Iodine Status and Thyroid Function of Vegans versus Non- Vegan Adults Kristen, Tony, Kelly, and Kelsie
Feb 20, 2016
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 SourceFairly 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 statusDamaging effects of iodine deficiency
Can be easily prevented with adequate intakeOur 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
Subjects 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.
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.
Recruitment/Selection
Flyers posted at local grocery stores and college campuses
$20.00 monetary incentive per subject upon completion
Testing will be in the winter 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
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
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 using vitamin/mineral supplementsFemale subjects who are pregnant or lactating
Screening/Methods
Baseline assessment (signing consent document) Answer food/medical history questions
Food frequency questionnaire
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
24hr dietary recall using 5-step, multi-pass approach
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 19992. Pearce EN, Pino S, He X, et al. Journal of
Clinical Endocrinology and Metabolism 20043. 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