What is vitamin D?
Vitamin D is a fat-soluble vitamin that is synthetized in our skin when we are exposed to ultraviolet (UV-B) sunlight during spring and summer. Vitamin D can also be obtained from foods of animal origin; however, only few foods contain significant amounts of this vitamin. Oily fish (such as salmon, herring, and eel), egg yolk, liver, butter and cheese are among the best natural sources of Vitamin D.
The UK government’s National Diet and Nutrition Survey has consistently shown low intakes of vitamin D containing foods in the UK population. Public Health England now recommend that everyone in the UK should take a food supplement of 10 μg of vitamin D throughout the autumn and winter, (https://www.gov.uk/government/news/phe-publishes-new-advice-on-vitamin-d)