# Analysis of Fluoride Content of Different Types of Salts Used in the Indian Diet: An In Vitro Study

## TL;DR

This study measured fluoride levels in different Indian salts and found black salt had the highest, suggesting the need for clearer labeling.

## Contribution

The study provides new fluoride content data for commonly used Indian salts, highlighting variability and the need for consumer awareness.

## Key findings

- Black salt had the highest fluoride content (77.5 ± 19.9 ppm), significantly higher than iodized salt.
- Fluoride levels varied across salt types, but all were within prescribed limits.
- Rock salt showed high variability in fluoride content (40.8 ± 52.4 ppm).

## Abstract

Introduction

Salt is an essential component of the Indian diet. Edible salt contains fluoride, and its concentration varies depending on the source and manufacturing process. This study aimed to assess the fluoride concentration of commonly available varieties of edible salts in India.

Methodology

This in vitro study was conducted with four different types of edible salts viz. iodized salt, rock salt, pink salt, and black salt. Two brands of each salt available in the market were procured. Fluoride estimation was conducted using the sodium 2-(parasulphophenylazo-)- 1,8-dihydroxy-3,6-naphthalene disulphonate (SPADNS) method using Fluoride High-Range Checker® HC (Hanna Equipments India Pvt. Ltd., Mumbai, India) with HI739-26 reagent. The reaction between fluoride and the reagent forms a colorless complex in the sample. The concentration is then determined from the color produced, measured in parts per million (ppm).

Results

Iodized salt showed the least fluoride content (12.5 ± 7.5 ppm), while it was highest for black salt (77.5 ± 19.9 ppm). There was a statistically significant difference between the study groups (p=0.009). Rock salt also showed high amounts of fluoride (40.8 ± 52.4 ppm).

Conclusion

Fluoride content in different types of edible salt varied, though well within the prescribed limits. This calls for nutritional labelling of fluoride to help the consumer make informed choices.