N° 24 | June 2008

From Research to Policy: Economic Interventions Support Increases in Fruit and Vegetable Intake

Interventions using nutrition education to increase consumption of fruits and vegetables have reported some successes, although the magnitude of the behavior change has been modest1. Recent analyses seem to point to the potential for more “upstream” strategies, including policy, pricing, and environmental changes to affect food access and availability in addition to consumer information and motivation2.

Strategies to promote the choice of fruits and vegetables by lowering their cost relative to those of alternative foods has gained attention as the evidence continues to mount regarding their potential for positive health effects with increased intakes. These strategies have been little tested most likely due to the cost of implementation, although the available evidence shows that they are highly effective. Reducing the prices of fresh fruit and baby carrots in work sites and secondary schools has resulted in substantially increased sales of these items3,4. Two published reports on the provision of coupons for the purchase of fruits and vegetables at farmers markets, one with lowincome older adults over a 5-year period5 and the other for participants in the Special Supplemental Nutrition Program for Women, Infants and Children (WIC) in Connecticut (U.S)6, showed high levels of coupon use.

Review of the WIC Food Packages – An Opportunity for Policy Change in the U.S.

The WIC program is a governmentally funded, locally administered public health program in the US that provides supplemental foods of high nutritional quality, nutrition education, and referrals to health care for low-income and nutritionally at-risk women and children, during critical periods of growth and development. The WIC program was developed prior to the appreciation of the relationship of intake of fruits and vegetables to chronic disease risk. The supplemental foods selected at the time the program was initiated were to provide nutrients most limited in the diets of pregnant and breastfeeding women, infants, and children up to the age of 5 years –calcium, iron, vitamin A, and vitamin C and protein. The supplemental food packages have traditionally consisted of nutrientdense foods such as: fluid milk, cheese, eggs, dry beans, peanut butter, fruit juice, and iron-fortified cereals and formula for infants. There has been considerable discussion about adding fruits and vegetables to the WIC supplemental food package. A report issued by the Institute of Medicine (IOM) in 2005 recommended a number of changes to the packages including the addition of fruits and vegetables for all participants older than 6 months of age7. At the time of this study, the only fruits and vegetables provided were juice (for all participants older than 4 months) and fresh carrots for breastfeeding women.

Can Economic Incentives be Utilized to Improve
Consumption of Fruits and Vegetables?

The objective of the present study was to determine whether an additional economic subsidy to purchase fresh fruits and vegetables for postpartum WIC participants would result in increased consumption. The WIC program provides an ideal setting for investigating means to improve consumption of fruits and vegetables because it is targeted to a low-income population and is designed to improve dietary quality both by offering high-quality, nutrient-dense foods and through nutrition education. The program reaches about half of all infants born in the United States, along with their mothers and about 25% of preschool children8.

The current study measured two interventions to increase fruit and vegetable intake and compared these to a control site. The interventions were carried out at a major supermarket and a yearround farmers’ market. Study participants had recently delivered and were either breastfeeding or non-breastfeeding postpartum women, English or Spanish-speaking and at least 18 years of age. Following a 2-month monitoring period to document baseline fruit and vegetable intake, participants at the two intervention sites were issued $10 worth of vouchers per week in $1 units for the supermarket site and $2 units for the farmers’ market site to buy produce of the participants’ choice. Control participants were provided with a set of coupons of lesser value ($13 per month) redeemable for disposable diapers, in compensation for their time participating in interviews. The intervention was carried out for six months and participants were followed for an additional six months to track changes in fruit and vegetable intake.

Dietary intake was assessed four times during the 14-month study (at study entry, 2 months after study entry, end of 6-month intervention and 6 months following the end of the intervention) using a multiple pass 24-hour dietary recall. Participants’ descriptions of total food consumption were disaggregated into component food parts and fruits and vegetables converted to standard serving sizes by the same methods outlined by USDA for analysis of national food consumption data. Other variables collected included: demographics, other governmental program participation, food security, breastfeeding rates, and participants’ height and weight.

Incentives Supported Increased
Fruit and Vegetable Intake

Based on a mixed modeling approach, total consumption of fruits and vegetables increased over the course of the study. At baseline, participants at the farmers’ market site reported consuming on average 5.4 servings of fruits and vegetables, at the supermarket site 6.9 servings, and at the control site 5.0 servings. At the end of the intervention, participants reported consuming on average 7.8 servings at both the farmers’ market and supermarket sites and 4.8 servings at the control site. Six months after the intervention, the increase in fruit and vegetable intake was sustained. Farmers’ market and supermarket participants reported consuming 7.5 and 7.4 servings on average while the control site reported consuming a total of 4.9 servings. The increases in fruit and vegetable intake demonstrated with use of this subsidy translate to approximately 1 serving per 4,186 kJ (1,000 kcal) or 2 servings per 8,372 kJ (2,000 kcal) per day. Increases in fruit and vegetable intake were primarily realized by increases in consumption of vegetables.

Research Supports Policy Change

The results of this study together with a similar, longer-term study (5 years) conducted in a rural county in Northern California, were used to support the recommendations suggested in the 2005 IOM report on making changes to the WIC food packages7. After an open comment period, the USDA’s Food and Nutrition Service published an interim final rule on December 6, 2007, revising the WIC food packages to include fruits, vegetables, and whole grains. These revisions align the WIC food packages with the 2005 Dietary Guidelines for Americans and infant feeding practice guidelines of the American Academy of Pediatrics, reflecting recommendations from the Institute of Medicine's report, "WIC Food Packages: Time for a Change"7. State agencies in the U.S. are now engaged in the planning process and must implement the provisions no later than August 5, 20098.

  1. Bowen DJ, Beresford SA. Dietary interventions to prevent disease. Ann Rev Public Health. 2002;23:255-286.
  2. Glanz K, Yaroch AL. Strategies for increasing fruit and vegetable intake in grocery stores and communities: policy, pricing, and environmental change. Prev Med. 2004;39:S75-S80.
  3. French SA, Jeffrey R, Story M, Hannan P, Snyder MP. A pricing strategy to Promote low-fat snack choices through vending machines. Am J Public Health. 1997;87:849-851.
  4. French SA, Jeffrey R, Story M, et al. Pricing and promotion effects on low-fat vending snack purchases: the CHIPS Study. Am J Publ Health. 2001;91:112-117.
  5. Balsam A, Webber D, Oehlke B. The Farmers’ Market Coupon Program for low-income elders. J Nutr Elder. 1994;13:35-42.
  6. Anliker JA, Winnie M, Drake LT. An evaluation of the Connecticut Farmers’ Market coupon program. J Nutr Educ. 1992;24:185-1991.
  7. Institute of Medicine. WIC Food Packages: Time for a Change. Washington, DC: National Academy Press; 2005.
  8. US Department of Agriculture, Economic Research Service. Briefing rooms: the WIC program. Available at: http://www.ers.usda.gov/Briefing/WIC. Accessed March 16, 2005.
Return