Dietary flavonoid intake and psychological well-being - A bidirectional relationship.

Higher flavodiet scores were associated with a greater likelihood of sustained happiness over time.

• Sample size for happiness analysis: n = 44,659, with flavonoid intake measured in 1990 and happiness assessed over 1992-2000.
• RR Q4 vs Q1 (95% CI): 1.03 (1.02-1.05), representing a 3% greater likelihood of sustained happiness.
• Associations were assessed using generalized estimating equations, adjusting for potential confounders.
• The flavodiet score was used as a measure of overall flavonoid-rich dietary patterns.

Higher flavodiet scores were associated with a greater likelihood of sustained optimism over time.

• Sample size for optimism analysis: n = 36,723, with flavonoid intake measured in 2002 and optimism assessed over 2004-2012.
• RR Q4 vs Q1 (95% CI): 1.06 (1.01-1.11), representing a 6% greater likelihood of sustained optimism.
• Associations were assessed using generalized estimating equations, adjusting for potential confounders.
• Data were drawn from the Nurses' Health Study.

Specific flavonoid-rich foods were associated with a 3-16% greater likelihood of sustained psychological well-being across both happiness and optimism facets.

• Foods associated with sustained PWB included strawberries, apples, oranges, grapefruit, and blueberries.
• The magnitude of association ranged from 3% to 16% greater likelihood of sustained PWB depending on the food and PWB facet.
• Analyses examined both happiness (1992-2000) and optimism (2004-2012) as outcome measures.
• These associations were observed in both analytical samples from the Nurses' Health Study.

Total flavonoid and flavonoid subclass intakes were associated with a 2-18% greater likelihood of sustained psychological well-being.

• The range of association (2-18% greater likelihood) varied across total flavonoids, specific subclasses, and the two PWB facets (happiness and optimism).
• Both total flavonoid intake and individual subclass intakes were examined separately.
• Associations spanned both analytical samples: n = 44,659 for happiness and n = 36,723 for optimism.
• Analyses adjusted for potential confounders using generalized estimating equations.

Higher baseline levels of happiness or optimism were associated with a greater likelihood of sustaining higher flavonoid intake over up to 18 years.

• This finding was from secondary analyses examining the reverse direction of association.
• The follow-up period for sustained flavonoid intake extended up to 18 years.
• Data were drawn from the Nurses' Health Study for both PWB facets.
• This bidirectional association was observed for both happiness and optimism as baseline predictors of sustained flavonoid intake.

The study design used two separate analytical samples from the Nurses' Health Study to examine associations between flavonoid intake and two distinct facets of psychological well-being.

• Flavonoid intake measured in 1990 (n = 44,659) was examined in relation to sustained happiness (1992-2000).
• Flavonoid intake measured in 2002 (n = 36,723) was analyzed in relation to sustained optimism (2004-2012).
• Three levels of flavonoid exposure were examined: overall flavodiet score, specific flavonoid-rich foods, and total flavonoid and subclass intakes.
• Generalized estimating equations were used to assess associations, adjusting for potential confounders.

Consuming approximately 3 servings per day of flavonoid-rich foods was identified as the intake level associated with sustained psychological well-being.

• This threshold of ~3 servings/day was highlighted as the dietary target associated with sustained PWB.
• The association was observed across both happiness and optimism facets of psychological well-being.
• The finding was based on data from the Nurses' Health Study with follow-up periods spanning multiple years.
• The authors suggest this finding supports integrated interventions targeting both diet and well-being to promote long-term health and reduce chronic disease risk.