| Study period | ||||||
---|---|---|---|---|---|---|---|
 | Enrolment | Allocation | Post allocation | ||||
Timepoint | t−2 | t−1 | t0 | tbaseline | t6-month | t12-month | w1–52 |
Enrolment: | |||||||
 Initial eligibility screen | ♦ |  |  |  |  |  |  |
 Informed consent | ♦ |  |  |  |  |  |  |
 Nutritional deficiencies screen |  | ♦ |  |  |  |  |  |
Allocation |  |  | ♦ |  |  |  |  |
Interventions: | |||||||
 Vitamin D |  |  |  | ♦ | ♦ | ♦ |  |
 Omega-3 LCPUFAs |  |  |  | ♦ | ♦ | ♦ |  |
 Vitamin D + omega-3 LCPUFAs |  |  |  | ♦ | ♦ | ♦ |  |
 Placebo |  |  |  | ♦ | ♦ | ♦ |  |
Assessments: | |||||||
 Nutritional biomarkers | |||||||
  Serum 25(OH)D |  |  |  | ♦ | ♦ | ♦ |  |
  RBC fatty acids |  |  |  | ♦ |  | ♦ |  |
  Calcium |  |  |  | ♦ | ♦ | ♦ |  |
  Albumin |  |  |  | ♦ | ♦ | ♦ |  |
  Iron studies |  |  |  | ♦ |  |  |  |
  Vitamin B12 |  |  |  | ♦ |  |  |  |
  Folate |  |  |  | ♦ |  |  |  |
  Full blood count |  |  |  | ♦ |  |  |  |
  Vitamin A |  |  |  | ♦ |  |  |  |
 Primary outcome | |||||||
  Social Responsiveness Scale-2 |  |  |  | ♦ |  | ♦ |  |
  Sensory Processing Measure |  |  |  | ♦ |  | ♦ |  |
  Aberrant Behaviour Checklist |  |  |  | ♦ |  | ♦ |  |
 Secondary outcome | |||||||
  Gastrointestinal symptoms |  |  |  | ♦ |  | ♦ | ♦ |
 Dietary assessment | |||||||
  Dietary Index Children’s Eating |  |  |  | ♦ |  | ♦ |  |
  Behavioural Paediatric Feeding Assessment Scale |  |  |  | ♦ |  | ♦ |  |
  4-day food diary |  |  |  | ♦ |  |  |  |
  Nutritional supplements and dietary regimen |  |  |  | ♦ |  |  |  |
 Other assessments | |||||||
  Sociodemographics |  |  |  | ♦ |  |  |  |
  Medical history |  |  |  | ♦ |  |  |  |
  Sun exposure and skin colour |  |  |  | ♦ |  |  |  |
  Compliance and adverse events diary |  |  |  |  |  |  | ♦ |