Dietary Supplement Safety in Older Adults: A Review of Published Case Reports

Objective: This review summarizes recent case reports where the consumption of dietary supplements by older adults may have caused an adverse event. Data Sources: In December 2023, PubMed was surveyed for case reports published from 2000 onwards, using two medical subject heading (MeSH) terms, "aged" and "dietary supplements," where the latter was combined with the MeSH subheadings "adverse effects," "poisoning," or "toxicity." Major clinical trials for dietary supplements were identified at ClinicalTrials.gov, an online database of clinical research studies, or in PubMed, and screened for information on adverse effects. Data Synthesis: The described search strategy yielded 820 publications, including 122 case reports, which were then manually screened for relevant and informative case reports involving dietary supplements and people 65 years of age or older. Consequently, 41 publications were selected describing 46 individual case reports. Etiologies of adverse events included interactions of dietary supplements with prescribed medication, ingestion of higher-than-intended or instructed supplement doses, intake of the same supplement from multiple sources, and supplement contamination. Prominent adverse events encompassed hypercalcemia (vitamin D), thyroid test interference (vitamin B7), neuropathy (vitamin B6), oxalate nephropathy (vitamin C), and interactions with warfarin therapy (vitamins E and K, and omega-3 fatty acids). Conclusion: Health care practitioners are advised to consider dietary supplements as contributors to adverse clinical symptom presentations, while patients are encouraged to provide current records of their prescribed medications and dietary supplements to their health care providers. This is particularly important for older adults where both medication intake and supplement consumption are high.