In Western countries, where food is plentiful and enriched, true vitamin and mineral deficiencies are rare, but low levels of these nutrients, even when they don't qualify as a deficiency, may be related to some depressive symptoms. No vitamin or combination of vitamins is effective for treating depression or mania, several vitamins and minerals, including the following, can have a significant effect on brain development and function:
B-complex vitamins: Your body uses the B-complex vitamins in a variety of ways to build and maintain a healthy nervous system. Taking them together in the appropriate relative concentrations is important because too much of one may lead to a deficiency of another. No reliable or replicated studies indicate specific benefits of B vitamins (other than folic acid) in treating bipolar disorder or depression. Here's what you need to know about the B vitamins:
B-1: B-1 (or thiamine) deficiencies can cause severe neurologic problems. Diet-related thiamine deficiencies are rare in the U.S., but deficiencies due to alcohol abuse aren't uncommon.
B6: Isolated B-6 deficiency is rare, but old age, alcohol abuse or dependence, autoimmune disorders, renal failure, and medications such as valproate (Depakote), carbamazepine (Tegretol), and the anti-asthma medication theophylline (Aerolate) increase the risk of low B-6 levels. B-6 can be dangerous in high doses, so don't take B-6 beyond a traditional supplement unless prescribed by a physician.
B-12: B-12 deficiency can cause symptoms of depression or other psychiatric illnesses. It's uncommon, but strict vegetarianism (vegan diets), old age, certain stomach and intestinal illnesses, weight-loss surgery, and certain medications, including those used to treat acid reflux and peptic ulcers and the diabetes medication metformin (Glucophage) increase the risk for B-12 deficiency. Doctors often check B-12 levels in people with acute depression. (Research has discovered a genetic link between B-12 deficiency and bipolar disorder in some families.)
Folic acid: Folic acid is one of the B vitamins, but it isn't always included in B-complex supplements. It's critical in the development of the human nervous system, so pregnant women must take folic acid supplements. People who abuse alcohol, have certain illnesses, or take a number of different medications are at risk for folate deficiencies, which can present with a variety of cognitive, emotional, and behavioral symptoms. A prescription strength version of folic acid — L-methylfolate (Deplin) — is now approved as an augmenting agent for people who aren't responding to antidepressant therapy alone. Doctors may check for folic acid levels as part of an initial work-up of depression.
Make sure your doctor checks for both folic acid and B-12 levels before supplementing with folic acid. High folic acid levels may mask a vitamin B-12 deficiency. Both folic acid and B-12 deficiencies cause anemia — low red blood counts. If you start taking a folic acid supplement when you also have a B-12 deficiency, the anemia may get better, but the nervous system damage from the B-12 deficit will still occur.
Vitamin D: Several studies indicate a link between low levels of vitamin D and depression, but as of the writing of this book, no clear evidence shows that low levels of vitamin D cause depression. Even so, your doctor may want to check your vitamin D levels to determine whether supplementation may be useful to you.
Magnesium: A magnesium deficiency is rare, but high-risk groups include older adults and people who abuse alcohol, have diabetes, or are afflicted with a number of other medical conditions that require a variety of medications. Low body stores of magnesium may be related to a number of health problems, including mood regulation and migraine headaches. Magnesium is part of one of the pathways that lithium affects, so many doctors are intrigued to consider its possible relationship to bipolar disorder. A couple of small studies have suggested that magnesium may be a useful add-on in the treatment of mania.
Zinc: Zinc is a trace element that plays a key role in managing the oxidative stress (cell damage) process, which has been associated with bipolar disorder. Some recent data confirm a strong association between lower zinc intake and depressive symptoms, but only in women — not in men. People who abuse alcohol or have gastrointestinal disorders, especially if chronic diarrhea is present, and people who've had weight-loss or other intestinal surgery are at risk of zinc deficiency. People with sickle cell disease, pregnant and nursing women, and vegetarians are also at risk of lower zinc levels.