Vitamin D

Vitamin D

What is Vitamin D and why is it needed?

  • Fat soluble vitamin that is needed for optimal health to maintain strong bones as well as muscle function

  • 2 different forms: D2 (ergocalciferol) and D3 (cholecalciferol); D3 is preferable and is converted to ‘active’ Vitamin D in the liver and kidney
  • Main source is from exposure to ultraviolet B (UVB) radiation from sunlight
  • Small amounts are found in foods such as oily fish (salmon, tuna mackerel) egg yolks and some fortified foods such as milk, cereals and margarine
  • Food alone does not provide enough vitamin D

Risks and prevalence of deficiency

    • Deficiency can lead to several health issues such as increased risk of bone injuries, chronic musculoskeletal pain and viral respiratory tract infections.
    • Recent studies have shown low levels among athletes
  • Defined serum 25(OH) Vitamin D levels are:\r\n
    • deficiency: serum levels <20ng/ml (50nmol/L)
    • insufficiency: serum levels <32ng/ml (75nmol/L)
    • sufficiency: serum levels >32ng/ml (75nmol/L)
    • Higher levels may be preferred for athletes to allow a larger safety margin and optimize performance

Which athletes are most at risk?

  • Those with low exposure to sun in training environment
  • Dark skin pigmentation
  • Wearing clothing that covers most or all of their body
  • Regularly use sunscreen or avoid the sun
  • Missing limbs ( ie. athletes with a disability)
  • GI malasbsorption (celiac disease or fat malabsorption)
  • Family history of bone injury, disorders or Vitamin D deficiency

Athletic performance benefits of vitamin D supplementation if athletes have sub-optimal levels

  • Strength
  • Power
  • Reaction time
  • Balance

How much is recommended? (these are based on no or limited sunlight exposure)

  • Recommended dietary intake = 600IU/day
  • Upper level intake = 4000IU/day

Can I take too much Vitamin D?

  • Yes, too much vitamin D can be harmful; toxicity is generally caused by supplement overuse
  • The safe upper limit for vitamin D is 4000IU/day for an adult