Trial Information

Randomized Placebo-Controlled Trial (RPCT) of Maize/Zinc in Guatemala

Poor mineral nutrition, especially deficiencies of iron and zinc, is a major cause of
maternal and, especially, infant morbidity/mortality in developing world countries. The
objectives of this study are to determine whether: a) linear growth velocity between 6 and
12 months in infants receiving a 5mg Zn supplement will be greater than that for infants
receiving placebo; b) linear growth velocity will be greater for infants receiving
complementary foods containing low phytate maize than for the infants fed wild-type conrol
maize. In addition, Zn metabolic studies will be performed. The objective of the metabolic
stuides are to measure key variables of Zn homeostasis in maternal participants during
changes in the reproductive cycle and in infants during a time when they are most vulnerable
to Zn deficiency.

The primary outcome measurement is linear growth velocity between 6 and 12 motnhs.
Secondary outcomes are weight gain, diarrheal incidence/prevalence and infant
neurodevelopmental measures. Optional maternal and infant biochemical data will be collected
from a convenience sample comprised of willing participants.

One additional component to this study is to collect information on the nutritional status
of the women receiving low-phytate vs. control maize and the infants enrolled in this study.

The current protocol for infants in this study specifies measurements of exchangeable zinc
pool (EZP) at 6 and 12 months of age; in order to lesson the burden of study participation
we plan to conduct the metabolic studies in infants at only nine months of age. In addition
to decreasing the number of infant studies, this chanage will enable families who are only
participating in the metabolic studies (not simultaneously enrolled in the sibling cohort)
to cease all study demands at the end of the ninc month measurement (an overall decrease of
three months in study participation).

The primary outcome measure for this study is the quantity of zinc absorbed (mg/day)from
complementary foods and a Zn supplement at age 9 months. The rationale for measures of zinc
absorption in infants is that the low phytate complementary feeding is expected to have a
beneficial public health effect only if it results in enhanced mineral, especially zinc,
absorption. Therefore, confirmation of increased zinc absorption can be regarded as the
first logical stage of any efficacy study.

The sample size of 420 is required in order to observe a 6% increase in growth rates for Zn
supplemented infants compared to placebo treated infants within each maize group with 80%
power.