Diabetes Risk in East London and Its Association With Vitamin D by Ethnic Group (DELVE)

The goal of this study is to investigate the relationship between vitamin D status and a diabetes risk factor, postprandial glycaemic response in White, South Asian and Black African Caribbean populations in East London. The main question\[s\] it aims to answer are: * Are there differences in postprandial glycaemic response to a sugar water drink or orange juice between White, South Asian and Black African Caribbean people in East London? * Is there a relationship plasma 25(OH)D and the postprandial glycaemic response to a sugar water drink or orange juice consumption? * What are the knowledge and perceptions of vitamin D intake between White, South Asian and Black African Caribbean people in East London? * Is there a difference in dietary vitamin D intake between the three ethnic groups? Participants will make two visits to the lab, approximately 2.5 hours each. The order of the two drinks will be randomized via Excel Random function. For each visit, the blood sugar levels will be measured at fasting (0) and every 30 minutes up to 2 hours postprandially (5 times total) using a finger prick. At baseline only (visit 1), participants will fill out a knowledge and perception survey, provide a 4-day estimated food diary, provide a 7 ml blood sample via phlebotomy, and have their height, weight and body fat percentage measured.