'This is the first study of its kind to report a relationship between optimism and healthier levels of carotenoid concentrations,' said lead investigator Julia Boehm, of the Harvard School of Public Health.
Can Eating Greens Make You More Optimistic About the Future?
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JANUARY 18, 2013
Anna Hodgekiss, Daily Mail

People who eat plenty of fruit and vegetables tend to be more optimistic about the future, new research suggests. Scientists have discovered that optimistic folk have higher levels of plant compounds called carotenoids in their blood. A commonly-known carotenoid is beta-carotene, a pigment found in high levels in orange fruit and veg and green, leafy vegetables.
Read more: Daily Mail