In Nutritional Therapy practice when we are faced with patients who seem to be struggling with depression and are finding recovery hard as well as trying to prevent recurrence after resolving their current symptoms we often think – B Vitamins
But what is the evidence for this apparently normal recommendation – is there anything of substance that supports the therapeutic use of these water soluble vitamins.
To date most studies have been conducted using a cross sectional approach, (a class of research methods that involve observation of some subset of a population of items all at the same time, in which, groups can be compared at different ages with respect of independent variables) rather than the preferred prospective style investigations (an analytic study designed to determine the relationship between a condition and a characteristic shared by some members of a group). A prospective study may involve many variables or only two; it may seek to demonstrate a relationship that is an association or one that is causal. Prospective studies produce a direct measure of risk called the relative risk.
Biochemically, vitamin B-6, folate, and vitamin B-12 are involved in the metabolism of homocysteine, S-adenosyl methionine, and methionine, an essential amino acid. The latter 2 compounds are critical to the production of neurotransmitters and methylation in the brain. Although the exact mechanism is unknown, the prevailing homocysteine hypothesis of depression suggests that deficiencies in vitamin B-6, folate, and vitamin B-12 can lead to elevated homocysteine concentrations, which have been associated with depression.
We examined whether dietary intakes of vitamins B-6, folate, or vitamin B-12 were predictive of depressive symptoms over an average of 7.2 y in a community-based population of older adults.
The study sample consisted of 3503 adults from the Chicago Health and Aging project, an ongoing, population-based, biracial (59% African American) study in adults aged 65 y. Dietary assessment was made by food-frequency questionnaire. Incident depression was measured by the presence of 4 depressive symptoms from the 10-item version of the Center for Epidemiologic Studies Depression scale.
The logistic regression models, which used generalized estimating equations, showed that higher total intakes, which included supplementation, of vitamins B-6 and B-12 were associated with a decreased likelihood of incident depression for up to 12 y of follow-up, after adjustment for age, sex, race, education, income, and antidepressant medication use. For example, each 10 additional milligrams of vitamin B-6 and 10 additional micrograms of vitamin B-12 were associated with 2% lower odds of depressive symptoms per year. There was no association between depressive symptoms and food intakes of these vitamins or folate. These associations remained after adjustment for smoking, alcohol use, widowhood, caregiving status, cognitive function, physical disability, and medical conditions.
Our results support the hypotheses that high total intakes of vitamins B-6 and B-12 are protective of depressive symptoms over time in community-residing older adults.
In this large, US population–based study of older adults, higher total intakes of both vitamin B-6 and vitamin B-12 were associated with a decreased likelihood of the development of depressive symptoms over an average of 7.2 y. For example, each additional 10 mg of vitamin B-6 and 10 µg of vitamin B-12 via total intake from food and supplements were associated with 2% lower odds of development of depressive symptoms per year.
Williams et al found consistent evidence to support the value of vitamin B-6 supplementation for depression among premenopausal women. In the assessment and treatment of depressive symptoms in older adults, clinicians and other health care professionals should be mindful of the patient’s nutritional status in general, and whether there are vitamin insufficiencies in these nutrients before treatment
 Hvas, AM, Juul, S, Bech, P & Nexo, E. Vitamin B6 level is associated with symptoms of depression. Psychother Psychosom 2004;73:340–3 View Abstract
 Kamphuis, MH, Geerlings, MI, Grobbee, DE & Kromhout, D. Dietary intake of B6-9-12 vitamins, serum homocysteine levels and their association with depressive symptoms: the Zutphen Elderly Study. Eur J Clin Nutr 2008;62:939–45 View Abstract