Low Levels of Vitamin B6 and B12 Linked to Depression

If you’re feeling blue, you may want to examine your diet. A new study featured in the American Journal of Clinical Nutrition found that higher intakes of vitamins B6 and B12 are associated with a lower likelihood of depression in older adults.

The study focused on 3503 community-dwelling adults aged 65 years or older from the Chicago Health and Aging Project (CHAP). Researchers examined subjects’ dietary consumption of vitamin B6, B12 and folate and the incidence of depression over approximately 7 years. The risk of developing depression dropped 2% for every 10 mg increase in Vitamin B6 from both food and supplements. A risk reduction of 2% was also demonstrated with each 10 mcg increase of Vitamin B12. No association between folate intake and depression was observed.  Foods rich in vitamin B6 include bananas, avocados, chicken or turkey breast, fish (such as salmon, cod or halibut), wheat germ, whole grains, beans, peanuts and walnuts.  Foods naturally rich in vitamin B12 include fish, meat, poultry, eggs and dairy, although a growing number of non-animal foods (such as breakfast cereals) are now fortified with vitamin B12 as well.

Vitamin B12 deficiency is common among older adults, and so is depression.  This makes it difficult to discern whether inadequate intakes of these nutrients are a cause or an effect of depression. One of the noteworthy strengths of this study was the design: it observed participants over the course of several years as opposed to at a random point in time. Although this doesn’t necessarily get to the bottom of the cause-versus-effect matter, it does support the prevailing hypothesis that relatively low intakes of the B vitamins may contribute to depression.

While these study results imply a relationship between vitamin B6, vitamin B12 and decreased depression, this does not mean that these B vitamins are the new Prozac. In fact, one of the researchers, Kimberly Skarupski, urges caution in the interpretation and application of these results. She says these B vitamins “may be proxies for other unmeasured factors, such as an overall healthy diet.”

Recent data shows that 20% of older adults have a marginal depletion of vitamin B12. This may be related to reduced stomach acidity as we age, which can prevent food-bound vitamin B12 from being liberated and available for absorption.  In other cases, the lack of intrinsic factor as we age, which impairs our ability to absorb vitamin B12 from food and supplements. Both vitamins B6 and B12 play critical roles in the production of neurotransmitters, or “chemical messengers” in the brain, including Serotonin, (the brain’s “feel good” neurotransmitter).

When assessing depressive symptoms in older adults, then, clinicians should evaluate their overall nutritional status and rule out any vitamin deficiencies. For people over 50, especially vegetarians, supplementing with a multivitamin or a B Complex can help bridge the vitamin B12 gap, as can fortified breakfast cereals or sprinkling nutritional yeast onto meals and snacks. This will fill in the ‘nutrient gaps,’ and may simultaneously reduce the risk of depression.

Source: Skarupski, Kimberly A. Longitudinal association of vitamin B-6, folate and vitamin B-12 with depressive symptoms among older adults over time. American Journal of Clinical Nutrition. American Society for Nutrition, 2010.


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