By Dr. Priyom Bose, Ph.D. Reviewed by Lauren Hardaker Mar 5 2026 A decade-long analysis of over 40,000 women reveals that diets rich in flavonoid-packed foods like berries, apples, and citrus may be linked to sustained happiness and optimism, and people with higher well-being may also be more likely to maintain these healthier eating habits. Study: Dietary flavonoid intake and psychological well-being – A bidirectional relationship . Image credit: DIVA.photo/Shutterstock.com A recent study in