Knowledge, Self-Efficacy, and Perceived Barriers on the Low-Iodine Diet among Thyroid Cancer Patients Preparing for Radioactive Iodine Therapy

Abstract

The purposes of the study were to assess knowledge, self-efficacy, and perceived barriers on a low-iodine diet among thyroid cancer patients and to identify strategies for nutrition education. A self-administered questionnaire was developed based on a review of literature and pilot-tested. A total of 121 female thyroid cancer patients participated in a survey and 117 responses were used for data analysis. An average knowledge score of the thyroid cancer patients was 4.5 point (available score: 0-10 point). Majority of the respondents knew that seaweeds such as lavers, brown seaweeds, and sea tangles contain large amount of iodine. However they mistook the low iodine diet as a low salt diet and were not aware of foods and seasonings that are allowed on the low iodine diet. While self-efficacy related to consuming various fruits and vegetables, to choosing potatoes and sweet potatoes for snacks, and restricting consumption of eggs, milk and milk products, and processed foods was rated highly, self-efficacy for preparing foods without using sea salts was rated low. The self-efficacy score increased as their interest on the dietary life and perceived cooking skills were greater. Most perceived barriers toward practicing the low iodine diet were related to preparation of the low iodine menus. As their interest in the dietary life and cooking and perceived cooking skills were greater, the patients perceived barriers on practicing the low iodine diet less. While the patients showed higher self-efficacy and lower barrier perception on selecting foods low in iodine and restricting food high in iodine, they showed lower self-efficacy and higher barrier perceptions on preparing low iodine meals. Clinical dietitians should recognize the gap between what the patients should know and what they really know and identify strategies on how to improve self-efficacy and reduce perceived barriers on the low iodine diet. Recent literature and the findings of the study reveal that incorporating cooking classes into nutrition education for thyroid patients is effective to enhance self-efficacy and to reduce perceived barriers on the low iodine diet.

A Survey of UK Centres on Low Iodine Diet Recommendations prior to Radioiodine Ablation Therapy for Differentiated Thyroid Cancer

“…Over half of the clinicians (53%) indicated that people coped very well with the diet, although some suggested that there are groups of people who struggle and that some people attempt to follow a very restrictive no-iodine diet. Two studies, both conducted in South Korea, reported that people believed the LID to be important but found it difficult to follow because they enjoyed foods high in iodine, struggled to find alternatives and found it difficult to eat outside the home [18,19]. Difficulties with food eaten outside of the home were also reported by people in Brazil [20].…”

Thyroid cancer mortality is higher in Filipinos in the United States: An analysis using national mortality records from 2003 through 2012

“…Post-thyroidectomy thyroid cancer patients are often placed on low-iodine diets before radioactive iodine (RAI) treatment in order to enhance I-131 uptake and maximize the destruction of cancerous thyroid cells 13 . One study found that among a cohort of Korean females, approximately 37% did not know that fish pastes, hams, and sausages contained high levels of iodine, and 36% over-estimated the amount of dairy they were allowed to consume on a low-iodine diet 14 . It is plausible that Filipino patients have similar misunderstandings and a higher intake of iodine-rich foods, such as seafood and dairy, than other patients preparing for RAI treatment, which may render the treatment less effective, or may modulate tumor behavior.…”

Low iodine diet in differentiated thyroid cancer: a review

“…In areas where the average estimated iodine intake is high, individuals may require a longer length of iodine restriction. Moreover, duration can influence an individual's adherence to iodine restriction, as patients find difficulty implementing and complying with this dietary change due to a low level of knowledge about how to prepare a LID …”

“…Strict adherence to a LID may be a source of anxiety for patients and can be time‐consuming for medical staff to implement . A Korean study surveying 117 female patients with thyroid cancer found that they had a low level of knowledge on the food types that are allowed and restricted in a LID . Additionally, patients often mistook the low iodine diet as a low salt diet.…”