Micronutrient (MN) deficiencies are highly prevalent in India, particularly among women of reproductive age (WRA) and preschool aged children (PSC). MN fortification of a staple food or condiment can be an effective strategy for improving the MN status of nutritionally vulnerable populations, as the approach is cost-effective, utilizes existing delivery systems, can deliver multiple MNs simultaneously, and does not require behavior change by the population. Salt is a particularly attractive vehicle for multiple MN fortification in India, as it is universally consumed in fairly consistent amounts; and 93% of households already use adequately iodized salt.

The overall goal of this study is to evaluate the nutritional impact of quintuply-fortified salt with iron in the form of FePP (FePP-Q5S, i.e. salt fortified with iron in the form of ferric pyrophosphate plus ethylenediaminetetraacetic acid as an enhancer of absorption; zinc in the form of zinc oxide; vitamin B12; folic acid; and iodine) vs. quintuply-fortified salt with iron in the form of eFF (eFF-Q5S i.e. salt fortified with iron in the form of encapsulated ferrous fumarate; zinc in the form of zinc oxide, vitamin B12, folic acid, and iodine) vs. iodized salt (IS) for the improvement of micronutrient status among nonpregnant WRA and preschool-aged children (12-59 months of age) in Punjab, India.

Enrolled women (and their affiliated households) will be randomized to receive 1 kg of their assigned study salt per month for 12 months, and will be instructed to use the study salt in place of their usual salt. Blood and urine samples will be collected from participant WRA and PSC at enrollment, 6 months and at the end of the 12-month intervention period. The change in the mean concentration of various MN biomarkers will be considered primary outcomes. Stool samples will also be collected from a subgroup of women and children to assess changes in the gut microbiome over the intervention period.

Inclusion criteria for women of reproductive age:

1. 18-49 years of age;
2. Not currently pregnant (self-reported);
3. Not severely anemia (defined as a hemoglobin concentration < 8 g/dL);
4. Not planning to become pregnant within the next year;
5. Permanent resident of the study village with no plans to move or travel outside the village for more than 4 weeks over the next 12 months;
6. No serious health problems that requires regular visits to a health facility;
7. Willingness to use refined salt provided by the study as a primary source of household discretionary salt.

Exclusion criteria for women of reproductive age:

1. Age <18 or > 49 years of age;
2. Pregnant at the time of enrollment (self report) or planning to become pregnant within the next year;
3. Severely anemic (i.e. hemoglobin concentration < 8 g/dL);
4. Not a permanent resident of the study area;
5. Planning to leave the study area for at least one month over the study period;
6. Serious health problem that interferes with eating practices and/or requires hospitalization;
7. Unwilling to use refined salt provided by the study as the primary source of the household's discretionary salt.

Inclusion criteria for preschool children:

1. Child 12-59 months of age at the time of enrollment;
2. Child's mother or primary female caregiver has been enrolled into the parent trial;
3. Not severely anemic (defined as a hemoglobin concentration < 7 g/dL);
4. Child's family is a permanent resident of the study village with no plans to move or travel outside the village for more than 4 weeks over the next 12 months;
5. No serious medical problems that interfere with the child's eating practices;
6. Child's mother or primary female caregiver is willing to use refined salt provided by the study as the primary source of the household's discretionary salt for the course of the study.

Exclusion criteria for preschool children:

1. Child age < 12 or > 59 months of age;
2. Child's mother has not been enrolled in the parent trial;
3. Severely anemic (i.e. hemoglobin concentration < 7 g/dL);
4. Child's family is not a permanent resident of the study village and/or has plans to travel outside the village for more than 4 weeks over the next 12 months;
5. Serious health problem that interferes with the child's eating practices;
6. Child's mother or primary female caregiver is unwilling to use refined salt provided by the study as the primary sources of the household's discretionary salt for the course of the study.

As soon as the manuscripts summarizing the study's primary outcomes are published, all datasets will be posted to Open Science Framework and made available to the public in accordance with the Gates Foundation's Open Data Policy.

Data will become available as soon as the manuscripts summarizing the study's primary endpoints have been published. Data will be made available indefinitely.

Study salts will be packaged in color-coded, polyethylene bags.