Dietary quality, as measured by fruit and vegetable intake, is a powerful
protective factor against a number of common chronic diseases, including
several causing premature death and disability. Low income is well-established
as a risk factor for poor dietary quality in the United States. The
Special Supplemental Nutrition Program for Women, Infants and Children
(WIC) program provides a context for investigating means to improve fruit
and vegetable consumption in a vulnerable population.
WIC was designed and developed before the relationship of fruit and
vegetable intake to chronic disease risk was well-established, and the foods
were selected to supplement the nutrients that were thought to be most
limited in the diets of low-income women and children, namely protein,
calcium, vitamin A, and vitamin C. Recently, there has been discussion
about adding fruits and vegetables to the WIC food package, potentially on
a cost-neutral basis. A recent report by the Institute of Medicine reviewed
the current public health context for the development of WIC food packages
and proposed criteria for the inclusion of food items. Fruits and vegetables
were among the highest priority food groups. This research investigated
whether providing supplemental financial support targeted for purchase of
fresh fruits and vegetables would result in high uptake of the supplement
and whether the individuals would continue to consume more fruits and
vegetables after financial support was discontinued.
A nonequivalent control group design was used to provide vouchers for
fresh fruits and vegetables to low-income women participating in the Public
Health Foundation Enterprises WIC program in Los Angeles, CA. The study
recruited 602 women who were enrolling for postpartum services at three
selected WIC program sites (approximately 200 per site). Sites were
assigned to: intervention with vouchers redeemable at a local supermarket;
intervention with vouchers redeemable at a nearby year-round farmers'
market; and a control site with a minimal nonfood incentive for participation
in interviews. Vouchers were issued bimonthly, at the level of $10 per week.
Interventions were carried out for 6 months, and participants’ diets were
followed for an additional 6 months after the intervention. Quantitative 24-
hour dietary recalls were conducted at four interviews for each participant.
At the intervention sites, two extra interviews spaced 2 months apart were
held to obtain information on the fruits and vegetables purchased with the
vouchers. Specifically, participants were asked to respond to the question
“What did you buy with your fruit and vegetable coupons last week?”
Voucher redemption rates were obtained from scanned data from the supermarket’s
corporate headquarters. In the farmers’ markets, vouchers presented
for purchase were collected by the farmers’ market manager and turned into
the city government’s accounting department for tallying. Vouchers were then
mailed to the study’s research staff, who re-counted the redeemed vouchers
and logged the tallies into an electronic database.
In all, $44,000 worth of vouchers were issued for the supermarket and
$44,960 for the farmers’ market. Redemption rates were 90.7 percent for the
farmers’ market and 87.5 percent for the supermarket. Overall, participants
reported purchasing 27 and 26 different fruits, and 34 and 33 different
vegetables in the farmers’ market and supermarket outlets, respectively. Five
fruits and five vegetables accounted for about 70 percent of the items
reported for each group. The 10 most frequently reported items were
oranges, apples, bananas, peaches, grapes, tomatoes, carrots, lettuce, broccoli
and potatoes. A larger number of item purchases were reported for the
farmers' market although the total number of types of fruits and vegetables
did not differ significantly between the two market settings.
Participation in the interventions increased consumption of fruits and vegetables
with use of the supplement and that increase was sustained 6 months after
the intervention. At baseline, participants at the farmers’ market reported eating
2.2 servings/1,000 kilocalories (kcal) on average, 2.9 servings/1,000 kcal at the
supermarket site, and 2.6 servings/1,000 kcal at the control site. Six months
postintervention, this same comparison was made, and the increase in participant
fruit and vegetable intake reported by intervention site was sustained.
Participants at both the farmers’ market and supermarket sites reported eating
4.0 servings of fruits and vegetables/1,000 kcal on average, while control site
participants reported eating 3.1 servings/1,000 kcal on average. The difference
in consumption between each of the intervention sites and the control site was
statistically significant even after adjusting for multiple factors. The results
were unaffected when evaluating consumption of fruits and vegetables
excluding beans and potatoes, and fruits and vegetables excluding juices.
Increases in vegetable consumption were primarily responsible for the overall
increases in fruit and vegetable intake.
A linear regression analysis using baseline demographics, government program
participation, body composition, food security status, reported energy intake,
reported fruit and vegetable intake, infant feeding method, and treatment site
explored which of these factors were associated with fruit and vegetable intake
six months post-intervention. The results indicated that higher reported intake
of fruits and vegetables 6 months postintervention was associated with reported
fruit and vegetable intake at baseline, preference for speaking Spanish, and
participating at either the farmers’ market site or the supermarket site compared
to the control site.
In summary, the variety of choices of fruits and vegetables exhibited in this
study leads to the conclusion that, in this setting, low-income consumers make
varied and nutritious choices from available produce. The findings point to the
potential for dietary improvement with a targeted subsidy that allows free
choice within the fresh produce category. Neither the supermarket nor the
farmers’ market found the study particularly burdensome, and both outlets
were positive about their participation. No specific barriers arose to voucher
redemption by participants or retailers. In addition to the economic intervention,
the high intake of fruits and vegetables may be attributed to the large
proportion of Latinos included in the study population. The study participants’
sustained intake of fruits and vegetables may reflect retained cultural food
behavior habits and the study’s timing at a critical point in a family—the birth
of a child and the surrounding concern for a healthy child.