Vitamin D (typically D3) is found in multivitamin/mineral formulations but is also sold as a single supplement or combined with calcium. Until recently most supplements contained 400 IU, the Daily Value used on labeling. But doses have been increasing.
Dairy foods have had both good and bad press of late. Yet dairy still gets kudos for its unique contributions to the diet, and no one is suggesting you forgo buying it at the supermarket, unless you are a vegan or have dairy allergies.