Safety and efficacy of oral DMSA therapy for children with autism spectrum disorders: Part A--medical results
Authors:
Adams, J.B., Baral, M., Geis, E., Mitchell, J., Ingram, J., Hensley, A., Zappia, I., Newmark, S., Gehn, E., Rubin, R.A. and Mitchell, K.
https://pubmed.ncbi.nlm.nih.gov/19852789/
doi: 10.1186/1472-6904-9-16
Summary of the Article
The article, published in BMC Clinical Pharmacology in 2009, investigates the safety and efficacy of dimercaptosuccinic acid (DMSA) therapy in children with autism spectrum disorders (ASD) who show evidence of heavy metal exposure. DMSA, an FDA-approved chelating agent for lead poisoning, was used off-label to reduce toxic metal levels and assess its medical effects in this population. The study was conducted in two phases: Phase 1 involved a screening round of DMSA for all participants, and Phase 2 was a randomized, double-blind, placebo-controlled trial for those with high toxic metal excretion. However, the significant effects of the initial DMSA round in Phase 1 led to the study being interpreted as a comparison between one round versus seven rounds of DMSA rather than a true placebo-controlled trial.
Participants were children aged 3-8 with ASD, no mercury amalgam fillings, and no prior chelation therapy. The study measured outcomes such as urinary excretion of toxic metals, essential mineral levels, red blood cell (RBC) glutathione, complete blood count (CBC), and blood chemistry, focusing on medical rather than behavioral effects (the latter being covered in a separate paper).
Key Findings
Toxic Metal Excretion: DMSA significantly increased urinary excretion of toxic metals, particularly lead (638-713% increase), tin, bismuth, and initially mercury. Lead excretion remained elevated across multiple rounds, while mercury excretion dropped after the initial dose.
Essential Minerals: DMSA increased excretion of some essential minerals (e.g., potassium, copper, manganese), with notable losses of potassium (57% RDA) and chromium (88% RDA) during treatment days. These losses were deemed minor and manageable with diet or supplementation.
Glutathione Levels: Many children had abnormal RBC glutathione levels at baseline (high or low). A single round of DMSA normalized these levels, with the effect lasting at least 1.5 months, possibly by reducing toxic metal burden.
Platelet Counts: Elevated platelet counts (indicative of inflammation) were common at baseline (18% above reference range) and normalized in about half of the cases after one round of DMSA, with effects persisting for months.
Safety: DMSA was generally well-tolerated, with no significant adverse effects on liver or kidney function. Mild, temporary side effects (e.g., lethargy, sleep issues) occurred in a few participants, with a small dropout rate due to adverse events (4 out of 49 in Phase 2).
Specific Answers to Query Questions
Type of Diet Used
Finding: The study did not involve a specific dietary intervention. The focus was on DMSA therapy, not diet. Participants were required to maintain their existing diet, medications, and supplements unchanged during the study, with the only stipulation being a multi-vitamin/mineral supplement containing at least the RDA of zinc for at least two months prior to and during Phase 2.
Duration of Diet
Finding: Since no specific diet was implemented, there was no "diet duration." DMSA therapy itself was administered in rounds: one round in Phase 1 (3 days of 10 mg/kg-dose, 3 times daily) and up to six additional rounds in Phase 2 (each round consisting of 3 days on DMSA followed by 11 days off), totaling up to 7 rounds for some participants. The full treatment spanned several months depending on the number of rounds.
Symptoms Improved
Finding: This paper focused on medical outcomes, not behavioral symptoms (covered in a separate paper). Medical improvements included:
Normalization of abnormal RBC glutathione levels.
Reduction of elevated platelet counts (a marker of inflammation).
Behavioral symptom improvements were not detailed here.
Percentage of Participants Improved
Finding: The study did not quantify behavioral improvement percentages, focusing instead on medical outcomes:
Most participants showed improved glutathione levels after one round of DMSA (exact percentage not specified, but described as a "dramatic normalization" in 38 participants measured 1-2 months post-Phase 1).
Approximately 50% of participants with elevated platelet counts (initially 18% of 77) had normalized levels after one round.
Specific percentages for overall improvement were not provided due to the medical focus.
Time for Symptoms to Improve
Finding: Medical improvements occurred rapidly:
Glutathione normalization was observed 1-2 months after one round of DMSA (3 days), with effects lasting at least 1.5 months.
Platelet count normalization occurred within 1-2 months post-Phase 1 and persisted for several months.
Behavioral improvement timelines were not addressed in this paper.
Pros and Cons of DMSA Therapy (Considerations)
Since the query asks about a "diet" but the study involves DMSA therapy without a dietary component, the pros and cons below pertain to the therapy itself, as this aligns with the article’s focus.
Pros
Effective Metal Removal: Significantly reduces toxic metal levels, especially lead, potentially lowering body burden.
Biochemical Benefits: Normalizes glutathione and platelet counts, which may reduce inflammation and improve overall functioning.
Safety Profile: Generally well-tolerated with mild, temporary side effects compared to more intensive lead poisoning regimens.
Cons
Side Effects: Temporary adverse effects (e.g., lethargy, sleep issues, behavioral changes) occurred in some participants, leading to a few dropouts.
Mineral Loss: Increases excretion of essential minerals like potassium and chromium, requiring monitoring and possible supplementation.
Unclear Long-Term Effects: Optimal duration and long-term safety remain uncertain, with 80% of participants still excreting high metal levels after 7 rounds, suggesting longer treatment might be needed.
Conclusion
The study demonstrates that DMSA therapy is a safe and effective method for reducing toxic metal levels in children with ASD, with notable improvements in glutathione and platelet counts. However, it is not a dietary intervention, and behavioral outcomes were not covered in this paper. The therapy requires careful monitoring of essential minerals and further research into long-term effects and optimal duration.
