Systematic Review of the Literature to Inform the Development of a South African Dietary Polyphenol Composition Database

Association of dietary flavonoid intake with the prevalence and all-cause mortality of depressive symptoms: Findings from analysis of NHANES

BACKGROUND

This study aimed to explore the relationship between flavonoids intake and the prevalence and all-cause mortality of depressive symptoms in American adults.

METHODS

Analyzing 2007-2008, 2009-2010, and 2017-2018 NHANES data, we examined the association between dietary flavonoid and depressive symptoms, including specific subclasses assessment and mortality outcomes tracking until December 31, 2019. Our methodology included weighted multivariate logistic regression, weighted cox proportional hazards regression and restricted cubic spline (RCS) models, supported by stratified and sensitivity analyses.

RESULTS

Among the 12,340 participants in total, 1129 exhibited depressive symptoms. The multiple logistic regression analysis showed a significant reduction in total flavonoid and subclass intake in individuals with current depressive symptoms. Adjusted odds ratios (ORs) for the highest quartiles were 0.69 for anthocyanidins and 0.63 for flavones. Interaction effects emerged in non-hypertensive, higher-income, and normal-weight groups for flavones intake. The RCS model indicated an L-shaped association between depressive symptoms and total flavonoid intake, with inflection points at 346 mg/day. During a median follow-up of 119 months, 148 deaths occurred among patients with depressive symptoms. Hazard ratios (HRs) for all-cause mortality showed a significant positive correlation between total flavonoid intake and survival in model 1 (HR = 0.56), with an optimal intake range of 45.2-948.3 mg/day according to the RCS model.

LIMITATIONS

The study relied on U.S. population survey data, potentially limiting generalizability. Unmeasured confounding factors may exist, and genetic factors were not considered.

CONCLUSIONS

Adequate intake of flavonoids, especially anthocyanidins and flavones, is associated with reduced odds of depressive symptoms. Additionally, optimal intake ranges of flavonoid intake for mental health benefits were observed for all-cause mortality in population with depressive symptoms.

Development, validation, and application of a South African Dietary Polyphenol Data Quality Assessment Tool

There is a wealth of South African scientific literature studying and reporting on dietary polyphenols in research articles and academic literature. The evaluation of data quality is critical to ensure polyphenol data compiled from various scientific journals and academic texts are acceptable in terms of compilation standards. This study aimed to develop, validate, and apply a country specific South African dietary polyphenol data quality assessment tool (SADPDQAT). The evaluation tool considered nine evaluation categories with a maximum score of 5. For each literature source assessed, a quality score and confidence code was assigned. Validation analysis revealed generally consistent results between raters with an average percentage agreement of 65 %, no scores falling outside of Bland-Altman limits of agreement and a moderate internal consistency α = 0.533 which was improved to 0.616. Applying the tool to 383 scientific studies showed that most literature obtained a quality score between 70 and 79 % resulting in a confidence code of "B" (n = 166, 43 %) and a score between 60 and 69 % resulting in a confidence code of "C" (n = 125, 33 %). The SADPDQAT can be used to evaluate a variety of dietary polyphenol containing literature and aids in setting priorities for further research in this area.

Dietary Polyphenols: What is the Estimated Intake in Population Studies With Adults and Elderly People?

Estimates of dietary intake of polyphenols have been limited to specific samples from certain population groups, and different databases have been used to quantify the levels of these compounds, which makes it difficult to compare results. PURPOSE OF REVIEW: This review collated estimates of polyphenol intake from population studies including adults and elderly from different parts of the world by using a single database: Phenol-Explorer. RECENT FINDINGS: Through seven population-based studies performed in five different countries, it was possible to identify that Brazil was the country with the lowest intake of polyphenols, whereas Poland had the highest dietary intake. The most ingested subclasses of polyphenols in different countries were phenolic acids and flavonoids, and non-alcoholic beverages (coffee, tea, and orange juice) were the foods that most contributed to the intake of polyphenols. Despite the attempt to standardize this study to obtain worldwide intake estimates that could be comparable, gaps were found regarding the assessment of food consumption, standardization to obtain the polyphenol content of foods in Phenol-Explorer, calculation in aglycone equivalents, and caloric adjustment of the estimates. There is a need for more studies on the dietary polyphenols intake of representative samples of populations from different countries to collate more data on the quantities consumed and the main contributing foods.