Vitamin D

(Applicable to countries with similar weather to Britain, cultures that cover the majority of their skin and people that use high sun protection factor).

Throughout evolution, we have been exposed to sunlight which triggers the body to synthesize vitamin D, but as concerns about skin cancer have increased, many of us have avoided the sun or used extra high SPF and blocked out the UV light. This has lead to a rapid decrease in our vitamin D levels.

Vitamin D is essential to preventing the childhood disease rickets and the adult version called osteomalacia. A possible reason as to why we are seeing an increase in osteoporosis amongst the elderly.

What to do?

It is virtually impossible to obtain optimal intake through the diet, the sun has always been our primary source. Therefore, adequate vitamin D can be obtained through the summer months (March - October) with little and often exposure to the sun and then supplementation through the winter months (November - February). A supplement that provides 10ug would be beneficial, but there is no recommended daily allowance (RDA) as of yet. We would not advise supplementing above 20ug a day until further research has been carried out or an RDA has been established.

(You do not need to supplement if you live below 41 degrees latitude).