In-Focus Brief on Depression

Clinical depression has been estimated as affecting about 17 million people in the US alone. The risk of developing the illness is increased if there is a family history, although much is still unknown about the genetics of the disease.

Depression is what scientists call a multifactorial disease with multiple causes, including stress, hormone imbalance, biological rhythm variation and post-natal condition. In depression, changes occur in the brain at the neurotransmitter level, and a number of effective drugs have been developed to treat the symptoms of depression by correcting the levels of these 'neurotransmitters'. Much less well known is the fact that nutrition plays a role in depression, with evidence of vitamin deficiencies a common finding among studies

There are basically two forms of the disorder, uni-polar depression and bi-polar depression (alternating episodes of mania and depression). These disorders are known to result from chemical imbalances in the brain. Abnormal brain chemicals include the neurotransmitters 5-HT (5-hydroxytryptamine, previously known as serotonin), norepinephrine and dopamine. For example, lower levels of 5-HT in depression is a common finding among studies.

In addition certain proteins that are responsible for recognizing these neurochemicals are known to be abnormal. These receptor proteins are the target for a number of drugs that have proven effective in alleviating the symptoms of depression. Drugs include the tricyclic antidepressants such as clomipramine and amitriptyline, and the serotonin reuptake inhibitors such as Prozac and Luvox (trade names for fluoxetine and fluvoxamine, respectively).

A number of studies, including some recent studies, as well as studies conducted by the founder member of BalanceYourNutrition, have found that vitamin deficiencies are more prevalent among subjects with depression compared to normal individuals. Vitamin deficiencies that have been found include vitamin B1, vitamin B6, vitamin B12 and folate deficiency. Besides some of the other functions of these vitamins (go to our nutrient education section for further information), they also play important roles in neurotransmitter metabolism. For example, dopamine synthesis in the brain depends on vitamin B1 which acts as a cofactor for its metabolic enzyme. 5-HT synthesis also depends on vitamin B6 acting as an enzyme co-factor.

Severe folate and vitamin B12 deficiency in themselves causes symptoms of depression. Other scientific studies have shown that not only can vitamin deficiencies be detected in patients with depression, but also that a vitamin supplementation program in some subjects can alleviate many of the symptoms. For example, a pilot study conducted at Harvard medical school found that in elderly patients with depression, giving 10 mg each of vitamin B1, B2 and B6 resulted in improvement in ratings of depression as well as cognitive function.

Low folate levels, in particular, are also known to result in a poor response to antidepressants. In a large study, scientists in the UK looked at the response to the antidepressant fluoxitine in subjects receiving folate (500ug) and found that
symptoms improved in 94 % of these subjects compared to 61% in a group receiving a placebo. These authors conclude that "folic acid is a simple method of greatly improving the action of fluoxitine and probably other antidepressants".

As severe folate and vitamin B12 deficiencies causes anemia (macrocytic type), which is easily picked up in a blood test, the question is - would vitamin deficiencies be detected easily in normal routine clinical chemistry lab results in major depression? The answer to this appears to be no, since a recent study has shown that folate and vitamin B12 deficiencies occur in depression, without any evidence of anemia. The authors go on to suggest that folate and vitamin B12 measurements should be considered when evaluating resistance to antidepressants. This finding is just one example of how sub-clinical deficiency can exist and go unnoticed in routine lab tests. It illustrates how  bioanalysis can detect sub-clinical deficiencies that ordinary tests fail to pick up.

Clearly nutrition plays an important role in depression and much more remains to be learned about the role of nutrition in this disorder. Removing vitamin, as well as mineral deficiencies, and optimizing your nutritional status could go a long way to removing your risk of developing depression and in helping to treat the condition.

Tip: To find articles related to depression and nutrition go to our literature search link under resources

Need to check for vitamin deficiency?
There are several nutritional test profiles that you can have done. See our Bioanalysis Center for more information.

References:
J Psychoses Res 2000 Sep 1;49(3):183-187. Anemia and macrocytosis in the prediction of serum folate and vitamin B12 status, and treatment outcome in major depression.
J Am Coll Nutr 1992 Apr;11(2):159-63. Brief communication. Vitamin B1, B2, and B6 augmentation of tricyclic antidepressant treatment in geriatric depression with cognitive dysfunction.
J Affect Disord 2000 Nov;60(2):121-30. Enhancement of the antidepressant action of fluoxetine by folic acid: a randomized, placebo controlled trial.