Vitamin B12 For Athletes

January 22, 2018

Power Shots.  Deficiency in this Vitamin will affect your energy and performance.

About 20 years ago I was shown a movie on the treatment of animals. I haven’t touched meat since. Plant based meals have been shown to reduce your inflammatory load, however, people (like myself), restricting their diet from animal products may be more vulnerable to a Vitamin B12 deficiency.  Vitamin B12 levels can affect your performance, therefore I book routine check ups to make sure my levels are satisfactory.  Having a Vitamin B12 Injection is like receiving a Power Shot.  Within a few hours, I have a surge of energy and motivation!

Vitamin B12 is a water-soluble vitamin that assists in the utilization of proteins, carbohydrates and fats.  Because of this, Vitamin B12 is an important nutrient when considering athletics and appropriate weight loss and body composition programs.

The B Vitamins are co-factors in the production of red blood cells, DNA synthesis as well as the production of the myelin sheath that surrounds the nerves.

What are the Symptoms of a Vitamin B12 Deficiency?

A Vitamin B12 deficiency is what we call a Macrocytic Anemia. This means abnormally large red blood cells – the opposite of iron deficiency anemia.

Sometimes a deficiency can be hard to detect as the liver can store this vitamin for a few years.  Therefore, it may take a few years for a vegetarian to notice symptoms.

The most common symptom of deficiency is fatigue (also common in an iron deficiency).

Other possible symptoms of deficiency are headache, swollen or sore tongue and it can affect the absorption levels in the gut.  A deficiency left untreated long term, can result in nerve cell damage.  This may look like tingling (pins and needles) in the hands and feet. Other possible neurological symptoms are vision changes, confusion, lack of co-ordination, irritability and memory loss. Therefore it is important to maintain adequate Vitamin B12 levels to avoid permanent neurological affects.

Why do people become deficient in Vitamin B12?

When looking at deficiencies we tend to break it down into three sub categories.  I want to help you find the cause of your fatigue.  A thorough intake will help determine which sub category your deficiency falls into:

  1. Intake: Either you are not eating enough Vitamin B12 rich foods. Vitamin B12 is found mostly in animal products therefore the vegetarian/vegan populations tend to be deficient.
  2. Utilization: You may be utilizing too much Vitamin B12.  The B Vitamins are also considered our “stress” vitamins.  This means, we burn through them during times of elevated stress levels.  We end up burning the candle at both ends, becoming depleted and fatigued.
  3. Absorption: You may not be absorbing enough Vitamin B12. This vitamin is absorbed in the small intestine.  Patients who are also suffering from gastrointestinal disorders, such as small intestinal bacterial overgrowth (SIBO), Celiac or Crohn’s may not be absorbing Vitamin B12 optimally due to an underlying inflammatory load and unfavourable microbiome.  This type of deficiency is called Pernicious Anemia.

Adequate stomach acid and intrinsic factor are required to release the vitamin from the protein.  Alcohol abuse, aging, smoking, diabetes, thyroid disorders, medications such as antacids and Type 2 Diabetes medications as well as gastric bypass surgery can all affect your absorption levels.

Those taking more than 3000mg of Vitamin C a day may end up creating a deficiency of Vitamin B12.  Having a professional assess your daily supplements can help identify unique causes of deficiency.

Does Vitamin B12 affect my fertility?

Vitamin B12 can play a role in supporting the endometrial lining as well a sperm production.  A deficiency may encourage irregular ovulation and increase the risk of miscarriage

How do I know if I am deficient?

Test.  If you are vegetarian, have digestive concerns or fatigue a requisition for blood work can be written by your ND.

What can I expect after a Vitamin B12 Injection?

Many report an increase in energy and stamina.  This can help to stabilize mood by combating depression and modulate stress levels.

How often do I have to have a Vitamin B12 Injection?

Depending on your lab values, the frequency could range from weekly to monthly until your levels fall back into the normal ranges.

If you are competing, it is importation to have a shot prior to the big day to understand how you respond. Once this is determined, many athletes will have a shot 2-5 days before the competition.

During training, monthly or seasonal Vitamin B12 injections can be considered to keep you energized, sharp and increase stamina during training.

Why would I have an injection vs. oral supplementation?

Depending on the severity of the deficiency, injections allow for higher absorption and retention.  In those suffering from gastrointestinal disorders, injections bypass stomach and are absorbed directly into the blood stream. In our clinic, we use a highly absorbable form Vitamin B12 called methycobalamin.

What are the side effects?  The risk of Vitamin B12 toxicity is rare, therefore there is no upper intake limit.  Possible side effects are pain, redness, or itching at the site of the injection, mild diarrhea, acne muscle cramps and irregular heartbeat.

How does Vitamin B12 apply to Athletics?

Unfortunately studies involving athletics and Vitamin B12 do not elicit drastic changes – unless a deficiency is present.  Any athlete running in a deficient state will have a negative impact on their performance.  A study run by Spradley states, that Vitamin B12 should reduce fatigue and therefore improve muscular endurance.   Since Vitamin B12 is crucial to the production of nerve cells, RNA/DNA and red blood cells, energy levels come into play.  Decreased red blood cells would reduce the oxygen carrying capacity of the blood therefore reducing aerobic performance.

Sleep is vital to recovery.  Vitamin B12 plays a role in the production of melatonin encouraging sleep, a stabilized mood and motivation allowing the much needed recovery to occur.  Because of this and its involvement in the nervous system, Vitamin B12 can improve cognitive function in the aging athlete.

Athletes considering adding Vitamin B12 to their training review must should come in for a dietary review and systematic intake considering daily energy intake whether they should be adding a supplement to their training routine.


Lukaski 2004 endurance

Woolf 2006 supplement

Montoye 1955 and first to look at b12 and athletic performance improvement In 88 yard sprint

Improves concentration and reaction time

Spradley 1012

Dr. Jennifer Tanner, has a broad, evidence based practice with a focus on sports and performance based medicine. Being a marathon runner and having been a competitive equestrian, an active lifestyle is important. Dr. Tanner uses a variety of tools including Acupuncture and Clinical Nutrition, putting an emphasis on “food as medicine” and addressing the root causes of inflammation . In conjunction with the Integrative Health team, Dr. Tanner is thrilled to help people achieve an optimal state of health and pursue their performance based health goals!


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