Fortified Salt: UCSF Study Reveals a New Weapon Against Micronutrient Deficiencies

The simple act of adding iodine to household salt has been one of public health’s greatest success stories, preventing widespread cognitive impairment in children around the world. Now, new technology is allowing scientists to transform the everyday condiment into a vehicle for multiple essential vitamins and nutrients to combat these widespread deficiencies.

A new study, led by UC San Francisco in collaboration with the Postgraduate Institute of Medical Education and Research, Chandigarh (PGIMER), put this new technology to the test in communities in India. Published in The American Journal of Clinical Nutrition, the year-long trial evaluated whether a salt fortified with five key nutrients — vitamin B12, folic acid, iron, zinc, and iodine —  could improve the nutritional status of nearly 1000 women.

The Problem: A Hidden Hunger

The trial focused on a region of Punjab, India, where the burden of micronutrient deficiency is particularly high among women. At the start of the trial, nearly 60% of participants were iron-deficient, 62% had vitamin B12 insufficiency, and 70% had folate insufficiency. These are not minor issues; such deficiencies can lead to serious health consequences for women and their future children, including impaired cognitive function and an increased risk of birth defects.

"Conducting a trial of this scale in a real-world community setting was essential to understanding the potential impact of fortified salt," says Christine McDonald, ScD, MS, associate professor of pediatrics at UCSF and senior author on the study. "Our study team worked diligently to recruit and follow up nearly 1000 women so we could rigorously evaluate the nutritional impact of this intervention where it’s needed most.”

 

Major Improvement in B Vitamin Status

After receiving the fortified salt for one year, the odds of vitamin B12 and folate (B9) insufficiency were more than 80% lower in comparison to women who received only iodized salt. Notably, the B12 response was highest among the participants with poor status at the start of the study.

"These findings confirm salt as a powerful vehicle for improving micronutrient status, particularly in settings where micronutrient deficiencies are prevalent and the consumption of other fortified foods is low," says McDonald. "Building on the robust system already in place for iodized salt, new microencapsulation technology provides a feasible and cost-effective way to deliver several more essential nutrients at once.”

The study notes that the total cost of the premix for iron- and iodine-fortified salt in India is approximately $0.16 per person per year, and that the incremental cost to add nutrients like vitamin B12 and folic acid to that premix would be minimal, making for a highly scalable solution.

An Important Lesson: The Complexity of Iron

Despite the success with vitamin B12 and folate, the fortified salt had only a minimal impact on participants’ iron status and did not improve the overall prevalence of anemia. The researchers explain that this may be due to the comparatively lower levels of iron fortification in the salt in combination with other elements of a person’s diet, which may inhibit absorption.

"The iron and anemia results highlight that there's no single magic bullet," says McDonald. "Our findings underscore the need for integrated solutions that might combine fortification with other public health interventions to more comprehensively address anemia and iron deficiency."

A Major Step Forward for Global Health

The findings demonstrate that fortified salt is a powerful, effective, and highly scalable tool for improving the nutritional status of women, which is a foundational investment in the health of the next generation. While the results for iron highlight the complexity of anemia, success with B vitamins provides a clear and cost-effective path forward. McDonald’s research offers a blueprint for how a simple, everyday product can be enhanced to give every child the best possible start in life.

Authors: Other UCSF authors include Yvonne E Goh, PhD, and Mari Manger, PhD. For all authors, see the paper.

Funding: This work was supported by the Bill & Melinda Gates Foundation (INV 002945).