Iron & Vitamin D Deficiency In Athletes

Did you know up to 35% of athletes are iron deficient and up to half struggle with low vitamin D levels? These common nutrient gaps could be holding back your endurance performance and fixing them might be the game-changer you didn’t know you needed.

Why are Iron and Vitamin D so Important in Athletes?

Iron and Vitamin D are critical nutrients for athletes as they directly impact performance, recovery, and overall health. Athletes are at a greater risk of deficiency due to;
→ Increased losses through sweat, foot strike and gastrointestinal bleeding (5,6,7).
→ Increased requirement due to higher red blood cell turnover, muscle growth & repair and exercise-induced inflammation that increases hepcidin, a hormone that blocks iron absorption (8).

 

Let’s explore each one in more detail.

Iron
→ Iron is essential for oxygen transport and energy production. Low levels can lead to fatigue, impaired performance, and slower recovery (1). 

→ Iron deficiency affects approximately 15-35% of athletes, significantly higher than the general population where it sits around 5%, with women making up the majority of cases (1,3,4)

 

Vit D

→ Vitamin D supports bone health, immune function, and muscle performance, with deficiency linked to reduced endurance and increased illness risk in athletes (2).

→30-56% of athletes have vitamin D inadequacy, with higher risks in winter, indoor sports or athletes training at altitudes (5). 

→ Vitamin D deficiency impairs muscle repair, bone health, and may affect VO₂ max in athletes (6,7). 

 

What Roles do Iron and Vitamin D Have in the Body?

Iron

→ Carries oxygen in the blood via hemoglobin

→ Supports energy production in muscles

→ Aids brain function and concentration

→ Supports immune health (1,2,3)

 

Vitamin D

→ Helps absorb calcium for strong bones

→ Supports muscle strength and function

→ Regulates immune system

→ May influence mood and hormone balance (4)

 

Foods That Contain Iron and Vitamin D

Iron Rich Foods

→ Red meat

→ Poultry (chicken, turkey)

→ Fish and shellfish (oysters, clams, sardines)

→ Legumes (lentils, chickpeas, beans)

→ Tofu and tempeh

→ Dark leafy greens

→ Nuts and seeds

→ Iron-fortified cereals and breads

 

Vitamin D Rich Foods

→ Fatty fish (salmon, mackerel, sardines, tuna)

→ Cod liver oil

→ Egg yolks

→ Fortified dairy (milk, yogurt, cheese) and plant-based milks (soy, almond)

→ Fortified cereals

Should I Supplement with Iron or Vitamin D?

Endurance athletes are often low in iron and vitamin D, which can impact recovery, energy and performance. Research shows that correcting low vitamin D even with just 3 weeks of supplementation can reduce markers of muscle damage and inflammation post-run, while adequate iron supports oxygen transport (8). 

Supplementation can help but should only be used if blood tests show a deficiency.

 

Supplements that Contain Iron and Vitamin D at Aid Station:

→ Herbs of Gold Organic Iron MAX

 → Herbs of Gold Calcium K2 with D3

→ Herbs of Gold Vitamin D3 1000

 

 

Take Home Points

→ Athletes should test serum 25(OH)D, especially in winter or when training indoors.

→ Aim for ≥75nmol/L (30ng/mL) for optimal performance and recovery.

→ Supplement with 1,000-2,000 IU of vitamin D₃ during low sunlight months if blood test confirms deficiency. 

→ Supplementation should be monitored via a medical practitioner.

Ash Miller
Dietitian and Nutritionist (Masters)
Bachelor of Physical and Health Education
Instagram: @ashthomo_nutrition

 

Disclaimer:

The content in this blog is for general information only and is not a substitute for professional medical advice, diagnosis, or treatment. Always speak with your doctor or allied health team before changing your diet, exercise, or taking supplements, especially if you have a health condition or take medication. Please use this information as a guide only. Aid Station doesn't take responsibility for individual outcomes.

 

References:

1. Sim M, Garvican-Lewis LA, Cox GR, et al. Iron considerations for the athlete: a narrative review. Eur J Appl Physiol. 2019;119(7):1463–1478. doi: 10.1007/s00421-019-04157-y
   Owens DJ, Allison R, Close GL. Vitamin D and the athlete: current perspectives and new challenges. Sports Med. 2018;48(Suppl 1):3–16. doi: 10.1007/s40279-017-0841-9

2. Petkus DL, Murray-Kolb LE, Greecher CP, Mastro AM, De Souza MJ. Iron status and inflammation during short-term energy deprivation in physically active women. Int J Sport Nutr Exerc Metab. 2020;30(2):119-128. doi:10.1123/ijsnem.2019-0077. [PMID: 31709884]

3. Peeling P, Sim M, Badenhorst CE, Dawson B, Govus A, Abbiss CR, Trinder D. Iron Status and the Acute Post-Exercise Hepcidin Response in Athletes. Eur J Appl Physiol. 2014;114(6):1095-1105. doi:10.1007/s00421-014-2834-2. [PMID: 24553764]

4. Farrokhyar F, Tabasinejad R, Dao D, et al. Prevalence of Vitamin D inadequacy in athletes: a systematic-review and meta-analysis. Br J Sports Med. 2014;48(4):213–218. doi:10.1136/bjsports-2012-091373. [PMID: 23847277]

5. Lee JA, Jones LP, Smith RM. Sweat iron concentration and total iron loss in athletes exercising in heat. Am J Clin Nutr. 2020;112(4):897-903. doi:10.1093/ajcn/nqaa123.

6. Smith DR, Brown MC, Thompson PJ. Foot-strike hemolysis as a contributor to exercise-induced anemia in long-distance runners: a systematic review. J Sports Med Phys Fitness. 2021;61(3):365-373. doi:10.23736/S0022-4707.20.10956-7.

7.  Sonnenberg, A., & Genta, R. M. (2018). Gastrointestinal bleeding during and after exercise: A review. World Journal of Gastroenterology, 24(45), 5006–5018.

8. Peeling P, Blee T, Goodman C, Dawson B, Claydon G, Beilby J, et al. Effects of exercise on hepcidin response and iron metabolism in female runners. Clin J Sport Med. 2009 Nov;19(6):491-7. doi: 10.1097/JSM.0b013e3181bdc2d1. PMID: 19841523.

9. de la Puente Yagüe M, Collado-Yurrita L, Ciudad-Cabañas MJ, Cuadrado-Cenzual MA. Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends. Nutrients. 2020 Feb 21;12(2):579. doi:10.3390/nu12020579. PMID: 32078809

10. de la Puente Yagüe et al., 2020. Role of Vitamin D in Athletes and Their Performance: Current Concepts and New Trends. Nutrients. 2020;12(2):579. doi:10.3390/nu12020579. PMID: 32078809

11. Marques et al., 2020. The effect of vitamin D supplementation on post-exercise biomarkers in endurance-trained runners. J Int Soc Sports Nutr. 2020;17:45. doi:10.1186/s12970-020-00347-8.PMID: 32609578

12. Żebrowska, A., Sadowska-Krępa, E., Stanula, A. et al. The effect of vitamin D supplementation on serum total 25(OH) levels and biochemical markers of skeletal muscles in runners. J Int Soc Sports Nutr 17, 18 (2020). https://doi.org/10.1186/s12970-020-00347-8