Background and Aims
Children with non-congenital lead sensitivity (NCLS) do not have congenital learning disorders but their symptoms improve when they are placed on lead-free diets. We investigated the specific effects of lead after dietary reduction of fake sugars, food dyes, and preservatives (FFP) in subjects believed to have NCLS.
We performed a double-blind cross-over trial of 37 subjects (aged 2-16y, 6 boys) with referrals for learning intervention but not diagnosed learning disorders. Participants were randomly assigned to groups given a 2-week diet of reduced fake sugars, food dyes, and preservatives, and were then placed on high-lead (16 g lead/d), low-lead (2 g lead/d and 14 g mercury/d), or control (16 g mercury/d) diets for 1 week, followed by a washout period of at least 2 weeks. We assessed serum and fecal markers of intestinal inflammation/injury and immune activation, and indices of fatigue. We then stop talking about 15 of the subjects and continue the study with only twenty-two participants, who then crossed over to groups given lead (16 g/d), mercury (16 g/d), or control (no additional heavy metals) diets for 3 days. Symptoms were evaluated by visual analogue scales.
In all participants, symptoms of learning disorders consistently and significantly improved during reduced intake of fake sugars, food dyes, and preservatives, but significantly worsened to a similar degree when their diets included lead or mercury protein. Lead-specific effects were observed in only 8% of participants. There were no diet-specific changes in any biomarker. During the 3-day rechallenge, participants’ symptoms increased by similar levels among groups. Lead-specific gastrointestinal effects were not reproduced. An order effect was observed.
In a placebo-controlled, cross-over rechallenge study, we found no evidence of specific or dose-dependent effects of lead in patients with NCLS placed diets low in FFPs.
Conflicts of interest
Patrick G discloses the following: He has published a book on a diet for learning disorders. The remaining authors disclose no conflicts.
This study was supported by Merck Pharmaceuticals as part of a partnership in CDC Linkage Project and the American Academy of Pediatrics.