It is well known that our food choices play a role in our long-term physical health. It is less recognized that nutrition can have profound effects on our mental health and our behavior. Overall, malnutrition in childhood can affect the brain throughout the lifespan, while specific food components can affect our short-term well-being. Sugar, wheat, and milk are among the most common dietary triggers for ADHD symptoms. Fluctuating blood sugar levels and partially-digested foods can also cause a wide range of symptoms from fatigue to hyperactivity. This article will discuss the dietary influences on behavioral problems in children, review how laboratory testing can be critical in identifying food sensitivities, and how to enhance digestion for maximum absorption of nutrients.
One of the most debated treatments for ADHD is the Feingold Diet, introduced in the early 1970’s by pediatrician and allergist Ben Feingold, MD. He initially suggested that children who are allergic to aspirin (which contains salicylates) may react to artificial food colors and naturally occurring salicylates. The Feingold Diet eliminates artificial food additives like flavorings, preservatives, sweeteners, and colors to reduce hyperactivity. The research over the years on the Feingold Diet has been mixed – some studies show no behavior change and some show increases in hyperactivity when children consume artificial ingredients. A landmark study conducted in the UK on three hundred 3-year-old and 8/9-year-old children in the general population found artiﬁcial colors or a sodium benzoate preservative (or both) in the diet resulted in increased hyperactivity (McCann et al., 2007). This study led the European Union to ask manufacturers to voluntarily remove several artificial food colors from foods and beverages or to add a warning label that the artificial food color “may have an adverse effect on activity and attention in children” (Arnold et al., 2012). Conversely, in the US, the FDA reviewed the study and determined that a causal relationship between consumption of color additives and hyperactivity in children could not be definitively established (Arnold et al., 2012).
Genetics often play a role in how a child’s ADHD symptoms are exacerbated. The children most likely to be affected by food additives have a genetic inability to metabolize the compounds. Genetic tests were conducted on the 300 UK children from the artificial food color study. Children with specific variations in the HNMT gene, which helps break down histamine in the body, had stronger behavioral reactions to artificial food colors than children without this variation (Stevenson et al., 2010). This means that in some children, food additives spur the release of histamine that in turn affect the brain.
The Barbados Nutrition Study was a longitudinal case-control study that began in the late 1960’s and investigated the physical, mental, and behavioral developmental effects of infant malnutrition. The 204 participants of this study experienced a single episode of moderate to severe malnutrition during their first year of life. Data was collected on these children through adulthood and compared to data from healthy children. By the end of puberty, all children completely caught up in their physical growth. However, cognitive and behavioral issues persisted into adulthood.
The consequences of malnutrition in infancy manifested in many ways. IQ scores of the children with a history of malnutrition at age 5-11 were significantly lower than those of the control children. 50% of the malnourished children had scores at or below 90 while only 17% of the control children had scores this low (Galler et al., 1983). According to teacher reports, attentional deficits, including shorter attention span, poorer memory, and more distractibility and restlessness, were found in 60% of the malnourished children compared to only 15% of the controls. They also had worse social skills, general health, sleepiness in the classroom, and emotional stability (Galler et al., 1983). When the children were reassessed on these measures at age 9-15, a history of early malnutrition was still associated with behavioral impairment at school, especially attention deficits (Galler & Ramsey, 1989).
Behavior problems reported by teachers when the participants were aged 5-11 significantly predicted conduct problems at age 11-17 (Galler et al., 2012). Age at 5-11, children malnourished as infants had lower performance on 8 out of 9 academic subject areas. 37 children (36 malnourished, 1 control) were below the expected grade for their age (Galler, Ramsey, & Solimano, 1984). Compared to control children, previously malnourished children at age 5-11 had significantly worse scores on parent-rated measures of good behavior (no antagonism between mother and child, obedience), social skills, mother-child relationship, frustration level, eating habits, sleeping habits, and school avoidance. Compared to their siblings, previously malnourished children had significantly worse scores on social skills, good behavior, helpfulness, mother-child interaction, eating habits, toilet training, and language (Galler, Ramsey, & Solimano, 1985). When the children were reassessed on these measures at age 9-15, the same results were seen, especially for aggression and distractibility (Galler & Ramsey, 1989). Problems with self-regulation, displayed as reduced executive functioning and aggression toward peers, persisted through adolescence (Galler et al., 2011).
Years later when the subjects were aged 37-43, attention problems were assessed using an adult ADHD scale and a computerized test of attention-related problems. There was a higher prevalence of attention deficits in the previously malnourished group relative to controls. 69% of the previously malnourished participants had at least one test score that fell within the clinical range for attention disorders (Galler et al., 2012). Previously malnourished participants also had worse educational attainment and income across the entire 40-year study (Galler et al., 2012).
Multiple connections have been made between sugar, hyperactivity, and the risk for ADHD. In group of almost 400 school-age children, researchers found that children with the greatest “sweet” dietary pattern had almost four times greater odds of having ADHD compared to those who ate sweets (ice cream, refined grains, sweet desserts, sugar, and soft drinks) less often (Azadbakht & Esmaillzadeh, 2012). In a similar study on 1,800 adolescents, having a “Western” dietary pattern (higher intakes of total fat, saturated fat, refined sugars, and sodium) more than doubled the odds of an ADHD diagnosis (Howard et al., 2011). Likewise, a study on 986 children, average age 9 years, found a high intake of sweetened desserts (ice cream, cake, soda) was significantly associated with worse inattention, hyperactivity-impulsivity, aggression, delinquency, and externalizing problems. In contrast, a high-protein diet was associated with better scores on these measures. A high level of sweetened dessert consumption was also associated with lower scores on tests of listening, thinking, reading, writing, spelling, and math (Park et al., 2012).
Certain foods may not only influence behavioral and physical symptoms, but may also modify brain activity. When children aged 6-15 with food-induced ADHD consumed provocative foods, they showed an increase in beta activity in frontotemporal regions during EEG topographic mapping of brain electrical activity (Uhlig et al., 1997). Beta waves are involved in normal waking consciousness and tend to have a stimulating effect; while too much beta can lead to anxiety.
A food sensitivity to a protein found in milk or a protein found in wheat is a prevalent but neglected cause of ADHD. Milk and milk products like cheese and butter contain a protein called casein. Casein is different from lactose which is a milk sugar. Grains like wheat, rye, and barley contain a protein called gluten. During digestion, casein becomes casomorphin and gluten becomes gliadorphin. For most people, these proteins are further broken down into basic amino acids. For some with ADHD, they have inactive dipeptidyl peptidase IV, a zinc-dependent enzyme that breaks down both casein and gluten, leaving these opioid peptides substances to build up.
Children with ADHD who have high levels of casomorphin or gliadorphin often have severe, uncontrolled symptoms. Both casomorphin and gliadorphin are morphine-like compounds which attach to opiate receptors in the brain. These substances can act like an addicting drug in susceptible children and cause fatigue, irritability, and brain fog. A child with high levels of casomorphin may have strong cravings for milk products (ice cream, yogurt) and may become irritable when he or she doesn’t eat these types of foods. The Gluten/Casein Peptide Test is a simple urine test that can measure levels of casomorphin and gliadorphin. If a child has high levels of casomorphin or gliadorphin, they should try to eliminate casein or gluten. Supplementation with DPP-IV enzymes can also be beneficial and often required for clinical improvement.
Malnutrition can negatively affect behavior and cognition, but certain nutrients can have detrimental effects on children as well. Louise Goldberg, pediatric dietitian, put it succinctly: “Food allergies and sensitivities can come at children with a one-two punch – first making them agitated, and next robbing them of nutrients that might rein in their behavior” (Peachman, 2013). We are biochemically unique and have different physiological and psychological responses to different foods. The right food for one child may the wrong food for another. For instance, peanut butter on whole wheat toast may be a nutritionally-balanced, energy-boosting snack for one child, while this snack would be harmful to a child who cannot tolerate neither nuts nor wheat. Medical testing can clarify which nutrients a child is sensitive to. Fortunately, eliminating offending substances can rapidly improve physical and behavioral symptoms.
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