vitamin D

Photo of a female athlete kneeling down on the ground as she is exhausted.

Training fasted involves exercising without food and/or energy drinks for a period of time. The most common fast lasts for 8/12 hours or extended to 16 hours as an overnight fast. During this period, we tap into fat stores in the form of ketone bodies and stored glycogen.

Runners often train fasted unconsciously as a morning run or gym session before breakfast.

This practice has gained popularity due to its potential effects on fat loss, and overall performance. However, it also comes with its share of pros and cons and is not for everyone. Here’s a list of some of the potential pros and cons:

Pros of Training Fasted:

Weight management: Training fasted may increase the body’s reliance on using stored fat for energy. Over time this aids fat loss and contributes to the maintenance of lean muscle mass, beneficial body composition and weight management.

Weight management: Reduced body fat, contributes to the maintenance of lean muscle mass and beneficial body composition. This can be beneficial for athletes competing in weight categories or sports dependant on body composition such as body sculpting.

Insulin Sensitivity: It can improve insulin sensitivity. When you do eat after exercise, the body absorbs nutrients more efficiently, which is beneficial for overall health and weight management. This assists with blood sugar control, energy levels and management of insulin resistance and diabetes.

Hormonal Responses: Training fasted can lead to increases in human growth hormone (HGH) key to muscle growth. Muscle growth is important to athletes in strength and body sculpting related sports.

Metabolic Adaptation: Proponents will argue that training fasted makes them more efficient at using fat stores for energy. In recent times the belief has gained traction in the endurance running community (especially ultra running).

Cons of Training Fasted:

Performance Impairment: Fasting and then training can lead to decreased performance, especially for high-intensity workouts. Without readily available carbohydrates athletes experience lower energy levels during and post exercise. Recovery, strength, and endurance are also impaired.

A recent review of 46 studies concluded eating before exercise prolongs aerobic performance. The debate becomes clouded in practice as endurance athletes can feel ok during low-to-moderate intensity training when training fasted. A runner can feel good on an easy 6km recovery run but rubbish doing 1km reps.

Muscle Breakdown: Training fasted could potentially lead to increased muscle breakdown due to the lack of readily available energy sources. This is detrimental to muscle gain and repair.

Hydration and Electrolyte Imbalance: Fasting can lead to dehydration and electrolyte imbalances, which can negatively impact workout performance and recovery.

Additional adrenal gland stress: It can increase adrenaline levels and cortisol levels. This is not a great scenario for those athletes with already high levels of stress.

Lower hormones: reduces male sex hormones (androgens) and negatively impacts libido and metabolic health. This is non-beneficial for men but beneficial for women with polycystic ovarian syndrome (PCOS). Training fasted does not appear to have any effect on estrogen or prolactin levels in women.

Training fasted may also reduce thyroid hormones -thyroid stimulating hormone (TSH) and T3- active thyroid hormones. This may contribute further to thyroid hormone imbalances.

Risk of Overeating Post-Workout: Some individuals compensate by consuming larger meals after exercise. Sugar and carbohydrate cravings increase as the day progresses. Poor food choices and excessive sugar intake peaks towards the end of the day. This can then result in disturbed sleep and reduced energy levels the following day.

Lack of Nutrients for Recovery: After exercise, your body needs nutrients for muscle repair, glycogen replenishment, and overall recovery. Fasted training can limit the availability of these nutrients at a critical time and delay recovery.

Individual Responses: Fasted training might be suitable for some individuals but not for others. Factors like genetics, training goals, and personal preferences can greatly influence the effectiveness and comfort of training fasted.

Increased Perceived Effort: For some athletes, training on an empty stomach can make training sessions feel harder. This can impact motivation and adherence to the training routine.

In summary, training fasted can have potential benefits such as increased fat loss and improved insulin sensitivity. However, training fasted also comes with potential downsides like impaired performance and muscle loss. Athletes are also at risk of reduce hormone levels, dehydration and nutrient deficiencies with prolonged fasting.

Your training goals, preferences, and how your body responds to fasted training is important to observe. We always recommend seeking professional help from a sports naturopath or nutritionist to ensure training fasted aligns with your specific circumstances.


Aird, T. P., Davies, R. W., & Carson, B. P. (2018). Effects of fasted vs fed‐state exercise on performance and post‐exercise metabolism: A systematic review and meta‐analysisScandinavian journal of medicine & science in sports28(5), 1476-1493.

Cienfuegos, S., Corapi, S., Gabel, K., Ezpeleta, M., Kalam, F., Lin, S.,  & Varady, K. A. (2022). Effect of intermittent fasting on reproductive hormone levels in females and males: a review of human trials. Nutrients14(11), 2343.

Kim, B. H., Joo, Y., Kim, M. S., Choe, H. K., Tong, Q., & Kwon, O. (2021). Effects of intermittent fasting on the circulating levels and circadian rhythms of hormones. Endocrinology and Metabolism36(4), 745-756.

Hackett, D., & Hagstrom, A. D. (2017). Effect of overnight fasted exercise on weight loss and body composition: A systematic review and meta-analysisJournal of Functional Morphology and Kinesiology2(4), 43.

Hansen, D., De Strijcker, D., & Calders, P. (2017). Impact of endurance exercise training in the fasted state on muscle biochemistry and metabolism in healthy subjects: can these effects be of particular clinical benefit to type 2 diabetes mellitus and insulin-resistant patients?. Sports Medicine47, 415-428.

Vieira, A. F., Costa, R. R., Macedo, R. C. O., Coconcelli, L., & Kruel, L. F. M. (2016). Effects of aerobic exercise performed in fasted v. fed state on fat and carbohydrate metabolism in adults: a systematic review and meta-analysis. British Journal of Nutrition, 116(7), 1153-1164.

Zouhal, H., Saeidi, A., Salhi, A., Li, H., Essop, M. F., Laher, I.,   & Ben Abderrahman, A. (2020). Exercise training and fasting: current insightsOpen access Journal of sports medicine, 1-28.

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

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.

Photo of a female athlete wearing a hoody on a dark gloomy day

Seasonal Affective Disorder (SAD), also known as seasonal depression or seasonal mood disorder, can have many impacts to your way of life, including your athletic performance. While SAD’s prevalence in Australia may differ from other regions, it is still important to explore the experiences of female athletes living with SADs. In this blog post, we will delve into the symptoms and unique challenges faced by female athletes in relation to SAD, and strategies to navigate through it.


It’s vital for female athletes to recognise the intersection between their mental health and athletic performance, and acknowledge that working on mental health can positively impact their overall performance and condition.

SAD is suggested to be linked to the circadian rhythms (‘body clock’) adjustments at certain times of the year and in response to variations in exposure to sunlight. This is thought to impact the hormones melatonin and serotonin, which affect sleep and mood.

Those most at risk are younger females, those with a family history of depression, bipolar disorder, or SAD. The risk increases the further away from the equator. Vitamin D deficiency is also linked to SAD and people with SAD may produce less Vitamin D. As Vitamin D plays a role in serotonin activity, Vitamin D deficiency and insufficiency have been associated with depressive symptoms.

SAD frequently co-occurs with other disorders including attention-deficit hyperactivity disorder (ADHD), addiction, and eating disorders.


Awareness of Seasonal Patterns
Athletes experiencing SAD may notice seasonal patterns to their moods.

Common observations over winter include:

  • Decline in mood, sadness and depression
  • Fatigue without explanation
  • Reduced motivation
  • Hopelessness
  • Social withdrawal
  • Overeating and carbohydrate cravings
  • Excessive sleeping

In summer SAD may look more like sleep issues, not feeling hungry, losing weight and feeling agitated and anxious.

By recognising these patterns and symptoms, athletes can better anticipate and prepare for the potential impact on training and performance.


Athletes and coaches may need to modify training schedules to accommodate SAD symptoms. This could mean adjusting the timing of workouts to coincide with optimal sunlight exposure in the middle of the day, incorporating more indoor training during the darker months, or allowing for flexibility in training intensity to accommodate fluctuations in mood and energy levels.


Openly communicate with coaches, supporters, friends and family about your experiences with SAD. By sharing your challenges and seeking understanding, you can foster a supportive environment that promotes positive mental health and helps alleviate the burden of SAD symptoms.

Seek Out a Mental Health Professional
Support from a mental health professional who specialises in sports psychology can be incredibly valuable. These professionals can provide tailored strategies to manage SAD symptoms, including cognitive-behavioural techniques, mindfulness practices and stress management tools.

In some cases your doctor may recommend light therapy.


Sunlight Exposure
Spend time outdoors during daylight hours, as sunlight exposure has a positive impact on vitamin D levels, sleep, mood and energy levels. Including outdoor activities, such as training sessions, walks and other outdoor hobbies, can help combat the effects of SAD.

Rest and Recovery
Prioritise sufficient sleep and establish consistent sleep routines to support your mental health and physical wellbeing.

Stress Reduction
Implementing stress reduction techniques, such as meditation, deep breathing exercises, or taking time with hobbies, people etc that bring joy, can help to alleviate SAD symptoms and promote overall mental wellbeing.

Vitamin D
We recommend athletes who suffer from SAD check their vitamin D levels every 6 months. Maintaining regular sunlight exposure and intake of vitamin D rich foods is essential to the prevention of deficiency. In many cases vitamin D supplementation is required.

Managing Seasonal Affective Disorder requires a comprehensive approach that integrates mental health and performance considerations. By recognising the unique challenges you face and implementing strategies such as adjusting training schedules, tapping into support networks and prioritising self-care, you can affectively navigate SAD while maintaining fitness and performance.


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 our website.


1. Armstrong, S. L., & McVeigh, D. (2019). A systematic review of athletes’ experiences with self-talk. Frontiers in Psychology, 10, 1518.
2. Fenton, G., McPherson, A., & Kinnafick, F. (2019). Qualitative inquiry into the lived experiences and coping strategies of female athletes with eating disorders. Psychology of Sport and Exercise, 42, 100-108.
3. Gulliver, A., Griffiths, K. M., & Christensen, H. (2012). Perceived barriers and facilitators to mental health help-seeking in young people: A systematic review. BMC Psychiatry, 12.
4. Pargman, D., & Wiese-Bjornstal, D. M. (2003). Examining links between emotional states and physical activity among individuals with high physical activity levels. Journal of Applied Sport Psychology, 15(4), 300-317.
5. Melrose S. Seasonal Affective Disorder(2015): An Overview of Assessment and Treatment Approaches. Depress Res Treat. doi: 10.1155/2015/178564.
6. Murray, G. (2004). How common is seasonal affective disorder in temperate Australia? A comparison of BDI and SPAQ estimates. Journal of affective disorders, 81(1), 23-28.


If you’re training hard, but don’t feel like you’re improving your athletic performance, then enriching your gut health through choosing the best probiotics to complement your gut microbiome could be the missing ingredient.

What are probiotics?
Probiotics are live microorganisms, mainly bacteria, and yeasts, that naturally reside in your gut (microbiome) and convey a health benefit. Your microbiome typically contains over 1000 different organisms, both beneficial and pathogenic.

Because a healthy gut microbiome strengthens your immune system and enhances your recovery from fatigue and overtraining, taking care of your gastrointestinal system is vital. This will enhance your general health and help to improve your athletic performance.

We consume probiotics via gut-friendly fermented foods such as yogurt, kefir, kimchi, kombucha, and sauerkraut, and commercially produced supplements.

Probiotics shouldn’t be confused with prebiotics. Prebiotics are carbohydrates and fibres such as inulin and other fructo-oligosaccharides found in foods like artichoke, bananas, and asparagus. The microorganisms in your gastrointestinal tract use prebiotics as fuel.

Supplements called ‘synbiotics’ contain both prebiotic molecules and probiotic organisms.2 Synbiotics offer a dual-action strategy for even greater health benefits. A diet rich in pre and probiotic foods support your gut to develop a robust immunity.

Understanding probiotics for runners

As the popularity of ‘gut health’ supplements for athletes increases, a basic knowledge of the assortment of beneficial probiotics in your supplement is helpful.

Probiotics are classified by their unique microorganism strain, which includes the genus, species, subspecies (if applicable), and an alphanumeric strain designation.

The seven core probiotic genera are Lactobacillus, Bifidobacterium, Saccharomyces, Streptococcus, Bacillus, Enterococcus, and Escherichia.

Lactobaccillus rhamnosus, Lactobaccillus acidophilus, and Saccharomyces boulardii are common commercially produced probiotic and yeast species. This ‘probiotic tree’ diagram highlights several commercially available probiotic strains.

Research on specific probiotic strains has expanded our knowledge of the health benefits and targeted treatments of probiotics for athletes. However, probiotic supplementation may not be appropriate or necessary for all athletes.

Probiotics for Runners

Certain probiotic species impart significant anti-inflammatory effects within your gut. In particular, Lactobacillus strains produce lactate, which is then converted into short-chain fatty acids by your gut bacteria. Butyrate is a pivotal short-chain fatty acid for intestinal homeostasis due to its anti-inflammatory properties and beneficial effects on intestinal cells, gut barrier function, and permeability.

Over thirty years of research supports the widespread use of Lactobacillus rhamnosus GG (LGG) for common gut-related issues such as diarrhoea, antibiotic use, infections, e.g., Clostridium, irritable bowel syndrome, inflammatory bowel disease, respiratory tract infections, and allergies in athletes.

Studies also show certain probiotics can improve vitamin D levels in athletes.

LGG along with L. acidophilus, and B. bifidum improve exercise-induced gastrointestinal symptoms. In fact, almost 60%of runners and endurance athletes who train intensely experience gut microbiome upsets and unwanted symptoms. Probiotics offer relief by supporting immune function and intestinal cell proliferation and function, as well as shortening the duration of gastrointestinal symptoms.5

Probiotic strains interact favourably with other probiotic species in the microbiome to improve the overall balance and composition of beneficial bacteria in your gut. For example, Lactobacillus fermentum (PCC) can increase the Lactobacillus genus seven-fold after 11 weeks of supplementation.

Probiotic supplements can help regulate blood sugar levels and maintain energy for training and performance. Also, yeast probiotics such as Saccharomyces cerevisiae are widely used to suppress the overgrowth of Candida or thrush fungal infections.

Lastly, new research demonstrates that probiotics can enhance sports performance. Runners taking Bifidobacterium longum (OLP-01) for five weeks significantly increased their running distance in a timed test. Bifidobacterium longum (OLP-01) also provided other health benefits such as increasing the abundance of gut microbiota in the runners.

There are a few final points to keep in mind before you add probiotics to your diet.

First, the quality of your probiotic supplement may vary significantly. Be careful about your choices as the label “probiotic” doesn’t necessarily mean this option will be suitable for your microbiome.

Second, a probiotic combination or an inappropriate supplementation duration may exacerbate unwanted symptoms in some situations. Therefore, it’s vital to consume high-quality, well-characterised live probiotics that deliver a therapeutic dose over an effective length of time.

Finally, the best probiotics for endurance athletes are selected case by case to improve your performance, recovery, immune and gut health. Be sure to seek professional advice for the most suitable probiotic therapy for your training and health circumstances.

Unsure if a probiotic supplement could help you?
Speak with Athlete Sanctuary’s sports naturopath and nutritionist about your health and sports performance goals today.

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://


  1. Hill C, Guarner F, Reid G, Gibson GR, Merenstein DJ, Pot B, et al. The International Scientific Association for Probiotics and Prebiotics consensus statement on the scope and appropriate use of the term probiotic. Nat Rev Gastroenterol Hepatol 2014;11:506-14.
  2. World Gastroenterology Organisation. Probiotics and prebiotics. 2017.
  3. Capurso, L. (2019). Thirty years of Lactobacillus rhamnosus GG: a review. Journal of Clinical Gastroenterology53, S1-S41. doi: 10.1097/MCG.0000000000001170
  4. Leite, G. S., Student, A. S. R. M., West, N. P., & Lancha Jr, A. H. (2019). Probiotics and sports: A new magic bullet? Nutrition60, 152-160.
  5. Salarkia, N., Ghadamli, L., Zaeri, F., & Rad, L. S. (2013). Effects of probiotic yogurt on performance, respiratory and digestive systems of young adult female endurance swimmers: a randomized controlled trial. Medical Journal of the Islamic Republic of Iran27(3), 141.
  6. West, N. P., Pyne, D. B., Cripps, A. W., Hopkins, W. G., Eskesen, D. C., Jairath, A., … & Fricker, P. A. (2011). Lactobacillus fermentum (PCC®) supplementation and gastrointestinal and respiratory-tract illness symptoms: a randomised control trial in athletes. Nutrition Journal10(1), 1-11.
  7. Gaziano, R., Sabbatini, S., Roselletti, E., Perito, S., & Monari, C. (2020). Saccharomyces cerevisiae-based probiotics as novel antimicrobial agents to prevent and treat vaginal infections. Frontiers in Microbiology11, 718.
  8. Lin, C. L., Hsu, Y. J., Ho, H. H., Chang, Y. C., Kuo, Y. W., Yeh, Y. T., … & Lee, M. C. (2020). Bifidobacterium longum subsp. longum OLP-01 Supplementation during Endurance Running Training Improves Exercise Performance in Middle-and Long-Distance Runners: A Double-Blind Controlled Trial. Nutrients12(7), 1972. doi:10.3390/nu12071972 
  9. Probiotic professionals


Iron and thyroid function

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 anaemiahere

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 menopausehere .

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://



  1. Kawicka, A., & Regulska-Ilow, B. (2015). Metabolic disorders and nutritional status in autoimmune thyroid diseases. Postepy Higieny i Medycyny Doswiadczalnej, 69, 80–90.
  2. Luksch, J. R., & Collins, P. B. (2018). Thyroid Disorders in Athletes. Current Sports Medicine Reports, 17(2), 59–64.
  3. Santin, A. P., & Furlanetto, T. W. (2011). Role of estrogen in thyroid function and growth regulation. Journal of Thyroid Research, 2011.
  4. Soliman, A. T., De Sanctis, V., Yassin, M., Wagdy, M., & Soliman, N. (2017). Chronic anemia and thyroid function. Acta Biomedica, 88(1), 119–127.
  5. 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.


Vitamin D deficiency

Vitamin D deficiency has consequences well beyond bone health.

Vitamin D is gold.

Vitamin D is so important to the body, immune cells, brain, colon, breast, and other cells have the ability to also activate it locally when required. Although labelled a vitamin, calcitriol (bio-active vitamin D) acts more like a hormone within the body. It is involved in many essential functions well beyond bone health.  Vitamin D is critical for inflammatory modulation, hormonal and immune functions as well as cardiovascular, mental health and pancreatic function. The active form of vitamin D interacts with receptors in the intestine, bone, brain, heart, immune cells and skeletal muscle.  Vitamin D functions as a modulator of up to 1000 genes involved in cellular growth and protein synthesis.

Vitamin D plays an important role in an athlete’s health, training and performance.

Studies show it may even be necessary for optimal muscle function and performance as muscle performance is impaired by suboptimal vitamin D status. Deficiency induces atrophy of fast twitch muscle fibers, impairs calcium uptake and prolongs time to peak contractile tension and relaxation. Studies also show Vitamin D deficiency may delay rehabilitation from injury.

In sporty pregnant women, low vitamin D levels are linked to pre-eclampsia, gestational diabetes and adverse pregnancy outcomes. Vitamin D also plays a part in regulating insulin, blood sugar balance and thyroid hormones. Research shows that a deficiency of vitamin D is associated with a high risk of thyroid antibodies, which are found in individuals with autoimmune thyroid disorders.

Vitamin D is most commonly known in the athletic community for its influence on bone health and prevention of bone injury. Vitamin D influences bone health by upregulating expression of genes that enhance intestinal calcium absorption, and reabsorption by the kidneys along with increasing bone-building cell activity. Studies show calcium absorption significantly increases when vitamin D levels are sufficient. Calcium absorption is reduced to 10-15% with low vitamin D levels and stress fracture risk significantly increases.

Typically, 80% of our vitamin D is obtained from the sun and 20% from food sources.

Signs of Vitamin D deficiency

  • fatigue and tiredness
  • lower back pain
  • recurrent colds and infections and poor immunity
  • stress fractures
  • heaviness in the legs
  • recurrent injuries
  • muscle pain, weakness, poor muscle contraction and relaxation
  • mental health issues, low mood, seasonal sadness and depression
  • hormonal imbalances and PMS
  • anaemia and low iron
  • pale floating stool
  • photosensitivity

According to Sunsmart Australia, one-third of Australians are low in Vitamin D.

10 Reasons your vitamin D is low

Vitamin D can be made by our body when skin is exposed to sunlight through a complex activation process, however, what many people fail to realise is that this process doesn’t always occur efficiently or reach levels required for optimal health. Vitamin D production may vary depending on the time of day of sun exposure, season, cloud cover, smog, latitude, skin pigmentation, age, and sunscreen use.

We often see patients with low levels of vitamin D despite being out in the sun daily. There are several reasons why vitamin D levels drop despite sunlight exposure.

1. As vitamin D is fat-soluble and stored in fat cells, individuals with low body fat, may be disposed to vitamin D deficiency as their storage tank is smaller.

2. Activation and production of vitamin D are inhibited by magnesium deficiency, inflammation, and excessive use of sunscreen.

3. Individuals with any form of malabsorption issues, liver or kidney issues, coeliac’s disease, Crohn’s, vegans, and thyroid issues can be prone to deficiencies.

4. Anyone with a history of anaemia should also be aware of the bidirectional influence between iron and vitamin D. The activation of vitamin D in the kidneys requires iron-containing compounds ferredoxin reductase and ferredoxin. Iron deficiency may therefore contribute to the inactivation of vitamin D. Vitamin D deficiency may also be associated with higher hepcidin (a pro-inflammatory mediator) in the liver.  Hepcidin will elevate ferritin stores and down-regulate intestinal absorption of iron from food and impair storage iron release. Hundreds of athletes have used our handy anaemia tool to help determine the likely risk of having low iron or anaemia.

5. Diets containing limited seafood, eggs or dairy such as vegan diets may also reduce vitamin D intake.

6. Insufficient direct UVB exposure (due to smog, cloud cover or latitude), early- or late-day training, indoor training, geographic location further away from the equator and sunscreen use (SPF of 15 lowers vitamin D synthesis capacity by 98%).

7. Disruption to the microbiota and gut inflammation may also affect the availability of vitamin D.

8. In addition some individuals may find it difficult to increase their vitamin D levels if they have low antioxidant status.

9. Medications such as anticonvulsants, corticosteroids, cimetidine, theophylline, statins or the weight loss drug orlistat.


As a general guide, Osteoporosis Australia recommends most people should have levels of at least 50 nmol/L at the end of winter, which means people may have higher levels during summer (60-70 nmol/L). However, in order to maintain optimal health, athletes should aim for serum levels over 90 nmol/L ideally between 100 and 130 nmol/L.


Daily sunlight exposure on your skin especially on large areas such as the back, chest, legs and arms (25-60 minutes in winter) without suntan cream, is a great way to keep levels topped up. Athletes living in southern states of Australia and New Zealand need 30 minutes of direct skin exposure (springtime) on large areas of skin such as back, arms, chest or legs closer to midday. Athletes living closer to the equator may require 15 minutes before 10 am. During this time avoid putting sunscreen on, then for the rest of the day, cover up. Lunchtime exercise with as much skin exposure as possible (within decency) is a great way to give yourself a vitamin D fix, especially in winter months.

Get tested biannually- before winter and again in spring.

Consume vitamin D-rich foods on a daily basis such as oily fish like cod, salmon, sardines or tuna, egg yolks, sun-dried mushrooms, and fortified milk, butter and fortified cereals. Some individuals may benefit from cod liver oil which also contains vitamin A and essential fatty acids.

When levels are low, take a quality supplement in the correct dosage range and a probiotic. Certain probiotics such as Lactobacillus rhamnosus LGG and Lactobacillus plantarum enhance levels synergistically.

Obtain adequate magnesium-rich foods such as spinach, pumpkin seeds, almonds, black beans, oyster mushrooms, avocado, figs, yogurt or kefir and banana. Chocolate also contains magnesium.


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://

Do you want to know more about Robust Immunity?

Before we dive into how to maintain robust immunity in athletes, let’s do a quick recap on how our immune system works.

The immune system is a busy network throughout our entire body including cells, vessels, lymphoid tissue, nodes, nodules, bone marrow and organs.

Bone marrow is where millions of new blood cells are produced every day. Bone marrow also serves as the site where cells are stored and matured before they enter the circulatory system.

Our immune system would not be complete without the gut-associated lymphoid tissue (GALT) – and Peyer’s patches in the small intestine.  Nearly 80% of our immune system is actually based in the digestive tract.

The thymus gland is a small gland known as the “seat of courage” and is located behind the breastbone. Our thymus helps regulate the immune system and is a storage tank for immune cells such as lymphocytes and monocytes responsible for eradicating viruses.

Our spleen is an oval shaped mass of lymphatic tissue which acts as a large blood filter. It recycles iron, captures and destroys pathogens and initiates the maturation and release of immune system when the body requires it (e.g. to fight infections).

Our lymph nodes act as a filtering system for the clear fluid called lymph which contains waste and immune cells. The lymphatic vessels act as the super highway carrying lymph between the 600 lymph nodes in our body located in our limbs, armpits, abdomen and groin.

Lymphatic nodules also contain lymphatic tissue and are positioned on mucous membranes in our respiratory system and gastrointestinal tract, tonsils and adenoids.

The immune system has many lines of defence.

 Our immune system is equipped with a multi-tiered response approach. A healthy immune system is always ready (24-7) to battle with foreign invaders.

The immune system includes our first line of defence which acts like the bouncers of your body deciding what can come in and what can’t such as the skin, mucous membranes, gastrointestinal tract and secretions like mucous, acidic vaginal secretions, bile, gastric acid (HCL), saliva, tears, and sweat.

The next line of defence kicks in when the bouncers have gone on a smoko and a pathogen is detected by the body. This part of our system also houses our infection-fighting cells such as our natural killer cells and phagocytes which act like Pac-men against microbial invaders. Our immune system also releases antimicrobial proteins such as complement and interferon which interfere with virus replication and protein which co-ordinate cell-to-cell communication. This part of the system deals with viruses, fungi, parasites etc.

Our immune system also keeps a record of every germ it has ever defeated so it can recognise and destroy the microbe quickly if it enters the body again.

Maximise what’s needed for robust immunity in athletes

In addition to enjoying a balanced wholefoods diet containing real foods rich in colour and vitality colourful rainbow on your plate, there are key foods to include in your diet you want to enhance your immune system.

The big guns

Vitamin C builds resistance to infection and stimulates immune cells and proteins such as interferon which help eradicate viruses. Vitamin C rich foods include veggies such as red capsicum, spinach, parsley and sweet potato. Fruits such as kiwi, berries, paw paw, pineapple citrus, guava, broccoli, mango, and currants are great sources of vitamin C.  Rosehip, Camu Camu, and Kakadu plum provide concentrated forms of vitamin C and can be found in powdered forms such as Wild C.

To optimise absorption vitamin C is best ingested with bioflavonoids. Lots of foods rich in vitamin C also contain bioflavonoids but they can also be found in celery, garlic, red onions, garlic, grapes, apricots and green tea.  In some circumstances, it is beneficial to supplement vitamin C. Vitamin may cause gastric upset in large doses. Dividing the doses throughout the day can reduce the side effects.

Zinc is responsible for supporting immune cell production and proliferation which fight off infections such as viruses. Common deficiency signs may include frequent colds, extended recovery periods, poor wound healing, low stomach acid changes in smell or taste and white spots on nails.

Zinc is lost through perspiration and displaced when other nutrients such as iron and copper are high as they share a common carrier in the body. Zinc supplementation should be under the guidance of a qualified practitioner to get the right dose and timing correct because high doses can impact other nutrients ( iron and copper) which may then contribute to immune dysfunction.

Foods rich in zinc include pumpkin seeds, fresh local seafood shellfish and oysters, tahini, peanuts, liver, eggs, nuts and seeds and legumes. Just remember to soak or sprout legumes, nuts and seeds to break down the phytates that may bind to zinc and reduce zinc’s bio-availability.

Obtaining adequate protein will supply the amino acids for antibodies and immune protein production.

Keeping well hydrated is also important for our first line of defence. Ginger and lemon drinks are a great alternative to water.

Immune modulators

Vitamin D, A, E and selenium are important antioxidants, immune modulators and help maintain healthy mucus membranes.  Exposing your unprotected skin to direct sunshine for 15-20 minutes daily will help boost vitamin D levels. Vitamin A-rich foods include cod liver oil, orange coloured foods such as carrots, sweet potato and apricots and kohlrabi. Vitamin E is found in nuts and seeds (such as sunflower seeds), eggs, and dark green leafy vegetables. Selenium is rich in Brazil nuts, alfalfa, meat eggs, onion, garlic and broccoli.

Shiitake and reishi mushrooms and green tea are also supportive of the immune system and build robust immunity in athletes.

Look after your gut health with pre and probiotic rich foods (think fibre and fermented foods like kimchi, sauerkraut, kefir, tempeh, kombucha, and quality yogurt). Choline found in lecithin from soy, eggs, beef, pork, olives, and broccoli, assists with the formation of the mucosal layer in the respiratory system and gut.

Include herbs and spices in your cooking that support healthy immune responses. Turmeric, ginger, Ceylon cinnamon (Cinnamomum verum), Cayenne peppers, garlic, horseradish, parsley, garlic, onions, oregano and thyme are all good choices.

What to avoid for robust immunity in athletes

Avoid substances that reduce immune system function.

1. Studies show sugar reduces the capacity of white blood cells within 1 hour of consumption and can last for up to 5 hours afterwards. Sugar can also feed some pathogens. Skip the middle isles of a supermarket where the processed foods are and spend more time selecting fresh foods.

2. Avoid too much caffeine or other stimulants that will stress our nervous system, impact on sleep but also deplete stores of zinc, and magnesium which we need in times of stress.

3. Avoid excessive alcohol and it may also suppress the immune system.

4. Avoid late nights binging on Netflix and obtain adequate sleep. This means at least 8 hours per night ideally hitting the pillow before 10pm. Sleep deprivation can increase your risk of picking up infections and reduce robust immunity in athletes.

5. Avoid or minimise unnecessary stress. Focus on what you can control and let go of the rest. Your mindset matters in times of stress and unpredictability. Be as flexible as you can with everything including your training, work, family and routine. Stress heightens cortisol which in turn smashes your infection-fighting cells.  Consider ways of dispelling stress other than more exercise such as meditation, mindfulness, relaxing activities such as reading or creative activities and watching comedies rather than more bad news stories.

6. Avoid over-exercising. Keep your exercise balanced. Robust immunity in athletes requires regular exercise, however moderation is the key. Too much exercise of long duration and intensity can make athletes more susceptible to respiratory infections.  For more information on exercise and its impact on the immune system click here 

For further information on the suitability of these measures for your particular situation, contact us for an individual assessment.

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://