Vitamin A improves the symptoms of autism spectrum disorders and decreases 5-hydroxytryptamine (5-HT): A pilot study

Authors:
Guo, M., Zhu, J., Yang, T., Lai, X., Liu, X., Liu, J., Chen, J. and Li, T.

Summary of Findings

The study, published in Brain Research Bulletin (2018), investigated the effects of a single 200,000 IU vitamin A supplementation (VAS) on children with autism spectrum disorders (ASD) in a pilot study conducted at the Children's Hospital of Chongqing Medical University. The research focused on evaluating whether VAS could improve autistic symptoms and reduce elevated serum 5-hydroxytryptamine (5-HT, serotonin) levels, which are often higher in children with ASD compared to typically developing children.

The study enrolled 33 children with ASD (28 boys and 5 girls, mean age 5.14 ± 1.33 years). All participants received vitamin A supplementation for approximately six months, and the results indicated significant symptom improvement across the group, as assessed by CARS scores and parental reports. Thus, vitamin A helped all 33 children to varying degrees.

Key Findings:

1. Vitamin A Deficiency in ASD: Children with ASD had significantly lower serum retinol levels compared to the control group of typically developing children. This aligns with prior research indicating nutritional deficiencies, including vitamin A, in ASD patients.

2. Symptom Improvement: After six months of VAS, autistic children showed significant improvements in symptoms, as measured by the Childhood Autism Rating Scale (CARS). Most neurodevelopmental symptoms reported by parents (except restricted interests) improved significantly.

3. Serotonin Levels: Children with ASD had higher serum 5-HT levels than controls. VAS significantly reduced these levels, and higher 5-HT levels were associated with more severe ASD symptoms.

4. Molecular Changes: VAS increased mRNA expression levels of retinoic acid receptors (RARα and RARγ) and decreased tryptophan hydroxylase 1 (TpH1) mRNA expression, suggesting that vitamin A modulates serotonin synthesis and related gene expression, potentially contributing to symptom improvement.

5. Severity Correlation: Children with severe ASD (based on CARS scores) had higher 5-HT and lower retinol levels compared to those with mild-moderate ASD, indicating a link between vitamin A status, serotonin levels, and symptom severity.

Conclusion: The study suggests that vitamin A supplementation can improve nutritional status, reduce serum 5-HT levels, and alleviate autistic symptoms in children with ASD, making it a potential adjunct therapy alongside behavioral and speech therapies.

https://pubmed.ncbi.nlm.nih.gov/29122693/

doi: 10.1016/j.brainresbull.2017.11.001

Results and specific symptom improvement

Outcome Measures with Statistically Significant Improvement (P < 0.05)

The following CARS outcome measures showed a statistically significant reduction in scores after vitamin A supplementation, indicating an improvement in these specific symptoms of ASD:

• Relating to People:

  • ASD: 2.59 ± 0.79

  • ASD + VAS: 2.22 ± 0.72

  • P = 0.0255

  • Observation: The score decreased, suggesting better social interaction skills.

• Emotional Response:

  • ASD: 2.74 ± 0.83

  • ASD + VAS: 2.38 ± 0.91

  • P = 0.0270

  • Observation: Lower scores indicate improved emotional regulation or responsiveness.

• Body Use:

  • ASD: 2.44 ± 0.78

  • ASD + VAS: 2.18 ± 0.78

  • P = 0.0374

  • Observation: A reduction implies better coordination or reduced unusual physical behaviors.

• Adaptation to Change:

  • ASD: 2.34 ± 0.76

  • ASD + VAS: 2.03 ± 0.69

  • P = 0.0345

  • Observation: Improved adaptability to changes in routine or environment.

• Taste/Smell/Touch:

  • ASD: 2.30 ± 0.91

  • ASD + VAS: 1.94 ± 0.95

  • P = 0.0426

  • Observation: Lower scores suggest reduced sensory sensitivities.

• Anxiety:

  • ASD: 2.46 ± 1.04

  • ASD + VAS: 2.25 ± 0.90

  • P = 0.0446

  • Observation: A decrease indicates reduced anxiety levels.

• Verbal Communication:

  • ASD: 2.94 ± 0.74

  • ASD + VAS: 2.60 ± 0.68

  • P = 0.0450

  • Observation: Improved verbal communication abilities.

• Non-Verbal Communication:

  • ASD: 2.43 ± 0.68

  • ASD + VAS: 2.13 ± 0.73

  • P = 0.0308

  • Observation: Enhanced non-verbal communication skills.

• General Impression:

  • ASD: 3.01 ± 0.76

  • ASD + VAS: 2.58 ± 0.77

  • P = 0.0169

  • Observation: A lower score reflects an overall positive change in ASD symptoms.

• Total CARS Score:

  • ASD: 36.83 ± 5.87

  • ASD + VAS: 34.46 ± 6.79

  • P = 0.0141

  • Observation: The overall CARS score dropped significantly, indicating a broad improvement in ASD symptom severity.

Outcome Measures with No Statistically Significant Improvement (P > 0.05)

For the following measures, the changes in scores after vitamin A supplementation were not statistically significant, meaning there is insufficient evidence to conclude that the supplementation had an effect:

• Imitation:

  • ASD: 2.66 ± 0.96

  • ASD + VAS: 2.33 ± 0.78

  • P = 0.1640

• Object Use:

  • ASD: 2.38 ± 0.66

  • ASD + VAS: 2.22 ± 0.80

  • P = 0.3567

• Visual Response:

  • ASD: 2.23 ± 0.77

  • ASD + VAS: 2.31 ± 0.82

  • P = 0.2257

• Listening Response:

  • ASD: 2.00 ± 0.78

  • ASD + VAS: 2.14 ± 0.87

  • P = 0.2134

• Activity Level:

  • ASD: 2.49 ± 0.80

  • ASD + VAS: 2.39 ± 0.84

  • P = 0.8571

• Level and Consistency of Intellectual Response:

  • ASD: 2.72 ± 0.84

  • ASD + VAS: 2.76 ± 0.74

  • P = 0.3738