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Promotion of fruit and vegetable consumption among low income groups using a pricing strategy
DOI 10.1186/ISRCTN56596945
ClinicalTrials.gov identifier
EudraCT number
Public title Promotion of fruit and vegetable consumption among low income groups using a pricing strategy
Scientific title Promotion of fruit and vegetable consumption among low income groups using a pricing strategy: a randomized controlled trial
Acronym N/A
Serial number at source NL22568.029.08
Study hypothesis The study examines whether price discounts and nutrition education are effective in stimulating fruit and vegetable purchases among low income groups.

1. Lowering the price of fruits and vegetables will lead to higher purchases of these products
2. Nutrition education will lead to higher purchases of fruits and vegetables, but not in the same amount as the price discounts
3. Price discounts on fruits and vegetables combined with nutrition education will provide the largest increase in fruit and vegetable purchases
Lay summary Background and study aims:
A sufficient intake of fruits and vegetables forms one of the principal components of dietary recommendations. In the USA and Europe, intake of fruits and vegetables are far below the minimum recommended levels. Increasing the intake of these products to meet dietary recommendations could reduce the burden of some diseases. There is growing opinion that making fruits and vegetables cheaper may be a good strategy to promote their purchase. Mainly consumers with a lower socio economic status perceive fruits and vegetables to be expensive and indicate they would buy more of those products if they would become cheaper. Evidence on the true effects of making healthy foods cheaper is limited and mostly restricted to small scale studies.

Who can participate?
Adults, who could speak Dutch, had a lower socio-economic status and were regular shoppers at the supermarkets that joined this study.

What does the study involve?
We conducted an experiment on the effects of providing a 50% discount on fruits and vegetables, and we tested the additional effect of nutrition education.

What are the possible benefits and risks of participating?
Participants will benefit from cheaper fruit and vegetables, and a more balanced diet. There are no known risks associated with participating in the study.

Where is the study run from?
Four supermarkets in the Netherlands.

When is the study starting and how long is it expected to run for?
The study started in September 2010 and ended in July 2011.

Who is funding the study?
Netherlands Organization for Health Research and Development (ZonMw).

Who is the main contact?
Dr Ingrid Steenhuis
Ethics approval Medical Ethical Commitee of the VU Medical Centre Amsterdam,12 February 2009
Study design Parallel single-center randomized controlled trial
Countries of recruitment Netherlands
Disease/condition/study domain Obesity, Healthy diet
Participants - inclusion criteria 1. Adults (18 years or older)
2. Familiar with the Dutch language
3. Lower socio-economic status (based on education level and working status)
4. Regular shoppers at the participating supermarkets
Participants - exclusion criteria Does not meet inclusion criteria
Anticipated start date 01/09/2010
Anticipated end date 01/07/2011
Status of trial Completed
Patient information material Not available in web format, please use the contact details below to request a patient information sheet
Target number of participants 180
Interventions The trial contained four research arms:
1. Price discounts on fruits and vegetables
2. Nutrition education with a special focus on fruits and vegetables
3. Price discounts on fruits and vegetables plus nutrition education
4. Control (no intervention)

The nutrition education consisted of two elements, being recipe books and telephone counseling. This telephone counseling consisted of four different calls, taking around 20 minutes each, that were conducted by a qualified dietitian.

The pricing intervention consisted of a 50% discount on fruits and vegetables. The discounts were provided to the participants by use of specifically designed coupons. Participants were sent discount coupons for seven types of vegetables and five types of fruits every two weeks. The coupons were sent by post and participants were provided with two coupons for each item.
Primary outcome measure(s) 1. Purchases of fruit and vegetables (grams): measured at baseline, 1 month, 3 months, 6 months (end of intervention) and 9 months (3 month follow-up) using cash receipts and schemes listing purchased fruits and vegetables during a two-week period
2. Intake of fruit and vegetables (grams) measured at baseline, 1 month, 3 months, 6 months (end of intervention) and 9 months (3 month follow-up) using a validated shortened Food frequency questionnaire (FFQ) specifically developed for fruit and vegetable intake
Secondary outcome measure(s) 1. The concepts of TBP (attitudes, social norm, and perceived behavioral control) were measured as proposed by Conner and Sparks (1996)
2. Behavioral intention and awareness of own consumption levels were measured in accordance with earlier studies (see Brug et al. 2006)
3. Levels of action planning and levels of coping planning were measured as proposed by Scharzer and Renner
4. Some additional concepts that previously have found to be of importance in food pricing studies were measured, being levels of habit strength (using scal of Verplanken) and price perception (using scale of Lichtenstein). Scores for all these concepts were measured by summing the scores of the relevant items and dividing this by the number of relevant items. All items were measured on a 5 point Likert scale
5. Finally, participants were asked to report some basic personal characteristics, their use of the discount coupons, their evaluation of the nutrition education, and frequency of shopping at the participating supermarket
Sources of funding Netherlands Organization for Health Research and Development (ZonMw) (Netherlands) ref: 50-50105-96-426
Trial website
Publications 1. 2013 results in http://www.ncbi.nlm.nih.gov/pubmed/23446898
Contact name Dr  Ingrid  Steenhuis
  Address VU University Amsterdam
De Boelelaan 1085
  City/town Amsterdam
  Zip/Postcode 1081 HV
  Country Netherlands
  Email ingrid.steenhuis@vu.nl
Sponsor Netherlands Organisation for Health Research and Development (ZonMw) (Netherlands)
  Address Laan van Nieuw Oost-Indië 334
Postbox 93 245
  City/town The Hague
  Zip/Postcode 2509 AE
  Country Netherlands
  Tel +31 (0)70 349 51 11
  Fax +31 (0)70 349 51 00
  Email info@zonmw.nl
  Sponsor website: http://www.zonmw.nl/en/
Date applied 18/10/2011
Last edited 01/03/2013
Date ISRCTN assigned 19/12/2011
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