Correlational finding on Happiness and subject: What one eats

StudyFord et al. (2013): study ZZ Anglo-America 2002
TitleIntake of Meditteranean Foods Associated with Positive and Low Negative Affect
SourceJournal of psychosomatic research, 74 (2013) 142 - 148
DOIdoi: 10.1016/j.jpsychores.2012.11.002
Public30+ aged, Adventist church atendees, North America 2002-2007
SampleProbability sample (unspecified)
Respondents N =9255

Author's labelFresh fruits
Page in Source 143-146
Our classificationWhat one eats
Selfreported  intake of fresh fruits during the last 
1  never or rarely
2  1-3 times per month
3  1-6  times per week
4  1-4 times per day
Observed distributionMales: 168, females 171
Assessd usung Food Frequency Questionnaire (FFQ), which 
contains a list of 200 food items.

Fresh fruits are: Grapes in season and out of season, 
plum in season and out of season, appricot in season, 
cantaloupe in season and out of season, strawberry in 
season and out of season, blueberry in season and out 
of season, cherry in season and out of season, 
persimmons in season, apples, oranges, grapefruits, 
bananas, fruit salad fresh.

Intake expressed in standard servings in grams
Food intake was energy adjusted using the residual 

Observed Relation with Happiness
A-BW-cy-mq-v-5-dBeta=+ p < .001
positive affect:  Beta = +.06(<.001)
negative affect:  Beta = -.03 (.001)

Beta's controled for:
- age
- gender
- ethnicity
- frequency of vigorous physical activity
- hours sleep
- total energy intake
- use of alcohol

Stronger positive among females

Appendix 1: Happiness measures used
CodeFull Text
A-BW-cy-mq-v-5-dSelfreport on 10 questions.

This scale consists of a number of words that describe different feelings and emotions. As I read each item, I ask that you refer to your response card an d tell me to wgat extent you have felt in that way during the past year :
A excited
B enthusiastic
C alert
D inspired
E determined
F distressed
G scared
H upset
I nervous
J ashamed

Answer options:
1 not at all
2 a little
3 somewhat
4 quite a bit
5 very much

Negative affect score (NAS): F to J
Positive affect score (PAS): A to G
Affect Balance Score (ABS): PAS - NAS

Name: Shortened Watson's PANAS; Kiercher version

Appendix 2: Statistics used
Type: test statistic.

Measurement level: Correlates: all metric, Happiness: metric.
Range: [-1 ; +1]

beta > 0 a higher correlate level corresponds to a higher happiness rating on average.
beta < 0 a higher correlate level corresponds to a higher happiness rating on average.
beta = 0 no correlation.
beta = + 1 or -1 perfect correlation.
Ruut Veenhoven, World Database of Happiness, Collection of Correlational Findings, Erasmus University Rotterdam.