E155: Brown HT

What is E155 (Brown HT)?

Brown HT (E155), also known as Chocolate Brown HT or Food Brown 3, is a synthetic brown bisazo dye derived from coal tar. It is the final member of the "Southampton Six" — the six artificial food colorings strongly linked to hyperactivity in children through a pivotal 2007 clinical study. Brown HT has one of the widest bans of any European-permitted food dye, being prohibited in the USA, Canada, Belgium, France, Germany, Japan, Norway, Sweden, Switzerland, and Austria, among others.

Source and Production

Brown HT is a bisazo dye produced synthetically:

Precursor Amines: Aromatic diamine precursors are sourced from petrochemical processes 2. Double Diazotization: Both amine groups are diazotized to create a bis-diazonium salt 3. Dual Coupling: Coupling with naphthalene derivatives creates the two azo linkages 4. Sulfonation: Sulfonate groups added for water solubility and stability 5. Purification: Crystallization yields the food-grade disodium salt

This complex structure produces a deep brown color particularly suited to chocolate and cocoa-flavored products.

Common Uses in Food

E155 is used primarily in products where a chocolate or warm brown color is desired:

Chocolate-flavored biscuits and cakes
Chocolate substitutes and flavored products
Some confectionery
Packet dessert mixes
Certain sauces
Bread and baked goods with chocolate flavor
Beverages with chocolate or caramel flavor

Health and Safety

Southampton Study Findings

Brown HT was one of the six dyes tested in the 2007 McCann et al. randomized controlled trial. The study demonstrated that consuming a mixture of these six dyes (along with sodium benzoate E211) significantly increased hyperactive behavior in both toddlers and primary school-aged children. The effect was measurable at doses representing real-world dietary exposure.

Safety Concerns

Hyperactivity: Strong clinical evidence from Southampton study for behavioral effects in children
Allergic reactions: Azo dye structure predisposes to cross-reactions in aspirin-sensitive individuals
Asthma: Potential to trigger respiratory symptoms in sensitive people
Genotoxicity: Some laboratory studies raised concerns about DNA-damaging potential, though real-world risk is uncertain

Regulatory Status

European Union: Permitted with mandatory warning label on products containing the dye
United States: Not approved by the FDA
Canada: Not permitted
Several EU/European countries: Historically banned (Belgium, France, Germany, Norway, Sweden, Switzerland, Austria) before EU harmonization forced acceptance
Japan: Not permitted
ADI: 1.5 mg/kg body weight/day

Identification on Labels

Brown HT may be identified on packaging as:

E155
Brown HT
Chocolate Brown HT
Food Brown 3
C.I. 20285

Alternatives

Natural brown and chocolate colorings:

Caramel colors (E150a-d): Natural browns from heated sugar — though some have their own concerns
Cocoa powder: Natural chocolate coloring and flavor
Carob extract: Natural brown from carob pods
Coffee extract: Natural brown coloring

Conclusion

E155 (Brown HT) has perhaps the broadest international ban of any food coloring still approved in parts of Europe. Its inclusion in the Southampton Six study provides strong evidence for behavioral effects in children at dietary exposure levels. The fact that many EU member states historically banned it, and that the broader regulation still requires warning labels, underscores the legitimate safety concerns. Consumers should be particularly cautious about this additive in products given to children.