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

Hypothesis Healthy vegan (diet excluding meat and dairy) adults aged years will have poorer iodine status than non-vegan adults of similar age, gender and BMI. Healthy vegan (diet excluding meat and dairy) adults aged years will have poorer iodine status than non-vegan adults of similar age, gender and BMI. This population may be at risk for negative subclinical effects on metabolic rate. This population may be at risk for negative subclinical effects on metabolic rate.

Objectives Recruiting subjects from Missouri, we will test the above hypothesis by comparing iodine status and metabolic rate between young adult vegans and non-vegans. Recruiting subjects from Missouri, we will test the above hypothesis by comparing iodine status and metabolic rate between young adult vegans and non-vegans. Observational study Observational study

Specific Aims 24 hour urine iodine excretion 24 hour urine iodine excretion Anthropometrics (body weight, height, waist circumference, body composition) Anthropometrics (body weight, height, waist circumference, body composition) Fasting serum T3 and T4 levels Fasting serum T3 and T4 levels Basal metabolic rate (indirect calorimetry) Basal metabolic rate (indirect calorimetry) Dietary intake (24 hr diet record, food frequency questionaire) Dietary intake (24 hr diet record, food frequency questionaire) Physical activity (Int’l Physical Activity Questionaire) Physical activity (Int’l Physical Activity Questionaire)

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