Nutrition, the keystone of life, is a frequently overlooked aspect of child and adolescent psychiatry, and medicine in general. Traditional foods that ensured health, fertility, and survival over millions of years, and that determined our modern genotype, are scarcely found on a modern American table. The burden of modern diet-related illness has created vast markets for the vitamin and mineral fortification of processed foods, nutrient supplements, and “neutraceuticals.” These approaches do not entirely solve the problem, and may present new ones. Vitamins, minerals, and fatty acids work synergistically and in balance with one another. Too much of one nutrient may cause a deficiency of another. For example, too much zinc may result in a copper deficiency, and too much omega 6 essential fatty acid can result in a relative deficiency of omega 3 essential fatty acid. Furthermore, nutrients are best utilized by the body in the contexts from which they arise, from plants and animals with which humans evolved. While synthetic vitamins, chelated minerals, and nutrients extracted from foods in commercial settings have shown usefulness, they are less likely to be as safe and effective as nutrients acquired from a diet of whole foods.
The study of nutrition as it relates to mental health is at its embryonic stage, particularly as it relates to children and adolescents. The evidence base is limited, and most studies suffer from methodologic limitations. Nonetheless, field researchers persist in investigating the role of nutrition in health, the scientific literature is increasingly addressing how nutrition affects mental health, and emerging evidence leaves tantalizing clues as to how medical providers may benefit patients using promising approaches with a few to no side effects.
Given the scope and complexity of this important subject, not all aspects of nutrition and mental health can be addressed here. What follows is an overview of nutrition as it applies to the mental health of children and adolescents, with suggestions as to how the medical provider can use nutrition to augment psychiatric treatment.
Conduct Disorder and Antisocial Personality Disorder
Aggressive behaviors in children and adolescents are marked by irritability, restlessness, impulsivity, and a tendency toward violence. While such traits are observed in children and adolescents with conduct disorder, these traits overlap with other diagnoses of childhood and adolescence known as the disruptive behavior disorders, including attention deficit hyperactivity disorder (ADHD) and oppositional defiant disorder (ODD). The influence of nutrition on these conditions is just beginning to come into focus.
In 2002, a landmark study was published in the British Journal of Psychiatry by Bernard Gesch. “The Young Prisoners Study” reported that offenders were often inclined to choose foods lacking in essential nutrients which could influence their behaviors. Therefore, he conducted a double-blind, placebo-controlled study of the effect of dietary supplementation with physiologically adequate amounts of vitamins, minerals, and fatty acids. He divided a population of 231 prisoners ages of 18 and 21 years into two groups, one receiving placebo and one receiving a selection of vitamins, minerals, and fatty acids (here referred to as “nutrients”) for 4 months. Investigators then tracked offenses among the inmates. At the conclusion of the study, prisoners receiving placebo showed no change in baseline behaviors, while prisoners receiving nutrients improved markedly. Among those receiving nutrients, there were 26% fewer violations overall, with serious breaches of conduct, including violence, reduced by 37%.
Studies of specific nutritional deficiencies in conduct disorder are small, but the evidence that exists is intriguing. Iron is a mineral essential to brain health. It is a cofactor in the metabolism of tyrosine to dopamine and functions in the enzyme system involved in the production of serotonin, dopamine, norepinephrine, and epinephrine. Studies by Webb and Oski suggest that iron deficiency may play an important role in the aggressive behaviors and conduct disorder by male adolescents and Rosen has found iron deficiency among incarcerated adolescents to be nearly twice that found among nonincarcerated peers.
Hypoglycemia has been linked to criminal and violent behavior. Studies from Finland report that criminals with a history of violence are more inclined to experience hypoglycemia, particularly when under the influence of alcohol, which enhances the action of insulin, further reducing blood sugar levels. By promoting high insulin levels, foods containing highly refined and processed starches and sugars have the potential to cause hypoglycemic symptoms 2 to 4 hours after they are ingested. This is most likely to occur when insulin remains in the bloodstream long after glucose has been metabolized, leading to a hypoglycemic “overshoot.” The child or adolescent whose brain is starved for glucose may complain of hunger, blurred vision. He or she may exhibit slurred speech, irritability, and may act out aggressively.
Glycemic load is defined as an indicator of glucose response or insulin demand that is induced by total carbohydrate intake. There is a correlation between the glycemic load of a child’s meals and snacks and the child’s propensity for hypoglycemia. Fiber and fats, which modify glycemic loads, are frequently absent from cereals and snacks marketed to children. For example, when served with fat-free milk, highly refined boxed cereals are free to promote elevated blood sugar and hypoglycemic overshoots via the action of insulin produced in the pancreas. Teachers observe the resultant midmorning slump when children cannot attend to lessons and are inclined to misbehave.
The best approach is to serve meals and snacks that are balanced in terms of fat, complex carbohydrates, and protein. For example, a piece of whole-milk cheese, in which carbohydrate is combined with fat and protein, is a preferred snack choice to a primarily carbohydrate food, such as a cracker or an apple. The former choice holds greater potential to promote satiety and blood sugar stabilization over time. Fiber is also recognized for its ability to slow the release of sugar to the bloodstream, thereby stabilizing blood glucose as well; however, bran from most commercially processed whole grains is also high in phytates, which prevents the absorption of minerals from the diet. Fermenting (e.g., sourdough) and soaking (“sprouted”) grains, nuts, beans, and lentils prior to cooking reduce the phytate content.
Grain, bean, and lentil products prepared in this fashion should be included as part of a healthy meal plan.
The correlation of low total serum cholesterol levels and death from suicides and accidents in adults is well documented. Adult subjects with total cholesterol concentrations lower than 160 mg/dL are found to score higher on aggressive hostility, anxiety, phobia, and psychoticism in several studies. Similar trends appear in a recent study of youth. In a 2005 study of non-African American children, Zhang showed children and adolescents with low total serum cholesterol, defined as less than 145 mg/dL, displayed more violence and were nearly threefold more likely to be suspended from school than peers with higher cholesterol levels. From these findings, Zhang postulates that low total serum cholesterol is either a risk factor for aggression, or perhaps a risk marker for other biologic variables that predispose to aggression. Other investigators examining this issue speculate cholesterol modulates serotonin, and the absence of adequate cholesterol reduces serotonin availability.
Lithium is the mineral salt best known to psychiatrists. First recognized in 1949 as a medical approach for bipolar disorder, lithium has since found a number of other psychiatric uses, including the management of anger in intermittent explosive disorder and as an adjunct to antidepressant treatment for major depressive disorder. Children with bipolar disorder, conduct disorder, and extremely aggressive behavior have been shown to improve with lithium treatment.
Lithium is found in a number of food sources, such as vegetables and grains. It is also found in the water supplies in many areas in the United States (US). The role, if any, that dietary lithium plays in humans is not entirely understood. During gestation, lithium concentrates in organs and, as gestation progresses, becomes less concentrated. Autopsy studies show lithium to be most concentrated in the cerebellum, followed by the cerebrum and the kidneys. Unexplained gender differences exist, with women concentrating 10% to 20% more lithium in the cerebrum and cerebellum than men.
The concentration of lithium in tissue and blood may impact human behavior. Dawson and colleagues examined the relationship between lithium in tap water and urine and found an inverse association with rates of psychiatric admissions and homicides. The lower the lithium levels in the water (and subsequently in the urine), the higher the rates of psychiatric problems and serious crimes. Other investigators have found similar results. Using crime rate data from 1978 to 1987, Schrauzer and Shrestha found highly significant inverse associations between water lithium levels and the rates of homicide, suicide, and forcible rape. Significant inverse associations were also found between water lithium levels and possession of narcotics, burglary, theft, and in juveniles, running away. Subsequently, they also found that the lithium content in the scalp hair of incarcerated violent criminals was lower than that of nonincarcerated controls. While these data do not demonstrate cause and effect, they suggest a role for lithium.
Omega 3 Essential Fatty Acids EPA and DHA
Fatty acid deficiencies are common in children with behavior and learning problems. Signs of fatty acid deficiency include thirst, frequent urination, rough, dry or scaly skin, dry, dull or “lifeless” hair, dandruff, and soft or brittle nails. Follicular karatosis, or hard, dry skin around hair follicles, are characteristic. Temper tantrums and sleep problems have been found on standardized rating scales to be more common in children with lower fatty acid concentrations.
Fatty acids are called “essential” if they cannot be manufactured by the body and need to be obtained exogenously. Ideally, the intake of omega 3 essential fatty acids is in balance with
omega 6 essential fatty acids in ratios ranging from 1:1 to 1:4. But, the modern Western diet promotes an abundance of omega 6 fatty acids, from commercial vegetable oils and grain-fed livestock, with scant intake of omega 3 fatty acids from rich sources such as oils from wild (not farmed) fish, fats from wild game, and fats from pasture-finished livestock, including chickens and dairy animals. Modern trends in food production result in omega 3 to omega 6 essential fatty acids intake ratios that range from 1:13 to 1:20 in favor of omega 6.
Nutritionally adequate supplies of the omega 3 essential fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) can only be obtained from animal sources. While alpha linoleic acid (ALA), an essential fatty acid found in plants sources such as flaxseed, can be converted to EPA and DHA in humans, conversion is too limited to prevent deficiency. For this reason, vegan children and vegetarian children for whom fish or other rich animal sources are not included in meals are at particular risk for deficiencies in EPA and DHA.
Omega 3 essential fatty acids comprise as much as 30% of human neuronal membranes. The functions of omega 3 fatty acids are wide ranging and include neurotransmission enhancement, neuroprotection, and anti-inflammatory roles. Thus, in 2006, the American Psychiatric Association (APA) issued a consensus statement regarding the role of the omega 3 essential fatty acids EPA and DHA in mental health. The APA now recommends “Patients with mood, impulse control, or psychotic disorders should consume 1 g EPA + DHA per day.” Fish oil supplements provide rich sources of omega 3 fatty acids. For children who do not swallow capsules well, flavored liquids, small flavored capsules, and chewable forms are available.
Side effects of fish oil are rare, and generally mild. The most common complaints are gastroesophageal reflux and belching. These side effects can usually be avoided by ensuring oils are fresh, cooling oil preparations in the refrigerator, and dosing at bedtime. The literature generally indicates that omega 3 essential fatty acids are safe for use in diabetics, but some data suggest they may alter glucose metabolism. There is one report of hypomania in a depressed adult who took 330 mg DHA and 220 mg EPA three times per day. Symptoms of hypomania resolved 2 days after discontinuation of DHA and EPA. While concerns have been raised as to the potential for bleeding and bruising, fish oil supplementation does not appear to be responsible in most cases. There is a report of an adult taking warfarin who experienced a significant change in coagulation status when fish oil was doubled from 1000 mg to 2000 mg per day; so caution should be exercised in patients taking anticoagulants.
Attention Deficit Hyperactivity Disorder
Attention deficit hyperactivity disorder (ADHD) has been related to a multitude of factors, including diet, sensitivities to food additives, heavy metal and other toxicities, low protein/high carbohydrate diets, mineral imbalances, essential fatty acid deficiencies, phospholipids deficits, amino acid deficits, thyroid disorders, vitamin B complex-related disorders, and phytochemicals. As attributions are numerous, many with scant scientific support, only a few key nutrients of interest will be discussed here.
Omega 3 Essential Fatty Acids EPA and DHA
More research exists on ADHD and essential fatty acids than any other nutrient. Interest in the role of these fatty acids in ADHD spans three decades and suggests that fatty acid deficiency may be common in people with ADHD and particularly affect their performance in the classroom. However, deficiencies have also been linked with behavior, learning, and health problems in boys both with and without a diagnosis of ADHD. Treating individuals with low omega-3 fatty acids with 1 g of EPA + DHA each day, as recommended by the APA, is unlikely to do harm, and may result in symptom improvement over subsequent months.
Additives and Preservatives
The notion that a link exists between consumption of food dyes and preservatives and hyperactivity has been resurrected in recent years. Most often derived from petroleum products and coal tar, brightly colored dyes are added to foods to give the impression of freshness, sweetness, and/or ripeness. Dyes in colors attractive to children are abundant in candy, gum, cereals, sport drinks, popsicles, gelatin, cookies, frostings, and many other food items. Swanson and Kinsbourne, citing the Food and Drug Administration (FDA), note that Americans now consume five times as much food dye as they did 30 years ago.
In 1973, Dr. Benjamin Feingold, a pediatric allergist, suggested that artificial food colorings caused hyperactivity in children. His theories ignited a firestorm of controversy in the US. It took another 30 years for researchers to confirm Dr. Feingold’s suspicions. In 2004, Schab and Trinh performed a meta-analysis of previous studies and demonstrated that food colorings worsen hyperactivity in children with hyperactivity syndromes. Then, on September 6, 2007, the Lancet reported definitive findings from a double-blind, placebo-controlled study performed at the University of Southampton. In this study, 153 three-year-old and 144 eight-to nine-year-old normal children from a range of socioeconomic backgrounds had all artificial colors, flavors, and preservatives removed from their diets. Children in the active group were next presented with a challenge drink containing artificial food colorings and sodium benzoate, a preservative common to soft drinks and processed foods in the US. Included among these colorings were four common coal tar-derived azo dyes: Sunset yellow (F D & C Yellow # 6), Tartrazine (F D & C Yellow # 5), Quinoline yellow (FD&C Yellow # 10), and Allura red AC (F D & C Red # 40). The addition of food colorings to sodium benzoate was significantly associated with hyperactivity in this normal population of children. In light of this study, Dubik noted in the AAP Grand Rounds, “Thus, the overall findings of the study are clear and require that even we skeptics, who have long doubted parental claims of the effects of various foods on the behavior of their children, admit we might have been wrong.” They recommended “a trial of a preservative-free, food-coloring-free diet is a reasonable intervention” for hyperactive children.
Symptoms of iron deficiency can mimic ADHD, or complicate its treatment. Iron deficiency in the US is common and appears to be on the increase, despite iron fortification of cereals and other foods. As reported by Looker in 2002, data from the National Health and Nutrition Examination Survey (NHANES) 1999-2000 reveal that iron deficiency affects from 1 in 20 to 1 in 14 children between the ages of 1 and 11 years. Adolescent girls tend to be more affected than boys, with 9% of 12- to 15-year-olds and 16% of 16-to 19-year-olds affected. Children who are iron deficient, with or without anemia, experience cognitive and behavioral difficulties that may interfere with normal development. Iron deficiency renders affected individuals more susceptible to absorption of lead and cadmium; the presence of pica heightens this risk. Additionally, symptoms of lead toxicity overlap with symptoms of ADHD. Iron deficiency is more common among adolescent girls after menarche, particularly when menorrhagia is present. Athletes and the obese are also at particular risk. Children and adolescents deficient in iron may complain of fatigue, poor concentration, and impulsivity along with a decline in school performance. Iron deficiency may be accompanied by involuntary limb movements during sleep (nocturnal myoclonus) and restless legs syndrome (RLS), which erodes the quality of sleep. Children affected by these conditions are frequently hyperactive and impulsive in the classroom as they struggle to remain alert. Iron-deficient adolescents may decline in scholastic and athletic performance, as well as exhibit conduct problems.
Some studies suggest iron deficiency is prevalent among children and adolescents with ADHD. Konofal and colleagues measured ferritin levels of 53 children and young adolescents diagnosed with ADHD who had been medication-free for 2 months. They found ferritin
levels to be abnormally low (average of 22 ng/mL) in 84% of the ADHD population and only 18% of controls (average of 44 ng/mL). One third of the iron-deficient ADHD population had extremely low levels of serum ferritin. Furthermore, lower ferritin levels corresponded with more severe ADHD symptoms per a standardized ADHD rating scale.
Preliminary studies also show restoring iron decreases ADHD symptoms in children who are iron deficient. In a 2005 case study, Konofal and colleagues described an iron-deficient (serum ferritin 13 ng/mL), but not anemic (Hgb 12.9 mg/dL), 3-year-old male with symptoms of ADHD and disturbed sleep. After 8 months of iron supplementation, ferritin increased to 102 ng/mL and the child’s ADHD symptoms improved per parent’s and teacher’s scores on standardized ADHD rating scales. Sleep also improved. In 2008, these investigators conducted a similar intervention for 23 nonanemic but iron-deficient (ferritin levels <30 ng/mL) children of ages 5 to 8 years who met the criteria for ADHD. In this placebo-controlled study, 18 children received 80 mg oral iron sulfate per day over 12 weeks, while 5 children received a placebo. After 12 weeks, the children receiving iron supplementation showed significant decreases in ADHD symptoms compared to their controls as measured by standardized rating scales; decreases reportedly comparable to treatment with stimulants. These preliminary studies are worth taking seriously. When the lower limit of ferritin is defined as 30 ng/mL or higher, children evaluated for ADHD appear to be at increased risk for iron deficiency. Additionally, restless leg syndrome (RLS) is frequently comorbid with ADHD. According to the American Academy of Family Physicians, iron deficiency plays a role in RLS as well, and persons with ferritin levels less than 50 ng/mL are at heightened risk. Given this, it seems reasonable to investigate iron stores in children and adolescents evaluated for ADHD. Where suspicion of iron deficiency is low, children and adolescents with presumed ADHD may undergo an initial screening with a serum ferritin and a C-reactive protein (CRP). If ferritin is above 50 ng/mL but CRP is high, the ferritin value may be falsely elevated due to inflammation. In this case, further laboratory investigation into iron status is appropriate. Where suspicion of iron deficiency is high, obtaining an iron panel along with ferritin and CRP is recommended. Recommended dietary allowances for iron are presented in Table 23.1
According to the US Department of Agriculture (USDA), zinc deficiency is common; up to 62% of young children in the US do not get enough zinc in their diets. Zinc is important for various aspects of cellular metabolism. Without adequate zinc, neurotransmitter synthesis is
compromised. Several controlled studies show that a deficiency of zinc is associated with ADHD, which improves when zinc sulfate supplements are provided. Animal proteins, including beef, lamb, pork, crabmeat, turkey, chicken, lobster, clams and salmon, are the richest and most bioavailable dietary sources of zinc. Infants and children are at particular risk for zinc deficiency when diets are poor in meat. While plant sources are common, absorption and utilization of zinc from these sources is poor. Also, diets high in phytates, such as high plant fiber diets, are also shown to enhance the elimination of diet-acquired zinc, increasing the likelihood of deficiency. There appears to be at least one food-coloring connection to zinc deficiency as well. In 1990, Neil Ward showed that children with ADHD lose zinc when exposed to the food dye tartrazine (FD & C Yellow #5).
TABLE 23-1 Recommended Dietary Allowances for Iron for Infants, Children, I Adolescents, and Adults
7 to 12 months
1 to 3 years
4 to 8 years
9 to 13 years
14 to 18 years
19 to 50 years
Source: Dietary Supplement Fact Sheet: Iron Office of Dietary Supplements-National Institutes of Health-http://ods.od.nih.gov/factsheets/iron.asp.
TABLE 23-2 Recommended Dietary Allowances for Zinc for Infants, Children, Adolescents, and Adults
Birth to 6 months
7 month to 3 years
4 to 8 years
9 to 13 years
14 to 18 years
a Adequate intake (Al).
Source:Institute of Medicine, Food and Nutrition Board. Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc. Washington, DC: National Academy Press, 2001.
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