Clinical trial NCT06992947: Impact of Healthy Food Subsidies on Diet Quality and Food Security
Official title: Does the British Columbia Farmers' Market Nutrition Coupon Program Improve the Diet Quality and Food Security of Parents and Children With Lower Incomes? A Dose-response, Pragmatic Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: NOT_YET_RECRUITING
Phase: NA
Conditions: Food Insecurity
Keywords: Randomized controlled trial
diet quality
food insecurity
low-income
healthy food subsidy
adults
children
parental shielding
dose-response
farmers market
Lead sponsor: University of Calgary
Sponsor class: OTHER
Collaborators: name: Canadian Institutes of Health Research (CIHR)
name: British Columbia Farmers' Market Nutrition Coupon Program
name: BC Association of Farmers' Markets
First posted: 2025-05-28
Enrollment: 552
Sex: ALL
Minimum age (years): 6
Maximum age (years): 64
Standard ages: CHILD
ADULT
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Primary purpose: PREVENTION

Brief summary: The British Columbia Farmers' Market Nutrition Coupon Program (FMNCP) provides lower-income households with coupons to purchase healthy foods at farmers' markets. This pragmatic randomized controlled trial (RCT) will examine the effectiveness and cost-effectiveness of two higher subsidies for healthy food ($54/weeek or $81/week), compared to the usual FMNCP healthy food subsidy ($27/week), on the diet quality (primary outcome), food insecurity, and other health-related outcomes of 276 parent-child dyads with lower incomes. 276 parent-child dyads who are enrolled in the FMNCP will be randomly assigned to one of the three subsidy arms. Participants will receive 16 weeks of coupons that can be redeemed over 26 weeks. Outcomes will be assessed in one parent (18-64 years) and child (6-17 years) from each household pre-, mid- and post-intervention.

Detailed description: Background: The British Columbia Farmers' Market Nutrition Coupon Program (FMNCP) is a healthy eating initiative designed to facilitate access to nutritious food for lower-income households. The program provides households with 16 weeks of coupons valued at $27/week to purchase healthy foods at BC farmers' markets, including fruits, vegetables, dairy, meat, poultry, fish, eggs, nuts, fruit and vegetable plants, honey and herbs. The expectation is that individuals will purchase and consume healthier foods when they are financially supported to do so, and that their overall well-being and health will improve as a result.

In a prior randomized controlled trial (RCT) in adults, the investigators found that the FMNCP did not improve adults' diet quality; however, it did reduce household food insecurity by 79%. It is hypothesized that parents in the prior RCT predominantly used their subsidies to feed their children and that higher subsidies are needed to ensure both parents and children benefit. A novel dose-response RCT among parent-child dyads is essential to examine how variations in subsidy amounts affect distinct outcomes among parents and children.

This pragmatic RCT will examine the effectiveness and cost-effectiveness of two higher subsidies for healthy food, compared to the usual FMNCP healthy food subsidy, on the diet quality (primary outcome), food insecurity, and other health-related outcomes of 276 parent-child dyads with lower incomes. The primary outcome is overall diet quality post-intervention. Secondary outcomes mid- and post-intervention include: 1) Other dietary outcomes: overall diet quality (mid-intervention only), diet quality components, food purchasing, intake of ultra-processed foods; 2) Food insecurity: food insecurity status and severity, nutrition security, parental shielding; and 3) Self-reported health-related outcomes: mental well-being, sense of community, perceived stress, perceived health, food literacy, BMI.

Methods: In this single-blind, three-arm, parallel-group pragmatic RCT, 276 parent-child dyads in lower-income households will be randomized to receive the usual FMNCP healthy food subsidy ($27/week) or a subsidy that is two ($54/week) or three times ($81/week) higher. Participants will receive 16 weeks of coupons that can be redeemed over 26 weeks. Outcomes will be assessed in one parent (18-64 years) and one child (6-17 years) from each household pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season). Dietary intake will be collected via two 24-hour dietary recalls using the Automated Self-Administered 24-hour Dietary Recall at each time point to assess diet quality. Foods purchased with coupons will be assessed by analyzing pictures taken by participants. Food insecurity and other health-related outcomes will be assessed using validated self-reported instruments. Mixed effects regression will assess the effects of the interventions, relative to the usual food subsidy, on outcomes in parents and children. A full incremental analysis will quantify the cost-effectiveness ratios of the three healthy food subsidies.

Eligibility criteria: Inclusion Criteria:

* Meet existing FMNCP-specific annual household income eligibility cut-offs that account for the local cost of living
* Have 2-5 members in the household, specifically with a parent 18-64 years and a child 6-17 years. If there are multiple eligible individuals, the parent who is the primary food shopper and the youngest child will be enrolled.
* Parent-child dyads must reside together ≥5 days/week
* Are the only dyad in their household participating in the study
* Have access to the internet and a camera
* Able to communicate in English or have someone to translate

Exclusion Criteria:

* Trying to conceive, pregnant or breastfeeding
* Participating in other trials that might interfere with the intervention
* Reside in a facility that provides meals (e.g., shelter, long-term care) or where they cannot prepare meals (e.g., hotel)
* Anticipate being outside of their community for \>2 consecutive weeks during the study
* Expect to move to a non-FMNCP community during the study
* Expect a significant change in their household income or composition during the study

Primary outcomes:
measure: Overall Diet Quality in Parents
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Overall Diet Quality in Children
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
Secondary outcomes:
measure: Overall Diet Quality in Parents
timeFrame: Assessed pre- and mid-intervention (i.e., after 8 weeks of coupons have been distributed)
measure: Overall Diet Quality in Children
timeFrame: Assessed pre- and mid-intervention (i.e., after 8 weeks of coupons have been distributed)
measure: Diet Quality Component Scores in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Diet Quality Component Scores in Children
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Percent Energy from Ultra-Processed Foods in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Percent Energy from Ultra-Processed Foods in Children
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Household Food Insecurity Status
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Parental Shielding
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Household Food Insecurity Severity
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Household Nutrition Security
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Proportion of Coupons Spent on Foods Classified as Minimally Processed, Culinary, Ingredients, Processed, and Ultra-processed
timeFrame: Assessed each time participants purchase food using FMNCP coupons from pre- to post-intervention (i.e., when the farmers' market a household shops at closes for the season)
measure: Proportion of Coupons Spent on Foods Classified as Very Poor, Poor, Fair, Good and Excellent Choice
timeFrame: Assessed each time participants purchase food using FMNCP coupons from pre- to post-intervention (i.e., when the farmers' market a household shops at closes for the season)
measure: Proportion of Coupons Spent on Foods Classified as Sell Most, Sell Sometimes and Do Not Sell
timeFrame: Assessed each time participants purchase food using FMNCP coupons from pre- to post-intervention (i.e., when the farmers' market a household shops at closes for the season)
measure: Mental Well-Being in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Mental Well-Being in Children
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Sense of Community in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Perceived Stress in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Perceived Stress in Children
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Food Literacy in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Self-Rated Health in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Self-Rated Health in Children
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Body Mass Index in Parents
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Body Mass Index Z-Scores in Children
timeFrame: Assessed pre-, mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
Other outcomes:
measure: Coupon Receipt
timeFrame: Assessed bi-weekly from pre- to post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Coupon Redemption
timeFrame: Assessed each time participants purchase food using FMNCP coupons from pre- to post-intervention (i.e., when the farmers' market a household shops at closes for the season)
measure: Nutrition Skill-Building Activity Attendance
timeFrame: Assessed based on written records recorded from pre- to post-intervention (i.e., when the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses by Sex
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses by Gender
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses by Ethnicity
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses by Household Size
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses by Household Food Insecurity Status at Baseline
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses According to the Average Value of FMNCP Coupons Redeemed Prior to Dietary Recalls
timeFrame: Assessed mid- (i.e., after 8 weeks of coupons have been distributed) and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
measure: Subgroup Analyses by Child Age
timeFrame: Assessed pre- and post-intervention (i.e., 1-2 weeks before the farmers' market a household shops at closes for the season)
Locations:
city: Communities across BC
country: Canada
facility: Participants recruited in 93 communities across British Columbia, Canada
state: British Columbia
Study officials:
affiliation: University of Calgary
name: Dana Lee Olstad, PhD, RD
role: PRINCIPAL_INVESTIGATOR
References: