts of various additives, the Real Bread Campaign offers insights. Beneath the Crust: The chemical cocktail in our daily bread

Conclusion

The journey from iodine to modern dough conditioners reflects a continuous effort to balance production efficiency, product quality, and consumer health. Iodine was initially added for nutritional purposes but was later deemed unnecessary and potentially excessive. Its immediate replacement, potassium bromate, proved effective for bakers but was ultimately discarded in many regions due to safety concerns. The modern solution relies on a combination of ascorbic acid (Vitamin C) and various enzymes to naturally strengthen gluten, enhance fermentation, and extend freshness. This shift has not only improved the safety profile of commercial bread but also aligns with the contemporary push for cleaner ingredient lists and more transparent food production.

Frequently Asked Questions

Iodine was added to bread in the mid-20th century primarily as a nutritional fortifier to help combat widespread iodine deficiency in the population. It was used in the form of potassium iodate, which also acted as a dough conditioner.

The practice was phased out around 1980 due to concerns that rising total dietary iodine intake could lead to excess consumption, which can be problematic for people with certain thyroid conditions. The industry moved to other dough conditioners that did not contribute to iodine intake.

Yes, following the discontinuation of iodine additives, potassium bromate was widely adopted as the replacement dough conditioner. It was a potent and effective oxidizing agent for strengthening gluten.

While banned in Europe, Canada, and many other countries due to its classification as a possible carcinogen, potassium bromate is still technically permitted in the U.S. under specific usage limits. However, most major U.S. bakeries have voluntarily stopped using it.

Ascorbic acid (Vitamin C) is a modern, safer alternative to bromate. In dough, it acts as an oxidizing agent, strengthening the gluten network to improve loaf volume, crumb structure, and dough handling.

Baking enzymes are biological catalysts added to dough to improve specific qualities. Examples include amylases (for yeast food and crust color), xylanases (for better gas retention and softness), and lipases (for crumb softness and shelf life).

Yes. Europe generally allows fewer additives in bread and has banned substances like potassium bromate. European bakers often favor longer fermentation processes. U.S. commercial baking historically used more additives for high-speed production, although consumer trends are pushing for cleaner labels and fewer additives in both regions.