thyroid hormones Archives - Athletes Sanctuary

Iron deficiency is one of the most common issues athletes face. Iron and thyroid health go hand in hand and the effects of exercise on the thyroid gland and hormones are not well understood.

Iron and thyroid function
Undiagnosed iron deficiency presents an increased risk of impaired thyroid function. Active women have high-energy lives, managing work, family and training, and many will accept low energy and brain fog as simply a result of being overworked or as an inevitable part of hormonal changes.

However, low thyroid function, iron deficiency, overtraining and hormonal changes also present with many of the same symptoms.

Signs that your thyroid function may be underactive (hypothyroid) include fatigue, unexplained weight gain, headaches, low blood pressure, dry skin, constipation and cold intolerance. These early signs of cellular hypothyroidism can appear when blood pathology remains within standard ranges.

As with most chronic issues, there are multiple factors that may contribute to dysfunction.

The Link between Exercise and Thyroid Function

In athletes, endurance and high-volume training promotes thyroid function. During exercise, your hypothalamus stimulates the pituitary gland to secrete thyroid-stimulating hormone (TSH), which in turn signals your thyroid to synthesise and release the thyroid storage hormone T4 and active thyroid hormone T3.

These hormones influence your body’s metabolism and allow it to increase exercise intensity. Over time, this repeated, high demand of your thyroid during prolonged intense exercise may impact your thyroid function, causing it to slow down and consequently lose the ability to produce sufficient hormones.

Iron and Thyroid Function

Normal thyroid function is dependent on several nutrients to regulate the synthesis of thyroid hormones. Iodine, iron, tyrosine, selenium, and zinc are needed to facilitate the conversion of T4 to T3 . A deficiency of any one of these nutrients would result in reduced T3 production, causing you to experience hypothyroid symptoms. Vitamins A and D also play important roles in cell receptor behaviour to regulate thyroid hormone metabolism.

While iodine is the key mineral for healthy thyroid function (read more…here) it is not uncommon to find iron deficiency in hypothyroidism. Although widely recognised for its influence on red blood cell production, iron is also an important component of thyroid peroxidase, an enzyme essential for thyroid hormone biosynthesis.

Iron deficiency interferes with the normal functioning of the thyroid, contributing significantly to fatigue, exercise intolerance and lightheadedness.

Increased menstrual bleeding can lead to iron deficiency. Many of us dismiss low energy as a symptom of a busy, active lifestyle and so iron deficiency frequently goes undiagnosed in perimenopausal women. For athletes, iron plays a critical role in exercise performance as outlined in our blog “Increase your iron absorption and rebound from anaemia” here

The most common causes of iron deficiency include inadequate dietary iron intake, inflammation, poor iron absorption in the gut, parasites, iron loss through sweat, urination and faeces, blood loss through menstruation. Pregnancy, breastfeeding or high-volume exercise will also significantly increase iron demands. Take our free anaemia quiz to see if you may be iron deficient here

Thyroid Function and Sex Hormones in Women

Your thyroid function is sensitive to fluctuations in sex hormone levels, particularly oestrogen. Oestrogen stimulates the production of the thyroid hormone precursor, thyroglobulin, and increases the protein that carries thyroid hormones in your blood.

As oestrogen changes (such as during peri-menopause) so too does thyroid hormones, which play an important role in metabolism, muscle strength, energy production and expenditure, heart function, and temperature regulation.

As oestrogen levels rise and fall later in life, menstruation may become irregular and heavier. Peri-menopausal women may experience symptoms for over ten years as described in our blog on “Natural solutions for menopause” here .

During peri-menopause declining oestrogen may impact thyroid function and can lead to inadequate production and circulation of thyroid hormones.

Exercise During Hormonal Changes

Despite common misconceptions, women can train and perform well throughout peri-menopause, and beyond, if they listen to their bodies and be mindful of maintaining adequate dietary intake of key nutrients. It is important to recognise that both iron deficiency, thyroid function and hormonal changes can impact your ability to exercise.

Years of consistent exercise accumulate like pages in a book. As a mature you know your body very well. The pathway to success utilises your book of wisdom and skills. Mature athletes can benefit from greater recovery, individualized strength and conditioning and modified programs. Focussing on the balance between training intensity and volume will help you to achieve your desired goals.

If you suspect your symptoms are impacting on your quality of life and sport, it’s time to seek support to help you navigate the journey.

Blood serum pathology and functional tissue mineral testing can be a good starting point due to the critical role nutrients play in hormonal and thyroid function.

With the right self-care and a holistic approach to health, you can continue to achieve your life goals and physical challenges irrespective of hormonal changes.

About the Author: Kate Smyth is a Sports naturopath, nutritionist and female-centric running coach. She is the founder of the Athlete Sanctuary- a holistic healthcare clinic for athletes of all levels and sporting codes. Kate has a thirst for knowledge with two bachelor’s and a master’s degree under her belt. She has been involved in sports for many decades and competed for Australia in the Commonwealth Games and Olympic Games marathons with a personal best time of 2 hours 28 minutes. For more information visit www.https://https://athletesanctuary.com.au/wp-content/uploads/2023/03/normatec-3-lower-body-system-thumb_720x-1.webp.com.au/wp-content/uploads/2020/05/Seed-Cycle-Blends-scaled-1.jpg.com.au

References

Kawicka, A., & Regulska-Ilow, B. (2015). Metabolic disorders and nutritional status in autoimmune thyroid diseases. Postepy Higieny i Medycyny Doswiadczalnej, 69, 80–90.
Luksch, J. R., & Collins, P. B. (2018). Thyroid Disorders in Athletes. Current Sports Medicine Reports, 17(2), 59–64.
Santin, A. P., & Furlanetto, T. W. (2011). Role of estrogen in thyroid function and growth regulation. Journal of Thyroid Research, 2011.
Soliman, A. T., De Sanctis, V., Yassin, M., Wagdy, M., & Soliman, N. (2017). Chronic anemia and thyroid function. Acta Biomedica, 88(1), 119–127.
Wouthuyzen-Bakker, M., & Van Assen, S. (2015). Exercise-induced anaemia: A forgotten cause of iron deficiency anaemia in young adults. British Journal of General Practice, 65(634), 268–269.

In this article, we discuss how to obtain accurate pathology tests. Whilst this article is not meant to serve as a diagnostic tool, it may help you understand why pathology tests are useful and how to get the most reliable test results.

Longer-term patterns of pathology results can provide a holistic picture of your overall health and the progression of underlying issues. We monitor key nutrients that provide warning signs of underlying imbalances that, if left unchecked, can contribute to ill health and disease. One abnormal blood marker in pathology tests doesn’t always mean there is an issue. Pathology tests should always be considered in conjunction with your symptoms and physical appearance and discussed with your practitioner so that the context and relevance of your results can be determined.

WHAT PATHOLOGY TESTS ARE MOST USEFUL?

Your GP or naturopath can arrange pathology testing for you. Your healthcare practitioner will determine the exact pathology tests you require. The following tests may be useful for active individuals as a good starting point.

*Full blood count and haematology—these examine your white and red blood cells and provide a general picture of your immune system and overall health.

*Liver function tests (LFTs) provide some clues as to how your liver is working and whether it is under stress.

*Electrolytes– potassium, sodium, chloride and other key electrolytes required for sports performance and optimal health.

*Fasting blood glucose- is a general marker that indicates how well your body is modulating your blood sugar. Issues with blood sugar stabilisation may cause symptoms such as sugar cravings, frequent urination, fatigue, and energy drops after meals.

*Insulin helps us understand how hard your pancreas is working to maintain normal blood sugar levels. This marker is useful if you have a family history of diabetes or have been prediabetic or ” insulin resistant” in the past. Insulin resistance is more common as we age. In women, it is more common over the age of 40 and in perimenopause and postmenopause.

*C- reactive protein (CRP) is an inflammatory marker. CRP is useful when interpreted in conjunction with iron studies. Iron storage may be impacted by states of high inflammation.

*Iron studies- provide information on your iron storage (ferritin), the protein carriers for iron (transferrin), and how effectively your body is saturating these carriers and transporting iron around your body (transferrin saturation).

*Thyroid hormones- TSH, T3 and T4 provide information on how your thyroid is functioning and can be an early warning sign of autoimmunity and nutrient deficiencies such as iodine, selenium, tyrosine and zinc.

*Vitamin B12 (active and inactive) is also suggested for plant-based patients or athletes who infrequently consume red meat.

* Nutrients—If you experience mental health issues (especially seasonal sadness/ low mood), autoimmunity, frequent colds or infections, bone health issues, hormonal issues, or are peri or postmenopausal, nutrients such as vitamin D, copper, and serum zinc may also be useful markers.

Tests may be repeated every few months to ensure a patient is responding to treatment and maintaining a balanced state of health.

How to get the most accurate pathology tests

Prepare for your blood tests.

Fast for 12 hours (have dinner and then postpone breakfast until after your blood draw).
Sip water the morning of your blood test so you are not dehydrated when you have your test. Dehydration can make your veins more difficult to locate.
Take a snack to have immediately after your blood draw.

AVOID

Strenuous exercise for a minimum of 24 hours. Ideally, at least 48 hours if possible. This includes running, cycling, or strength training. Most patients find it easiest to do a blood test the morning after a rest day. A walk or gentle exercise is ok before a blood draw.
If you plan to check your iron levels, avoid a blood test when you are unwell or have an infection. An infection may influence your test results. Wait until you are feeling better before having your iron test.
Stop supplements, including iron or other vitamin tablets or powders, for 24-48 hours before your blood tests.

We use a number of pathology collection centres across Australia including Clinical Laboratories, Dorevitch, and Nutripath to obtain accurate pathology results. We may also recommend functional testing such as detailed heavy metal and mineral testing and comprehensive microbiome tests during our clinical assessments.

About the Author: Kate Smyth is a Sports naturopath, nutritionist and female-centric running coach. She founded the Athlete Sanctuary– a holistic healthcare clinic for athletes of all levels and sporting codes. Kate has a thirst for knowledge, and she has two bachelor’s degrees and a master’s degree under her belt. She has been involved in sports for many decades and competed for Australia in the Commonwealth Games and Olympic Games marathons with a personal best time of 2 hours 28 minutes.

The amino acid leucine is of particular importance to female athletes keen to optimise recovery across the menstrual cycle. Leucine is one of the nine essential amino acids the body needs to obtain through the diet. Leucine along with other amino acids, are required for protein synthesis, tissue repair and nutrient absorption.

The demand for protein changes throughout the menstrual cycle. The fluctuations in estrogen and progesterone have a profound effect on muscle turnover and protein synthesis. Amino acids like leucine are harder to access during the high hormonal phase (day 12 to day 23 of a typical 28 day cycle). It is suggested to be harder for females to build and maintain muscle during this hormonal phase making it even more important to ensure adequate intake of essential amino acids during this time.

Strength training including weights or resistance stimulates muscles to take up leucine (and other amino acids) and triggers muscular growth. Leucine can help prevent the deterioration of muscle with age so it is super important for masters athletes to obtain adequate leucine in order to optimise recovery.

The richest sources of bio-available protein including leucine are in eggs, milk, fish, and meats. Milk contains both whey and casein protein. Whey is more easily absorbed and is higher in leucine than casein. Whey is also digested at a much faster rate than casein, ensuring blood leucine levels rise soon after ingestion and triggering protein synthesis responsible for building muscle. Hence why many athletes swear by chocolate milk as their preferred recovery drink. Female athletes need additional leucine to optimise recovery and would benefit from options such as a post-workout smoothie including yogurt, milk, protein powder or almond butter.

Recent research also suggests that the combination of other highly bio-available proteins rich in leucine results in more favourable muscle hypertrophy compared to other proteins such as whole milk protein, casein and soy protein.

Vegans and athletes with dairy intolerance

Athletes who choose to avoid dairy need not feel they are missing out. Interestingly, a recent study found both whey and rice protein isolate administration post-resistance exercise improved body composition and exercise performance with no differences between the two groups when taken in adequate amounts.

Leucine-rich foods

Leucine can also be found in plant-based proteins included including soy, lentils, kidney beans, tofu, quinoa, hummus, rice, and almonds. These plant proteins contain approximately 50% less leucine. Therefore vegan athletes need to pay attention to getting enough high-quality plant proteins that offer the optimal amount of leucine (about 2.5 grams per meal or snack).

Vegans want to consistently enjoy soy, beans, legumes, seeds and/or nuts regularly at every meal and snack. Don’t have just porridge for breakfast; add organic soy milk and walnuts. Don’t snack on just an apple; slather apple slices with peanut butter. A blend of rice and pea protein powders makes a good substitute for whey-based protein powders. Some plant-based protein powders also provide added amino acids, making them a good choice for dairy-intolerant or plant-based athletes.

As a general guide 2 grams of leucine can be found in 120 grams beef, 130 grams almonds, 400 grams tofu, 3 eggs, 600ml cow’s milk or 900ml soy milk, 380 grams lentils, 350 grams kidney beans, 70 grams cheddar cheese, 350 grams yogurt, 27 grams whey protein isolate, 50 grams rice protein powder.

Elite athletes with large volumes of training may struggle to obtain adequate leucine from their diet alone, especially if vegan. These athletes may consider using protein and collagen powders including leucine, isoleucine and valine 30 minutes pre and post-workouts in addition to a diet rich in leucine to optimise recovery.

This table compares the leucine content of plant and animal foods.

Animal food	Plant food (swap)	Leucine (g) approx
Eggs, 1 large	Peanut butter, 2 tablespoons	0.5
Milk, ½ cup	Soy milk, low fat, 1 cup	0.5
Tuna, 25 grams	Black beans, 1/2 cup	0.7
Chicken, 60 grams cooked	Tofu, extra firm, 170 grams	1.4
Cheese, 14 grams	Almonds, 21 grams	0.3
Beef, 40 grams	Lentils, 1 cup	1.3

We recommend including a variety of leucine rich foods in your diet in order to optimise recovery.

Most women’s daily protein intake should account for 30% of their diet to optimise recovery. A gram of protein per kilogram of body weight is adequate for recreational athletes, while elite athletes may require up to 1.8 grams per kilogram of body weight, especially when competing in power and high-end endurance sports. On lighter recovery days protein intake can be reduced slightly keeping in mind other processes in the body require adequate protein intake (hormones and immune cells for example).

Consuming 20-25 grams of protein within 30 minutes of finishing a session is ideal for optimal recovery while having a protein-rich snack such as a high protein, low-fat yogurts such as YoPro or Chibani Fit at bedtime can boost protein synthesis by 22 %.

When you wake in the morning you are in a catabolic state after fasting for 10-12 hours during the night while sleeping. Having a protein-rich breakfast is really important to optimise recovery, restock your glycogen stores, fuel your daily activities and prevent overeating and sugar cravings later in the day. Great breakfast options to optimise recovery include scrambled eggs on toast or an omelette with sweet potato and veggies, a protein-rich smoothie, porridge with added yogurt or protein powder or scrambled tofu.

Iodine and thyroid hormones are essential to sports performance and yet many athletes are iodine deficient.

Thyroid hormones perform many key functions in the human body including regulation of body temperature, metabolism and play an important role in how an athlete creates and uses energy. Thyroid hormones bind to receptors on each cell’s membrane surface and inside the cell at the mitochondria where energy is made. Binding activates the cell’s energy and metabolic functions.

Iodine is a key trace mineral stored primarily in the thyroid gland. The thyroid gland produces the key thyroid hormones thyroxine (T4) and triiodothyronine (T3), using iodine and other key nutrients such as selenium and tyrosine. To further convert thyroid hormones into activated forms the body can use, sufficient levels of magnesium, iron, selenium, vitamin C and zinc are also required.

Key hallmarks of iodine deficiency and low thyroid function in athletes include:

Fatigue and low stamina can really cause havoc to an athlete’s training and racing season
Lethargy, muscle aches, cramps, pains and weakness
Low basal body temperature (temperature first thing in the morning)
Intolerance to cold weather
Cold hands and feet
Slow brain function, poor memory and “foggy” brain
Constipation
Joint pain
Thin, brittle hair or hair loss
Dry flaky skin
Menstrual disorders and fertility problems
Weight gain and slower metabolic rate

Iodine is primarily lost through sweat, although some are also excreted in the urine. Some studies suggest athletes may lose more iodine through sweat in an hour of vigorous exercise than through their entire daily urine output. High levels of sweating during exercise can deplete iodine levels and result in dehydration and poor performance.

The recommended iodine intake is 150ug/ day but some studies show on average athletes may lose nearly 50% of this requirement in sweat alone. Athletes living in more humid conditions (even without exercise) can lose a greater amount of sweat than those living in cooler environments.

Athletes performing at high intensity for prolonged periods of time, particularly in a humid environment, have a significantly increased risk of becoming iodine deficient if they don’t pay special attention to replacing this important nutrient.

What else can impact iodine and thyroid function?

It is important to keep in mind there are lots of things that impact the thyroid gland.

Chronic physical or emotional stress and high cortisol will result in elevations of another thyroid hormone called reverse T3 (rT3). Pesky rT3 inhibits our active thyroid hormone T3.

Heavy metals and chemicals, a low carbohydrate diet and fasting and selenium deficiency can also reduce T3 levels. There are many chemicals and metals in our environment known as “endocrine disruptors” that inhibit healthy thyroid function. Polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) are common in our environment containments (in soil and food grown in that soil including meat, electronics, electrical cables, paints, plastics, furniture ) which can disrupt thyroid hormone signalling at the receptor level.

Perchlorate found in food and water inhibits the thyroid’s ability to absorb iodine from the bloodstream while long-term consumption of fluoridated drinking water is associated with hypothyroidism (low thyroid function).

Dioxins, BPA (found in cling wrap, drinking bottles and plastics) or bisphenols in tinned foods and plastic containers and plastic wraps, are also endocrine disruptors.

Non-stick cookware, fragrances, detergents, cosmetics and skincare, foods exposed to pesticides and herbicides, flame retardant material, new carpets, furniture and clothing may also be sources of endocrine disruptors.

When a female athlete has excess oestrogen, it may reduce the efficiency of thyroid hormone by 25%. Female athletes with high testosterone levels or insulin resistance may also have reduced thyroid efficiency due to a reduction in the globulin that carries thyroid hormone around the body (thyroid binding globulin) which means not enough thyroid hormone can circulate. But the hormone dance doesn’t stop there.

Low thyroid function due to low iodine or other nutrients can also cause receptor sensitivity issues with other female hormones such as progesterone causing PMS symptoms, irregular periods and fertility issues.

Cortisol up-regulates estrogen and high oestrogen also up-regulates cortisol which increases the binding of T4 up to 3 times, resulting in lower thyroid hormone activity, lowered metabolism and weight gain.

As thyroid hormones influence the tight junctions in the stomach and small intestine, athletes with low iodine and thyroid can also suffer from digestive complaints such as gas, bloating, diarrhoea or constipation and digestive infections.

Approximately 20% of our thyroid hormone T4 is converted to T3 in the gut by bacteria. So if digestion is disrupted and inflammation exists, the conversion will be impacted. Thyroid hormones also influence the tight junctions in the stomach and intestine that prevent large undigested molecules from passing into our bloodstream. Hence why thyroid abnormalities are also associated with leaky gut, food intolerances, constipation, reflux, heartburn, and dysbiosis (gut microbiome imbalance).

Thyroid hormones also influence the foundation of our immune system in the stomach called Gut Associated Lymphoid Tissue (GALT). GALT is made up of several types of lymphoid tissue that store immune cells, such as T and B lymphocytes. The majority of infectious agents invading the human body gain access through the gut and GALT protects us against these pathogens. Therefore, an athlete can be more susceptible to infections if thyroid hormones are low or iodine deficiency exists. n

Other nutrients have an impact on iodine and thyroid function. Many athletes suffer from anaemia or low iron and believe their fatigue and poor performance may just be iron related. The situation is a double-edged sword as iron deficiency impairs thyroid hormone synthesis and low thyroid function impairs gastric secretions which reduce iron absorption from food.

Another tricky synergy exists between zinc, copper and thyroid function. Zinc is required for T4 and T3 production and therefore zinc deficiency may lead to low gastric secretions and low iron. Zinc and copper also antagonise each other so low zinc may lead to high copper. Excess copper slows thyroid function and depletes zinc.

Iodine concentration in foods is variable depending on soil concentrations and the amount of fertilizer used with farming methods. Therefore, our food iodine content also varies greatly in grains, meats and vegetables. Although the daily recommended iodine intake is 150ug, it can still be tricky even when eating iodine food sources due to such variability.

Metabolic acidosis is a condition when the body’s pH is too acidic (pH of 7.35 or lower). This may occur in athletes from prolonged exercise at high intensity leading to lactic acid build-up. Chronic metabolic acidosis may decrease T4 and T3 and increase TSH concentrations and may lead to subclinical hypothyroid states.

Tracking athletes’ basal (morning) body temperature can assist with identifying issues with thyroid function. Anything less than 36.4c suggests your thyroid may need some attention.
Athletes should not rely on blood tests to confirm thyroid function status. Under activity of the thyroid gland results in low basal temperatures and symptoms of low thyroid function are not detectable by the standard laboratory tests-thyroid stimulating hormone (TSH), T4 and T3.
Athletes should consume sufficient sources of iodine on a regular basis. Good food sources include seafood (wild sea fish contain more iodine than freshwater fish), kelp and other seaweeds (wakame, Kombu, Nori), kelp noodles, Sushi are a rich source of iodine. Other reasonable sources include milk and yogurt, navy beans, eggs, cranberries, strawberries and some meats.
Since 2009 all packaged bread has added iodine in Australia although freshly baked bread may not disclose the amount added. Iodized salt is also available but keep in mind too much salt is not great for blood pressure and even sea salt and Himalayan salt contains 90% sodium chloride which is not desirable as chloride inhibits iodine absorption.
Be mindful of high intake of goitrogenic vegetables. The cabbage family including cabbage, kale, broccoli, cauliflower, Brussels sprouts, radishes, turnips, watercress, spinach contain isothiocyanates (goitrogens) which may block the uptake and utilisation of iodine in the thyroid gland. Cooking these vegetables reduces the goitrogens and the likelihood of their impact.
Although controversial, some evidence suggests soy supplements such as soy protein powders should be avoided if you have been diagnosed with low thyroid function as they may also reduce the genetic expression of the enzymes needed to produce thyroid hormones.
Get your vitamin D levels checked. Vitamin D deficiency is common in Australia and in athletes with low body fat this issue can be even more prevalent as Vitamin D is stored in fat cells. Vitamin D is associated with hypothyroidism and thyroid autoimmune conditions while studies show serum vitamin D > 125 is associated with a 30% reduced risk of hypothyroidism.
Get your hormones, cortisol, iron, zinc, copper and iodine levels checked.
Improve your gastric acid secretions by consuming bitter foods (endive, rocket, radicchio, chicory, dark chocolate) on a regular basis or sip lemon in water or apple cider vinegar before meals.
Reduce your exposure to endocrine disruptors by drinking filtered water, installing filters on shower heads, choosing natural water sources to swim in rather than chlorinated pools, eating pesticide-free or ideally organic foods, choosing organic personal care products, cosmetics and detergents, avoiding storage of food in plastics and instead use wax wraps and choose low emitting products when renovating or building your home.

If you suspect you may be suffering from iodine deficiency or reduced thyroid function, consider making an appointment with the Athlete Sanctuary to help navigate your recovery process.

thyroid hormones

JOIN US

INSTAGRAM

athletesanctuary

facebook

CONTACT

CLINIC ADDRESS

QUICK LINKS