Researchers say that dietary effects on and treatments of Attention-deﬁcit/hyperactivity disorder (ADHD), including food additives and colors, deserve further investigation.
Researchers Took Note
ADHD is a common developmental syndrome that confers elevated risk of school failure, peer rejection, family conflict, substance use disorders, delinquency, underemployment, depression, accidental death, suicide, and physical health problems.
While genetic factors are estimated to make up about 75% of the risk for ADHD, researchers suggest that food additives, which include synthetic food colorings and flavors, also influence ADHD, via either allergenic or pharmacologic mechanisms.
Artificial food colors and other food additives (AFCA) have long been suggested to affect behavior in children. The main putative effect of AFCA is to produce overactive, impulsive, and inattentive behavior, ie, hyperactivity.
Over past decades, there have many researches and studies on the effect of AFCA on ADHD. The average effect sizes that researchers observed are small in clinical terms, but they could be quite substantial from the perspective of population-wide prevention efforts. Although there has not been a consensus among the researchers, the overall pooled result is sufficiently robust that it would not be easily overturned.
EU Parliament Took Action
In 2007, a group of UK researchers undertook a randomized, double-blinded, placebo-controlled, crossover trial to test whether intake of artificial food color and additives (AFCA) affected childhood behavior. A total of 153 children were included in this study.
The children in this study were randomly grouped; one group was given regular drinks with artificial food colorings, and one group was given placebo drinks without artificial food coloring. Both groups consumed the drinks for an extended period of time, and their behaviors were closed watched and measured by researchers.
The researchers found an adverse effect of food additives on the hyperactive behavior of 3-year-old and 8/9-year-old children, and they suggested that although the use of artificial coloring in food manufacture might seem superfluous, the same cannot be said for sodium benzoate, which has an important preservative function.
This study prompted the European Union Parliament to require warning labels on foods containing six colors.
Approved Food Color Additives in US & EU
In U.S., there are nine certified color additives approved by the FDA for use in food:
FD&C Blue No. 1: Confections, beverages, cereals, frozen dairy desserts, popsicles, frostings & icings
FD&C Blue No. 2: Baked goods, cereals, snack foods, ice cream, confections, and yogurt
FD&C Green No. 3: Cereal, ice cream, sherbet, drink mixers, and baked goods
Orange B: Only approved for use in hot dog and sausage casings
Citrus Red No. 2: Only approved for use to color orange peels
FD&C Red No. 3: Confections, beverages, cereals, ice cream cones, frozen dairy desserts, popsicles, frostings & icings
FD&C Red No. 40: Cereal, beverages, gelatins, puddings, dairy products, and confections
FD&C Yellow No. 5: Confections, cereals, snack foods, beverages, condiments, baked goods, and yogurt
FD&C Yellow No. 6: Cereals, snack foods, baked goods, gelatins, beverages, dessert powders, crackers, and sauces
All but Orange B are also approved for use in Europe; but in Europe, warning labels are now required on FD&C Red #40 (Allura Red AC), FD&C Yellow #5 (Tartrazine), FD&C Yellow #6 (Sunset yellow), and three colors used in Europe but not the United States: Quinoline Yellow, Carmoisine, and Ponceau.
Sources consulted: Donna McCann, et al. 2007. “Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial.” In Lancet, 370: 1560–67. Joel T. Nigg, et al. 2012. “Meta-Analysis of Attention-Deﬁcit/Hyperactivity Disorder or Attention-Deﬁcit/Hyperactivity Disorder Symptoms, Restriction Diet, and Synthetic Food Color Additives.” In Journal of the American Academy of Child & Adolescent Psychiatry, Volume 51, Number 1, pp. 86-97.