Is Psychological Well-Being Linked to the Consumption of Fruit and Vegetables?

Abstract

Little is known about the influence of people’s diet on their psychological well-being. This study provides evidence 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. 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). The pattern is robust to adjustment for a large number of other demographic, social and economic variables. 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.

Appendix: Data Description

Scottish Health Survey

	Mean	Standard deviation
Life satisfaction	7.6266	1.8858
Warwick-Edinburgh	49.8446	8.4733
GHQ mental ill-being	10.7911	5.0023
Self-reported health	3.9902	0.9572

One portion of fruit and vegetables is 80 g of any fruit or vegetable as defined by the Department of Health. A portion of fruit includes orange juice.

1.1 Life Satisfaction Question

• All things considered, how satisfied are you with your life as a whole nowadays?

• 0—Extremely dissatisfied

• 1

• 2

• 3

• 4

• 5

• 6

• 7

• 8

• 9

• 10—Extremely satisfied

1.2 Self-Reported Health Question

• How is your health in general? Would you say it was

• 5…very good,

• 4 good,

• 3 fair,

• 2 bad, or

• 1 very bad?

Welsh Health Survey 2008

	Mean	Standard deviation
Happiness	3.7181	0.9086
Nervous	1.6889	0.9738
Downhearted and low	1.9329	1.0136

1.3 Survey Question

These questions are about how you feel and how things have been with you during the past 4 weeks. For each question, please give the one answer that comes closest to the way you have been feeling. How much of the time during the past 4 weeks. (1) Have you been happy? (2) Have you been very nervous? (3) Have you felt downhearted and low?—none of the time; a little of the time; some of the time; most of the time; all of the time?

Health Survey of England, 2008

	Mean	Standard deviation
GHQ	10.4975	4.8910

1.4 GHQ Definition

In the GHQ measure, individuals answer 12 separate mental-distress questions: “Have you lost much sleep over worry?”; “Been able to concentrate on things?”; “Felt you are playing a useful part in things?”; “Felt capable of making decisions about things?”; “Felt constantly under strain?”; “Felt you could not overcome your difficulties?”; “Been able to enjoy your normal day-to-day activities”; “Been able to face up to your problems”; “Been feeling unhappy and depressed?”; “Been losing confidence in yourself?”; “Been thinking of yourself as a worthless person?”; “Been feeling reasonably happy all things considered?”. People in the surveys are asked to answer on a scale from ‘much more than usual’ down to ‘much less than usual’.

Portions of fruit and vegetables per day (% of the population)

None	0.054
>0 portion but less than 2	0.171
2 portions or more but less than 3	0.166
3 portions or more but less than 4	0.169
4 portions or more but less than 5	0.139
5 portions or more but less than 6	0.116
6 portions or more but less than 7	0.072
7 portions or more but less than 8	0.043
8 portions or more	0.070

WEMWBS Well-being Survey Questions