Vitamins and minerals are essential nutrients that must be consumed each day. Vitamins and minerals don’t directly supply energy like carbohydrates, protein and fat, but play a role in essential processes for growth, maintenance of well being and preventing disease. Far too often, I see people taking numerous vitamin and mineral supplements without any purpose. While many of these supplements are only harmful to your wallet, some can be dangerous to your health. However, there are some vitamin and minerals supplements that athletes may require due to insufficient intake in diet or decreased demands with training. Read on to find out more.  

Vitamin D:

Role: Vitamin D plays an important role in calcium and phosphorus absorption as well as maintaining bone health. There is also research looking at the role of vitamin D in skeletal muscle health and some studies showing a relationship between good vitamin D status and reduced injury and acute respiratory illness prevention.  

Who should take: Little vitamin D is consumed through the diet but it can be made from UVB exposure from sunlight. Athletes with insufficient UVB exposure, such as those living in colder climates, training in early morning or evening, or who aggressively use sunscreen, are at risk of vitamin D deficiency.  

How to take: To maintain normal vitamin D levels, an intake of 800-1000 IU of vitamin D is needed per day. Health Canada recommends that all Canadians over 50 years of age take 400 IU of vitamin D per day as the ability to make vitamin D from UVB exposure reduces with age.   


Role: Iron helps carry oxygen in the bloodstream. Iron deficiency can lead to poor training adaptation and work capacity. Athletes tend to be at an increased risk of deficiency because of increased losses during training, such as through foot strike hemolysis.
Who should take:Only those with measurements showing deficiency, such as lab values of ferritin, transferritin saturation, serum iron, haemoglobin, haematocrit and mean corpuscular volume, should take an iron supplement.    

How to take: If iron status is low, then you need to supplement with iron greater than the Recommended Dietary Allowance (RDA) (18 mg/day for menstruating women and 8 mg/day for me). Athletes should follow-up with repeat lab measurements after supplementing with iron.  


Role: Calcium is well known for its role in building and maintaining strong bones, but that’s not all it does. Calcium also plays a role in regulating muscle contraction, nerve conduction and normal blood clotting.  
Who should take: There is no appropriate measurement for calcium status in the body. Low bone mineral density is a sign of chronic low calcium intake. Avoidance of dairy products or milk alternatives and/or disordered eating increases risk of suboptimal calcium intake
How to take: Calcium intake of 1500 mg per day and 1500-2000 IU of vitamin D per day are recommended to optimize bone health for those with menstrual dysfunction.   

Vitamin B12:

Role: Vitamin B12 is important for healthy red blood cells and keeping nerves working properly. Natural sources of vitamin B12 are only found in animal foods. Some plant-based foods, such as soy, rice or almond milk, are fortified with vitamin B12.  

Who should take: Those following a vegan or animal free diet who do not consume vitamin B12 fortified products. Vitamin B12 levels can also easily be measured through lab work to determine if deficient.
How to take: Ensure that through diet and if necessary, supplements, meeting RDA of vitamin B12, which is 2.4 mcg per day. If lab work shows deficiency, supplementation will be necessary to bring levels to normal range.

While aiming to get adequate vitamin or mineral supplements through food is ideal, there are some circumstances, as highlighted above, where taking a supplement might be warranted. While suboptimal levels of vitamin and mineral intake may be influencing performance and health, more is not always better, and guidance on what and how much of a vitamin and mineral supplement you take should be discussed with your healthcare professional.

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Categories: Megan Kuikman

Megan Kuikman

Hello! I’m Megan Kuikman. I’m a Registered Dietitian with specialized training in sports nutrition. My goal is to help athletes and active individuals achieve a healthy attitude towards health, training, and food. I empower athletes to fuel properly for training in order to restore their health and enhance performance. You can get in touch with me at:


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