Behavioral responses to artificial food colors

Comparative Toxicity of Vegan Red, E124, and E120 Food Dyes on Three Rapidly Proliferating Model Systems

The abuse of artificial food dyes and the evidence that they harm human health recently prompted a significant effort to introduce vegan substitutes prepared from fruits and vegetables. Not much information, however, has been collected on their possible effects on aquatic and terrestrial ecosystems once released as waste in surface waters. For this purpose, we analyzed the effects of a vegan red (VEG) preparation (concentration 1.2 g/L) on three rapidly proliferating models for terrestrial and aquatic ecosystem contamination. In particular, in vitro cells cultures (exposure for 24 h), Artemia salina nauplii and Cucumis sativus seedlings (exposure 5 days). A comparison was made with the effects exerted by the two dyes that vegan red is intended to replace: an animal dye, cochineal E120 and an artificial dye E124. The analyses of conventional endpoints, indicative of cell proliferation, differentiation, and growth rate, demonstrate that the three dyes affect development and that the vegan substitute is as unsafe as the E124 and E120. Vegan red in fact impairs cell growth in in vitro cells, delays naupliar hatching and early growth in Artemia, and reduces shoot/root biomass in Cucumis. Marked hyperplasia and hypertrophy of mesophyll are also observed in Cucumis leaves. Substitution in food and beverages, therefore, should be carefully reconsidered to avoid unnecessary environmental contamination.

A Randomization Permutation Test for Single Subject Mediation

In response to the importance of individual-level effects, the purpose of this paper is to describe the new randomization permutation (RP) test for a mediation mechanism for a single subject. We extend seminal work on permutation tests for individual-level data by proposing a test for mediation for one person. The method requires random assignment to the levels of the treatment variable at each measurement occasion, and repeated measures of the mediator and outcome from one subject. If several assumptions are met, the process by which a treatment changes an outcome can be statistically evaluated for a single subject, using the permutation mediation test method and the permutation confidence interval method for residuals. A simulation study evaluated the statistical properties of the new method suggesting that at least eight repeated measures are needed to control Type I error rates and larger sample sizes are needed for power approaching .8 even for large effects. The RP mediation test is a promising method for elucidating intraindividual processes of change that may inform personalized medicine and tailoring of process-based treatments for one subject.

Low-Level Chemical Sensitivity: A Perspective from Behavioral Toxicology

Low-level chemical sensitivity is hardly a new issue in environmental toxicology. It is, in fact, the focus of risk assessment. The risk assessment process is designed explicitly to estimate the health threats posed by low exposure levels, typically by extrapolating from high experimental or environmental levels. The conventional risk assessment structure, however, was designed primarily around cancer. It is only awkwardly applicable to neurobehavioral toxicants because of the multiplicity of endpoints that have to be considered in evaluating neurotoxicity. At the same time, neurotoxic risk assessment maintains certain advantages over cancer risk assessment because of diminished uncertainties over dose extrapolation. It does not have to depart as far from the range of observable data.

The main problem with extending the risk assessment model to issues such as Multiple Chemical Sensitivity (MCS) and Sick Building Syndrome (SBS) is the absence of a specific chemical whose concentration can be measured and then manipulated. A prototypical agent, however, such as a volatile organic solvent, might be selected and studied. Beyond the choice of agent, however, is the question of which behavioral criteria are likely to yield the most useful information. Although neuropsychological test batteries provide one source of data, they typically are administered in a setting other than the one allegedly provoking the syndrome. A different approach invokes what might be called a miniature work situation. Here, a test subject is evaluated in a setting that emphasizes sustained performance testing in the presence of target chemicals.

Effects of four food dyes on development of three model species, Cucumis sativus, Artemia salina and Danio rerio: Assessment of potential risk for the environment

Food dyes, or color additives, are chemicals added to industrial food products and in domestic cooking to improve the perceived flavor and attractiveness. Of natural and synthetic origin, their safety has been long discussed, and concern for human safety is now clearly manifested by warnings added on products labels. Limited attention, however, has been dedicated to the effects of these compounds on aquatic flora and fauna. For this reason, the toxicity of four different commercially available food dyes (cochineal red E120, Ponceau red E124, tartrazine yellow E102 and blue Patent E131) was assessed on three different model organisms, namely Cucumis sativus, Artemia salina and Danio rerio that occupy diverse positions in the trophic pyramid. The evidence collected indicates that food dyes may target several organs and functions, depending on the species. C. sativus rate of germination was increased by E102, while root/shoot ratio was ∼20% reduced by E102, E120 and E124, seed total chlorophylls and carotenoids were 15-20% increased by E120 and 131, and total antioxidant activity was ∼25% reduced by all dyes. Mortality and low mobility of A. salina nauplii were increased by up to 50% in presence of E124, E102 and E131, while the nauplii phototactic response was significantly altered by E102, E120 and E124. Two to four-fold increases in the hatching percentages at 48 h were induced by E124, E102 and E131 on D. rerio, associated with the occurrence of 20% of embryos showing developmental defects. These results demonstrated that the food dyes examined are far from being safe for the aquatic organisms as well as land organisms exposed during watering with contaminated water. The overall information obtained gives a realistic snapshot of the potential pollution risk exerted by food dyes and of the different organism' ability to overcome the stress induced by contamination.

Encapsulation of purple corn and blueberry extracts in alginate-pectin hydrogel particles: Impact of processing and storage parameters on encapsulation efficiency

Purple corn (PC) and blueberry (BB) extracts were encapsulated in alginate-pectin hydrogel particles to protect anthocyanins (ACNs) from degradation. Combinations of alginate to pectin ratios at 82 to 18% and 43 to 57% and total gum concentrations (TGC) at 2.2% and 2.8% TGC were prepared to encapsulate both PC and BB ACN. The alginate-pectin hydrogel particles containing PC or BB extracts were produced by dripping solution into pH 1.2 buffer. Blueberry extract encapsulation efficiency was significantly higher than that of purple corn extract due to ACN chemical structure differences and the compatibility between the ACN structures and alginate-pectin hydrogel structure at the low pH environment. Effect of initial ACN concentration in droplets, particle shape, alginate to pectin ratio, TGC, ACN source, and curing bath conditions on encapsulation efficiency after curing (EE_m) was investigated. The initial ACN concentration and particle shape didn't influence the EE_m, while the alginate to pectin ratio, TGC, ACN source and the pH of the curing bath showed significant effect on the EE_m. The EE_m was improved from 26% to 65% for PC ACN and from 48% to 116% for BB ACN by augmenting curing bath with ACN at various concentrations. The ACN retention during storage (AR_s) in hydrogel particles stored in pH 3.0 buffer was improved at low temperature and high particle weight to solution volume ratio. Higher amount of ACN was retained in the hydrogel particles when spherical particles were used. Encapsulation in hydrogel particles significantly reduced the anthocyanin photodegradation upon exposure to fluorescence light. The degradation of ACN was described with a first-order kinetics with half-life values of 630 h for encapsulated PC ACN and 58 h for PC ACN aqueous solution. Hydrogel production and subsequent storage conditions can be optimized to increase the anthocyanin delivered to human body using the low pH beverages such as fruit juices as a delivery vehicle.

ADHD impacted by sulfotransferase (SULT1A) inhibition from artificial food colors and plant-based foods

BACKGROUND

Five recent reviews have analyzed trials on the association between artificial food colors and ADHD; the 50 underlying studies and the reviews in aggregate were inconclusive. Recent work has shown human in vivo SULT1A inhibition leading to incremental catecholamines, and an inverted-U relationship between brain catecholamines and proper functioning of the prefrontal cortex where ADHD behavior can arise.

METHOD

This study re-examined the same underlying trials for evidence that SULT1A inhibitors were in the placebos and other inactive foods, that these "inactive" materials were symptomatic, and that ADHD symptoms exhibited an inverted-U response to SULT1A inhibition.

RESULTS

Nearly all the underlying diets, and many placebos and delivery vehicles, were found to contain SULT1A inhibitors. Eight publications provided evidence of ADHD symptoms caused by the "inactive" materials containing SULT1A inhibitors. Ten studies showed additional SULT1A inhibitors reducing the symptoms of some subjects.

CONCLUSION

SULT1A inhibitors in foods, including natural substances and artificial food colors, have a role in ADHD that can both worsen or improve symptoms. Mechanistically, SULT1A enzymes normally deactivate catecholamines, especially dopamine formed in the intestines; SULT1A inhibition can influence brain catecholamines through the intermediary of plasma tyrosine levels, which are influenced by dopamine inhibition of intestinal tyrosine hydroxylase. Biochemical measurements focused on SULT1A activity and plasma tyrosine concentrations are proposed for future work.

Amounts of artificial food colors in commonly consumed beverages and potential behavioral implications for consumption in children

Artificial food colors (AFCs) are widely used to color foods and beverages. The amount of AFCs the Food and Drug Administration has certified over the years has increased more than 5-fold since 1950 (12 mg/capita/day) to 2012 (68 mg/capita/day). In the past 38 years, there have been studies of adverse behavioral reactions such as hyperactivity in children to double-blind challenges with AFCs. Studies that used 50 mg or more of AFCs as the challenge showed a greater negative effect on more children than those which used less. The study reported here is the first to quantify the amounts of AFCs in foods (specifically in beverages) commonly consumed by children in the United States. Consumption data for all foods would be helpful in the design of more challenge studies. The data summarized here should help clinicians advise parents about AFCs and beverage consumption.

Food additives and behavior in 8- to 9-year-old children in Hong Kong: a randomized, double-blind, placebo-controlled trial

OBJECTIVES

To test the individual effect of artificial food colorings (AFCs) and a preservative on the behavior of the general Chinese population.

METHOD

One hundred thirty children (70 boys and 60 girls) in Hong Kong with a mean age of 8.64 years were enlisted to the study with a within-subject crossover between AFCs, a preservative (sodium benzoate), and a placebo capsule. Two behavior scores were used including the strengths and weaknesses of attention deficit hyperactivity disorder and normal behavior rating scale and the child behavior checklist-teacher report form.

RESULTS

Capsule A containing AFCs and Capsule B containing sodium benzoate had no significant adverse effect compared with placebo in both behavior scores. This result persisted when analysis was restricted to children with 85% consumption of capsule (per protocol analysis).

CONCLUSION

There seem to be no significant associations between AFCs and a preservative on Chinese children's behavior at the age of 8 to 9 years. Future directions and implications of this research are discussed.

The good, the bad, and the aggregate

To evaluate progress and focus goals, scientific disciplines need to identify relations that are robust across many situations. One approach is the literature review, which characterizes generality across studies. Some writers (e.g., Baron & Derenne, 2000) claim that quantitative literature reviews, but not narrative reviews, violate the methodological precepts of behavior analysis by pooling data from nonidentical studies. We argue that it is impossible to assess generality without varying the context in which relationships are studied. Properly chosen data-aggregation strategies can reveal which behavior-environment relations are general and which are procedure dependent. Within behavior analysis, reluctance to conduct quantitative reviews may reflect unsupported assumptions about the consequences of aggregating data across studies. Whether specific data-aggregation techniques help or harm a research program is an empirical issue that cannot be resolved by unstructured discussion. Some examples of how aggregation has been used in identifying behavior-environment relations are examined.

Food additives, essential nutrients and neurodevelopmental behavioural disorders in children: A brief review

In recent decades, changing lifestyles in Canadian homes has led to demand for foods with long shelf lives that are cosmetically appealing, palatable, easy to prepare and to consume. Food additives, especially preservatives and artificial colours as well as suboptimal intake of essential nutrients, have been linked to hyperactive behaviours and poor attention in a subgroup of children. Although other risk factors (ie, genetic, etc) for these conditions have received more attention in the scientific literature, the authors believe that there is enough evidence to consider dietary influences as a modifiable risk factor. This would involve raising awareness among clinicians and, subsequently, reviewing food regulatory processes to better protect children in Canada - similar to the regulations recently undertaken by the British Food Standards Agency. Conflicts of interest due to food and medication industry support for organizations advocating for children would need to be resolved by open communication between government regulatory agencies, academia and industry. Canadian parents and children need to be advised to limit unnecessary food additives and consume a diet rich in essential nutrients while more complete relationships are being explored further.

Synthetic food colors and neurobehavioral hazards: the view from environmental health research

BACKGROUND

The proposition that synthetic food colors can induce adverse behavioral effects in children was first enunciated in 1975 by Feingold [Why Your Child Is Hyperactive. New York:Random House (1975)], who asserted that elevated sensitivity to food additives underlies the signs of hyperactivity observed in some children. Although the evidence suggested that some unknown proportion of children did respond to synthetic food colors, the U.S. Food and Drug Administration (FDA) interpreted the evidence as inconclusive. A study published in 2007 [McCann et al. 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. Lancet 370:1560-1567 (2007)] drew renewed attention to the hypothesis because of the study's size and scope. It led the FDA to review the evidence, hold a public hearing, and seek the advice of its Food Advisory Committee. In preparation for the hearing, the FDA reviewed the available evidence and concluded that it did not warrant further agency action.

OBJECTIVES

In this commentary I examine the basis of the FDA's position, the elements of the review that led to its decision and that of the Food Advisory Committee, and the reasons that this is an environmental health issue.

DISCUSSION

The FDA review confined itself, in essence, to the clinical diagnosis of hyperactivity, as did the charge to the committee, rather than asking the broader environmental question of behavioral effects in the general population; it failed to recognize the significance of vulnerable subpopulations; and it misinterpreted the meaning of effect size as a criterion of risk. The FDA's response would have benefited from adopting the viewpoints and perspectives common to environmental health research. At the same time, the food color debate offers a lesson to environmental health researchers; namely, too narrow a focus on a single outcome or criterion can be misleading.

Meta-analysis of attention-deficit/hyperactivity disorder or attention-deficit/hyperactivity disorder symptoms, restriction diet, and synthetic food color additives

OBJECTIVE

The role of diet and of food colors in attention-deficit/hyperactivity disorder (ADHD) or its symptoms warrants updated quantitative meta-analysis, in light of recent divergent policy in Europe and the United States.

METHOD

Studies were identified through a literature search using the PubMed, Cochrane Library, and PsycNET databases through February 2011. Twenty-four publications met inclusion criteria for synthetic food colors; 10 additional studies informed analysis of dietary restriction. A random-effects meta-analytic model generated summary effect sizes.

RESULTS

Restriction diets reduced ADHD symptoms at an effect of g = 0.29 (95% CI, 0.07-0.53). For food colors, parent reports yielded an effect size of g = 0.18 (95% CI, 0.08-0.24; p = .0007), which decreased to 0.12 (95% CI, 0.01-0.23; p < .05) after adjustment for possible publication bias. The effect was reliable in studies restricted to food color additives (g = 0.21, 95% CI = 0.06-0.36) but did not survive correction for possible publication bias and was not reliable in studies confined to Food and Drug Administration-approved food colors. Teacher/observer reports yielded a nonsignificant effect of 0.07 (95% CI = -0.03 to 0.18; p = .14). However, high-quality studies confined to color additives yielded a reliable effect (g = 0.22, 95% CI = 0.10-0.41, p = .030) that survived correction. In psychometric tests of attention, the summary effect size was 0.27 (95% CI = 0.07-0.47; p = .007) and survived correction. An estimated 8% of children with ADHD may have symptoms related to synthetic food colors.

CONCLUSIONS

A restriction diet benefits some children with ADHD. Effects of food colors were notable were but susceptible to publication bias or were derived from small, nongeneralizable samples. Renewed investigation of diet and ADHD is warranted.

Artificial food dyes and attention deficit hyperactivity disorder

Attention deficit hyperactivity disorder (ADHD) is one of the most common behavioral disorders in children. Symptoms of ADHD include hyperactivity, low frustration tolerance, impulsivity, and inattention. While the biological pathways leading to ADHD are not clearly delineated, a number of genetic and environmental risk factors for the disorder are recognized. In the early 1970s, research conducted by Dr. Benjamin Feingold found that when hyperactive children were given a diet free of artificial food additives and dyes, symptoms of hyperactivity were reduced. While some clinical studies supported these findings, more rigorous empirical studies conducted over the next 20 years were less positive. As a result, research on the role of food additives in contributing to ADHD waned. In recent years, however, interest in this area has revived. In response to more recent research and public petitions, in December 2009 the British government requested that food manufacturers remove most artificial food dyes from their products. While these strictures could have positive effects on behavior, the removal of food dyes is not a panacea for ADHD, which is a multifaceted disorder with both biological and environmental underpinnings.

A research model for investigating the effects of artificial food colorings on children with ADHD

The United Kingdom and European Union recently restricted the use of artificial food colorings (AFCs) to improve the health of children. These decisions provide an interesting case study of the role of scientific evidence in the assessment of food additives and risk to children's health and formulation of food policy. Although there continues to be uncertainty concerning the link between AFCs and attention-deficit/hyperactivity disorder (ADHD), policy decisions have been made that have far-reaching implications. In addition, publicity surrounding the policy changes may shape public perceptions concerning effective management of ADHD. We believe that the balance of existing evidence neither refutes nor supports the link between AFCs and ADHD, which highlights the need for carefully designed studies to further investigate the link between AFCs and ADHD. In this article we describe a model for such studies. In developing our model, we drew from current investigative standards in ADHD research, such as those used in the landmark Multimodal Treatment Study of Children With ADHD. These standards encompass methodologic considerations including sample selection, outcome assessment, and data analyses. It is our hope that this model research methodology may prove valuable in addressing design considerations in future studies of AFCs and ADHD with the goal of producing reliable data that will enable policy-makers to better formulate effective, evidence-based food-policy decisions.

Dietary sensitivities and ADHD symptoms: thirty-five years of research

Artificial food colors (AFCs) have not been established as the main cause of attention-deficit hyperactivity disorder (ADHD), but accumulated evidence suggests that a subgroup shows significant symptom improvement when consuming an AFC-free diet and reacts with ADHD-type symptoms on challenge with AFCs. Of children with suspected sensitivities, 65% to 89% reacted when challenged with at least 100 mg of AFC. Oligoantigenic diet studies suggested that some children in addition to being sensitive to AFCs are also sensitive to common nonsalicylate foods (milk, chocolate, soy, eggs, wheat, corn, legumes) as well as salicylate-containing grapes, tomatoes, and orange. Some studies found "cosensitivity" to be more the rule than the exception. Recently, 2 large studies demonstrated behavioral sensitivity to AFCs and benzoate in children both with and without ADHD. A trial elimination diet is appropriate for children who have not responded satisfactorily to conventional treatment or whose parents wish to pursue a dietary investigation.

The renaissance of field experimentation in evaluating interventions

Most experiments are done in laboratories. However, there is also a theory and practice of field experimentation. It has had its successes and failures over the past four decades but is now increasingly used for answering causal questions. This is true for both randomized and-perhaps more surprisingly-nonrandomized experiments. In this article, we review the history of the use of field experiments, discuss some of the reasons for their current renaissance, and focus the bulk of the article on the particular technical developments that have made this renaissance possible across four kinds of widely used experimental and quasi-experimental designs-randomized experiments, regression discontinuity designs in which those units above a cutoff get one treatment and those below get another, short interrupted time series, and nonrandomized experiments using a nonequivalent comparison group. We focus this review on some of the key technical developments addressing problems that previously stymied accurate effect estimation, the solution of which opens the way for accurate estimation of effects under the often difficult conditions of field implementation-the estimation of treatment effects under partial treatment implementation, the prevention and analysis of attrition, analysis of nested designs, new analytic developments for both regression discontinuity designs and short interrupted time series, and propensity score analysis. We also cover the key empirical evidence showing the conditions under which some nonrandomized experiments may be able to approximate results from randomized experiments.

Developing ADHD

Over the past 50 years the concept of attention deficit/hyperactivity disorder (ADHD) has developed from the notion of a specific form of brain dysfunction to that of a heterogeneous set of related behaviours. The great advances in genetics, neuroimaging and neuropsychiatry have made it one of the best understood forms of complex mental disturbance--but much remains to be done to translate understanding into practice. More effective treatment may come from identifying and treating more specific components of disorder and by a focus on identifying the factors determining course in the longer term so that they, as well as the core features of disorder, can become targets for intervention.

Effects of diet on behaviour and cognition in children

Diet can affect cognitive ability and behaviour in children and adolescents. Nutrient composition and meal pattern can exert immediate or long-term, beneficial or adverse effects. Beneficial effects mainly result from the correction of poor nutritional status. For example, thiamin treatment reverses aggressiveness in thiamin-deficient adolescents. Deleterious behavioural effects have been suggested; for example, sucrose and additives were once suspected to induce hyperactivity, but these effects have not been confirmed by rigorous investigations. In spite of potent biological mechanisms that protect brain activity from disruption, some cognitive functions appear sensitive to short-term variations of fuel (glucose) availability in certain brain areas. A glucose load, for example, acutely facilitates mental performance, particularly on demanding, long-duration tasks. The mechanism of this often described effect is not entirely clear. One aspect of diet that has elicited much research in young people is the intake/omission of breakfast. This has obvious relevance to school performance. While effects are inconsistent in well-nourished children, breakfast omission deteriorates mental performance in malnourished children. Even intelligence scores can be improved by micronutrient supplementation in children and adolescents with very poor dietary status. Overall, the literature suggests that good regular dietary habits are the best way to ensure optimal mental and behavioural performance at all times. Then, it remains controversial whether additional benefit can be gained from acute dietary manipulations. In contrast, children and adolescents with poor nutritional status are exposed to alterations of mental and/or behavioural functions that can be corrected, to a certain extent, by dietary measures.

Do food or additives cause behavior disorders?

The possible role of foods or additives in causing behavioral disorders in children, particularly ADHD, has been a controversial subject both among health care providers and the public. However, a critical review of the literature provides very limited support for such a relationship. On encountering such cases, the healthcare professional should first establish an accurate diagnosis of the suspected "abnormal" behavior based on specific standard criteria. It is important to counsel the family regarding the standard of care practice and about the limited evidence of a role of foods and additives in causing behavior problems. If parents strongly suspect a specific dietary item, a trial of elimination may be warranted. If the child's behavior shows definite improvement, a challenge in a double-blind, placebo-controlled fashion under the supervision of an experienced physician would be necessary to verify the relationship.

Attention-deficit/hyperactivity disorder: an overview of the etiology and a review of the literature relating to the correlates and lifecourse outcomes for men and women

This paper provides a summary of the current conceptualization of what AD/HD is, and its etiology, and then reviews some of the recent literature on the correlates and lifecourse outcomes for individuals diagnosed with Attention-Deficit/Hyperactivity Disorder (AD/HD). The intention is to synthesize that which is known, and to identify important gaps in the literature and knowledge base, which secondary analysis of prospective large-scale longitudinal cohorts, tracking individuals from birth to adulthood, could help to fill. This review highlights the fact that such datasets are rare and that their analysis offers important opportunities for advancing knowledge, particularly of the adult outcomes of childhood AD/HD.

Old and new controversies in the alternative treatment of attention-deficit hyperactivity disorder

Use of complementary and alternative medicine (CAM) for treatment of attention-deficit hyperactivity disorder (ADHD) has become widespread in both referral and primary care populations. We review the purported mechanism of action and available evidence for selected CAM therapies for ADHD. Enduring controversies, such as elimination of artificial food additives, colors, and/or preservatives; the effect of sugar on behavior in children; and the use of EEG biofeedback, have been well studied but lack support as effective sole treatments for ADHD. The initial evidence for some emerging CAM therapies, such as essential fatty acid supplementation, yoga, massage, homeopathy, and green outdoor spaces, suggests potential benefits as part of an overall ADHD treatment plan. More rigorously designed studies are needed to evaluate their effectiveness as single therapy for ADHD.

Do artificial food colors promote hyperactivity in children with hyperactive syndromes? A meta-analysis of double-blind placebo-controlled trials

Burgeoning estimates of the prevalence of childhood attention-deficit/hyperactivity disorder (ADHD) raise the possibility of a widespread risk factor. We seek to assess whether artificial food colorings (AFCs) contribute to the behavioral symptomatology of hyperactive syndromes. We searched ten electronic databases for double-blind placebo-controlled trials evaluating the effects of AFCs. Fifteen trials met the primary inclusion criteria. Meta-analytic modeling determined the overall effect size of AFCs on hyperactivity to be 0.283 (95% CI, 0.079 to 0.488), falling to 0.210 (95% CI, 0.007 to 0.414) when the smallest and lowest quality trials were excluded. Trials screening for responsiveness before enrollment demonstrated the greatest effects. Despite indications of publication bias and other limitations, this study is consistent with accumulating evidence that neurobehavioral toxicity may characterize a variety of widely distributed chemicals. Improvement in the identification of responders is required before strong clinical recommendations can be made.

The effects of a double blind, placebo controlled, artificial food colourings and benzoate preservative challenge on hyperactivity in a general population sample of preschool children

AIMS

To determine whether artificial food colourings and a preservative in the diet of 3 year old children in the general population influence hyperactive behaviour.

METHODS

A sample of 1873 children were screened in their fourth year for the presence of hyperactivity at baseline (HA), of whom 1246 had skin prick tests to identify atopy (AT). Children were selected to form the following groups: HA/AT, not-HA/AT, HA/not-AT, and not-HA/not-AT (n = 277). After baseline assessment, children were subjected to a diet eliminating artificial colourings and benzoate preservatives for one week; in the subsequent three week within subject double blind crossover study they received, in random order, periods of dietary challenge with a drink containing artificial colourings (20 mg daily) and sodium benzoate (45 mg daily) (active period), or a placebo mixture, supplementary to their diet. Behaviour was assessed by a tester blind to dietary status and by parents' ratings.

RESULTS

There were significant reductions in hyperactive behaviour during the withdrawal phase. Furthermore, there were significantly greater increases in hyperactive behaviour during the active than the placebo period based on parental reports. These effects were not influenced by the presence or absence of hyperactivity, nor by the presence or absence of atopy. There were no significant differences detected based on objective testing in the clinic.

CONCLUSIONS

There is a general adverse effect of artificial food colouring and benzoate preservatives on the behaviour of 3 year old children which is detectable by parents but not by a simple clinic assessment. Subgroups are not made more vulnerable to this effect by their prior levels of hyperactivity or by atopy.

Biological contributions to the presentation and understanding of attention-deficit/hyperactivity disorder: a review

Attention-deficit/hyperactivity disorder (ADHD) is the most commonly diagnosed disorder in children today with estimated prevalence rates falling between 3 and 5% of children (American Psychiatric Association, 1994). From inception, research has focused on studying varying facets of this disorder with initial efforts primarily focusing on treatment outcome. However, prominent efforts have been made in recent research efforts to shed light on the etiology of this disorder. Such research has discovered the contribution of genetic inheritance, as well as environmental factors that lead to the development of this disorder. Furthermore, studies using neurological and neuropsychological assessment measures have implicated the involvement of various Parts of the brain. This article critically reviews this body of research in light of its impact on the current specific neuropsychologically based etiological theories, as well as the most beneficial directions for future research.

Alternative and controversial treatments for attention-deficit/hyperactivity disorder

ADHD is a syndrome that can be treated effectively, safely, and economically with stimulant medications. There is no equal alternative to these agents in short-term treatment of ADHD symptoms. However, many families seek alternatives to stimulants and other drug treatments for a variety of reasons. Alternative approaches reflect the complexity and heterogeneity of the disorder by being equally manifold, complex, and often obscure in their modus operandi. Scientific evidence suggests that individualized dietary management may be effective in some children. Trace element supplementation also may be beneficial when specific deficiencies are present. At this point, nootropics, herbs, and homeopathy are being seriously researched regarding their role in neurologic functioning, but evidence to support their role in the specific treatment of ADHD is inconsistent or lacking. Self-regulatory techniques such as hypnotherapy and biofeedback do not alter the core symptoms of ADHD but may be helpful in controlling secondary symptoms. These methods are unique in ADHD treatment because children can become active agents of their own coping strategies. There is no scientific evidence to support the validity of vision therapy, oculovestibular treatment, or sound training (Tomatis method) as treatment modalities for ADHD. However, auditory stimulation with individualized music may help to improve situational performance in cognitive tasks. Regardless of the treatment approach, the diagnosis of ADHD and other comorbidities first must be established through a standard medical evaluation. The standard treatment options always should be presented and discussed carefully. If alternative approaches are sought, the merits of available options should be reiterated. If the primary care provider is not comfortable or knowledgeable about an acceptable method, referral to capable and responsible practitioners in the community who are experienced in these areas should be considered. The primary care provider, the alternative "specialist," and the family all should be willing to engage in "collaborative research," applying the same standards for treatment evaluation that one would apply in mainstream methods. Communication among all parties involved in a treatment strategy is the key to demystifying alternative approaches, creating strong therapeutic relationships, and optimizing management.

Functional food science and behaviour and psychological functions

The impact of ingesting various foods on psychological and behavioural functions is a topic of both interest and concern to the general public. In this article, the scientific literature concerning demonstrated cause-and-effect relationships is reviewed, beginning with methodological considerations specific to the quantification of particular behaviours and psychological events. The essential function of food is to satisfy hunger and the need for essential nutrients. The contributions of macronutrients to appetite and satiety are described, as well as their impact on metabolism and energy balance. Functional properties of macronutrient substitutes (high-intensity sweeteners, fat replacers) and flavour enhancers are examined in relation to their contribution to hunger, satiety, and energy balance. The effects of foods and individual nutrients on the performance of diverse psychomotor tasks are studied with consideration given to the various validated quantitative tools used to assess behaviour. The effects of food components on activation, sedation, and affective states such as dysphoria are also reviewed, with special attention given to brain function and neuroactive substances such as serotonin and the endorphins. The case of hyperactivity in children is given special emphasis with reference to the potential influence of sugar and food additives. Safety issues related to food constituents and additives are discussed. Finally, a set of criteria is proposed for the evaluation and elaboration of studies in the behavioural and psychological fields, along with suggestions for future research.

Randomized single-subject experimental designs

Books on single-subject methodology tend to focus on traditional operant research techniques and thus provide little or no discussion of random introduction of treatments and statistical tests based on such randomization, i.e. randomization tests. Those books are the principal references to which researchers must turn for a comprehensive coverage of single-subject methodology, and so many researchers are likely to be unaware of the relevance of randomization (random assignment of treatment times to treatments) and randomization tests to single-subject experimentation. That is unfortunate because randomization is necessary in order to draw valid statistical inferences about treatment effects. The role of randomization in providing control over major threats to internal validity is explained in this article, and a number of randomized single-subject designs and their applications are provided. Appropriate rank tests are specified, and sources of free software for other, more complex, statistical tests are given.

Effects of a few food diet in attention deficit disorder

Seventy-eight children, referred to a diet clinic because of hyperactive behaviour, were placed on a 'few foods' elimination diet. Fifty nine improved in behaviour during this open trial. For 19 of these children it was possible to disguise foods or additives, or both, that reliably provoked behavioural problems by mixing them with other tolerated foods and to test their effect in a placebo controlled double blind challenge protocol. The results of a crossover trial on these 19 children showed a significant effect for the provoking foods to worsen ratings of behaviour and to impair psychological test performance. This study shows that observations of change in behaviour associated with diet made by parents and other people with a role in the child's care can be reproduced using double blind methodology and objective assessments. Clinicians should give weight to the accounts of parents and consider this treatment in selected children with a suggestive medical history.

Randomization tests: application to single-cell and other single-unit neuroscience experiments

The application of randomization tests for statistical determination of the significance of experimental manipulations on single cells and other types of single units in neuroscience is described. Applications of standard parametric tests like analysis of variance (ANOVA) and t tests to data from single-subject experiments have been severely criticized for lack of validity and those criticisms are relevant to parametric statistical tests for data from other types of single-unit experiments. A broad class of statistical tests known as randomization tests, on the other hand, has been free of such criticism. Randomization tests have been applied to data from various types of single units in neuroscience, where their validity in the absence of random sampling makes them especially valuable. Until the advent of computers, the computational requirements of randomization tests rendered them impractical. Randomization test computer programs are now readily available. Procedures for access to a public domain program are given in the text.

Simulation study of methods to detect periodontal associations when they are inconsistent among subjects

Most statistical methods used to evaluate associations between indices of clinical periodontal diseases and purported prognostic markers test for effects across subjects. If associations exist within only a subset of subjects, however, associations may be masked, particularly in small studies. This issue was explored by using simulation to study four methods for detecting periodontal associations. Built into the simulations was the possible biological reality that a non-zero association between the two variables of interest (squared correlation coefficients, rho 2, ranged from 0.1 to 0.9 depending on simulation), measured at 16 sites per subject, did not exist in all of 10 hypothetical subjects. The four methods for testing the null hypothesis that rho = 0, or a related hypothesis; were: (1) Sites, analysis based on 160 sites incorrectly considered independent observations; (2) Subjects, analysis based on one score for each of 10 subjects; (3) Each subject, separate analyses based on sites within each of 10 subjects, family-wise type I (alpha) error corrected for multiplicity, and (4) the Each Subject method where P-levels were estimated using permutation procedures rather than t-distributions. Each Subject methods were found to have greater relative power (although there are differences in null hypotheses) under conditions of heterogeneity in rho and are considered to be particularly relevant in exploratory periodontal research when the primary interest is establishing the existence of a relationship, even if in only a subset of subjects.

An olfactory-limbic model of multiple chemical sensitivity syndrome: possible relationships to kindling and affective spectrum disorders

This paper reviews the clinical and experimental literature on patients with multiple adverse responses to chemicals (Multiple Chemical Sensitivity Syndrome-MCS) and develops a model for MCS based on olfactory-limbic system dysfunction that overlaps in part with Post's kindling model for affective disorders. MCS encompasses a broad range of chronic polysymptomatic conditions and complaints whose triggers are reported to include low levels of common indoor and outdoor environmental chemicals, such as pesticides and solvents. Other investigators have found evidence of increased prevalence of depression, anxiety, and somatization disorders in MCS patients and have concluded that their psychiatric conditions account for the clinical picture. However, none of these studies has presented any data on the effects of chemicals on symptoms or on objective measures of nervous system function. Synthesis of the MCS literature with large bodies of research in neurotoxicology, occupational medicine, and biological psychiatry, suggests that the phenomenology of MCS patients overlaps that of affective spectrum disorders and that both involve dysfunction of the limbic pathways. Animal studies demonstrate that intermittent repeated low level environmental chemical exposures, including pesticides, cause limbic kindling. Kindling (full or partial) is one central nervous system mechanism that could amplify reactivity to low levels of inhaled and ingested chemicals and initiate persistent affective, cognitive, and somatic symptomatology in both occupational and nonoccupational settings. As in animal studies, inescapable and novel stressors could cross-sensitize with chemical exposures in some individuals to generate adverse responses on a neurochemical basis. The olfactory-limbic model raises testable neurobiological hypotheses that could increase understanding of the multifactorial etiology of MCS and of certain overlapping affective spectrum disorders.