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

Overview and Physiology

Essential for normal development and metabolism Controlled by thyroid gland

Major component of thyroid hormones (T3 & T4) BMR Macronutrient metabolism Muscle contraction Developmental growth Sexual maturation

Low hormone TSH release overstimulation of thyroid increased gland size (goiter)

Iodine Deficiency

Symptoms: Apathy Reduced mental functioning Lack of physical energy

During pregnancy: Spontaneous abortion Increase infant mortality Cretinism Cognitive defects

“Single most important preventable cause of brain damage worldwide” –World Health Organization

Dietary Source

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

Significance

Lack of primary research regarding US iodine status

Damaging effects of iodine deficiency Can be easily prevented with adequate intake

Our study will: Expand current findings Increase understanding of iodine status Study relationship between dietary choice and

iodine status Raise awareness of iodine status in developed

countries (US)

Significance

Hypothesis

Healthy vegan (diet excluding meat and dairy) adults aged 20-45 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.

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.

Observational study

Specific Aims

24 hour urine iodine excretion

Anthropometrics (body weight, height, waist circumference, body composition)

Fasting serum T3 and T4 levels

Basal metabolic rate (indirect calorimetry)

Dietary intake (24 hr diet record, food frequency questionaire)

Physical activity (Int’l Physical Activity Questionaire)

Expected Results

Hypothesis: “Healthy vegan adults aged 20-45 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:1. Thomas Remer, Annette Neubert and Friedrich

Manz. British Journal of Nutrition 1999

2. Pearce EN, Pino S, He X, et al. Journal of Clinical Endocrinology and Metabolism 2004

3. 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

Urinary iodine test efficacy depends on adherence by subjects

Self-reporting subjectivity/ inaccuracy is possible