A study done in the United Kingdom suggests that normal amounts of caffeine can cause a significant reduction in nighttime episodes of hypoglycemia in type 1 diabetics. The study involved 19 patients with long-standing type 1 diabetes. They were put on a low-caffeine diet that was supplemented for 2 weeks with either two 250-mg caffeine capsules given twice daily or placebo capsules. Then they were switched to the opposite capsules for another 2 weeks.
The researchers found that with the caffeine supplement the average duration of nighttime hypoglycemia was 49 minutes; with the placebo, it was 132 minutes. They stated, however, that the underlying physiologic cause remains unclear and may be related to an alteration in non-rapid-eye-movement sleep, a common side effect of caffeine.