As diabetes increases at an alarming rate, strategies for prevention of this disease must be developed. For a given individual, there are both biologic (e.g., genetic) and environmental (e.g., lifestyle) factors that comprise her individual risk of diabetes. Researchers can take advantage the accumulating knowledge of these individual factors to design individualized strategies for diabetes risk assessment and prevention. For example, a mutation in a particular gene, SLC30A8, which encodes a zinc transporter, has been shown to increase the risk of diabetes probably through impairment of insulin secretion. In the proposed research project, the investigators aim to conduct a pilot study to see the effect of zinc supplementation on insulin secretion in people with and without this genetic mutation to see if zinc can improve insulin secretion in those with the mutation. The results from this study will help the investigators to plan a larger, more definitive study to determine if zinc supplementation can be used to prevent or treat diabetes in those with this mutation in SLC30A8.