A novel analytical method reveals that meta-analyses examining vitamin D supplementation and cancer mortality are exceptionally fragile to small data changes. Applying Ellipse of Insignificance and Region of Attainable Redaction techniques to three conflicting vitamin D meta-analyses, researchers found that recoding just 5 patients out of 133,262 total participants could flip results across the statistical significance threshold. Even more striking, adding merely 3 hypothetical patients to one supposedly significant meta-analysis of 38,538 participants was sufficient to render the findings null. This fragility analysis challenges the assumption that larger sample sizes automatically ensure robust conclusions. The methodology provides a systematic way to assess how much missing or additional data could alter meta-analytic findings, addressing a critical gap in evidence evaluation. For the vitamin D-cancer question specifically, a comprehensive analysis of all available trials showed no association between supplementation and cancer mortality. This preprint awaits peer review, and its conclusions about meta-analytic reliability may influence how we interpret conflicting nutritional research. The work suggests that apparent contradictions in vitamin D studies may reflect inherent statistical fragility rather than genuine biological differences, underscoring the need for cautious interpretation of meta-analytic evidence.