- Chemical name: calciferol
- RDA: 5 micrograms
- Top sources: cod liver oil, herring, mackerel, sardines, trout, salmon, fresh tuna (all oily fish), eggs, cheddar cheese
- Absorption: enhanced by fat or oil, so most sources stated above will have good absorption rates
- Cautions: fat-soluble so excessive intakes will be stored
- Use in sport: low levels of vitamin D have been found to be associated with loss of muscle tone and it may be involved in the production of insulin-like growth factor, which has an anabolic action. Inadequate intakes of vitamin D may increase risk of bone fracture, impair immune function and increase susceptibility to upper respiratory tract infections
Vitamin D is required for the absorption of calcium (and phosphorus) from food; it directly increases the rate of mineral deposits on bones. Most of our vitamin D is formed through exposure to sunlight – UV rays change it from an inactive to an active form. Vitamin D plays a role in maintaining blood calcium levels, healthy teeth and immune system and the process of cell division.