Coffee and glucose levels:
A study of 30 healthy nonsmoking individuals found that caffeine consumption can increase glucose concentrations. Participants went without coffee, tea, chocolate or coke for 4 weeks and were then given 200 mg oral caffeine or placebo (decaffeinated coffee) An 75g oral glucose tolerance test (OGTT) found similar blood insulin levels in both groups, but blood glucose levels were found to increase in the caffeine group at the 2nd, 3rd, and 4th hours compared to placebo. (23)
Caffeine and skin cancer:
Caffeine may reduce the risk of developing skin cancer, specifically basal cell carcinoma (BCC), according to a study of 112,897 participants (72,921 female nurses and 39,976 male health professionals). When participants were ranked according to caffeine consumption, with the highest consumption at the top and the lowest at the bottom, they found for women, the top 20% of caffeine consumers had an 18% lower risk of BCC than the bottom 20%. For men, the risk was lowered by 13%. The researchers also found that drinking 3 cups of caffeinated coffee was linked to a 21% lower risk of developing BCC in women and a 10% lower risk in men, compared to drinking less than 1 cup per month. And caffeine from other dietary sources (tea, cola, and chocolate) also had a similar effect: the higher the intake, the lower the risk of BCC. (24)