Blanchflower DG, Oswald AJ, Stewart-Brown S (2013) National Bureau of Economic Research Working Paper No. 18469, first release October 2012,
Humans run on a fuel called food. Yet economists and other social scientists rarely study what people eat.
We provide simple evidence consistent with the existence of a link between the consumption of fruit and vegetables and high well-being. In cross-sectional data, happiness and mental health rise in an approximately dose-response way with the number of daily portions of fruit and vegetables. The pattern is remarkably robust to adjustment for a large number of other demographic, social and economic variables.
Well-being peaks at approximately 7 portions per day. We document this relationship in three data sets, covering approximately 80,000 randomly selected British individuals, and for seven measures of well-being (life satisfaction, WEMWBS mental well-being, GHQ mental disorders, self-reported health, happiness, nervousness, and feeling low).
Reverse causality and problems of confounding remain possible. We discuss the strengths and weaknesses of our analysis, how government policy-makers might wish to react to it, and what kinds of further research -- especially randomized trials -- would be valuable.