BACKGROUND: Traditional methods to improve population diets have largely relied on individual responsibility, but there is growing interest in structural interventions such as pricing policies. OBJECTIVE: The aim was to evaluate the effect of price discounts and tailored nutrition education on supermarket food and nutrient purchases. DESIGN: A 2 x 2 factorial randomized controlled trial was conducted in 8 New Zealand supermarkets. A total of 1104 shoppers were randomly assigned to 1 of the following 4 interventions that were delivered over 6 mo: price discounts (12.5%) on healthier foods, tailored nutrition education, discounts plus education, or control (no intervention). The primary outcome was change in saturated fat purchased at 6 mo. Secondary outcomes were changes in other nutrients and foods purchased at 6 and 12 mo. Outcomes were assessed by using electronic scanner sales data. RESULTS: At 6 mo, the difference in saturated fat purchased for price discounts on healthier foods compared with that purchased for no discount on healthier foods was -0.02% (95% CI: -0.40%, 0.36%; P = 0.91). The corresponding difference for tailored nutrition education compared with that for no education was -0.09% (95% CI: -0.47%, 0.30%; P = 0.66). However, those subjects who were randomly assigned to receive price discounts bought significantly more predefined healthier foods at 6 mo (11% more; mean difference: 0.79 kg/wk; 95% CI: 0.43, 1.16; P < 0.001) and 12 mo (5% more; mean difference: 0.38 kg/wk; 95% CI: 0.01, 0.76; P = 0.045). Education had no effect on food purchases. CONCLUSIONS: Neither price discounts nor tailored nutrition education had a significant effect on nutrients purchased. However, the significant and sustained effect of discounts on food purchases suggests that pricing strategies hold promise as a means to improve population diets.
AD - School of Population Health, The University of Auckland, Auckland, New Zealand. c.nimhurchu@ctru.auckland.ac.nz AN - 20042528 BT - American Journal of Clinical Nutrition ET - 2010/01/01 LA - eng M1 - 3 N1 - Ni Mhurchu, ClionaBlakely, TonyJiang, YannanEyles, Helen CRodgers, AnthonyRandomized Controlled TrialResearch Support, Non-U.S. Gov'tUnited StatesThe American journal of clinical nutritionAm J Clin Nutr. 2010 Mar;91(3):736-47. Epub 2009 Dec 30. N2 -BACKGROUND: Traditional methods to improve population diets have largely relied on individual responsibility, but there is growing interest in structural interventions such as pricing policies. OBJECTIVE: The aim was to evaluate the effect of price discounts and tailored nutrition education on supermarket food and nutrient purchases. DESIGN: A 2 x 2 factorial randomized controlled trial was conducted in 8 New Zealand supermarkets. A total of 1104 shoppers were randomly assigned to 1 of the following 4 interventions that were delivered over 6 mo: price discounts (12.5%) on healthier foods, tailored nutrition education, discounts plus education, or control (no intervention). The primary outcome was change in saturated fat purchased at 6 mo. Secondary outcomes were changes in other nutrients and foods purchased at 6 and 12 mo. Outcomes were assessed by using electronic scanner sales data. RESULTS: At 6 mo, the difference in saturated fat purchased for price discounts on healthier foods compared with that purchased for no discount on healthier foods was -0.02% (95% CI: -0.40%, 0.36%; P = 0.91). The corresponding difference for tailored nutrition education compared with that for no education was -0.09% (95% CI: -0.47%, 0.30%; P = 0.66). However, those subjects who were randomly assigned to receive price discounts bought significantly more predefined healthier foods at 6 mo (11% more; mean difference: 0.79 kg/wk; 95% CI: 0.43, 1.16; P < 0.001) and 12 mo (5% more; mean difference: 0.38 kg/wk; 95% CI: 0.01, 0.76; P = 0.045). Education had no effect on food purchases. CONCLUSIONS: Neither price discounts nor tailored nutrition education had a significant effect on nutrients purchased. However, the significant and sustained effect of discounts on food purchases suggests that pricing strategies hold promise as a means to improve population diets.
PY - 2010 SN - 1938-3207 (Electronic)0002-9165 (Linking) SP - 736 EP - 47 T2 - American Journal of Clinical Nutrition TI - Effects of price discounts and tailored nutrition education on supermarket purchases: a randomized controlled trial VL - 91 ER -