You optimise your training load. You track your recovery. You invest in your nutrition. So when the research points to antioxidants reducing oxidative stress from exercise, supplementing seems like a logical performance lever to pull.

But what if that investment was quietly working against your returns?

This is one of sport nutrition's most counterintuitive findings: in certain situations, high-dose antioxidant supplements can interfere with the very physiological adaptations your training is designed to produce. For athletes focused on long-term gains, understanding this trade-off isn't optional but rather strategic.

The Signal You Don't Want to Silence

Exercise generates reactive oxygen species (ROS). In excessive amounts, ROS cause cellular damage. But at the levels produced during regular training, ROS function as critical signalling molecules. Thes are the biological triggers that tell your body to adapt and grow stronger.

This is hormesis in action: a controlled stressor driving a beneficial response. Specifically, ROS signals initiate mitochondrial biogenesis, boost your body's own antioxidant enzyme production, improve insulin sensitivity, and drive muscle remodelling. These are the fundamental physiological upgrades that separate a trained athlete from an untrained one.

Flood your system with high-dose antioxidant supplements, and you risk silencing those signals and potentially blunting the return on every training session.

Chronic supplementation with approximately 1,000 mg/day of vitamin C and/or 200–400 IU/day of vitamin E has been shown to reduce activation of key pathways involved in mitochondrial development and endogenous antioxidant defences.^[1][2] A 2026 review published in Antioxidants framed this as a redox balance problem: the goal isn't zero oxidative stress, it's the right amount.^[2]

This concern applies specifically to chronic, high-dose supplementation. Context matters: illness, extreme training loads, and specific recovery protocols are different conversations.

The scale of this issue is significant as vitamin C is taken by nearly 60% of athletes^[3] many of whom may be unknowingly compromising their adaptation response.

The Smarter Play: Food First

Dietary antioxidants sidestep this problem. Consumed through whole foods, antioxidants arrive in lower doses alongside other nutrients and phytochemicals that modulate their absorption making interference with training adaptation far less likely.^[2]

Vitamin C from whole foods also plays a critical structural role beyond antioxidant activity — it is essential for collagen synthesis and tendon repair, and enhances iron absorption both critical for athlete health and energy production.

Beyond vitamin C and E, other whole-food antioxidant sources offer targeted recovery benefits: blueberries have demonstrated reductions in exercise-induced muscle soreness and inflammation, while tart cherries support both recovery and sleep quality without the risk of blunting adaptation.

Top 10 Vitamin C–Rich Foods

Per 100g — FSANZ Australian Food Composition Database (AFCD)^[5]

Vitamin E–Rich Foods

Per 100g — FSANZ Australian Food Composition Database (AFCD)^[5]

 The Bottom Line

Stand firm and demand a return on every investment including nutritional ones. Antioxidant-rich whole foods deliver recovery support, structural benefits, and immune resilience without compromising adaptation. Routine high-dose vitamin C or E supplements may do the opposite.

Build your antioxidant strategy around food first. Reserve supplementation for specific, evidence-based applications and let your training deliver the results it was designed to produce.

The Magnesium-Bone Connection

Research suggests 20% of individuals constantly consume lower quantities of magnesium than recommended.  So why is magnesium so essential for athletes? The answer lies in the intricate relationship between magnesium and various bone-related processes:

• Mineralisation: Magnesium is a cofactor for the enzymes responsible for bone mineralisation. It helps convert vitamin D into its active form, which is crucial for calcium absorption, the primary mineral in bones. Lower levels of magnesium are related to osteoporosis in menopausal women. One study suggested 30–40% of women are deficient in magnesium.
• Bone Density: Athletes often put their bones under repetitive stress. Magnesium plays a vital role in maintaining healthy bone density and structural integrity. Low levels can decrease bone density, making athletes more susceptible to fractures.
• Bone Turnover: Magnesium helps regulate the balance between bone formation and bone resorption. This is crucial for athletes as it ensures their bones adapt to training demands without becoming brittle or porous.

For Athletes

Apart from its direct impact on bone health, magnesium offers several other benefits for athletes:

• Muscle Function: Adequate levels are essential for proper muscle function. It helps muscles contract and relax, preventing cramps and promoting efficient performance.
• Energy Metabolism: Magnesium is a co-factor for enzymes involved in ATP (adenosine triphosphate) production, the primary energy source for athletes during exercise.
• Immune Support: Intense physical activity can temporarily weaken the immune system. Magnesium aids immune function, helping athletes recover from workouts and training stress.
• Recovery and tightness: Magnesium helps with restless legs, tight muscles, headaches and insomnia.
• Hormonal Balance: Magnesium helps reduce fluid retention, menstrual cramps, anxiety, mood swings and cravings related to the menstrual cycle.

Meeting Your Needs

As an athlete, meeting your nutrition requirements to ensure optimal bone health and overall performance is crucial. Here are some dietary sources of magnesium to consider:

• Nuts and Seeds: Almonds, peanuts, cashews and pumpkin seeds are excellent.
• Dark Leafy Greens: Spinach and kale are rich sources to add to your diet.
• Whole Grains: Choose whole-grain options like brown rice and sourdough bread.
• Legumes: Beans and lentils are magnesium-packed additions to your diet.
• Cocoa and brewer’s yeast also contain magnesium.

Supplements can be considered in cases where dietary intake may fall short, but it's always advisable to consult with a healthcare professional or sports nutritionist before taking any supplements.

Magnesium is an essential yet often overlooked mineral for bone health in athletes. From mineralisation to bone density and regulating bone turnover, magnesium is pivotal in maintaining strong, resilient bones, making it a crucial element in an athlete's nutrition regimen. So, next time you plan your meal, don't forget to include magnesium-rich foods to keep your bones strong and support your overall athletic performance.

Contact the Athlete Sanctuary and learn how we can help you increase your bone health, well-being, and performance.

Mushrooms are a great inclusion in your diet as they have many health and nutritional benefits. Mushrooms contain several B vitamins, including niacin, folate, biotin, pantothenic acid and riboflavin. Mushrooms also provide antioxidants and essential minerals (selenium, copper and phosphorous), are easy to cook, and are low in fat, sodium, and kilojoules. When exposed to light they also contain vitamin D, which is important for bone health, hormones, and immunity.

Here we are exploring mycotherapy - the use of mushroom compounds for health. Medicinal mushrooms are included in many health and sports products.

Here we explore five medicinal mushrooms and their potential health benefits for athletes:

Cordyceps (Cordyceps sinensis): Energy and stamina

Cordyceps have been shown to enhance cellular oxygenation to improve lung capacity and endurance and reduce fatigue during exercise.  You will find this medicinal mushroom in several sports products as it contains cordycepin, a compound that increases energy through ATP (adenosine triphosphate) production. For the same reason, it may also help relieve chronic fatigue.

A 2022 study demonstrated that supplementation with 2 grams of cordyceps per day improves the aerobic performance of amateur marathoners over 12 weeks. We are hopeful that further research will also show this benefit for well-trained and elite athletes.

Cordyceps is antiviral, immune-modulatory, antioxidant, and effective in reducing cholesterol and blood pressure.

Tip: Add cordyceps to a customised herbal elixir for an all-around boost of energy.

Reishi (Ganoderma lucidum): Stress buster  

Reishi is referred to as the "King of Medicinal Mushrooms" because of its ability to support multiple systems in the body. Reishi is soothing for the nervous system and helps the body adapt to stress. It lowers the stress hormone cortisol and helps to stabilise insulin. This makes Reishi useful for low mood, sleep issues, anxiety, and recovery from physical and mental stress. With over 400 active compounds its benefits are extensive. Reishi strengthens the immune system by boosting white blood cells and the natural killer cells in your body. It is also useful for liver function, and libido in both sexes.

Tip: Add powdered reishi to your post-workout smoothie or snacks to help with recovery and sleep. We also encourage athletes and performers to focus on Reishi as part of their pre-race preparation to avoid illness impacting their performance.

Lion's Mane (Hericium erinaceus): Brain function

Lion's Mane enhances cognitive function and memory, which can be beneficial for athletes' mental sharpness and focus. Study’s show Lion’s Mane’s active compounds hericenone and erinacine, reduce memory loss and are therefore of interest for use in patients with dementia and Alzheimer’s.

This fluffy white mushroom even looks like the nerves it helps to regenerate in the gut-brain axis. By doing so it helps regulate the nervous system and heal the gut making it useful for leaky gut and IBS.

Tip: Include Lion’s main powder or liquid tonic for mental clarity and digestive issues.

Chaga (Inonotus obliquus): Injuries and inflammation

Chaga has strong anti-inflammatory properties, which can help reduce exercise-induced inflammation and muscle soreness. It's rich in antioxidants, which can aid in overall health and recovery.

Tip: Chaga powder tastes nutty and can be a great additive to coffee or broth.

Shiitake (Lentinula edodes): Immunity

Shiitake mushrooms are known for their immune-boosting properties. For athletes, a robust immune system is crucial for staying healthy and avoiding training interruptions due to illness.  If you struggle with ongoing infections, explore suggestions on building a robust immune system.  Shiitake is also used to enhance lung function, gut health and as an antioxidant.

Tip: Alongside reishi, we encourage athletes to use a medicinal mushroom blend with high quality shiitake as part of pre- and post-event preparation and for ongoing colds and infections.  Shiitake mushrooms can be found in most supermarkets and are great in stir-fried vegetable dishes and stews.

Summary

It's important to note that while these medicinal mushrooms offer potential health benefits for athletes, individual responses may vary. Athletes should consult with their naturopath before incorporating these mushrooms into their diet or supplement regimen, especially if they have underlying health conditions, allergies, or are taking medications. Additionally, athletes should use these mushrooms as part of a well-balanced diet and training program to maximise their benefits.

Want to know more? Contact the Athlete Sanctuary and learn how we can help you to increase health, wellbeing and performance.

Naturopathic practitioners (Naturopaths) aim to maintain optimal health through a balanced and yet comprehensive approach. Naturopathy complements other conventional medical and allied health practices.

Potential benefits of sports naturopathy for athletes include:

Holistic Approach: Sports naturopathy takes a holistic approach to health, considering the physical, mental, and emotional aspects of an individual. A naturopath is trained in nutritional medicine, biochemistry, herbal medicine, pharmacology, and pathology. A scientific medicine and a complex holistic approach can be particularly beneficial for athletes as it addresses the whole person, rather than just isolated symptoms.

Individualised Treatment: Naturopaths create personalised treatment plans for athletes based on their specific nutritional needs, sporting goals, and health conditions. This facilitates targeted and effective interventions.

Nutrition and Dietary Guidance: Proper nutrition can enhance energy levels, prevent illness and nutrient deficiency, and enhance overall sports performance. A food first approach focusses on using food as medicine. A naturopath will also provide balanced and nutritious guidelines to meet an athlete's nutritional requirements.

Natural Solutions:  Heavily researched and synergistic natural solutions such as vitamins, minerals, and herbal medicines are used to support an athlete's health and performance. These supplements are chosen based on scientific evidence and matched to the individual's needs. We draw on the vast number of published research papers on global medical databases and carefully assess the integrity, quality, and validity of papers and underlying research projects.

Stress Management: Athletes can experience high levels of physical and emotional stress as part of living a very full life. Adaptogens are a category of natural medicines that modify stress hormones such as cortisol and support calming neurotransmitters like GABA. Adapatogens better equip the athlete to consistently perform well under pressure by adjusting the nervous system’s response to stress.

Injury Prevention and Repair: Naturopathic treatments promote healing of bone fractures, muscle, tendon and ligament damage, and underlying inflammation. Naturopathic anti-inflammatory medications and nutrition have been shown to have similar effects as non-steroid anti-inflammatory medications with limited side effects.

Detoxification: Where appropriate gentle detoxification approaches can help athletes maintain optimal organ function and overall health.

Pain Management: Sports naturopathy offers various natural solutions that ease pain as part of injury management, neurological issues, painful periods and headaches. These approaches may help athletes manage pain without relying solely on pharmaceutical medications.

Enhance Recovery: Poor recovery can be a sign of underlying health imbalances. Minerals and herbal medicines promote muscle relaxation and reduce inflammation. Sports naturopathy complements other recovery techniques such as water running, anti gravity, Normatec recovery systems, cold water and sauna therapy. A naturopath may also refer to massage, kinesiology, bowen, osteopathy, and myopathy.

Optimise Immune Function: Immune support is crucial for athletes who are prone to overexertion and increased susceptibility to illness. So often athletes get run down and sick right before competition and in the weeks following. A preventative approach including key immune boosting nutrients, wholefood medicines and herbs can be beneficial and well tolerated during times of high stress.

Digestive Health: Proper digestion and absorption of nutrients is a key foundation in sports naturopathy. Naturopaths work to resolve digestive symptoms such as bloating, diarrhoea, and urgency, which are common issues.

Long-Term Wellness:. By addressing the root causes of health issues and providing preventive strategies, athletes can aim for sustained peak performance over time and minimise health issues.

It's important to remember that while sports naturopathy can offer these potential benefits, as with all medical interventions, individual responses may vary. Athletes should consult with a qualified sports-focused naturopath to create a comprehensive and well-rounded approach to their health and performance.

What Makes Tart Cherries So Powerful?

Tart cherry juice for athletes is one of the most well-researched natural recovery tools available and it's one that many competitors are yet to discover. Used for decades to manage gout and osteoarthritis, tart cherries are now gaining serious attention in sports science for their ability to accelerate muscle recovery, reduce inflammation, improve sleep quality and enhance multi-day performance.

Here at Athlete Sanctuary, we're passionate about evidence-based natural medicine, and tart cherry juice ticks every box.

Tart cherries are rich in bioactive phytochemicals

• Anthocyanins — potent anti-inflammatory and antioxidant compounds
• Flavonoids and flavanols
• Phenolic acids

Tart cherries contain a significantly higher anthocyanin content than sweet cherries, along with an impressive nutritional profile: potassium, calcium, iron, magnesium, and vitamins A, C, B6, E and folate. Some sources suggest tart cherries contain up to 19 times more vitamin A and beta-carotene than strawberries and blueberries.

Does the evidence stack?

Repeat Sprint Recovery

A 2016 study involving soccer players found that tart cherry juice significantly accelerated recovery following prolonged, repeat sprint activity — movement patterns common across soccer, AFL and rugby. Researchers concluded that polyphenol-rich foods such as tart cherry juice are effective in supporting recovery from various forms of strenuous exercise. ^[2]

Marathon Running — Strength, Inflammation & Antioxidant Status

A 2010 study of recreational runners competing in the London Marathon found that supplementing with tart cherry juice twice daily for 5 days before and 2 days after the race led to: ^[3]

• Improved muscle strength recovery
• Reduced inflammatory markers and uric acid
• 10% greater total antioxidant status
• Lower oxidative stress compared to placebo

Back-to-Back Performance

Studies involving trained cyclists demonstrated significant benefits from Montmorency tart cherry concentrate across 3 days of 109-minute road cycling races, taken twice daily for 7 consecutive days. Researchers observed reduced oxidative stress, inflammation and muscle damage, concluding that tart cherry juice has direct application for athletes competing in back-to-back events. ^[1]

Next-Day Performance

A 2016 study of well-trained water polo players found that tart cherry juice supplementation supported recovery and improved next-day performance, further reinforcing its application across team and multi-day sport formats. ^[4]

How Tart Cherry Juice Supports Recovery

Tart cherry juice works through four key mechanisms:

1. Reduces muscle damage. Lowers creatine kinase (CK) — a pathology marker for muscle breakdown. ^{[2] [3]}

2. Reduces inflammation. Studies show reductions in IL-6, TNF-α, IL-8, IL-1-β and CRP — key markers of systemic inflammation^{. [1] [2] [3]}

3. Reduces oxidative stress. With an ORAC rating of 12,800, tart cherries rank among the highest antioxidant foods in the world. ^[1]

4. Improves sleep quality- Tart cherries naturally increase tryptophan and melatonin levels, supporting deeper, more restorative sleep which is an athlete's most powerful recovery tool.

How to Use Tart Cherry Juice for Recovery and Sleep

Tart cherry juice is best used strategically, not daily. It is most beneficial during:

• Multi-day competitions (rugby, AFL or touch football tournaments)
• Marathon or ultramarathon events
• Multi-day cycling events or triathlons
• Intense training blocks or back-to-back training days

Note: Consistent daily use during a training/adaptation phase is not recommended, as anti-inflammatory compounds may blunt the training stimulus your body needs to adapt and improve.

Recommended Protocol

• Dose: 30ml of tart cherry concentrate diluted in 100ml of water — equivalent to approximately 60–90 cherries per serve
• Frequency: Twice daily (morning and evening)
• Timing: Evening dose ideally taken 1 hour before bed to support melatonin production and sleep quality
• Duration: Begin 2–3 days post-event or strenuous session

What About a Pre-Loading Phase?

Some studies have used a 4–5 day pre-loading phase prior to competition. However, current evidence does not clearly confirm that the active compounds accumulate in the body over multiple days, so the necessity of pre-loading remains uncertain. More large-scale athlete trials are needed. ^{[2] [3]}

What to Look For When Buying Tart Cherry Juice

Not all tart cherry products are equal. Here's what to consider:

• Variety: Look for Montmorency or Balaton tart cherry varieties — these are the most studied. Montmorency is more widely available in Australia.
• Cold-pressed: Anthocyanins are heat-sensitive, so choose products that are cold-pressed to maximise bioactive compound retention. ^[5]
• Sugar content: Most juices contain around 25g of sugar per 250ml, but at 30ml per serve, you're only consuming approximately 3g of sugar — not a concern for most athletes. Low-sugar options with stevia or vanilla extract are available.
• Price: Expect to pay $26–$28 AUD for quality organic tart cherry juice (450–950ml). Budget options from chemists or supermarkets are less likely to be cold-pressed.
• Label check: Confirm the bottle specifically states the cherry variety used.

Tart cherry juice is an accessible, evidence-backed natural tool that may meaningfully support your recovery when used at the right time. Like all nutritional strategies, targeted, moderate use is far more likely to deliver results than overconsumption or uninformed daily use.

Symptoms can mimic other common issues such as anxiety or even menopause.

Symptoms of blood sugar dysregulation:

• Nausea
• Seeing flashes of light
• Moodiness and “hangry” relief after eating
• Negative attitude/ irritability
• Exaggeration of relatively minor problems
• Feeling emotionally flat or depression
• Lightheadedness or dizziness
• Sweating and flushes
• Sugar cravings
• Fatigue
• Heart palpitations
• Shakiness
• Paleness
• Cold/clammy skin
• Poor concentration and memory

Thyroid issues, hormonal imbalances, or high exercise demands can exaggerate these symptoms, especially with inadequate fueling in between multiple daily training sessions. There are a number of simple steps that may help stabilise blood sugar.

1. Protein is essential to blood sugar stabilisation and should be included in every meal including breakfast. Quality protein can be found in lean animal meats (kangaroo, lamb, beef, chicken) and fish. Vegetarian options include tofu, tempeh, legumes, eggs, dairy, and high-protein grains such as quinoa, buckwheat and amaranth. Vegans and vegetarians must practice protein source combinations to obtain all the essential amino acids.. For example: consume chickpeas with brown rice.

Athletes should ideally consume 1.2-1.6 grams of protein/kilogram of body weight which equates to 60-80 grams of protein for a 50kg female and 90-128 grams for an 80kg male athlete per day. It is beneficial to have 20 grams of protein with carbohydrates within 30- 60 minutes of completing a training session. A good option is a smoothie with a scoop of protein powder (pea, brown rice or whey if tolerated), a small can of tuna or 2-3 eggs.

2. Carbohydrates
Intake of low GI (Glycemic Index) carbohydrates will help keep blood sugar levels more sustained, and energy levels consistent. A high GI carbohydrate will cause a surge in blood glucose, triggering a response from the pancreas. This can contribute to the symptoms described previously.

Good sources of complex carbohydrates include porridge, Bircher muesli, brown, basmati or wild rice, barley, oats, buckwheat, quinoa, amaranth, teff, rye, sweet potato, and root vegetables with skins on. Sourdough bread, corn on the cob, bananas, fruit smoothies with protein powder, and homemade muffins using wholemeal flours such as hemp, chia or buckwheat are all good options. Consuming carbohydrates with quality fats and soluble fibre also reduces the GI of foods.

3. Magnesium
Magnesium assists with blood sugar control by supporting healthy insulin secretion.

Magnesium is abundant in amaranth (a grain), pumpkin seeds, dark chocolate and raw cocoa, wholemeal bread, quinoa, firm tofu and dark leafy vegetables. It is also found in oat bran, brown rice, cooked spinach, avocado, coconut water, kale, legumes, sesame seeds and cashews.

4. Chromium
Chromium deficiency reduces your body’s ability to use carbohydrates for energy and raises your insulin needs. Chromium may enhance the effects of insulin or support the activity of pancreatic cells that produce insulin. Chromium is found in meats, fish, poultry, wholegrains, dairy, broccoli, cheese, mushrooms, asparagus, green beans, apples, bananas, grape juice and potato.

5. Probiotics
Probiotics especially those containing more than one species of beneficial bacteria may help regulate blood sugar by influencing the way the body metabolises carbohydrates by reducing inflammation and preventing the destruction of pancreatic cells that make insulin.

Maintaining energy throughout the day

• Have regular meals throughout the day eating every 2 hours
• Consume protein at every meal. Aim to make up at least 1/3 of your meal from protein
• Stay hydrated by drinking water regularly (2-3 litres per day minimum)
• Cinnamon, nutmeg, cloves, vanilla, stevia, and ginger can all be used instead of sugar to add sweetness to food.
• Carbohydrates higher in fibre and from unprocessed sources are better
• Consume carbohydrates within 30 minutes of completing a session
• Fat reduces gastric emptying time and as a result, slows down the absorption of glucose from the meal. Consume beneficial fats with carbohydrates from raw nuts and seeds, fish, avocado and cold-pressed oils.
• Increasing the acidity of food or meals will slow gastric emptying time. A simple tip is to add vinegar dressing to salad or vegetables.
• Short-term supplementation of magnesium, chromium, probiotics or cinnamon, and other blood sugar-stabilising herbs and nutrients may be beneficial for some individuals.

Always seek help from a healthcare practitioner if your symptoms persist.

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 https://athletesanctuary.com.au/kate-smyth

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.

1. 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.
2. 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.
3. 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.
4. 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.
5. 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.
6. 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.
7. 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.
8. Get your hormones, cortisol, iron, zinc, copper and iodine levels checked.
9. 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.
10. 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.

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 https://athletesanctuary.com.au/kate-smyth

But is it really that good for you? This article explores a balanced perspective on caffeine use for sports performance.

Caffeine has been used for decades as a way of buffering fatigue, prolonging endurance and enhancing concentration in many team and individual sports.  Sure, it gives you a “pick me up” but at what expense?

While some athletes will get the beneficial effects of enhanced focussed and reduced fatigue, others can get so fired up, they get the shakes, diarrhoea and their “rev” is excessive so they make poor tactical decisions during events. Caffeine is an adenosine antagonist affecting dopamine transmission and altering neurotransmitter function.

With long-term and high-volume caffeine intake, an increased risk of overstimulating the nervous system occurs. For some individuals, this looks and feels like anxiety, headaches, migraines, poor sleep, depression, angina, nutrient depletion, elevated blood pressure, addictive habits towards caffeine and severe fatigue.

Caffeine also contains a diterpene known as cafestol which has been shown to increase serum LDL cholesterol, increase aortic stiffness, blood pressure, endothelial dysfunction and homocysteine all of which contribute to heart disease- Yikes!

The other “doozy” with caffeine is that even if you are currently enjoying just one cuppa a day you most likely already have caffeine tolerance. As time goes on you’ll need to have more and more caffeine to feel any benefits.

So at this point, if you are sitting back saying “ I am good I don’t drink coffee” just take a breath. Just because you don’t drink coffee, doesn’t mean you aren’t consuming an excessive load of caffeine. Caffeine is found in many commonly consumed drinks and foods. Let’s take a look at the most common ones:

So what to do?

The good news is that recent studies suggest the performance benefits of caffeine can be felt at low doses (1-3mg/kg) which are less likely to impact your health in other ways.  So theoretically speaking effects may be felt by athletes using the following amounts:

• 50kg athlete    50-150mg;      ( 1 coffee)
• 60kg athletes 60-180mg;
• 70kg athlete    210mg;
• 80kg athlete    80-240mg
• 90kg athlete    90-270mg      ( 2 coffees)

Top tips for caffeine use for sports performance:

1. If you are using caffeine for the first time try small amounts initially and infrequently so you don’t develop resistance. Attempt any trialling caffeine as part of your race day nutrition and hydration plan during training several times prior to race day, in similar conditions first to avoid unsavoury surprises.
2. Caffeine may make you temporarily feel good it can also cause adverse performance effects. Caffeine displaces vitamins and minerals essential for athletic performance such as magnesium, zinc and B vitamins. Caffeine can irritate the kidneys and is a diuretic increasing the risk of dehydration in hot weather so you may need to increase your fluid intake. The most common issue with caffeine is diarrhoea. Taking caffeinated foods or drinks with food may help mitigate this problem.
3. Avoid caffeine after lunchtime to avoid sleeping difficulties.
4. High caffeine intake is inflammatory and prolonged use can contribute to systemic inflammation which underpins nearly all chronic conditions. Our suggestion is to enjoy caffeine in moderation and use a targeted approach in regard to sports performance.
5. Smart considered and moderate use of caffeine may provide a performance edge but it will not suddenly turn you into some kind of superhero breaking world records. You still have to invest in sound balanced nutrition and hydration strategies, train smart, rest well and allow the natural adaptation of the human body to occur!
6. As with all products, always remember to check each ingredient on the packaging of any sports product because some substances that may appear relatively benign may be banned under the Australian (ASADA) and World Drug Agency Association (WADA) guidelines. Rule of thumb- always do your own thorough research before using any supplement despite its popularity!
7. If you are currently a heavy coffee drinker, wean yourself off coffee gently so you don’t go into an unprovoked tirade at your family or work colleagues as you deal with the headaches associated with detoxification. By reducing your intake gradually by ½ a cup a day, you are also more likely to allow your tolerance to reduce so when you settle for smart and more moderate use, you can obtain benefits at a lower dose. In some individuals’ withdrawal may be more comfortably achieved with the use of herbal adaptogens, liver support, activated vitamins and dietary intake of brassica family vegetables (broccoli, cabbage, kale, cauliflower) to ease the transition.
8. If you are looking for coffee substitutes or reduced caffeine products you may like to try roasted dandelion tea, ginseng, high-quality green leaf tea, chai tea or Rooibos tea.
9. Try different forms of caffeine in sports products rather than just coffee. Caffeinated sports products come in powders, gels, strips and tablets and all will be digested/ metabolised slightly differently in the body. Some athletes experience digestive issues with coffee but not strips, while others have issues with caffeinated gels but not powdered versions.
10. Limit decaffeinated coffee. It may have reduced caffeine but many of the extraction methods still use chemical solvents that may be toxic.

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 https://athletesanctuary.com.au/kate-smyth