Impact of folate biofortified food supplement on rural women's health and willingness-to-pay: A study based on a connected randomized controlled trial—Becker–DeGroot–Marschak experiment in China

We examined whether folate-fortified maize (FFM) improves the health of rural women of childbearing age and whether the health intervention is associated with the consumer willingness-to-pay (WTP) for FFM. First, a randomized single-blind FFM intervention trial was conducted in rural childbearing-aged women. Participants (n = 55) consumed one stalk of either FFM (treatment group) or ordinary maize (control group) daily. This dietary intervention lasted for 2 months, during which we assessed the participants' serum folate levels at baseline, mid stage (after 1 month), and final stage (after 2 months) to evaluate the health effect of FFM. We found that the serum folate level in the treatment group (13.31 ng/mL) was 3.40 ng/mL higher than that in the control group (9.91 ng/mL) in the final stage of the study. These findings suggest that regular dietary FFM intake significantly increased serum folate levels in rural Chinese women. Second, we further expanded our study by involving 181 local rural women with similar demographic characteristics to participate in a Becker–DeGroot–Marschak (BDM) bidding experiment to measure their WTPs for FFM. Results showed that local consumers were willing to pay 2.82 Chinese Yuan (CNY) per stalk of FFM, approximately 1.21 CNY higher than the price of ordinary maize. And women who participated in and completed the intervention trial had a higher preference for FFM during the evaluation. We provide evidence on the health improvement effect of biofortified foods and shed light on the associated consumer valuation and policy implementation.