Lowering salt intake to 5 gm a day won’t affect iodine levels: Study

Reducing daily salt intake to the World Health Organisation’s recommended level of 5 grams per day does not lower iodine levels among adults in India, a new study by the Centre for Chronic Disease Control has found.

The findings address a long-standing concern that lowering salt consumption, which is crucial for preventing hypertension, might affect iodine intake in a country that relies on mandatory iodised salt for deficiency control.

The study conducted in Delhi and Haryana is one of the first in India to simultaneously measure daily salt and iodine intake using 24-hour urine samples, which is considered the global gold standard.

The Centre for Chronic Disease Control (CCDC) researchers said the results provide strong support for the recommendations made by the World Health Organisation (WHO) and Government of India to reduce population salt intake as part of efforts to curb rising incidence of hypertension and cardiovascular diseases.

According to the study, the average salt intake among participants aged 20 years and above was 8.07 grams per day, which is significantly above the recommended limit. The research showed that iodine levels remained adequate even when salt intake was at or below 5 grams a day.

“One major concern around reducing salt intake has been the fear that iodine levels will fall,” said Dr Dorairaj Prabhakaran, Executive Director at CCDC and senior author of the study.

“But the study clearly shows that even with reduced sodium intake, iodine consumption remains sufficient. The belief that lowering sodium quantity will compromise iodine intake is misplaced,” he added.

India has more than 300 million people living with hypertension, making dietary salt reduction one of the most critical public health goals.

The WHO has set a target of reducing global salt intake by 30% by 2025, but recent reports show most countries, including India, are far from achieving it.

The CCDC analysis also highlights that iodine levels in salt samples collected from 205 households were within expected range.

CCDC Deputy Director and co-author of the study Prof Sailesh Mohan said the findings should reassure policymakers that salt reduction and iodine supplementation can continue simultaneously.