applied nutrition for thyroid health
TRANSCRIPT
Applied nutrition for thyroid health
By Kyla Williams DipION, BSc, MSc
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Summary
• The thyroid gland function
• Causes of thyroid issues
• Signs and symptoms of thyroid dysfunction
• Negative health effects of thyroid dysfunction
– Metabolism, skin health, digestive issues and fertility
• Tests to better understand the extent and type of thyroid dysfunction
• Nutritional and lifestyle approach to support thyroid health
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An introduction to the thyroid gland
• Positioned in the neck below thyroid cartilage
• Consists of 2 connected lobes
• Endocrine gland
– Secretes hormones directly to the blood
• Impacts energy metabolism, protein synthesis
– Regulates growth
– Regulates several functions in the body
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Functions of the thyroid gland
• T4 (thyroxine / tetraiodothyronine) production
• T3 (triiodothyronine) production
– Growth & development
– Metabolism
– Body temperature
– Heart rate
• Calcitonin production
– Regulates blood calcium and phosphate levels
– Calcitonin released from thyroid = blood calcium falls
– Effects long bone growth
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Functions of the thyroid gland
• Composed of follicles that absorb iodine
• Secretes T4 and T3 through a single layer of epithelial cells surrounding the follicles
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• Secrete T4 & T3Follicular cells
• Secrete calcitoninParafollicular cells (C cells)
Thyroid gland
Parathyroid glands
• 4 small glands, positioned on the back of the thyroid gland
• Different roles from the thyroid gland:
– Glands release PTH (parathyroid hormone – also known as parathormone)
• PTH controls calcium and phosphate homeostasis
• PTH has opposite effects to calcitonin:
– PTH causes osteoclasts to break down and
release calcium = increasing blood calcium levels
– Increases gastrointestinal absorption of calcium
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Thyroid stimulation
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Hypothalamus • Produces hormone TRH
• Stimulates pituitary gland
Anterior pituitary gland
• Produces thyroid-stimulating hormone TSH
• Stimulates thyroid gland
Thyroid gland• Produces
T4, T3 & calcitonin
Negative feedback loop
• When T4 levels are high = TSH production = thyroid function
• Exposure to cold = TRH = TSH production = thyroid function
• Glucocorticoids / sex hormones / high iodine = TSH = thyroid function
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Hypothalamus • TRH
Anterior pituitary gland
• TSH
Thyroid gland
T4 to T3 conversion
• Thyroid produces both T4 and T3
– T4 is produced in significantly greater quantities compared to T3
– Up to 80% of the T4 is converted in the body to T3
– T3 is more biologically active than T4
• Conversion by other organs: liver, kidney, spleen and thyroid
• It is possible to have normal levels of T4 and low levels of active T3 (with low or high TSH)
• ‘Free’ T4 and T3 have been transported to tissues and cleaved from their protein carriers
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Synthesis of T4 and T3 hormones
• T3 and T4 required for thyroid function
• Tyrosine and iodine are required
for synthesis of T3 and T4
• Ensure adequate tyrosine and iodine in the diet
IodineTyrosine
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Tyrosine
• Amino acid
• Rich food sources – eggs, cheese, turkey
• Can be synthesised in the body from phenylalanine
(food sources - chicken, fish, cheese, beans, etc)
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Tyrosine
Tyrosine supplements
• To support synthesis of T4 and T3
• Used in the body to produce noradrenalin and dopamine, anti-stress
• 500 – 1000 mg (3 x per day) 30 mins – 1hr before food
• Do not take if you have manic symptoms or high blood pressure
• Do not take alongside prescription thyroid medication
• Note: tyrosine supplements can cause digestive discomfort and migraines in some individuals
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Iodine
• Trace element
• Rich food sources include seaweed, fish, seafood and eggs
• Follicles in the thyroid gland absorb iodine
• Thyroglobulin (Tg) is a protein produced by the
thyroid gland which stores iodine
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Iodine
Thyroid dysfunction
• Hypothyroidism (underactive thyroid)
• Hyperthyroidism (overactive thyroid)
• Thyroiditis (inflammation of the thyroid gland)
• Thyroid cancer / nodules
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Hypothyroidism (underactive thyroid)
• Low production of T3 and T4
• High production of TSH
• Causes
– Thyroid abnormalities from birth
– Autoimmune (Hashimoto’s)
– Iodine deficiency
– Surgical removal of thyroid gland (cancer)
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Hypothyroidism (underactive thyroid)
• Symptoms
– Weight gain
– Feeling the cold
– Brittle hair
– Brittle nails
– Dry skin
– Swelling (goitre)
• Reduced metabolism, sluggish digestion (constipation) and reduced fertility
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Hyperthyroidism (overactive thyroid)
• Overproduction of T3 and T4
• Causes
– Autoimmune (Graves’ disease) – autoimmune disorder: antibodies attack thyroid gland and occasionally tissue behind eyes and over shins on legs. Possible genetic predisposition
– Plummer’s disease – benign lumps that produce too much T4
– Thyroiditis – inflammation of the thyroid gland: causes excess thyroid hormone stored to leak into bloodstream
• Overactive thyroid = enlarged = goitre (can be toxic)
• Thyroid grows due to lack of negative feedback
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Hyperthyroidism (overactive thyroid)
• Symptoms
– Enlarged swollen neck
– Elevated heart rate
– Increases cells’ sensitivity to adrenaline
– Anxiety
– Protruding eyes
– Weight loss
– Goitre, leading to other problems
– Intolerant of heat, excessive sweating
– Excess skin growth on lower legs (similar appearance to psoriasis)
• Increased metabolism, fast digestion (diarrhoea) and reduced fertility
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Thyroiditis
• Autoimmune inflammatory condition
• Fluctuating overactive / underactive thyroid leading to hormone and mood swings
• Hashimoto’s thyroiditis
• De Quervain's thyroiditis
• Postpartum thyroiditis
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Thyroid cancer / nodules
• Often no significant symptoms other than feeling lumps in neck
• With or without pain
• Refer to GP
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Medical treatment options
• Physical examination over the outside of the neck, feeling for abnormal growths and the size of the thyroid
• Blood tests (e.g. thyroglobulin)
• Neck ultrasound (to safely and sensitively measure abnormalities in thyroid gland)
• CT Scan
• MRI scan
• PET scan
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Diagnostic tests
• Measure basal temperature
• Test serum levels of TSH, total T4, T3, free T4, free T3
• Test T4 to T3 conversion, by testing for serum levels (for someone with possible selenium deficiency, very stressed)
• Test reverse T3 (metabolite of T4, inactive form)
• Test anti-TG (thyroglobulin) antibodies and anti-TPO antibodies
– To identify thyroid tissue damage due to autoimmune conditions, e.g. Graves’ disease, Hashimoto’s thyroiditis
• Test urine T3, T4 and T4/T3 ratio
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Diagnostic tests
• Test iodine
• Serum vs urine testing
– Blood tests most commonly used by GPs
– Urine tests are more sensitive, measuring levels over a 24 hour period
– Urine tests identify subclinical hypothyroidism
• References ranges
– GP ‘normal’ ranges not necessarily optimal
– Wide ranges, not necessarily normal for everyone
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Iodine
• Iodine
– Iodised salt
– Sourced from sea vegetables, fish
– Problems can occur with too little or too much
• Symptoms of deficiency
– Enlarged thyroid gland (swollen neck)
– Stunted growth
– Developmental delays including brain
• Some vegetables can block the absorption of iodine
– Containing goitrogens
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Micronutrients• Selenium
– Helps to regulate T4 to T3 conversion
– May reduce inflammation
• Zinc
– Deficiency associated with hypothyroidism
• Iron
– Consider malabsorption
– Required for T4 and T3 production
– Possible toxicity
• Copper
– Required for hypothalamus
– To be balanced with zinc
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Control inflammation
• Omega-3 EPA increases T4 production and improves sensitivity to thyroid hormones
• Anti-inflammatory diet including EPA
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Inflammatory diet
Omega-3 EPA
• Omega-3 EPA supplements may be beneficial for controlling inflammation
• 1000mg EPA without DHA most effective for inflammation
• Pure EPA derived from wild anchovies, sustainable source
• Pharmepa RESTORE: 90% EPA – 1000mg (added vitamin E)
• Pharmepa MAINTAIN: 80% EPA – 640 mg, GLA – 18mg (added vitamins B5, D3 & E)
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Directions for useAdults 1-2 (Pharmepa step 1: Restore) 2-4 (Pharmepa step 2: Maintain) capsules daily. Take with food for optimal absorption.
Antioxidants
• Antioxidants to reduce oxidative stress
• Reduce thyroid cell damage
• Selenium
• Vitamin E
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Foods to possibly avoid
• Aspartame and other artificial ingredients
– Chemical oestrogens
– May cause harm to thyroid gland
• Non-fermented soy
– Isoflavones in soy can mimic activity of oestrogen hormone = reduced thyroid activity
• Goitrogen-containing foods, inhibit uptake of iodine:
– Spinach, Brussels sprouts, broccoli, cabbage, cauliflower, strawberries, peaches
– Fully cook foods to reduce goitrogens
• Gluten
– Link between gluten intolerance and autoimmune diseases
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Lifestyle for thyroid health
• Moderate exercise is key
• Too much intense exercise can compromise
function of thyroid gland, making weight loss
very difficult
• Recovery and rest required
• Stress relief
• Adequate sleep supports recovery
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Summary – Nutrition protocol for thyroid health
1. Identify symptoms to consider thyroid abnormalities and thyroid activity
2. Refer to GP if client complains of swelling or lumps
3. Test for T4, T3, TSH and iodine
4. Consider protein consumption for intake of tyrosine, and intake of Iodine
5. Balance inflammation
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Summary – Nutrition protocol for thyroid health
6. Include plenty of nutrient-dense foods, providing selenium especially
7. Cut out offending foods such as gluten and aspartame
8. Offer lifestyle advice concentrating on thyroid health, not just weight loss / gain
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References(1) Taraghijou P, Safaeiyan A, Mobasseri M, Ostadrahimi A. The effect of n-3 long chain fatty acids supplementation on plasmaperoxisome proliferator activated receptor gamma and thyroid hormones in obesity. J Res Med Sci 2012 Oct;17(10):942-6.
(2) Venditti P, Di SL, Di MS. Vitamin E management of oxidative damage-linked dysfunctions of hyperthyroid tissues. Cell MolLife Sci 2013 Sep;70(17):3125-44.
(3) Sathyapalan T, Manuchehri AM, Thatcher NJ, Rigby AS, Chapman T, Kilpatrick ES, et al. The effect of soy phytoestrogensupplementation on thyroid status and cardiovascular risk markers in patients with subclinical hypothyroidism: a randomized,double-blind, crossover study. J Clin Endocrinol Metab 2011 May;96(5):1442-9.
(4) Stazi AV, Trinti B. Selenium status and over-expression of interleukin-15 in celiac disease and autoimmune thyroid diseases.Ann Ist Super Sanita 2010;46(4):389-99.
(5) Kuriyama C, Mori K, Nakagawa Y, Hoshikawa S, Ozaki H, Ito S, et al. Erythrocyte zinc concentration as an indicator todistinguish painless thyroiditis-associated transient hypothyroidism from permanent hypothyroidism. Endocr J 2011;58(1):59-63.
(6) Triggiani V, Tafaro E, Giagulli VA, Sabba C, Resta F, Licchelli B, et al. Role of iodine, selenium and other micronutrients inthyroid function and disorders. Endocr Metab Immune Disord Drug Targets 2009 Sep;9(3):277-94.
(7) Naiyer AJ, Shah J, Hernandez L, Kim SY, Ciaccio EJ, Cheng J, et al. Tissue transglutaminase antibodies in individuals withceliac disease bind to thyroid follicles and extracellular matrix and may contribute to thyroid dysfunction. Thyroid 2008
Nov;18(11):1171-8.
(8) Wall R, Ross RP, Fitzgerald GF & Stanton C (2010) Fatty acids from fish: the anti-inflammatory potential of long-chainomega-3 fatty acids. Nutrition Reviews. 68:280-9.
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www.igennus.com0845 1300 424
Kyla Williams DipION, BSc, MScNutrition Technical Advisor