Iodine Status and Thyroid Function of Vegans versus Non-Vegan Adults Kristen, Tony, Kelly, and Kelsie

Overview and Physiology Essential for normal development and metabolism Essential for normal development and metabolism Controlled by thyroid gland Controlled by thyroid gland Major component of thyroid hormones (T3 & T4) Major component of thyroid hormones (T3 & T4) BMR BMR Macronutrient metabolism Macronutrient metabolism Muscle contraction Muscle contraction Developmental growth Developmental growth Sexual maturation Sexual maturation Low hormone  TSH release  overstimulation of thyroid  increased gland size (goiter) Low hormone  TSH release  overstimulation of thyroid  increased gland size (goiter)

Iodine Deficiency Symptoms: Symptoms: Apathy Apathy Reduced mental functioning Reduced mental functioning Lack of physical energy Lack of physical energy During pregnancy: During pregnancy: Spontaneous abortion Spontaneous abortion Increase infant mortality Increase infant mortality Cretinism Cretinism Cognitive defects Cognitive defects “Single most important preventable cause of brain damage worldwide” –World Health Organization “Single most important preventable cause of brain damage worldwide” –World Health Organization

Dietary Source Fairly limited… Fairly limited… Table salt Table salt Sea-grown plants and animals Sea-grown plants and animals Dairy products Dairy products Some bread products Some bread products Vegetables grown in soil w/ high iodine levels Vegetables grown in soil w/ high iodine levels

Significance Lack of primary research regarding US iodine status Lack of primary research regarding US iodine status Damaging effects of iodine deficiency Damaging effects of iodine deficiency Can be easily prevented with adequate intake Can be easily prevented with adequate intake Our study will: Our study will: Expand current findings Expand current findings Increase understanding of iodine status Increase understanding of iodine status Study relationship between dietary choice and iodine status Study relationship between dietary choice and iodine status Raise awareness of iodine status in developed countries (US) Raise awareness of iodine status in developed countries (US)

Significance

Subjects Sample size =133 per group (between 20-45yrs old) Sample size =133 per group (between 20-45yrs old) Vegan: actively and consciously avoiding meat/dairy/eggs and meat derivatives of any kind including fish and shellfish. For at least 6 months prior to study selection. Vegan: actively and consciously avoiding meat/dairy/eggs and meat derivatives of any kind including fish and shellfish. For at least 6 months prior to study selection. Non-Vegan: standard Midwestern diet (no required or voluntary dietary restrictions of meat, eggs, or milk food sources. Non-Vegan: standard Midwestern diet (no required or voluntary dietary restrictions of meat, eggs, or milk food sources. Location: Recruitment will occur in the city of Columbia, Missouri. Lab and anthropometric testing will occur in the McKee research laboratory site under supervision of professionals. Location: Recruitment will occur in the city of Columbia, Missouri. Lab and anthropometric testing will occur in the McKee research laboratory site under supervision of professionals.

Recruitment/Selection Flyers posted at local grocery stores and college campuses Flyers posted at local grocery stores and college campuses $20.00 monetary incentive per subject upon completion $20.00 monetary incentive per subject upon completion Testing will be in the winter Testing will be in the winter College students would be gone in the summer College students would be gone in the summer Milk has more iodine in the winter due to shift from grass feeding to iodine-enriched grain feeding of livestock Milk has more iodine in the winter due to shift from grass feeding to iodine-enriched grain feeding of livestock Gives opportunity to exacerbate any differences between the two groups Gives opportunity to exacerbate any differences between the two groups

Exclusion Criteria Vegan subject doesn’t meet all of criteria of vegan diet for at least 6 months prior to recruitment Vegan subject doesn’t meet all of criteria of vegan diet for at least 6 months prior to recruitment Standard diet subject self imposes dietary restrictions of meat, eggs, or milk (or had in last 6 months) Standard diet subject self imposes dietary restrictions of meat, eggs, or milk (or had in last 6 months) Subject is diagnosed with a thyroid or iodine related illness in the last 5 yrs Subject is diagnosed with a thyroid or iodine related illness in the last 5 yrs Subject using vitamin/mineral supplements Subject using vitamin/mineral supplements Female subjects who are pregnant or lactating Female subjects who are pregnant or lactating

Screening/Methods Baseline assessment (signing consent document) Baseline assessment (signing consent document) Answer food/medical history questions Answer food/medical history questions Food frequency questionnaire Food frequency questionnaire Height, weight, waist circumference, DXA, BMR (indirect calorimeter), International PA Questionnaire, 10mL blood draw (fasting serum T3 and T4 levels) Height, weight, waist circumference, DXA, BMR (indirect calorimeter), International PA Questionnaire, 10mL blood draw (fasting serum T3 and T4 levels) Subject will consume an iodine supplement, take home a 24hr urine iodine loading kit, and return after a recorded supplement ingestion time Subject will consume an iodine supplement, take home a 24hr urine iodine loading kit, and return after a recorded supplement ingestion time 24hr dietary recall using 5-step, multi-pass approach 24hr dietary recall using 5-step, multi-pass approach

Expected Results Hypothesis: “Healthy vegan adults aged years will have poorer iodine status than non-vegan adults of similar age and gender; and thus may be at risk for subclinical malnutrition” Hypothesis: “Healthy vegan adults aged years will have poorer iodine status than non-vegan adults of similar age and gender; and thus may be at risk for subclinical malnutrition”

Expected Results Related Studies: Related Studies: 1. 1.Thomas Remer, Annette Neubert and Friedrich Manz. British Journal of Nutrition Pearce EN, Pino S, He X, et al. Journal of Clinical Endocrinology and Metabolism Swanson CA, Zimmermann MB, Skeaff S, et al. Journal of Nutrition 2012

Limitations/ Confounders Sample will come from Columbia, MO and may not be representative of total population Sample will come from Columbia, MO and may not be representative of total population Urinary iodine test efficacy depends on adherence by subjects Urinary iodine test efficacy depends on adherence by subjects Self-reporting subjectivity/ inaccuracy is possible Self-reporting subjectivity/ inaccuracy is possible