Blue 1

What this is

This page identifies Blue 1. The following evidence describes the shared six-dye assessment, including findings that apply only to specified members. Synthetic dyes are a group, and findings for one dye do not establish equal effects from all others. Controlled challenge studies support changes in activity or attention in some children, but results vary across doses, mixtures, observers and individuals. A review of 25 challenge studies found a behavioral signal in some trials; a later Hong Kong trial found no significant adverse effect. These studies do not show that dyes cause ADHD or that every child reacts. Laboratory studies also raise questions about particular dyes: Red 40 affected DNA and intestinal inflammation in mice, while other guideline tests were negative. A 2026 study found that Sunset Yellow worsened experimentally induced egg-protein allergy in mice given 40 milligrams per kilogram of body weight; this is not evidence that ordinary food exposure causes human allergy. West Virginia restricts the six named dyes in school nutrition meals, and California has enacted school restrictions beginning December 31, 2027, with specified exceptions. Those school rules contribute to the High display concern; the scientific assessment is Moderate. Generic “artificial color” wording can include other pigments, so the named ingredient matters.

Safety Review

The health areas reviewed when evaluating an ingredient. This does not mean the ingredient is proven to cause harm.

Controlled challenges support a meaningful but variable child-behavior concern, although mixtures, small samples, observer differences and a negative Hong Kong trial limit conclusions about individual dyes or the proportion of children affected. Red 40 and yellow-dye laboratory findings raise questions about DNA damage, gut inflammation and allergic responses, but negative guideline tests, artificial sensitization and uncertain dietary relevance prevent a claim of established human cancer or food-allergy causation. The Moderate scientific assessment applies to this identified synthetic-dye group and does not mean every member has equally strong evidence or that these dyes cause ADHD. The High display concern additionally reflects enacted restrictions on the six named dyes in school foods, rather than a claim of a nationwide food ban.