On the psychological side of dietary recommendations



See how happy this watermelon is? ...Do you, though? [WTLphotography/Flickr]

PROBLEM: We go on about eating for health, but we're usually talking about the physical side. The World Health Organization recommends five servings of fruits and vegetables a day for your body, but not much is known about how much is best for psychological well-being.



METHODOLOGY: Economists and public health researchers from the University of Warwick, in conjunction with Dartmouth College, used data from several randomized, cross-sectional surveys that accounted for the eating habits of about 80,000 people living in the U.K. The fruits and vegetables typically consumed by each person were compared with their life satisfaction, mental well-being, presence of mental disorders, self-reported health, happiness, nervousness, and how often they "feel low."

They factored in as many variables as they could think of, including other the rest of their diets, alcohol, and lots of demographic, social and economic factors.



RESULTS: A "remarkably robust" pattern was found, in which "happiness and mental health rise in an approximately dose-response way with the number of daily portions of fruit and vegetables." While in some cases it rounds out at the recommended five per day, well-being appears to peak at seven.