Copper is present in all body tissues, but is particularly concentrated in the liver and brain. It aids in the manufacture of collagen and haemoglobin, and, along with iron, is necessary for the synthesis of oxygen in red blood cells. It also acts as an antioxidant, increases iron absorption, and serves as a catalyst for a variety of enzymatic reactions.

The best food sources of copper include dark green leafy vegetables, eggs, organ meats, poultry, nuts, shellfish, and wholegrain breads and cereals.
Iodine is essential for healthy thyroid function due to the role it plays in the production of thyroid hormones. In this role, it is helps regulate metabolism and energy production in the body, as well as cellular oxidation. Since thyroid hormones plays a role in all body functions, iodine is of vital importance to overall health, yet iodine deficiency is estimated to affect at least 200 million people worldwide, due in part to depleted soil conditions.

The best food sources of iodine are iodized salt, followed by seafood and seaweed.