Lamberts Vitamin D 1000iu (25µg) is a high potency Vitamin D supplement. Vitamin D is essential for healthy bones, as well as teeth, and is also thought to be important for a healthy immune system. Research on vitamin D adds weight to the argument that we should all watch our vitamin D intake. As many as 60 percent of the UK population is vitamin D deficient and low levels have been linked to serious health problems in later life.