Could polyunsaturated fatty acids deficiency explain some dysfunctions found in ADHD? Hypotheses from animal research

Early monitoring of fatty acid profile in children with attention deficit and/or hyperactivity disorder under treatment with omega-3 polyunsaturated fatty acids

BACKGROUND

Cognitive effects of omega-3 polyunsaturated fatty acids (ω-3 PUFAs) might make them helpful in attention deficit/hyperactivity disorder (ADHD). However, the results derived from supplementation studies in children depend on the respective combinations and the study period. We aimed to investigate the serum fatty acid profile, attention scores and the tolerability in a group of ADHD children after receiving methylphenidate (MPH) and ω-3 PUFAs for 1 month.

METHODS

A combination of MPH (1 mg/kg/day) and eicosapentaenoic (EPA, 70 mg/day) + docosahexaenoic acids (DHA, 250 mg/day) was administered to 40 ADHD children (7-15 years). An analysis of serum fatty acids by gas chromatography and an assessment of attention by using the Magallanes Scale of Visual Attention (MSVA) were carried out before and after 1 month of treatment.

RESULTS

Our data revealed significant decreases of several ω-6 PUFAs, like arachidonic acid (P<0.0259). EPA and DHA concentrations increased by 27% and 3% respectively, and the ω-6/ω-3 index slightly decreased. The quality of attention significantly increased (P<0.026) and an improvement of ADHD core symptoms was reported both by parents and by teachers. No severe side effects occurred.

CONCLUSIONS

Results demonstrate that the combination of MPH and EPA+DHA at the tested doses has positive clinical effects and an adequate safety profile. Therefore, our study suggests that ω-3 PUFAs may represent a feasible and a safe adjuvant therapy in children with ADHD and might enhance the effects of MPH. Further long-term follow-up studies are required to confirm these initial findings.

Attention-deficit hyperactivity disorder in adults: A systematic review and meta-analysis of genetic, pharmacogenetic and biochemical studies

The adult form of attention-deficit/hyperactivity disorder has a prevalence of up to 5% and is the most severe long-term outcome of this common disorder. Family studies in clinical samples as well as twin studies suggest a familial liability and consequently different genes were investigated in association studies. Pharmacotherapy with methylphenidate (MPH) seems to be the first-line treatment of choice in adults with attention-deficit hyperactive disorder (ADHD) and some studies were conducted on the genes influencing the response to this drug. Finally some peripheral biomarkers were identified in ADHD adult patients. We believe this work is the first systematic review and meta-analysis of candidate gene association studies, pharmacogenetic and biochemical (metabolomics) studies performed in adults with ADHD to identify potential genetic, predictive and peripheral markers linked specifically to ADHD in adults. After screening 5129 records, we selected 87 studies of which 61 were available for candidate gene association studies, 5 for pharmacogenetics and 21 for biochemical studies. Of these, 15 genetic, 2 pharmacogenetic and 6 biochemical studies were included in the meta-analyses. We obtained an association between adult ADHD and the gene BAIAP2 (brain-specific angiogenesis inhibitor 1-associated protein 2), even after Bonferroni correction, with any heterogeneity in effect size and no publication bias. If we did not apply the Bonferroni correction, a trend was found for the carriers allele 9R of dopamine transporter SLC6A3 40 bp variable tandem repeat polymorphism (VNTR) and for 6/6 homozygotes of SLC6A3 30 bp VNTR. Negative results were obtained for the 9-6 haplotype, the dopamine receptor DRD4 48 bp VNTR, and the enzyme COMT SNP rs4680. Concerning pharmacogenetic studies, no association was found for the SLC6A3 40 bp and response to MPH with only two studies selected. For the metabolomics studies, no differences between ADHD adults and controls were found for salivary cortisol, whereas lower serum docosahexaenoic acid (DHA) levels were found in ADHD adults. This last association was significant even after Bonferroni correction and in absence of heterogeneity. Other polyunsaturated fatty acids (PUFAs) such as AA (arachidonic acid), EPA (eicosapentaenoic acid) and DyLA (dihomogammalinolenic acid) levels were not different between patients and controls. No publication biases were observed for these markers. Genes linked to dopaminergic, serotoninergic and noradrenergic signaling, metabolism (DBH, TPH1, TPH2, DDC, MAOA, MAOB, BCHE and TH), neurodevelopment (BDNF and others), the SNARE system and other forty genes/proteins related to different pathways were not meta-analyzed due to insufficient data. In conclusion, we found that there were not enough genetic, pharmacogenetic and biochemical studies of ADHD in adults and that more investigations are needed. Moreover we confirmed a significant role of BAIAP2 and DHA in the etiology of ADHD exclusively in adults. Future research should be focused on the replication of these findings and to assess their specificity for ADHD.

Diet in the treatment of ADHD in children - a systematic review of the literature

BACKGROUND

Attention-deficit/hyperactivity disorder (ADHD) is one of the most prevalent psychiatric conditions in childhood. Dietary changes have been suggested as a way of reducing ADHD symptoms.

AIMS

To provide an overview of the evidence available on dietary interventions in children with ADHD, a systematic review was carried out of all dietary intervention studies in children with ADHD.

METHODS

Relevant databases were searched in October 2011, with an update search in March 2013. The studies included describe diet interventions in children with ADHD or equivalent diagnoses measuring possible changes in core ADHD symptoms: inattention, hyperactivity and impulsivity.

RESULTS

A total of 52 studies were identified, some investigating whether ADHD symptoms can improve by avoiding certain food elements (20 studies), and some whether certain food elements may reduce ADHD symptoms (32 studies).

CONCLUSION

Elimination diets and fish oil supplementation seem to be the most promising dietary interventions for a reduction in ADHD symptoms in children. However, the studies on both treatments have shortcomings, and more thorough investigations will be necessary to decide whether they are recommendable as part of ADHD treatment.

Long-chainn-3 PUFA supplementation decreases physical activity during class time in iron-deficient South African school children

Both Fe deficiency and poorn-3 fatty acid status have been associated with behavioural changes in children. In the present study, we investigated the effects of Fe and DHA+EPA supplementation, alone or in combination, on physical activity during school days and on teacher-rated behaviour in healthy Fe-deficient school children. In a 2 × 2 factorial design, children (n98, 6–11 years) were randomly assigned to receive (1) Fe (50 mg) plus DHA (420 mg)+EPA (80 mg), (2) Fe plus placebo, (3) placebo plus DHA+EPA or (4) placebo plus placebo as oral supplements (4 d/week) for 8·5 months. Physical activity was measured during four school days at baseline and endpoint using accelerometers, and data were stratified into morning class time (08.00–10.29 hours), break time (10.30–11.00 hours) and after-break class time (11.01–12.00 hours) for analysis. Classroom behaviour was assessed at endpoint using Conners’ Teacher Rating Scales. DHA+EPA supplementation decreased physical activity counts during morning class time, increased sedentary physical activity, and decreased light- and moderate-intensity physical activities. Consistently, DHA+EPA supplementation increased sedentary physical activity and decreased light-intensity physical activity during after-break class time. Even though there were no treatment effects found on teacher-rated behaviour, lower physical activity during morning class time was associated with lower levels of teacher-rated hyperactivity and oppositional behaviour at endpoint. Despite a positive association between Fe status and physical activity during break time at baseline, Fe supplementation did not affect physical activity during break time and class time. Our findings suggest that DHA+EPA supplementation may decrease physical activity levels during class time, and further indicate that accelerometry might be a useful tool to assess classroom behaviour in healthy children.

Altered serum mono- and polyunsaturated fatty acid levels in adults with ADHD

Other than in children diagnosed with attention deficit hyperactivity disorder (ADHD), the connection between ADHD and lipids has not been sufficiently investigated so far in adults. Blood serum lipoproteins and fatty acids (FA) composition were measured and analyzed by colorimetry and gaschromatography in eight male and seven female adults diagnosed with ADHD as well as in 15 age- and gender-matched healthy control subjects. In ADHD patients, polyunsaturated FAs [docosahexaenoic, arachidonic and dihomogammalinolenic acid (p = 0.048; 0.003; 0.012)] showed lower concentrations, while monounsaturated acids (palmitoleic and oleic acid) as well as total and LDL cholesterol showed higher concentrations (p = 0.011; 0.005). ADHD scores positively correlated with palmitoleic (R = -0.56; p = 0.032), stearic (R = 0.53; p = 0.044), eicosapentaenoic (R = 0.62; p = 0.014), docosahexaenoic (R = 0.51; p = 0.050), gammalinolenic (R = 0.62; p = 0.018) and alphalinolenic acid (R = 0.56; p = 0.031) concentration. Even though the total and LDL cholesterol concentrations in blood serum were significantly higher among the ADHD patients than in controls, none of the ADHD symptom scores were significantly associated with any of the lipoproteine measures. We could demonstrate that a lack of polyunsaturated FAs in blood serum of subjects with ADHD persists into adulthood. Furthermore, we could show that adult ADHD symptomatology positively correlates with elevated levels of saturated stearic and monounsaturated FAs.