Guavas dont consist of iodine; therere good sources of copper, a mineral which plays a vital role in thyroid metabolism especially in hormone production and ingestion. . The guava has a thin yellow skin that sometimes bears a tinge of red. The flesh can be orangepink or white, depending on the variety. The fruit has small, hard seeds and a strong, sweet scent. Some of the commonest types of guavas are apple guavas, strawberry guavas, Costa Rican guavas and Jamaican guavas.