# Low-Iodine Diet: A Practical Guide

URL: https://thethyroidologist.com/topics/low-iodine-diet-guide/
Section: Topics
Last medically reviewed: 2025-11-15

> A practical guide to the low-iodine diet used before radioactive iodine treatment — what to avoid, what to eat and how long to follow it.

A low-iodine diet is sometimes recommended for one to two weeks before radioactive iodine treatment or scanning. Reducing iodine intake helps the thyroid take up the radioactive iodine more effectively.
The exact duration and instructions vary between centres — always follow your treating team’s advice.

## Why it is used

The thyroid takes up iodine avidly. If the body is saturated with ordinary iodine, radioactive iodine is diluted and less effective. A low-iodine diet reduces that competition.
It is used mainly before radioactive iodine for thyroid cancer and sometimes before a scan.

## What to avoid

Avoid iodised salt and salty processed foods, seafood and seaweed, dairy products in large amounts, egg yolks, and iodine-containing supplements or cough medicines. Some breads and restaurant foods contain iodised salt.
Check labels for iodine and avoid kelp or seaweed products.

## What to eat

Fresh fruits and vegetables, fresh meat and poultry, rice, pasta, potatoes, beans, unsalted nuts and home-cooked meals made without iodised salt are generally suitable.
Use non-iodised salt if needed, and drink water rather than iodine-rich beverages.

## Practical tips

Plan meals at home, read labels, and ask family members to help. The diet is temporary and not a permanent restriction. Ask your team for a written list, as recommendations vary.

## Frequently asked questions

### How long do I need the diet?

Usually one to two weeks before treatment, depending on your centre’s protocol. Follow the instructions you are given.

### Can I use normal salt?

Avoid iodised salt during the diet. Use non-iodised salt if your team permits it.

### Is the diet dangerous?

It is temporary and generally safe for most people, but ask your team if you have other dietary or medical conditions.

## Disclaimer

The content on this website is for general educational purposes only and does not constitute medical advice, diagnosis, or treatment. Always consult a qualified healthcare professional about your specific condition.

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