Nutrient- and non-nutrient-based natural health product (NHP) use in adults with mood disorders: prevalence, characteristics and potential for exposure to adverse events

BACKGROUND: To address knowledge gaps regarding natural health product (NHP) usage in mental health populations, we examined their use in adults with mood disorders, and explored the potential for adverse events. METHODS: Food and NHP intake was obtained from 97 adults with mood disorders. NHP data was used to compare prevalence with population norms (British Columbia Nutrition Survey; BCNS). Bivariate and regression analyses examined factors associated with NHP use. Assessment of potential adverse effects of NHP use was based on comparing nutrient intakes from food plus supplements with the Dietary Reference Intakes and by reviewing databases for reported adverse health effects. RESULTS: Two-thirds (66%; 95% CI 56 to 75) were taking at least one NHP; 58% (95% CI 47 to 68) were taking NHPs in combination with psychiatric medications. The proportion of each type of NHP used was generally higher than the BCNS (range of p’s < 0.05 to 0.0001). When intakes from food and NHP sources were combined, a small proportion exceeded any Lowest-Observed-Adverse-Effect-Levels: only for niacin (n = 17) and magnesium (n = 6), two nutrients for which the potential for adverse effects is minimal. Conversely, about 38% (95% CI 28 to 49) of the sample were taking a non-nutrient based NHP for which previous adverse events had been documented. CONCLUSIONS: The prevalent use of NHPs in this population suggests that health care providers need to be knowledgeable about their characteristics. The efficacy and safety of NHPs in relation to mental health warrants further investigation.