Inclusion Criteria:  Healthy men and women  Exclusion Criteria:  Less than 18 years old Pregnant or lactating Smokers Individuals that are not free-living e.g. institutes where meals are prepared in bulk such as nursing homes, prisons etc.  An inability to read, write or understand English Following a strict prescribed diet for any reason, insulin dependent diabetes, coeliac disease, Crohn's disease Disease or condition that requires chronic therapeutic nutritional or medical treatment.  Those taking supplemental vitamin D Those who have been on a sun holiday in the last 2 months