2)    Magnesium: Researchers have long known about magnesium’s sedative powers. Although some studies have linked a magnesium deficiency with depression, the results have been largely inconclusive. However, there is a definite link between taking magnesium supplements and other mood-stabilizing drugs. Working in combination, the mineral seems to aid the mood-stabilizing drugs' effect on the manic moods of patients.

3)    Chromium: There have been several research cases that linked added chromium picolinate to fewer instances of depression. It is also believed to help antidepressants work better. In a Duke University trial, 70 percent of patients given chromium picolinate improved versus none given a placebo.

Additionally, Inositol, a sugar molecule, seems to make brain receptors react better to serotonin, a mood stabilizer. Large doses of inositol helped alleviate depression, panic disorder and obsessive-compulsive disorder in one study at an Israeli university.

The Roles of Vitamins B and D

Vitamin B12 and other B vitamins help produce brain chemicals that affect key brain functions, including mood. Studies have shown that a lack of B vitamins may be linked to depression.

While diet plays a role in the lack of B vitamins, there also may be a physical problem that limits the body’s ability to absorb this key nutrient. Older adults, people with digestive disorders like celiac disease or Crohn's disease, and vegetarians may have problems getting enough B12. The vitamin is present in fish, poultry, lean meat, eggs and milk. Some breakfast cereals are also fortified with it.

Vitamin D is estimated to be lacking in 1 billion people worldwide. Those living in lands far from the equator, the elderly and dark-skinned individuals may not get enough of this key vitamin, which is the only vitamin that is a hormone and affects every cell in the body. While its role in building bones, muscles and teeth is well known, it also is key to regulating the immune system and such neurotransmitters as dopamine and serotonin that help brain function. Researchers have found Vitamin D receptors in various regions of the brain that are linked with depression.