Iodine deficiency – striking regional variations in Canada

Dr. Britz-McKibbin, Metabolomics TMIC

Dr. Philip Britz-McKibbin (TMIC’s McMaster Node leader) continues publishing his research work, which is of great interest to the broader community in Canada. This time his open access publication in Nutrients talks about biomonitoring for iodine deficiency across Canadian urban locations. “The Prevalence and Risk Factors Associated with Iodine Deficiency in Canadian Adults” is unique collaborative research with the Population Health Research Institute.

“Iodine is an essential micronutrient that is relevant to fertility, cognitive development and immune health”, says Philip Britz-McKibbin. “Although universal iodized salt programs historically have been successful to prevent severe iodine deficiency and goitre, there is a resurgence of mild to moderate deficiency in recent decades due to the increased consumption of processed foods and low-salt and other specialized diets (vegan or vegetarian), that are prone to iodine deficiency”

A validated capillary electrophoresis method was used for quantitative iodide, thiocyanate and nitrate determination in urine directly after a simple dilution step. Samples from 800 study participants from four Canadian urban locations (Hamilton, Ottawa, Quebec City and Vancouver) have been used in this biomonitoring study. 24 h urine samples have been used: although less convenient to collect, they offer greater reproducibility and accuracy than spot urine samples and they are the preferred method for assessing iodine status in epidemiological studies. Two abundant iodine uptake inhibitors, which can exacerbate risk of iodine deficiency, were measured together with iodide: thiocyanate and nitrate. Overall, the iodine status of surveyed Canadian adults was determined to be adequate on a population level with a low prevalence of moderate to mild deficiency or excessive iodine intake.

A few contributing factors to iodine deficiency in Canada have been discussed. Among these factors are the location and the dairy intake of the participants. Residents from Vancouver and Quebec City had about a 2.5-fold greater relative risk as compared to Hamilton or Ottawa.

The dairy intake had the strongest positive correlation with iodine status, mostly evident for residents in Hamilton and Ottawa. Greater bread and cereal intake, were marginally protective against iodine deficiency, whereas alcohol consumption increased risk for iodine deficiency.

Other environmental exposure factors may modulate iodine deficiency risk despite adequate iodine nutrition. Here, urinary thiocyanate and nitrate concentrations (and their excretion) were also measured in this study. The data reveal that urinary thiocyanate was strongly dependent on smoking status, while looking into the current smokers, never smokers and former smokers’ cohorts. Higher thiocyanate exposures measured for residents in Quebec City as compared to Hamilton, Ottawa, and Vancouver.

Consequently, residents from Vancouver and especially Quebec City may be at greater relative risk for iodine deficiency due to their suboptimal iodine nutritional status and greater combined exposures to thiocyanate and/or nitrate.

Summarizing the results of this work it is important to highlight that the general public should be mindful of the optimal iodine nutrition. Maintaining a healthy diet remains one of the most important factors for a better health and disease prophylactics.

“With changes to people’s diets, it may be time to rethink how to improve iodine intake, perhaps fortifying certain staple foods or beverages that would ensure most people would ingest adequate levels for optimal health”,

says Dr. Britz-McKibbin

The summary of this publication is prepared by Dr. S. Sapelnikova

Scroll to Top