Structured population data were available for 3 of 3 supporting studies. 2 studies described participants with type 2 diabetes. 2 studies described adult participants.

3 of 3 studies with duration data have follow-up of 12 weeks or less.

Placebo Group

Core clinician-reference fields are available or not applicable.

Participants received 500 mg of vitamin C daily for 8 weeks.

Vitamin C Group

Eligible patients (n = 70) were randomized to receive 500 mg of vitamin C daily or a matching placebo added to their hypoglycemic medication.

Participants received a matching placebo for 8 weeks.

Vitamin C may reduce oxidative stress in type 2 diabetes patients.

Participants received vitamin D supplementation alongside standard care.

Vitamin D Group

229 women with GDM were assigned to receive 200 IU of vitamin D twice daily or a placebo for 6 weeks alongside standard care.

Participants received a placebo alongside standard care.

Vitamin D supplementation reduces neonatal birth weight in gestational diabetes

Placebo group

Participants received 50,000 IU/week of vitamin D3 for 8 weeks.

Vitamin D3 group

Participants were assigned to either a vitamin D3 group ( n = 34), receiving 50,000 IU/week for 8 weeks.

Participants received identical placebo capsules.

or a placebo group ( n = 34). The control group received identical placebo capsules.

Vitamin D3 supplementation may reduce inflammation in type 2 diabetes patients

Structured population data were available for 5 of 5 supporting studies. 4 studies described participants with type 2 diabetes. 4 studies described adult participants.

2 relevant studies have unresolved authoritative design evidence and do not contribute to design-specific or RoB-specific claims.

Upstream consistency scoring indicates mixed findings across the evidence.

2 supporting studies do not have a displayable topic-matched quantitative effect.

Evidence uses heterogeneous comparison contexts: active_comparator, baseline_within_group, unknown_unresolved, usual_care.

2 supporting studies have high, serious, critical, unclear, or unavailable risk-of-bias information.

Structured population data were available for 3 of 3 supporting studies. 2 studies described participants with type 2 diabetes. 1 study described adult participants.

1 supporting study does not have a displayable topic-matched quantitative effect.

Evidence uses heterogeneous comparison contexts: placebo, usual_care.

2 of 3 studies with duration data have follow-up of 12 weeks or less.

1 supporting study has high, serious, critical, unclear, or unavailable risk-of-bias information.

1 study contains conflicting p-value and significance fields; those significance claims are suppressed.

Structured population data were available for 4 of 4 supporting studies. 2 studies described participants with type 2 diabetes. 2 studies described adult participants.

3 of 4 studies with duration data have follow-up of 12 weeks or less.

Vitamin D supplementation × Malondialdehyde (MDA)

Available supporting studies

Vitamin C may reduce oxidative stress in type 2 diabetes patients.

Vitamin D supplementation reduces neonatal birth weight in gestational diabetes

Vitamin D3 supplementation may reduce inflammation in type 2 diabetes patients