The classic vitamin D deficiency disease is rickets, yet as fear of sun-exposure has grown and lifestyles have become more sedentary, exposure to the sun has dropped dramatically and vitamin D deficiency and the incidence of rickets has surged. The skin cannot create vitamin D if covered in sunscreen or clothing, it is thought that a sun cream with SPF15 will reduce the skin’s ability to synthesize vitamin D by more than 95%.

Furthermore, many older people and those with dark skin or those who tend to wear more modest clothing are amongst the population groups that are most likely to suffer sub-optimal vitamin D levels.

Dietary sources include fortified foods, eggs and fatty fish.

Most commonly-available Vitamin D3 supplements are derived from the lanolin in sheep’s wool, however Viridian Nutrition's Vitamin D3 is vegan and naturally-derived from lichen.

Vitamin D contributes to the maintenance of normal bones, teeth, muscle function and immune function. Vitamin D contributes to the normal absorption/utilisation of calcium and phosphorus.